Turbo Conversions - Current Status
 

All that have done turbo conversions to your once NA cars: How are things still running?

How many years since your conversion?
Any issues:
Transmission holding up (915?)
Turbo oiling issues?
etc...

Although not very long ago, I did mine around October 2015 and all is still good. I regularly track it (detuned from .5 to .3)

I still have my 915 transmission, but I certainly baby it to some extent.

I know a lot of you did this conversion many years ago and am wondering how things are holding up.

Kyle

Mine is still going strong with no issues to report, other than a slipping clutch disk in the 915. That is probably what is keeping the 915 together at this point.

I have no leaking oil / smoke etc ... only the urge to turn up the boost which is currently set at 7psi :D I have a G50/01 on the bench and am planning to install it in the next year or so.

Cheers.

Sandeep

How old is your build and how much HP are you pushing? It looks like you have a similar build to mine.

I've had the turbo conversion going since summer 2015 ... making 300 RWHP / 300 RWTQ at 5000 rpm but the dyno chart drops from there due to the slipping clutch. I'm worried if I replace the clutch / PP with something stronger, I might damage the gearbox.

I use the car on the circuit as well as autocross at 7psi with no issues.

Cheers,

Sandeep

Mine had been converted for over a decade. No problems other than my tuning (too much timing) and engine assembling shortcomings (oil leaks).

Will be ready to finally go to the dyno here in the next couple of weeks, but for now on a very conservative timing map and rich fueling, it is running great. Did have an issue with the scavenge pump configuration but that has all since been sorted. I do only have about 200 miles on the engine since turbocharging so there is still (hopefully) a lot of miles ahead of me.

I've been kicking around the idea of turbocharging my 1980 3.0 and moving it to my '77 widebody. I have a BMW race car running a 1.8 ltr. motor that I've turbo'd and is controlled by MSII 3.57. I've already converted the 3.0 to EFI with the Bitz kit as well with MSII.

Any recommendations for spec'ing and sizing the turbo? Or any links to build threads I should research?

Thanks!

I've had mine converted since 2012 but started with a turbo engine so less of a conversion more a swap I guess however I did use the original 915 from the 76 build year car. It was a 8/31 r/p trans not the shorter one but soon as I raised boost to .8bar I started to see issues with the clutch (225 sachs sport) It did hold for a year though. Bought a centerforce which used a steel pressure plate which changed the rev nature enough I didn't quite like it as much but it held......enough to break a second gear set in the then almost 40yo transmission. I bought another trans and continued for a few more months maybe a year trying to baby it more but having a hard time with self control.....Broke another second gearset. I bought a lightly used 930 trans and tried to make it fit..couldn't make it fit (just one inch point one!) so I bought a short 930 and stock clutch set and it went together very well. Enjoyed the way I could hammer it with reckless abandon....well actually the stock clutch limited that a lot because it just couldn't hold over about 375-400hp.
Well something went wrong with my 930/51 so I traded it for a built carrera engine (3.3 cylinders and je 8.1/1 pistons sc cams ets..) with carrera manifold and new efi system and gt3582 turbo. With this new setup the stock clutch could not hold more than .5bar boost so I have removed the engine with only about 300 miles on a fresh build and 15quarts of liguid gold (mobile one vtwin) to again replace the clutch system and swap in favor of light weight 934/5 clutch and an aluminum flywheel. Should be back together tonight:)
During this time frame the car has gone through so much change that many friends or acquaintances think Iv'e had four cars. It went widebody and changed color.

I admit that I would not have had to make many of these changes if I would have not become addicted to boost..it's a sickness and I have it. If I had been able to control my urges and stay away from the pipe the original setup would more than likely help up much longer.
These cars and their 915 gearboxes are a kick to c\drive even with only .4-.5 bar!
If you can keep them down with .3bar efi or .5 bar cis then you'd more than likely get lots more life between clutch or trans issues.
Id do it all again too, Maybe a little differently I guess knowing what i know now but end result, I love.http://forums.pelicanparts.com/uploa...1534267540.JPG
http://forums.pelicanparts.com/uploa...1534267540.JPG
http://forums.pelicanparts.com/uploa...1534267540.JPG
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http://forums.pelicanparts.com/uploa...1534267540.jpg
http://forums.pelicanparts.com/uploa...1534267540.jpg
http://forums.pelicanparts.com/uploa...1534267540.jpg

http://forums.pelicanparts.com/uploa...1534267540.jpg
http://forums.pelicanparts.com/uploa...1534267540.jpg

http://forums.pelicanparts.com/uploa...1534268499.jpg
Not sure why I can't straighten it up...

Brando, I really like how the intercooler peeks out of the lid, looks cool. So I went turbo early 2012 but before that ran a Paxton supercharger for a few years. Ive been using the same rebuilt 915 the whole time but I do baby it. So far everything is holding up well but as I said, I take it easy on the gearbox and really don't drive it too much.

Thanks Rod, I did too but made the permanent change to a much bigger inter cooler and enclosed it with bigger tail. In the beginning I wanted to avoid the tail look but in the end gave in to the need for inter cooling ease.
BTW your car truly is beautiful.

These engines seem to take the conversion quite well as long as the boost is kept under control. It's the 915 that's the issue. I too, am now hooked on boost. Before my conversion, I knew nothing about turbos much less driven a car with one. :)

BTW, nice looking splitter. Did you make that?

Over a decade on mine. Just had the 915 rebuilt, but it was due to a friend missing a shift, it had 150k on it anyway, and had notchy 2nd gear. I don't baby the engine but am careful with the trans.

.5 bar Protomotive kit. Thinking about adding water injection and MAF, Todd can still supply both, and going to .7 with a more modern turbo.

Aside from quattrorunner's clutch experiences with a 915 above, what type of clutch / PP system are others on this thread running ?

I have a slipping clutch (stock + carrera 3.2 PP) that I have to deal with this winter, but not keen on blowing up my mostly stock mag 7:31 915 with upgraded diff side cover. My end goal is a G50/01 that I have but still a long way off from collecting parts.

Any thoughts on this ? Most of these builds seem to be in the 300 - 350 hp range.

Cheers,

Sandeep

I turbocharged my 2.7l last year.

Most of the miles I have on the conversion have been from tuning and sorting out issues, but so far, so good.

I'm running around 8 psi.

I haven't had it on a dyno, so all I know is that it is making a LOT more power than before.

IROC 912
I bet your car is a riot!
EFI gt3076r 3.2 carrera and close ratios make for a car that can outrun almost anything to 125mph.

KEP stage 2 in my G50

Sachs 915 "Power Kit" is a stock clutch cherry-picked off the line for top 10% of holding power. It'll seem OK with RoW power levels (930/60 == 300 HP) or slightly modified (+SC cams & open exhaust == +10%), but you'll have a service life of ~12-15,000 miles on a friction plate - e.g. you'll find to your surprise that you're down to the rivets when you drop to address something else.

I believe it actually slips at these power levels (hence the premature wear), but not so badly it's obvious and you notice.

Increase power significantly (e.g. bigger intercooler, K27/HF, headers), you'll be in the ballpark of 370 HP, 350 ft/lbs at the wheels - and a car that responds progressively to throttle - e.g. makes boost below 3000 RPM, like 6PSI @ 2400, given load.

You can't even progressively break the motor in with a (new) Power Kit at these levels - it'll very obviously break free and begin polishing the flywheel (e.g. it'll just get worse, and very quickly too) at any more than half-throttle in boost around max torque.

The good news is that a kevlar 6-puck clutch and an Sachs "Competition" RSR-style pressure plate will hold these power levels just fine.

There is, however, downside. Firstly, the increased spring/clamping pressure broke, one-by-one, break every aged part on the outside of the gearbox; actuating arm, bracket that holds the cable etc. - Save yourself the trouble and just replace them off the bat. I got pretty tired of hearing "huh, never seen one fail like that before"....

The puck clutch wants to be in or out. It'll complain/chatter loudly on hill starts or reversing up your sloped driveway, or anytime you're forced to slip it for more than 18" or so...

Stock 915 clutch, you can depress the pedal fully with one hand while lying with your head under the dash (e.g. at an awkward angle).

Competition PP? Ha. Nope.

The pressure plate will feel like a leg press after about 10 minutes in stop-go traffic, after which time you'll start to become seriously concerned as to whether you can continue to provide the finesse needed to slip the puck clutch, your leg will be shaking so much. After 20 minutes, you'll be audibly cursing.

The stock(-ish) 930/60 ate, chewed up and spat out my original '77 mag gearbox. The 5th gearset was dark blue, spun bearings, a real mess inside. Seemed no point rebuilding it - pretty clearly not up to the task.

A 7:31 C&P with a mag box and a 930 (or equivalent power/torque levels) really seems to be pushing the envelope a bit to me, as the 7:31 isn't considered advisable with a 3.0 SC...

I went with an '86 915, plate-type LSD (also a strengthening factor), WEVO bearing plate, factory cooler pump and internal oil bars, new bearings, synchros etc. And the clutch arrangement mentioned above.

It was lovely to drive, really nice... 915's will shift into 1st at 30 MPH without double-clutching if you really want to - although you'll not make a habit of it when you look at the price of the synchro's this wears..

One day, the 930 was bored and decided to eat 4 teeth off the 2nd gearset (which was both tall and kinda old); wasn't even trying at the time.

Being mindful of the transmission and it's weaknesses seriously interfered with the fun factor for me, until I went G50.


HTH.

Yes, the G50 is a tough transmission on par with a 930. The diff is weaker, but you can put a billet diff cover on for additional strength. Then you’ll never have to worry about it.