38927

I was just wondering. I would assume the 16v engine should beable to handle 4-5 psi w/ stock 951 engine managment including all essentials (turbo, intercooler, ecu, ect..)

On the other hand, i was thinking maybe a supercharged option might suite my need for more power. I would just want 7-8 psi delivered considering its an S motor and the knock might cause problems.

I really dont want too much hp since im getting older (lol 26 "I am old!") I just would like to put 200 or so hp to the wheels I wanna be able to get up and go when I need too.

I know there are gonna be a few of you that dont see this as a good idea. I still wanted to throw this out there to see what everyone would say before i start collecting parts.

-james

V2Rocket

youd have to come up with your own intake and exhaust manifolds for starters, as the turbo units wont work on an S engine.

in addition the S has such a high compression that tuning would be a nightmare...the S engine has automatic knock retarding and would suck away almost all the power you could potentially gain from boost.

i dont know what turbo youd use to only push 5 psi...

now the S head on a turbo block might be a different story, but again youd have to come up with your own manifolds.

38927

yeah your abosulutely right. however, what if I where too thicken up the headgasket to lower the compression a bit allowing a bit more boost.

I was thinking along the lines of a stock 951 turbo charger.

I do understand im gonna need some custom intake and exhaust manifold work for this all to work, but with mega squirt I dont think its something that a bit of time couldnt work out.

V2Rocket

thicker headgasket IMO is a bad idea, because that seriously alters the combustion chamber and can actually cause more knock because the flame front doesnt travel as well anymore.

youd want to do a build on that motor to get anything effective out of it; maybe try to modify the stock pistons to be lower compression (bowls ala the 951) or just put 951 pistons in it...a low-compression, high-boost motor will make more power than a high-compression, low-boost motor every day of the week. the only advantage to a high-compression motor is that it is capable of spooling up the turbo faster which reduces lag.

with a turbo youd be seriously underworking that turbine. if you were only to run that low of boost pressure youd want a smaller turbo, rather than consistently dumping off the K26.

alxdgr8

Since you have to make custom manifolds then I would stay very far away from KKK turbos...they are old and outdated. So many better options. A GT25 would probably perform great and would spool very quickly.

What's the comp ration on the S's?

38927

alxdgr8 944s' have a compression ratio of 10.9 (according to : http://www.petting-zoo.net/~gkm/944.html).

I would assume as long as the cr is down to atleast 10.1, the motor should hold up quite fine.

I agree a smaller turbo would be a good option along in addition to the kkk turbos being outdated. how is the GT25 in comparions of the 951's kkk in the terms of overall output?

-James

V2Rocket

yes, S's have 10.9:1 compression. not saying it cant be done but 5psi with that much compression is reaching the limits of regular pump gas. you could go with E85 if you want, several turbo guys have done this successfully with no ill effects and one of those guys is even running up to 35psi on his turbo motor (albeit with 8:1 compression).

like i said before, the thick headgasket idea has been explored in the past and has been troublesome.

no matter what you will need a very, very good and high-flowing fuel system and a very good intercooler for any level of boost at this CR.

Lorax

You could do more than 5 PSI.. turbocharging the "S" motor is what I have been trying to do for the last 6 months.

Buy an S motor, swap in turbo rods, and run e-85. The "S" head flows as well as the very best high $$$ 8v heads, and you can rev the hell out of it comparatively.

Don't bother putting the turbo in the factory spot, place it somewhere else and have someone frankenstein an intake for you.

Lorax

too small... gt30x would be better. With the S motor you can get mre rev's and afford to run a bit laggier of a turbo.

38927

could someone please clarify what E85 is for me. Im a bit confused. Some type of high flow fuel system i assume...

V2Rocket

sorry for any confusion, my knowledge of PSI/pump gas is based off my CA knowledge where we only get 91

93 might be able to handle a bit more.

85% ethanol, 15% gasoline.

Lorax

It's a widely available ethanol/gasoline mix.

Cheaper than gas, and around 108 octane depending on the time of year and where you are.

Lorax

well, I run 20-21psi on pump in my car, my recommendations might not suit everyone

38927

hmm.. so how realistic would it be to swap in the turbo rods. and if so are they a direct fit?

Lorax

Direct fit. They are forged and much stronger than the normal rods.

Personally I want a high compression turbo motor, but you could also swap in turbo pistons... People will tell you that the valves won't clear but I have heard people say they will also. I think they would, but I won't know till I can actually find a 944S head/motor.

Turbo rods are very cheap and strong.