high compression turbo setup

[quickcivic]

Hi guys! I am currenttly rebuilding an d16y7, and i read somwhere about
using the pm7 pistions from a zc. thougt i might give it a go since ive got them in the basement. i know i will bump the compression up to 12.35 or in the vincinity.
for the turbo i thought low boost maby 4-5 psi.
this setup will be under control of a turbosmart T-reg street fuel prssure regulator.
and an kenji`z ecu ready for installation for hondata 200.
planning to buy an intercooler and build 2.5" stainless exhaust complete
system.
I will also do the dpfi to mpfi with the d16y8 manifoil.
I will probely get hold of en external wastgate of some sort.
50 mm tial bow is already bougt.
i have done some diy clean up of the ports.
shoud i go for stronger rods?
or even stronger pistions?

the turbo is an homemde hybrid i like to call a t25-t3. it`s an ford transit diesel turbo mated to a t25 taken from nissan cherry turbo.
I used the center section from the diesel icluding turbinewheel and compressorwheel and the turbinhousingfrom the t25. it is milled out too make room for the turbinewheel. I will be using the y7 header since it is as small as it is. Only worry there is the small runners, will probably build me an better stainless in the future bigger whith runners

Is this an impossible task or safe?

[Printz]

I'd like to see how that turbo does.

[ryan89crx]

high comp OEM parts + turbo is a bad combination.

better have yourself a DAMN GOOD tuner. honestly, i wouldnt even bother if it were my setup

[NEP-tuningalltheway]

might last a couple days, if you do this get some good rods and aftermarket high comp pistons if you want and give it a shot DONT USE THE FMU and run neptune or crome and you better have one hell of a tuner like cortney green or someone

[98_4drCivic]

You may have issues keeping the bottom end together...but I will tell you from experience, the throttle response and part throttle power is AMAZING on a high compression turbo setup. If you're planning on doing any sort of track events (roadcourse, or AutoX) that would be the perfect setup, provided the bottom end doesn't take a shit :lol:

[Slowhatch]

x2 for what everyone said. tuning is going to be a bitch and will take a lot of dyno time, if you dont put a hole in the piston before you get done tuning.

[csaddict]

Thats gonna build huge heat and detination will own you, tuned or not.

[gpny]

I have 10:1 (220-230 comp) JE Forged pistons and 15PSI... I make 275hp. I dont turn up the boost because I want to avoid any detonnation.
You should stay in the 9:1 range if you boost, you'll be happier in the long run...
Yes, high comp + boost is fun, but if I had gone to a 9:1 piston, i'd be pushing 20-25psi on pump gas and more than 325hp with less worry of detonation.

[Clutchmaster]

Yeah high comp + turbo= boom......

[jungldbll]

Def way too high. Lower it down some and boost it more. I'm going with a 10.5:1 with about 12-15psi and I think that is a tad too high.

[jimmyb34]

rexinre had 10.5 comp i believe and running 15 ish psi.. if im not mistaken he had a problem with blowing out headgaskets

[lsturbohatch10]

if you have jeff evans as your tuner. then go for it, but not with pm7s or p29s cause ive read they have weak ringlands. im interested in seeing how that turbo does as well...

[SOHC_STUDENT]

If you can pull it off high comp + turbo is awesome. Low boost delay, lotsa power.

HOWEVER, like the others said you need a perfect tune from RPM 1.
http://sdsefi.com/meltdown.htm

I'll try and find a link to the 11comp 5psi D15 I was reading about a while back...

[kyle h.]

do it.

I'd try to bring the compression down to 12 or high 11s with a thicker headgasket.

[builthatch]

i like high compression turbo setups. 11:1+ with a few lbs of boost can offer you instant spool up and a nice relatively flat curve.

ask guys who have boosted ITR's....it's very fun.

low compression with big boost can be very similar in overall power production to high compression with low boost; cylinder pressure is the name of the game. you can get very high cylinder pressure with the second setup with relatively low boost.

many factors can come into play here tho- traction issues can be magnified if you do not set the car up correctly. but the response can be similar to a roots blower but with no parasitic drag from a blower belt. intake air and cylinder temps are critical- traditional intercooling coupled with misting is ideal. cylinder sealing is of the utmost importance- properly decking, head studs, possibly o-ringing (the right way, with wire AND head grooves). Good rings, good FORGED pistons, strong rods, properly clearanced bottom end, etc etc etc...

most cast pistons will not work very long with this, esp. pm7/p29. the ring lands are so thin and high it's asking for an instant disaster

the margin of error in a build becomes minute when you do a setup like this, similar, again, to when you build a big boost low CR engine, but the rewards can be great, esp. for a street car.

[ryan89crx]

rexinre had 10.5 comp i believe and running 15 ish psi.. if im not mistaken he had a problem with blowing out headgasketshe also was running forged internals.

the OP is talking about OEM parts...

[jimmyb34]

in that case i wouldnt do it.. youll probably blow the rings pretty quick on oem pistons with that high of comp

[jgredline]

Hello
I agree with Ryan89crx
Don't do it. We don't even run that high a comp on our race engines.
We have a full race D16Z6 running 45 psi of boost on methanol and are at 10.0 comp. In street engines, if anything we have found that 8.5 runs better. Heat is an enemy to any turbo engine. Heck its hard enough to run that kind of compression ratio on an all motor car on pump gas let alone a turbo charger.
good luck with your project
Javier

[all_rice]

so you guys think 10:1 is OK?? Or should it be lowered via a thicker head gasket??

[gpny]

so you guys think 10:1 is OK?? Or should it be lowered via a thicker head gasket??

I have 10:1 (220-230 comp) JE Forged pistons and 15PSI... I make 275hp. I dont turn up the boost because I want to avoid any detonnation.
You should stay in the 9:1 range if you boost, you'll be happier in the long run...
Yes, high comp + boost is fun, but if I had gone to a 9:1 piston, i'd be pushing 20-25psi on pump gas and more than 325hp with less worry of detonation.

[98_4drCivic]

i like high compression turbo setups. 11:1+ with a few lbs of boost can offer you instant spool up and a nice relatively flat curve.

ask guys who have boosted ITR's....it's very fun.

low compression with big boost can be very similar in overall power production to high compression with low boost; cylinder pressure is the name of the game. you can get very high cylinder pressure with the second setup with relatively low boost.

many factors can come into play here tho- traction issues can be magnified if you do not set the car up correctly. but the response can be similar to a roots blower but with no parasitic drag from a blower belt. intake air and cylinder temps are critical- traditional intercooling coupled with misting is ideal. cylinder sealing is of the utmost importance- properly decking, head studs, possibly o-ringing (the right way, with wire AND head grooves). Good rings, good FORGED pistons, strong rods, properly clearanced bottom end, etc etc etc...

most cast pistons will not work very long with this, esp. pm7/p29. the ring lands are so thin and high it's asking for an instant disaster

the margin of error in a build becomes minute when you do a setup like this, similar, again, to when you build a big boost low CR engine, but the rewards can be great, esp. for a street car.

That is the best post in this thread.


It really depends on what you're building your car for. High comp. + boost if you want it to spool rediculously fast (road course, or AutoX). If you just want to make a lot of power and go in a straight line, low compression + lots of boost. In a sense, boost and compression are very similar. They both make power for the same reason; There's more air and fuel into less space. As quoted, cylinder pressure is the name of the game, which can be aquired in more than one way.

As for the bottom end, if you only plan on running REALLY low boost, it could hold together....but I wouldn't count on it. If you have a spare motor laying around, and you aren't worried about blowing that one up, try it :lol:

[all_rice]

whooops thanks man

[Dweezil]

Just talking about ITR's and boost, here's a guy on a couple local message boards:

http://ffdet.com/members/jan/intro.html

[all_rice]

Just talking about ITR's and boost, here's a guy on a couple local message boards:

http://ffdet.com/members/jan/intro.html

Nice 295hp on 10psi.

[quickcivic]

thanks for all the reply guys. i think id better leave this project alone. and save my money on some good forged parts. just want too get boosted again.
the tiny little d15 just dont cut it. better work extra so i can order those parts. maby ill do it too the little d15 insted. or just turbo it as it is for now.