John.

I have been toying with the idea of developing a turbo conversion kit for the older 2.5 liter cars. I know a lot of people on here have asked about it and there really is no good answer unless you sell and buy a turbo 951. I think there are quite a few people who have clean early 944s and they really love them, and the problem with upgrading to a turbo is that a lot of them have been people's race toys and sometimes you get a car that has been driven exceptionally hard.

I was thinking for those people who are close to a rebuild anyway, you could take the opportunity to pull the motor and beef up the lower end with a 951 piston, or go to a custom made unit that can be run on a Nikasil coated block, or perhaps a custom made unit that will run on the Alusil and will be a bolt in replacement....??? Not sure which is best, probably a new set of custom made units.

Anyway, as I see it this is what it would consist of:

Turbo, probably a Garrett unit, or maybe an Aerocharger?
Custom Manifold, perhaps Stainless Steel
Remote Wastegate
Larger Injectors
Hot Wire MAF conversion with calibrator
Forged Pistons (JE units, or maybe something else?)
Air to Air "bar and plate" style intercooler mounted up front
Feed Pipes to and from the turbo
Additionally, maybe some means of electronic wastegate control for the boost freaks

There is ample room to do such a conversion, I am certain of it. After working on upgrading my old twin turbo 928 this project would be a breeze!

So, who out there would be serious about a conversion like this and what would you be willing to pay? I would estimate this conversion would run about 11-12 psig, perhaps a bit more? The turbo would sit on the exhaust side of the engine. Rough guess on power at the crank would be somewhere between 200-250, maybe more if it all works out well. I realize there are some guys selling these centrifugally driven blowers for the 944 with 9 or so lbs. of boost, but the boost levels those things develop are at the redline only, so at 3000 RPM you have maybe 3 lbs of boost, where the turbo car would be well over 6 or 8 lbs at that point. I am talking about a car that will produce excellent mid-range torque and will develop boost way down low. Plus you can then just buy the 951 turbo badge and slap it on the back.

Would it be as good as the factory car?, most certainly not, but I am 100% certain I can make a powerful and reliable 944 turbo out of the early 2.5 liter car.

Any interest?

xsboost90

it would certainly be a fun project,and i would definitly be interested in a year or so...how about a 2.7l though, anything for that? I understand i could stroke mine to a 3.0 and turbo it, how about a kit for that?

Peckster

What kind of experience do you have doing this kind of thing? Have you worked with 951s or 944s before?

Roral

how much money would a project like this be? (ball park fig.)

Bhj0887

My guessemate of around 3-5k. Turbo parts can get pretty damned expensive. Plus, if he's going to build the motor as well, add at least another 1.5k to that.

hacker-pschorr

You mention using a 944 turbo piston or a custom one. Working with Tim Murphy on his supercharger project for 928's, 951 pistons seam hard to find. Custom made one's are not cheap for these engines. I see the cost factor for the pistons alone putting this type of kit out of reach for most of us. Especially when you take into accout the value of a running 951.

Then you would also be looking at 951 connecting rods. So right there your looking at $1,600 (or more) in just rods and pistons.

Fuel Injectors $100+
How much are turbo's? I'm guessing as much as a supercharger so $1500 - $2500 there.

I'm guessing a kit would be minimum $5000+ in your parts cost alone, unless you have a way to buy everything wholesale or gong used.

Not trying to discourage your efforts, I love projects and custom cars. More power to you if you put together a kit like this. I'm currently talking to Tim Murphy about a supercharger for my 1981 928, those kits run about $8,000. I'd be better off buying an S4 instead but like you said, some of us are really attached to our cars. It would be neat for a bunch of NA bodied turbo's where around to shake things up when the ricer gangs pull up.

97xray

John,
what about a lower psi on higher compression piston? I'm ignorant, can you explain why people don't do this for the lower end torque?
I've got the Euro pistons and "think" that I can clearly feel the difference in lower end torque.
Is the higher compression to risky with boost??? and why?

Bhj0887

there was a good article about high compression vs low compression, I might be able to find it. Anyway, its going to be more difficult to tune a custom high comp. ratio turbo engine compared to a custom low comp. engine...Boosting will raise compression even higher, I'm going out on a limb here but, let's say you have 11:1 compression on your stock engine, boosting with a t3 turbo at around 10 psi will raise your compression way up to at least 14:1...not gonna be using 91 octane are we? Now, if we had the same exact set up with 8:1 compression you can probably boost up to 15 psi and have 14:1 compression.

I'll just find the article and post it...

Danno

Don't forget about an ignition-interceptor/massager for that combo. With a MAF and its massager, you'll be scaling the signal between the same 0-5v range as the stock AFM. However, you'll end up with 50-75% more air-flow in the upper RPMs. The interceptor/massager will scale the signal down to fit within the same voltage range and you end up using the same ignition values as stock. But the actual air ingested is more than stock and you'll end up with knocking & detonation. Also on pre- '85.5 cars, you need to scale the MAF between 0-8v, or upgrade them to the newer DME.

John..

On the issues of compression, I would not run more then about 5 lbs on top of the 9+:1 compression in the early 944, and that makes it not worth the effort, as you could get better gains for the dollar with NA performance parts at that point. I would guess 10 lbs is needed to make it worth the effort. Not sure why you would need those turbo rods....probably not worth the money for a street car as most rods let go because of RPM, not boost levels. I'm not talking about building track motors, just good reliable street motors that will give the owner years of enjoyment without headaches.

Turbos can be had for much, much less than those centrifugal blowers....need to investigate more on this front, but imagine a Garrett setup that you can pick and choose the turbine housing on?...Then there is the advantage of dial-a boost from the cockpit and 10 lbs by 4000 RPM....try that with a centrifugal blower set for a max of 10 lbs. Not possible with current setups.

The turbo would be the clear winner on top of the 944 engine (any engine for that matter), as the boost would be much stronger down low as compared to the centrifugal blower. I know of at least three Callaway 944s running IHI RHB-6 turbos that are really quite fast cars, in fact the road test I have from 1984 placed their straight line accelleration equal to or better than that of the 944 Turbo S of 1988/ 1989. These cars were dropped to 8:1 on the compression and ran stock ignition, though I agree some form of ignition conditioning is probably in order over the stock values. 10 lbs of boost was the norm, with some running 12 lbs. One article claimed 10 lbs of boost by 2500 RPM, though this seems a bit high... With today's technology, I can do what Callaway did 20 years ago and have a car that is just as powerful and just as reliable, probably better on either front. I look at the 944 as a good place to start this type of work becasue of its simplicity and availibility of parts.

I'm just looking at it this way, if you have a NA 944 that you love and want to keep (some like their looks better than the turbo), then there is probably a market (small perhaps) for such a conversion as some have already opted to go to the Centrifugal blowers on the NA 944 a long time ago. This would be a setup of my engineered design, not a copy of the factory turbo setup. Top side would remain basically stock looking.

As for my experience, well it is certainly adequate to do this type of work and I will leave it at that. The 944 isn't all that complex of a car by today's standards.

Hacker, maybe you should wait and let me build a turbo kit for the 1980-1982 928 L-Jet car.......

This type of thing may be a good chioce for those of you who have a tired 944 motor and are considering upgrading to a turbo, but love your car. I'm sure there are those people who already have a ton of money in interior, suspension and brakes that would hate to part with the car. Perhaps the whole package is of some interest...i.e. prepared motor, turbo setup and all the associated goodies? 2.5 liter would br the starting point, though there is nothing magical about the 2.7 that could not be handled in the same manner.

I'm just testing the waters to see if there is any interest.

elf89

Here's a thread about Todd Holyoak selling a Callaway 944 turbo. The web ad is not up anymore, but he had some detailed spec sheets from Callaway. You may want to e-mail him to see if they're still posted somewhere. Good luck!

Edit: Found the link to his 1984 Callaway 944 Turbo.

Crippler

Well it can be done, I fitted my 1984 n/a with a used Callaway kit and some 951 parts. Worked quite well.

hacker-pschorr

Interesting, but my car may be the test mule for Tim's supercharger kit. I do hope you get a kit together. The more options we have the more boosted 928's will be out there.

I would love to turbocharge/supercharge my 944S. The only reason I didn't go with the huntley SC kit was well, it was huntley.

John..

So there is a Canadian Crippler out there? Sounds like a cool setup. I have talked with Todd as well, I think he is in Mass and told me he really liked his Callaway 944, that is was as nice to drive as another factory 86 turbo.

I will start to do some homework on costs and see what is possible with such a conversion.

In the interim, Quick Carl is boosting an 81 car. He and I have discussed fueling options and I gave him some details on the hot-wire conversion from my twin. I'm sure both Carl and Tim will have some good results when this is all over. I would imagine a rather large single turbo setup with a header exhaust system for the 928, but would have to look it over.

So tell me Crippler, what are you running for the exhaust after the downpipe. How about fuel system, are you using the Miller Woods Microfueler still? To do this correctly it should have a larger cat at the minimum, and I would make my setup work with larger nozzles, 4 of them.

Sasha

I would love to turbo charge my 1987 944. I am not a boost freak and would be willing to live with 5-7psi boost as long as I don't have to rebuild the engine. I would be willing to spend 1.5-2K on a comprehenisve bolt on kit as long as we can make it California Smog legal.

But, I do realize this is an ideal solution and may not ever come true...

I think, however, this solution will generate huge amount of interest among "cheaperer" 944 owners all over the US. The end result does not compare to a 951, but would give a little (20-40hp) more power for less than a used 951. That little extra will at least bring the car to today's average power levels...

As an example, there is a possibility to turbocharge an early 90s 1.8L Mitsubishi Eclipse from parts (intake, exhaust, intercooler and turbo) that can be found on junk yards from other cars (Dodge colt, mistubishi mirrage, ford probe). The end result yields around 40hp (brings the car's power from 90 to 130 HP at about 6psi boost), but it is relatively inxepensive and the car has an extra kick (which it needs really bad)...

I think a similar "know-how" or even a kit will be very profitable/fun/popular for all 944 owners...
Thanks.