This is one for the books

In my last post I indicated my intention to rebuild the bottom end based on a slight change to the engine sound at start up, and my suspicion that perhaps the main or conrod bearings may be damaged or worn.

To my delight, no bearing damage at all. But whilst in there what I did find was a little horrifying to say the least and I am quite surprised we’d not suffered catastrophic failure due to an oil pressure issue.

A picture tells a thousand words so take a look at this image and try to guess momentarily what exactly you are looking at.

I know you will most likely recognize the oil pick up tube and screen, but what is all of that plastic crap that’s been sucked into the screen.

It is none other than a 25 year old sump oil level sensor! It is actually supposed to look like this:

Image courtesy of IPD. Did I mention that IPD are a great source of aftermarket Volvo parts.

I had never thought for a moment this part may create an issue and I don’t recall anyone experiencing the same failure, but given that fragile nature of plastic when exposed to high temps and oil thrashing around a sump for 25 years I guess it could be expected.

The actual float mechanism, the moving components are what broke away. It included a small metal sensor plate too, which I found sitting in the base of the sump, phew!!

Life is a learning curve right, but I am a little annoyed at myself that I chose to do this:

To get to the that outcome.

It’s not that hard to drop the sump off while the engine is in the car. Either way I did make the best of it, replacing a few parts which could only be a achieved by getting it to this stage.

Through this process she gained a new clutch plate, release bearing and slave cylinder, 4 new sub frame bushes, 2 new engine mounts and a bunch of other less significant parts. She is once again purring like a kitten.

Interestingly, there was never any indication that the float level sensor had failed based on the dashboard oil level warning light.

Such is life! I should be thankful for small mercies right.

7 years in the making

Speaking with one of my children the other day, not that he’s a child any longer but a 28 year old Nissan Skyline driver, and mentioned that I’m intending to rebuild the the B5234T bottom end over Christmas break and he was like, really! already!

It doesn’t seem so long ago that I commenced this project but it has actually been 7 years since the original build in 2013. I’ve no idea where that 7 years and 90,000 Klm’s went, but I do know its been a blast! 

None of my children had licences when I bought Ovlov in 2008, she was very original with a 140,000 Klms on the clock and I’m fairly sure the only modification was an aftermarket chip.

Then in 2013 I completed the original rebuild with a 19T turbo upgrade and original 5 speed M56 gearbox. Since then we’ve attended countless track days, tried 4 different configurations of turbo charger, experienced an insurmountable number of wide open throttle blasts, completed 2 dyno runs, changed the gearbox twice (none of which broke) and generally tinkered and played with just about every imaginable aspect of the vehicle. Ignition voltage boosters, an LSD, larger intake pipes, rechipped/tuned twice, larger exhaust, 3 inch DP, suspension mods, Intercoolers, radiators, wheel/rim changes, it’s a bloody long list.

Ive heard it said that the Volvo 5 cylinder engines can be thought of as a little frail at times but given my experience I can honestly say that if you prepare and maintain these engines properly they are an awesome engine. I can personally vouch for the fact they survive a significant flogging over an extended period of time. Maybe flogging is not the best word, but you know what I mean. With forged pistons and rods we’ve basically averaged a 300+ wheel horsepower output during this time, which the engine has held up to without major issue.

And with that in mind, I have decided that it’s time to rebuild the bottom end, which includes main bearings and rod bearings, a changed oil pump and the usual bits and pieces that would be appropriate to replace at this time, particularly items like engine mounts, subframe bushes etc. I can’t say for sure that I know that anything is definitely failing except for an inkling of a change in sound on cold starts…..just momentary. And in the spirit of this continued journey and keeping her alive, I think it’s fitting to take on some well deserved maintenance.

And in all fairness to the strength of the B5234T, the TD06 SL2 20G turbo comes in with such a flurry of boost, an experience that I’ve not refrained from enjoying, it is entirely reasonable to expect it may have taken a toll on the main or con-rod bearings.

In considering this maintenance I was also pondering removal of the cylinder head to clean up the valve seats etc but I’m not convinced there would be much to gain here. I’ve compression tested the engine and all cylinders are reading within a 5% variation of 170 psi, which is well within acceptable performance limits.

There are a couple of other niggly issues I’ll attempt to address at the same time, some suspension noise over harsh bumps and some fuel leaking around the upper tank area, particularly noticeable if hooning around a racetrack with a reasonable amount of fuel on board. I’ll also take the time to add an oil pressure gauge, something I’ve often felt would be worth having given the expectations around track days and managing engine longevity.

Until next time, happy modding!



It’s a wrap!

Can’t say I’ve seriously considered taking on the task of vinyl wrapping this old girl, until recently. It wasn’t so long ago I’d been thinking about purchasing another vehicle. Maybe something with a rotary engine or  serious track day performance, like a Renault RS of sorts.

Then comes along a world pandemic and everything changes, or stays the same, depending how you look at it.

And so, in the era of social distancing, limited recreational opportunities and the possibility of a reduced income, spending a few dollars less on recreating the old girl again seemed like the preferred option.

I’m new to the world or wrapping and the process has been a massive learning curve. Trying to picture in your mind how the car will look given the multitude of  colour options was half the battle. Then you have a bunch of vinyl manufacturers, probably only 4 or 5 that come with recommendations, then you need to spend quite some time watching a few very good YouTube vids from auto wrappers.

And when the day arrives for you to apply your first panel to wrap, a whole bunch of nerves and anxious moments take hold as you commence a very steep learning curve into the world of automotive wrapping. I think the anxiety comes as your realise that you can very quickly make a complete botch of it in a very short time, and at something like $55 meter AU it’s a fast way to spend some cash.

You definitely need to taper your enthusiasm and penchant for perfectionism with reality. As one well known YouTube wrapper rightly mentioned, nothing is perfect in this world and sometimes you just have to deal with that. For the most part, I’m confident people will look at her and say she’s got a fairly decent wrap, but when you do it yourself you tend to remember those little bits and pieces that you weren’t entirely satisfied with.

And without descending into a philosophical treatise concerning the goal of perfectionism, I feel the goal of contentment is far more valuable. I know right, I’m making it sound as though I did a shit job! 🙂 Not at all!

I’ve used a 3M product called Atomic Teal Gloss 1080. Excellent quality product but does require some technique to apply this particular wrap. For example, don’t bother trying to wrap a panel in temps below 18 degrees C. It seems to be vulnerable to tearing in cooler temps. Lesson number 53 in automotive wrapping! Ok Maybe not #53, but there’s a lot to learn!

The old girl is about 60% wrapped and I’ve been averaging 1 panel per day. Estimated time to complete, another 7 days. Oh, and in case your wondering, that’s about 3 hours each day and not the whole day.

For those who may have been wondering, mechanically she is running brilliantly. We’ve not undertaken any serious mechanical work for quite some time and I’ve continued to drive her most days up until now.

Newly Wrapped

Interestingly, when photographing this colour wrap it more than often shows up as quite blue as in the picture below. The above greener tone in the first pic is more realistic but even this doesn’t really capture the depth of colour.

It’s been quite a few weeks now since finishing the wrap. Very happy with it overall! Would definitely do it all again, but maybe not for a while.

Thought I’d throw those last two pics to show what it would have looked like in a grey or black wrap. These colours were on my shortlist at the time.  I feel like the matt black would have been a cool option…. a little more aggressive look!

On The Road Again

2019_0630_13343400 (3)

On the Road Again after extensive work including some touches with the Foliatec Anthracite plasti dip paint on the wheels and bumpers. I’ve also removed the rear spoiler to go for a different look for a little while.

Took some time today to run Ovlov through her paces, the main interest being to check the Air Fuel Ratio under acceleration following installation of the newly updated ECU. The previous ECU was running quite lean at WOT with an AF ratio of 14ish. This occurred following the change to the Kinugawa 20G turbo.

It’s only a very short video but everything looks pretty good. Here’s a brief rundown on what you’ll see.

  • Left gauge: AFR drops to 10 ish during each instance of WOT. This may be considered running a little rich but this is good given Ovlov will be tracked again at some stage.
  • Middle gauge: Boost fluctuates a fair bit at various times and to be fair to the car I was feathering the throttle a little to avoid wheel spin. It’s only really in 3rd gear that you’ll see boost stabilize at a little over 20psi.
  • Right gauge: Measures Air temp at inter cooler input and inter cooler output. In that very short run you’ll see top ( temp in)  climb from 35 deg C to 100+ Deg C, whilst inter cooler output varies from 22deg C to 23 deg C. Thank God for inter coolers!
  • The digital gauge at the bottom is simply the engine temp @ 72 Deg C…. probably a little cooler than normal (It’s a cool 14 Deg day in Canberra today)
  • The blinking LEDs below the boost gauge indicate detonation. I’ve never really calibrated this unit so can only use it as a guide. All LEDs flash brightly when sensor identifies detonation. I thought it may be useful at one time but really it hasn’t proven to be.

On the road the car feels great. I particularly like the Ford Focus M66 gearbox ratios which feel a little closer than the Volvo M66 in the midrange. This could also be partly the result of the improved performance of the ECU upgrade which feels to have unleashed additional low and mid range performance.

Overall the car feels great to drive, extremely punch through the gears and also friendlier for day to day kind of traffic driving.

It’s that time again!

It must be close to 2 years since we’ve undertaken an extensive maintenance program on Ovlov. Since that time we’ve addressed some minor issues and a couple of more major ones, like broken turbos, but invariably we get to a point where I have a list of items to address which are more than just a weekend job. As such my most productive approach is to take some time off work and smash it all out in one go. Now is that time!

The current maintenance list consists of some rather insignificant things, like painted brake calipers which are starting to look atrocious and more significant items, like clutch plate and gearbox replacement. It seems on this occasion in 2019, we’ve managed to accumulate a longer list than we ordinarily might. Perhaps I’ve been remiss and somewhat neglectful of her daily care over the past couple of years, but then again, maybe I’ve just been too busy working for the man, paying the bills and attempting to keep the wife happy! Some of those things are far more achievable than others.

I was trying to think of a word to describe this project and 2 came to mind, prototype and bespoke, neither word is fully appropriate but it’s been a process of building and modifying something which suits my personal driving style and interests. Slightly unique, a bit sleeperish, genuinely sporty to drive and a little old-school. It’s an ever evolving process but most of those aspects of her modification have been there since the outset. As such, we’ve tried a few things which didn’t work, we’ve fabricated a bunch of stuff to suit various mods and in the never ending quest for performance gains have added bits from other vehicles which were not originally intended for Ovlov This all adds somewhat to the complexity of this years maintenance program.

So, having said all that, what are we up for on this occasion:

Engine Removal – Given a bunch of years of experience doing this it’s definitely worth mentioning how simple it seems to me now, to drop the engine out of this vehicle whilst attached to the sub frame. You can actually achieve this in half a day of solid work. The process I use is to lower the engine onto a flat trolley then lift the front of the vehicle up using an engine hoist and simply wheel the engine out into your work area. May as well take advantage of the modular design Volvo invested so significantly into with the 850 series models. On this occasion I will still need to lift the engine off the sub frame to remove the gearbox but again, from here it’s a 10 minute job. It really makes the whole engine maintenance process a lot simpler, especially ease of access to gearbox and clutch.

The new second-hand m66 gearbox

Gearbox – Yep, the original M66 fitted in 2017 has been getting a little noisier and although I can shove some additives in her, hot days invariably yield a kind of rattly growl when under load.  Changing oil viscosity also effects the ease at which you can flick through the gears, particularly when cold. I can recommend the value of adding something like an 80w140 oil but even this fails to quieten her on a hot day now. Obviously something is failing and I’ve no idea what exactly. I feel sure I could have persevered with the old M66 for a while longer but when I spotted a local wrecker discounting M66 boxes from a couple of Ford Focus XR5’s (I think they call the Focus ST outside of Oz and NZ) I decided to snap one up. The M66 cost $250 for a 2010 model which is a pretty good deal and this is in part the reason for switching out the OEM M56 box back in 2017, spare parts availability. Thus far I’ve separated the box and installed the MFactory LSD. The box internals look great, though we won’t know fully til the rubber hits the road.

Sachs Left/M-Pact Right

Clutch Friction Plate – When we installed the M66 back in 2017, I chose the recommended Sachs SD 693 friction disk, which if I recall is originally designed to suit a Ford Probe. The clutch has worked very well especially given that we’re pushing a few Kw’s through it. My chief contention with this plate is the spring rattle which occurs at idle. If you want to see for yourself check out the vid here. Could be suitable for use as a tambourine in the local school band. Sounds ridiculous but yes, you can hear it and although it’s not horrifyingly loud, it’s notable and a little annoying. Given that I’m pulling the M66 out I may as well try an alternative option and therefore have chosen the M-Pact HD Multi-Friction Hi-Torque Assembly Disk (Sach disk Left in images and M-Pact Right in images – Available through Rock Auto) I like the theory behind this design, the design is a mix between high performance clutch plate and standard unit. God knows how much I hated the Spec Stage 3 high performance clutch plate that I tried in this vehicle a few years back. Endless shuddering on clutch release reduced drive-ability to crap status, especially in heavy traffic. I’m figuring we won’t see a repeat of this situation with the M-Pact design.

Drive shaft – It’s definitely worth mentioning that you don’t need to throw out your driveshafts when the rubber boots split. I purchased this driveshaft from Volvo about 7 years ago for around $450 dollars and as such it’s a quality unit. Yeah I know, $450 is ridiculous but it was moments like this which drove me to get more involved in Ovlov’s maintenance and reduce those ridiculous Volvo factory expenses. Driveshafts can suffer damage which causes them to be out of balance but generally speaking if you maintain them this shouldn’t occur. I repaired this shaft with a universal Ebay boot kit which cost me something like $30. Of course you can buy aftermarket shafts online but you can’t always be too sure of the quality. In the past I have snapped a driveshaft, subpar quality from Ebay!

As well as the above, a couple of issues which were noted when she was being driven were a knock in the front suspension over certain types of bumps and undulations and a whine from the cam belt area which tended to get louder on a hot day. Therefore we’ll replace strut mount tops, water pump, cam belt and associated bearings and pulleys.

In the interest of maintaining her outward facade we’ll repaint the bonnet and front bumper/air dam. And in like fashion, to maintain her inner appearance I’ve replaced the lining on the roof, which had been sagging for several years.

I also intend to replace the cam timing sensor and Lambda sensor. This car has only ever left me stranded on one occasion and this was due to a failed cam sensor. I’ve got into the habit of replacing this every few years. Probably not warranted and I guess I could always keep a spare in the glovebox. As for the lambda sensor, they seem to throw fault codes every couple of years and this may be the result of the modifications and associated performance gains, who knows. Either way, I don’t want to take any risks with regard to Air Fuel sensing.

At the conclusion of all this, a well earned polish!

I think that’s about it for now and I’ll add some other pics to this post as we progress. Happy modding!

Today’s job 17th April –  Repaint the front air dam – I decided to strip this back using paint stripper on this occasion. This makes the whole process quite quick but you need to be aware that paint stripper will soften the plastic itself if you leave it on for too long. This is nothing serious but will require some sanding before you put on your Plastic Primer Filler.

18th April  – Finished refitting the roof liner.  Not quite perfect but a heck of an improvement on the old.

19th April – Tried to make some headway with the bonnet/Hood respray. Decided to try and do the job right this time around by starting the job off in bare metal. Stripping back the original Volvo paint was quite a task and required around 2 litres of paint stripper as well as some scraping and sanding. Thus far we’ve applied the undercoat, base coat and 2k clear coat. We are yet to cut and polish the clear coat and although not perfect, am fairly happy with the finished product thus far.

20th April – Only a couple of jobs completed today.

24th April 2019 – I’ve been continuing the makeover theme for the last couple of days. I thought I’d have a go at improving the horribly discoloured and scratched bumper. I’m not a fan of painting bumpers as the paint invariably chips or flakes off so in that light I thought I’d have a go with one of the new rubber style plasti dip paints. Foliatec paints are a German product with a decent reputation so while I’m dipping my feet in the water so to speak, I’ll have a go on the rims as well. This stuff is super easy to apply and I’m just hoping that the paint proves reasonably durable.

26 April ’19 – Today I’ve pretty much completed cutting back the clear coat and polishing the bonnet. Overall I’m happy with the completed work though it is far from perfect. Ended up with some very light tiger stripes, but only visible in certain light. If I showed you the bonnet I’ve been using for the last 3 years you’d understand why I’ll be perfectly happy with this attempt. Have to add, that there are some great 3M cutting and polishing disks these days!

16th June – Ok so things have moved on slowly but we’re getting close now. The car is 95% reassembled and we’re ready to finish assembling the front spoiler and bumper.

I’ve spent a greater amount of time on this occasion to tidy up the engine bay. She’s still a bit cluttered but at least you won’t find too many electrical wires running here there and everywhere.

The Return of Kinugawa

Hard to believe I’m still finding things to play around with on this car! It’s been a quite a journey and according to WordPress my first Ovlov94 post was May 2013. The past five and a half years has flown by. If you’d asked me then if I’d still be playing around with this car today, I’m not sure how I’d have responded.

But I guess it’s been the “playing around” with and investing oneself into this car which is partly the reason for this longevity. I feel as though it will be incredibly hard to part with her now! It’s not a thought I can sustain for more than a moment as I consider doing likewise with a C30 or something a little more modern. Who knows where this may all end, and so for now the journey continues.

My previous post on this blog revolved around the Mamba turbo issues, specifically my disappointment with a bearing failure. Not that I blame Mamba per se, clearly they’re copying another manufacturers design, which in my humble opinion requires a little more development to prove reliable under extreme operating conditions. It was the last track day I attended that brought things to an end.

In light of my conclusion and the fact that I still intend to use Ovlov for occasional track day outings, I decided to revert to a journal bearing turbo, namely a Kinugawa TD06 SL2 20g. I’ve used 2 of the Kinugawa’s in the past, a 19t and a 20t. Both of these turbo’s performed beautifully and at no time did I have any reliability issues with either turbo.

The 20g is probably not an ideal turbo for track day outings with boost onset coming in a little later than the Mamba. If Ovlov was reserved only for track day use, then I think I’d have stuck with the Owen Hybrid TD04; great turbo for maximizing power and torque with lower rpm onset and extended power curve. But given this car is also used as a daily drive for several months of the year, I can’t help but want to experience those brief but stimulating moments of acceleration with a sh#t load of boost!

The specific variation of 20g turbo I chose, for those interested, was a unit which would ordinarily be at home on a Nissan RB25det or similar. Given there are so many variations and options on a turbo purchase these days, I’ve listed the specific unit info at the bottom of this post.

As with any significant turbo swap comes the inevitable bunch of changes to make it all work. I had to fabricate myself a 6 bolt exhaust flange adapter to suit the Nissan style turbo. Learning to TIG weld has been a game changer! The rear engine mount also required modification due to a slightly larger compressor side on the new Kinugawa. This would not normally be an issue except that I had to fabricate a new rear engine mount when I installed the M66 gearbox sometime ago.

A couple of other changes I threw at her whilst at it included the fitting of a Turbo beanie, something I’d not really looked into until recently, but they seem to make sense. Theory says that isolating heat to the turbine housing whilst reducing under hood engine temps is an efficiency gain. I also took the opportunity to fabricate a new intake airbox that completely encloses the existing POD filter whilst allowing fresh air only into the unit. Again, cooler air intake temps improve performance. This was a fun project and you can see the before and after pics below. Fairly happy with how it turned out. Realistically it’s just a variation on the oem unit but provides the opportunity for higher volumes of air flow.

Before photo – 4″ x 8″ Pod to replace OEM intake


After photo of Airbox – Pod filter enclosed


When I installed the POD filter to maximize airflow some time back I was always going to be pondering the benefits of doing so. Under hood summer temps in this car are significant, not such a  problem in a Canberra Winter, but right now in mid summer and 36 degree C days, it’s notable.

Having completed the above changes what can I say about the driving experience. The boost onset of the 20G is a little different to the Mamba GTX30171R. It reminds me of the 19t experience. Boost comes on with a blast, it just happens a little higher in the rev range. I don’t feel as though the driving experience has suffered and boost is adequate in the mid range, it’s just that things seems to come on with a greater flurry around 4500rpm, a little later than the ball bearing turbo.

If I had to take a guess, the butt dyno says very similar power output but I reckon if you looked at a dyno curve the Mamba would look less aggressive and more linear.

One thing I did note during a couple of WOT runs was the mixture is running a little lean. I’m not convinced of any issues with the set up as such so have ordered a new tune to suit the build from the Volvo dude in Portugal, Rui. Until then I’ve not been too willing to push her real hard, especially in this summer heatwave.

Well that’s about it for 2018. Let’s see what the new year has in store for Ovlov!

KANDO P/N– 331-02035-156 – ACCESSORIES-001

ITEM NAME– Kinugawa Bolt-On GTX Billet Turbo 3″ Anti Surge, TD06SL2-20G with 8cm Turbine Housing and 9 Blades, Turbine Wheel For NISSAN RB20DET RB25DET

APPLICATION  – Nissan Skyline R32 R33 R34 2.0L 2.5L RB20DET RB25DET Engine,  – Universal application: 2000~3500cc

CHRA/WHEEL SPEC – TD6SL2-20G, – Compressor wheel : 52.3 / 68.0 mm,   (GTX Billet 20G 11+0 baldes / Max boost to 5.0bar), – Turbine wheel : 54.1 / 61.0 mm,   (High flow TD06SL2 / light weight 9 blades)

COMPRESSOR HOUSING   3″ anti surge inlet, – 2″ compressor outlet, – A/R.60

TURBINE HOUSING – 8cm / AR.57, – T3 inlet flange,  6 bolt outlet – wastegate dia : 28.0 mm

COOLING/BEARING SYSTEM – Oil and water cooling – Journal bearing kit, (Performance thrust bearing kit)

ACTUATOR PRESSURE – 1.0bar / 14.7psi

BOOST/HP – boost limited : 2.8bar suggest boost : 1.5bar – max hp : 300~400hp


Mamba Turbo update

Apologies for the delay in responding to those who left messages requesting an update on the performance of the Mamba GTX3071R turbo. I’ve been focused on other projects and until recently hadn’t had any issues at all with the turbo. But, following our last track day event it became obvious something wasn’t quite right. That something was a whine emanating from under the bonnet… first it sounded like an alternator bearing failure, but sadly some further investigation led me to the turbo.

Not sure how many kilometers we’ve traveled with the Mamba but it’s been around 18 months and 4 track days. It was the last day track day which brought it undone. Having eliminated all of my previous boost leak issues with this turbo I was able to push hard during the four 15 minute sessions we took part in.

Over the born again life of rebuilt Ovlov this is the first turbo failure we’ve had, having run the Kinugawa, Owens and now Mamba turbos.

Having researched the issue I can’t say the Mamba turbo is a poor quality build by any means. I believe that the turbo design is carbon copy of the Garret GTX3071R, the internals are close to identical and from what I can gather the Garret versions also suffer with bearing failures. The replacement bearing kits are readily available, along with a few DIY replacement videos from committed YouTubers. Clearly there is a demand out there and the issue is a design and installation related matter.

I can’t say for sure if the Mamba turbo would have failed had I limited her to street use only. In my particular instance it may have been the significant heat generated on the hotside of the bearing cage which has caused the issue. Whether I may have contributed to this issue by not running the engine on for long enough following each track session, I don’t know. There is a belief that the significant heat generated on the hotside bearing needs a reasonable engine run-on time to allow the heat to dissipate more evenly. Whatever the case, disappointingly it failed.

I guess that leads to the question as to why choose a ball bearing turbo when a journal bearing turbo may actually prove more reliable. The answer is a no brainer really! In motor vehicle applications the ability to spool up quickly provides significant performance gains. The general consensus is the ball bearing Garrett turbo can spool up around 15% faster than journal bearing turbos. It is a recognized fact however that ball bearing turbos are a less reliable option when running for prolonged periods at high boost. This fact is substantiated by the aeronautical industry who continue to prefer journal bearing turbo applications on the basis of reliability.

So, where we are at right now is that I’ve completely disassembled the turbo. This is not a difficult task by any means and the more important aspect will be to reassemble the turbo and retain the original position of the shaft to compressor and impeller wheel position, so as to not upset the original balance.

As stated, what I found was the bearing no longer spins freely, smoothly or as quietly as it should. I’m sure that we could have got a bunch more K’s out of the turbo but it’s not worth the risk or the annoying whine, not to mention that spool up time and performance would have been effected. Here is a pic of the offending beast. It’s a little annoying that this unit will set you back around $300 bucks AU. That does make this whole process a little frustrating and I can’t honestly see how this cost is justified…but there you go!

In summary, I can’t say I’m not a little disappointed and it does leave me wondering if this turbo is suitable for Ovlov in the longer term, particularly given that I fully intend to continue with track day events. I should add; I don’t personally believe that a genuine Garrett equivalent would have fared any better.

At this point in time I’ll replace the bearing assembly and play it by ear. It would be a very easy option in the future to swap into something like a Kinugawa TD06SL2-20G, with very similar specs to the 3071, and we’d be reverting to a journal bearing turbo.

Having said all of that, I’d have no hesitation continuing to recommend the Mamba turbo as a suitable option for street use.

In the end I decided to go back to a Kinugawa journal bearing turbo. You can read more about that here. 

3″ Exhaust System Installed

They say miracles happen at Christmas, not that I’ve seen one recently but this has got to be close. I’ve been rabbiting on about installing a 3 inch exhaust system since Adam was a boy and now with Christmas holiday leave and some bloody minded determination, it’s done!

I knew full well that fabricating my own system was going to be a serious personal investment, 2 and 1/2 days in fact, crawling around under a car, pipe in, pipe out, minor adjustment, pipe back in, pipe back out…… and a whole bunch of welding.

I feel sure my wife sees me as some frantic mad-man on these occasions, able to be interrupted only for food, cold drinks and sleep. Endless angle grinding, cutting, cleaning, the continual sound of banging pipes ring out into the neighbourhood. Much preferred over the traditional Christmas bells.

I wasn’t sure how to approach the project initially, given the limited space under the vehicle but just in case anyone may be interested in doing likewise, this is how I approached it.

First thing was to go online and find a 3 inch exhaust kit to suit an 850 series. I scoured the images until I could basically breakdown the various pipe curves and angles required. Keeping in mind this was CAT back only. I’d already upgraded the front half to 3 inch when I upgraded to the Mambatek turbo.

Given the scouring of online images I narrowed the system down to the following components, all 3 inch/76mm pipe, some of which were earmarked for the chopping board.

  • 1 x Chrome Exhaust tip
  • 2 x 45 degree mandrel bends
  • 1 x 180 degree mandrel bend
  • 1 x 1 mtr straight pipe
  • 1 x 14 inch round exhaust muffler
  • 1 x 4″x9″ Oval 14″ Long Muffler
  • 1 x Exhaust Flange joining kit
  • 1 x 3″ Exhaust Clamp (to connect to existing)

And wallah! The miracle occurs. Just don’t be lookin’ too hard at my welding skills. I guarantee the joint will hold but they’re certainly not as pretty as a professional would accomplish. TIG welding is a bitch for newbies, but stainless welds are virtually unbreakable.

Gone is the cheap and cheerful OBX system which served us very well. Having installed the 3 inch system and made a few minor adjustments what I can say is that she rumbles a little louder at idle, roars like a lion at WOT and is not at all unreasonably loud when you’re trundling along at road speed.

I can’t speak for a performance change, and the reality is that the dyno in my backside is not a realistic measure of performance. Sure, she feels good and doesn’t run out of puff at WOT. At the point at which the rev limiter does cut in you get the impression the power curve is still on the way up. I guess a real dyno would testify to that.

So far as further modifications are concerned for Ovlov at this time, I can say with some sincerity that the list is now exhausted! 🙂

Seasons Greetings, drive safe and Happy Modding.

NA cam delete + other interesting stuff

There are at least 3 things I don’t fully understand in this world, spark plugs, camshaft design and women.

Granted, I’ll never understand women! Time permitting I may one day grasp something of the various types of spark plug technology and their suitability for various levels of high boost performance engines. But for now at least, spark plug technology remains a mystery.

  • Should I buy Silver, Copper, Gold, Iridium, Platinum or Nickle style plugs? Silver they say is the best conductor and Nickle, the least conductive.
  • What heat range should I be looking for in a mildly boosted engine and occasional track day use? (by mild, lets say 24psi) Some say go a stage cooler, others say beware it can cause fouling.
  • Does the manufacturer make a difference and if so which one should I buy? The more popular brands being NGK, Bosch, Denso, AC Delco and OEM.
  • Should I believe it when one site says Iridium is best, and another says Copper core is best?
  • What should I do with the thousands of opinions from online forums that seemingly contradict each other? Good lord, am I talking about women or plugs, I forgot!

Or is this some kind of marketing conspiracy to produce multi level pricing strategies for higher priced, so called, better performing products?! I think that’s more of a given than a genuine question.

Ok so here is what I can tell you and what it relevant to my build! When talking plugs, too large a spark plug gap will likely contribute to a miss fire at higher boost levels, say 20psi+. My personal experience would tend to suggest that .022″-.025″, converted to proper form of metric measurement .56 to .64 mm, is the best spark plug gap for a mildly boosted engine such as Ovlov’s and will minimise miss fire at 24psi.

As for the brand and type of core/electrode, yes there are significant variations. For example, your Iridium’s will last about 10 times longer than your Copper’s. Everything else is just too confusing!

Double Platinum

I should add that for the last 15,000ks I’ve been using a Bosch F5DPOR plug. Originally designed for Audi performance engines, these Double Platinum plugs are spoken of very highly, aside from some concern that the Double Platinum tip has been known to separate in very high performance installations i.e. 400hp+. Far more devastating a reality than I make it sound with these few simple words!

The reason I’m talking about this is we seem to have developed some spark blowout issues again, now that the old girl is running sweetly. And by sweetly I mean, producing some fairly high boost at an earlier onset than previously. And the reason for this is two fold!

Having resolved my exhaust manifold boost leak issues I turned the boost up. Secondly, I removed the NA cams and reinstalled the OEM turbo cams.

Reinstalling the turbo cams lead to a surprising holy crap moment concerning a performance change. The reason for removing the NA cams was the result of my feeling I’d lost a little too much low end HP and torque since installing the larger Mamba GTX 3071R Turbo.

When I originally undertook the NA cam swap a couple of years back I was still using the TD04 turbo, which produces a nice level of boost in the lower to medium rev range. The whole point of the NA cam swap at the time was to extend the boost range to higher RPMs via the different design and a retardation of the intake cam. At that time I didn’t feel a significant loss of power in the low and mid range. In fact it felt a little better.

Anyways, with the Mamba feeling a little laggy at the low end and my never ending search for performance gains, I went back to the original Turbo Throttle body; No significant change, zilch, none, aside from feeling like the throttle was a little more progressive or less sudden, so far as daily driving was concerned. WOT did feel a little less exhilarating!

Once more I reverted to the larger throttle body and this time reinstalled the Turbo cams with their original settings; Instant change! Low end response much improved. The ridiculous thing is that boost onset feels like it’s come back by about 500rpm. Silly to think that this would make such a difference.

I guess it kinda makes sense given the lower boost levels of the Mamba at lower rpm, and that the OEM Turbo cams with their more advanced timing setting will of course improve things in the lower RPM range. The downside will be a loss of power at the top end, and potentially some detonation related issues. But given the Mamba is able to pump a shite load more air I figure the top end losses won’t be too great.

Perhaps there is more to it than this. Perhaps it has something to do with cam overlap, another mystery which I’ve not fully understood, though the article on the attached link does provide some clarity! LINK.  Either way I know what I can feel in terms of a performance improvement and for a daily drive I’m going to like this quite a bit better, and am already.

And this my friends is why we are talking about spark plugs and the best plug to support mildly modified boosted engines, experiencing spark blowout. The gap, the gap, just focus on the gap!

I gotta add as a final note that the 850 Turbo article which had me rethink the NA cam swap was a well know modified 850 sedan referred to as Yellow Peril, in which the writer referred to a power loss with the NA cams. He too was using a turbo somewhat larger than the TD04 designed units.

I know you guys like pictures of car stuff!

Oh and by the way, the plugs I chose to use are NGK Iridium Spark Plugs BKR7EIX. They tell me that you need to be careful when gapping them as the centre electrode is quite fragile.

Happy modding!



Volvo Therapy

It’s been a while I know! I feel like I’ve been enjoying the fruits of my labour somewhat uninterrupted by further significant modifications. Having said that, I’ve missed crawling around under her hood/bonnet. (depends where you live)

I work in the community sector with people who are homeless and suffer mental illness and addictions etc. Often referred to as having complex needs. The frustration of working in this field is that you can’t fix people. Sure you can help make things a little better for them. Don’t get me wrong, we do have wins.

In that light I’ve discovered over the years the therapeutic value of working on cars. Perhaps not true for all people but at least I can fix them, make them work better. The sense of personal achievement and value to my own well being is something I’ve appreciated. Enjoying the fruits of my labour yes, but also rewarding and providing some down time from the ills of life.

I think this is in part why I cling to this old girl, aside from the fact that she’s quite impressive for ’94 vehicle, I need her in order to function effectively 🙂

I will admit however some frustration in the modification process is not at all uncommon. I don’t always get it right and the dumb-ass things I’ve done at times confound me. Given some hindsight this usually occurs when I’m pushing to get the job finished and frustration is creeping in. An obvious mistake, or what should have been obvious to me at the time is overlooked.

I discovered one example of this just recently. Having undertaken some fairly substantial work to rectify an ongoing boost leak between the turbo and manifold, (more shortly) I’d proceeded to drive the car for some weeks realizing that something wasn’t quite right.

In my mind I gather information whilst driving trying to piece things together like a puzzle. It went something like this. Boost is good, in fact very good, so good in fact it feels as though I’m having some spark blowout again…..Hmmm maybe! I’ll think about it. Then, Hmm, seem to be losing some boost momentum between gear changes, feels a bit laggy. Then Hmm, gosh the recirculating blow off valve sounds like it’s letting off a lot of pressure, noisier too.

I’m only giving her occasional wot so I don’t really pick up on the issue too much. Then last week I decide to give her a good run on some open road and next thing I hear is what sounds like an increased whine from the turbine at low revs. I’m thinking uh, oh, what now!

So here’s the dumb-ass thing! The manual boost controller is not connected to the waste-gate! Duh! The waste-gate is not actuating so yes, I have been getting significant boost. With no waste-gate the recirculating blow off valve is dumping all of the pressure (of course it’s going to sound noisier) and the result is a loss of power/boost at gear change. The whine in the turbo was a result of the boost pressure blowing back through the turbo when I gave her a decent run, and the intake pipe had popped off at the silicone hose connecting to the turbo.

I could kick myself cause such a small mistake can damage the turbo. This can occur when the reverse air pressure at high boost attempts to blow back through the turbo due to what is effectively a disconnected waste gate. Idiot!

Puzzle solved, no damage done from what I can tell. I feel some sense of accomplishment at having rectified my stupid mistake. Looks like all ok…… Spins fine and boosting perfectly well too.

I love the way ceramic ball bearing turbos spin so easily. Nicer than the OE TD04 journal/friction bearing.

Other than my balls-ups what I can tell you is that the Mamba turbo is running great. That statement does come with one other admission; now that I’ve removed the turbo adapter plate. In earlier posts I alluded to issues with boost leak at the manifold adapter plate. I’m not sure I ever really got my head around what was happening and no matter how often I re tightened the turbo to the manifold, it would invariably end up with a boost leak. At 24psi and 6000 rpm what happens is that the fuel mixture leans out, causes detonation and the potential for a catastrophic outcome.

The offending part

On most occasions this failure occurred on track days. As I said, I’m not sure I know exactly what was going on but am willing to guess possible hot spots, evidenced by slight bowing in the adapter plate.

The fix is not really that hard but you have to permanently modify your exhaust manifold by either machining off the flange or in my case some very patient flat filing then discarding the adapter plate. This of course meant that the turbo was now a half inch closer to the engine block which required some changes to the home fabricated engine mount and fiddling with the turbo drain pipe. Changes which were far more easily managed when the engine was outside the chassis.

Never the less, I’m not saying that the adapter plate was at fault, but in my case, it was! 🙂 I’d highly recommend modifying the manifold as pictured below.

The other change I made was to retap the 2 manifold threads and install 4 more substantial high tensile studs/bolts and nuts. So far so good!

What else I can tell you is that the clutch slips under WOT acceleration. I suspect that this has been exacerbated by the installation of the LSD. In the past it was quite easy to lose traction and spin up one wheel. Those days are long gone and no doubt the clutch plate is carrying that additional torque load. To be fair on my poor old clutch, it’s not like it affects daily driving much at all, provided you manage the rate at which boost comes in.

There are quite a few friction plate options out there that I can utilize with the M66, one being a performance plate designed for the ’91 Ford Probe Turbo. The other thing I don’t like about the Sachs SD 693 friction disk is that it rattles, or the torsional coil springs rattle that is, at idle. Something which I find a little annoying.

Other than this I’m yet to complete the 3″ exhaust, also need to repair or replace the clutch master cylinder which seems to be dying slowly.

I guess this will make for some therapeutic mental health time during the Christmas break!

Happy modding!