Getting ahead start on this.

Anyone know the cc (volume) of the 2v 951 head and the cc of the 4 valve 968 head?

Gotta get some custom pistons made. Probably from a Chevy slug.

 

volume not area .
surly if you are running E85 your not fussy about compression ratios ?
are you putting a 968 head on ?

 

Not being fussy. Trying to KEEP the higher compression ratio. I have to have a custom Piston made for a high compression turbo motor. Not too many people asking for both of those at the same time.
there's the 968 Turbo piston that lowers compression for the 3.0 liter. Then de-stroke that to 2.5 and you get even less compression. NOT the direction I need. Forged NA 968 pistons won't do. Not enough meat above the wrist pin, or too short piston skirt, the common flaw of turbo-ing the stock 3.0 liter. Forged piston, but it won't handle the boost.

 

951 Head = 55cc Aprox.
968 Head = 41cc Aprox.
Hope this help.

 

951 heads range from 56 to 62cc.

 

Using a 2.5L crank with a 968T piston in a down-sleeved 968 block would be an extremely poor approach to lowering the static compression since the piston would be sitting down in the hole 4.55mm at TDC + the compressed thickness of the head gasket.


TonyG

 

I don't think he is trying to lower it if I read correctly.

 

Ahhh... sorry, you're correct. My bad.


TG

 

What sort of c/r are you aiming at Bruce? Also what sort of boost are you intending to use?

 

Good news. Thanks.

thank you. Any suggestions for me?

Correct. Not lower.. Raise!

 

As close to 11:1 as I can get. Will be running between 15 and 20 lbs of boost.

 

sleeve the engine and run a conventional aftermarket style piston which you can have configured to your specifications.


TonyG

 

Bruce .... You and I really are on the same page. High compression turbo engine .

Haven't looked at it too much yet myself, but while doing this maybe you can get a longer rod in there too. Especially since you will be most likely looking at custom slugs.

I wonder though, how much the offset pin (stock design) will change things.

That put me on hold when I was initially looking at "Chevying" my engine... then big boost happened and ...well you know .

 

will you please get you're *** to a dyno.

Only a handful of guys on this board are running e-85 and i'm dying to see what setups produce what numbers on it.

 

OT Sorry Bruce,

John, If I can find the time I will get there. I really am not too worried about it at this point though for a number of reasons.

1) as of right now I am not optimally setup ie:
a) too big of turbo for the boost I am currently running (graph would look stupid)
b) the head is minimally ported
c) ignition is randomly giving problems at over 23 psi (has been since the engine swap)

2) I've been working on a true twin scroll crossover pipe to use with a smaller turbine housing for quicker spoolup

3) I am just enjoying driving the car and not trying to kill it (If I go to the dyno most likely I would turn it up, just my nature)

4) I am focused on the car in my avatar, if I start fooling with my DD again it will again prolong the progress

5) dyno numbers are only for seeing the gains from last time to me. The correction factors and such leave the door open for disputes. See my last dyno thread and what has never been mentioned about another car's (prominent one) numbers including correction factors. To me, I have realized it's not worth the hassle of defending.


Honestly IMO, I haven't at this time made enough changes to warrant dyno time. Or to put it another way the setup is not exactly where I would like it to be to drive an hr to do it.

I am really just keeping myself in check here.

please excuse the OT