Leonov

Can someone give me the specifics on the turbo system on the 944 turbo car?
How much pressure does the system need to properly cool the turbo?, how much boost can the stock K26 turbo handle?, anybody have any experiance with cometic gaskets? Large Oil cooler vs Factory?, K27, K26, or a T3/T4?

Stephencs601

I have a highly modified turbo. I went with a garrett rebuilt to handle higher boost and quicker spooling, 4" exhaust, upgraded head gaskit, Mtune, venturi delete, M030 suspension, and a lot more. I keep boost anywhere from 15 lbs to 19 lbs. The stock oil cooler works fine. The bigger the turbo, to longer the spool up. I also used the stock turbo cooler, it work well and do not forget to let car idle before shutdown to cooll turbo.

Dougs951S

The stock turbo in our cars is both water and oil cooled. As long as your oil and water temps are ok, so is your turbo temp. To that end, typical pressure in the cooling system is 16 psi. The stock #6 housing is restrictive, you really wouldn't want to run more than 17-18 psi on it because beyond that you're just pushing hot air. The cometic gasket is nice and probably seals the best, but is overkill for a stock of mildly modified car. If you are tracking the car, get a better oil cooler but the factory piece is enough for the street. If you are looking for a power upgrade, a k27 can make good power, but a garrret/KKK hybrid will probably be better if you don't mind paying for it. A full garret will not bolt to the stock exhaust which adds more money or fab work to fitting one. That being said, the garret hotside is definitely an improvement over the KKK so you decide what thats worth to you. Leave a k26 alone if you're looking to replace the turbo for any reason, there are hybrid turbos that will make much better power and spool up nearly as well as the stock piece. A 46 trim T04E comes to mind in that regard.

Leonov

I learn something new about these cars every day.
How is it piped to be cooled on oil and water?
Im thinking of beefing up my NAs block to handle ~10lbs of boost max.(Forged internals, Better head studs, NA-tune) What else would have to be done to an N/A block to handle a turbo?(Expecting the "Buy a Turbo, Its not worth it" replies.)

Dougs951S

Sell the N/A and buy a turbo. This has been covered 1000x over, its just not worth the money. Unless you can fabricate and happen to have a wrecked 951 to simply do a complete swap and I mean exhaust, motor, intake, fuel rail and injectors, fuel pump, transmission, clutch, brake booster, master cylinder, DME, AFM, tons of other sensors, cooling system, brakes, suspension, tons of other little small things, oil cooler, EVERYTHING, it simply isnt worth it. The turbo cars have so many upgrades compared to the n/a cars they are almost like two different platforms and it isnt just a case of "beefing" the motor up to handle some boost, slapping a turbo on it and calling it a 951. You'll spend 10 grand on your N/A just to produce what the factory already did a damn fine job of and have it be reliable.

Leonov

Expecting that kind of reply. I guess ill stick with my N/A.

Dougs951S

If you really want more power I would look into supercharging it. This is easier than turbocharging but even if you go absolute cheapest route you are looking at needing at a bare minimum: a supercharger, 944 turbo injectors, 944 turbo DME, a solid MAF conversion so you can tune the damn thing, deleting your AC and relocating your alternator, all the brackets you'll have to make yourself to mount everything, the proper sized belts to run everything after its all been shifted around and installed, possible mods to the throttle linkage may also be required and this is not even going through the hassle of installing a 944 turbo intercooler which will severely limit max boost so i consider an intercooler required, else there isnt much point in going this route in the first place. Then when all is said and done you have a car that you've invested more cash into than the car is worth, and it still has the brakes and suspension of a N/A. You will also need a beefier clutch at this point as the stock N/A clutch starts to slip at around 200 ft lbs of torque.

Reimu

You can get all the exhaust stuff from a turbo part out for cheap. I kind of wish I would have done a "high compression" turbo motor with the early forged internals of the n/a car with the lower compression. That with an M-tune and what not would be neat and the near instant power would be nice with a proper turbo.

Sure you wouldn't be breaking into insane power but its more than enough to have fun on curvy roads or autox.

Leonov

This is the kind of reply i like. Im not trying to make a 944, a 951. That i know/realise is impossible. That being said using the knowledgebase this forum provides can solve some of the short comings in a N/a to turbo setup. IIRC, The guys at Rouge tuning had a turboed N/a. It didnt last long because the ~15lbs of boost was to much, so keeping the Boost low, Beefing up the internals and fuel system would be the way to go. I acctully aquired a k26 turbo a while ago and some piping and have been tinkering with it. The problem that came to me was cooling the turbo. Ive yet to understand how the cooling system can be Oil and Water cooled. How are they seperated after exiting the bearings?

dirtyTurbo

I'm with Reimu, I don't think selling your car and buying a turbo is the best way to go 100% of the time. I've looked into turbocharging my n/a quite a few times now but I've never gone through with it because I have a 951 and plenty of other projects. As far as I'm concerned there's only a few hundred dollars that need to be spent on used 951 stuff(exhaust, intake, motor mount support). Of course it's no afternoon bolt on affair, but it's no where near as impossible as most of the people on here make it out to be. Off the top of my head:
Early cars header panels are welded on and need to be modified to take a 951 intercooler.
Engine management might be a pain if you don't want to go with stock 951 computers(which I wouldn't)
Oil pan would have to be swapped for a turbo one for the turbo oil drain.
It would probably be a good idea to go with an air cooled oil cooler from a turbo car

It wouldn't take much to get a basic +turbo project driving, but as said before it still wouldn't be a 951.

Leonov

So instead of going the route of a late model DME with NA tune, Use a Turbo DME with something like M-tune?

Reimu

Yeah, you'll want a turbo DME/KLR

People here always say to just sell and buy a 951 but really it depends on what you want, it isn't always the answer. Most of the 951s out there have worn out components that people here replace anyway- Sure the turbo suspension is better but you'll be replacing it as it'll be pretty much shot. Many 951 guys have to buy and swap in LSDs and this leaves turbo open transaxles $400 and down if you're worried about blowing up the n/a one. Which is funny because lots of kitcar guys with big mid engined V8s seem to get by on the wee n/a R&P better than we do...

If you want a nice looking properly matched 951 then sure sell the n/a and buy one. I bought a turbo S motor for $1200 and rebuilt it, upgraded all of the usual stuff that gets thrown out anyway, and bought a 951 trans for $75. The only real issue here is the bodywork which you can work around anyway with a little ingenuity. I could have sold my car and bought a cheaper 951 but it would've been a lot slower than my "n/a" currently is.

Leonov

Im planning on reinforcing my R&P, Cryogenics and a better backing plate probably. Fitting in something like a Stage 5 Header Panel from LR would be on the list. Stock intercooler should fit and work fine. An Engine builder im talking to thinks 9.5:1 compression is workable, so a thicker cometic gasket would lower it around that point. Im thinking <=10lbs of boost would be enough to not kill the motor and still have some fun.

odurandina

very informative thread.... i have nothing useful to add to this conversation, and i wouldn't want to infringe.... and i realize the guys might find it annoying if i bring this up.... but i now know that our engines are very accepting of $32~$120 gasket sealers.... so, by the same logic, gasket failure might be wholely preventable by adding right stuff to the coolant mix before a big hole develops. with 25 years of coolant eating throuth them, it's worth serious consideration..... and if you have a Range Rover.

oh, and the reason for my post;

i'm of the opinion that Shamrock Shakes should be permanently on the Mac menu.

Dougs951S

Don't bet on that cryo treated R&P to last long under turbo torque. Not trying to burst your bubble as I wanted to turbo my N/A as well, but I also wanted a balanced car, not a n/a with a turbo slapped on so I got a 951.

That being said, yes a driving turbocharged N/A can be done "cheaply" as long as you understand the limitations of what your are attempting. Sorry for my somewhat canned response, but most people who ask that question dont understand what they are asking and want to turn a 944 into a 951 by slapping on a 300 dollar ebay turbo and calling it done.

The clutch WILL have to be replaced, and you can bet on needing some wider rims and tires because the torque combined with the short gear ratios of the N/A box and lack of LSD( if you really decide to attempt using it ) and lower weight of the N/A car will ensure you get a ton of wheel hop.

Bare minimum to get a "drivable" turbo swap using the N/A block will be turbo oil pan, 951 exhaust bits and wastegate, clutch, 951 dme + klr, 951 fuel injectors and fuel rail, intercooler and boost pipes, 951 Idle control valve, manual boost controller, 951 intake manifold and throttle body with linkage and TPS, 951 coolant tank, water crossover pipe along with all the water hoses and pipes if you wanted to use a water cooled turbo like the factory did, all the oil lines and fittings for the turbo, plus you'll need a way to tune it and with the high compression that puts standard chips burned for the AFM out the window so you will need an M-tune MAF and special custom maps, and I'm sure there are other things I am not taking into account. That is an absolute bare bones minimum just so the car will start and run. I know you don't want to hear it, but much more goes into it than some people would have you believe.

Best case scenario I could see you pulling all this from a 951 part out and getting everything you need including the M tune for MAYBE 2k. You will likely spend more than that and that is assuming you do all the work yourself.

Is your car a euro spec or a us spec? The US cars have 9.5:1 compression while the euro cars have 10.6:1. An american spec car would be better suited to this. Even on 9.5:1, using the stock k26 don't expect much more than ~200 whp.

You would be much better off and cheaper to simply swap in a complete turn key 951 engine and exhaust.


to answer your question, the turbo of course is oil cooled in the sense that it has a constant flow of oil coming into it. This flow of oil is pre-oil filter. The stock turbo also has a water jacket cast into the turbo housing that is separate from the oil passages, and this is fed via a water crossover line this sits above the headers via the car's belt driven water pump. the stock system also uses a small, separate electric water pump activated by a temp switch to force extra water through the cooling jackets as needed, as well as when the car is shut down to prevent oil coking in the bearings from heat soak.