What is the max compression that you can run with a turbo. I understand that the higher compression the less boost and the lower compression the more boost. I am running 10.5:1 compression and would still lke to turbocharge the vehicle even at minimal amounts of boost. I posted on Neons.org and someone told me that there is a guy here running a Star Turbo Kit with 10.5:1 compression as well. Any help would be greatly appericiated.

you can run the highest compression you want, the thing is, the higher the comppresison, the less room for error you have (IE you blow your motor up easily if you don't tune it well)

Im running 20.3:1 :-) (Effective Compr. Ratio.)

sigh such little people know about turbo tuning. Everyone asks this question and they don't realize whats the whole picture here. You can run whatever compression you want so long as your block/internals can withstand it and you tune it so it won't detonate. Sure you can run more boost with a 8.6 setup on 91 octane than you can with a 10.5 . But your gonna have less lag with the 10.5 and possibly save more gas and have more torque. Just remember so long as you can feed it enough fuel and prevent detonation you'll be fine or keep from throwin rods and blasting your pistons.

Do you guys have any suggestions on what I will need to prepare for a turbo? Will I need larger injectors/fuel pump/FPR/SAFC? Much appericiated for the responses.

Bump

Check the main page under turbo section we have a link to a discussion about high compression and turbo.

I would not lower compression to turbo. It is safer and there is more room for error. But we have a well designed motor, with the proper fuel system, proper timing and tuning, you can run a 12.5:1 with a turbo and be making good power. For power I say high compression and turbo is the best way to go. A good street set up in my opinion would be 10.5:1.

****The key**** TUNING!!! You have to tune it properly, with higher compression and turbo there is a smaller margin for error, and a greater need to pay close attention to your motor and any changes.

10.5:1 and turbo is very do-able. And Stan has done it here for quite a while.

Una salus victus.
He will triumph, who knows when to fight, and when not to fight. - Sun Tzu

Michael J. Kulaga
e-mail: Michael_97RS@2gntDSM.zzn.com aol IM: MJKulga
http://highlander.dsmpower.com/

All motor in the making.

Injen CAI, 55mm TB, P&P Intake Manifold, Crower Stage 2 Cams, Hooker Header, GS-T Muffler, AFX UDP, S-AFC, 8.5mm Magnecor Wires, Crane Fireball HI-6DI2, FU/RU/RL STBs, TSW Blade 17x7.5, Bridgestone Potenza RE730, Front KVR Cross-Drilled Rotors & Carbon Fiber Pads

To Be Installed: P&P Milled Head, Rear Disc Brakes, Rear KVR Cross Drilled Rotors & Carbon Fiber Kevlar Pads, SS Brake Lines

Heh, I'm of a different school of thought. (sorry Mike! :-) )

I would go with no higher than 9.0:1 CR with a straight street turbo setup. Using shitty street level octane even as high as 93 octane and boosting levels as high as 15 psi, the level for error is too small. And in any case, even if tuning were as easy as it sounds, (and it isn't at all), you only get 4% more power for a full one compression point. Compare that to one psi, which is closer to 8-9% depending on turbo size, and you can quickly realize the superior worth of upping the boost versus upping the CR.

Now, if you've got the resources of a dyno (with wideband O2 sensor), and a shop to back you for any tuning mishaps, and the importance of eeking out ever ounce of power you can is of the higher priority, it makes total sense to have a relatively higher CR'ed (+10:1) car with turbo.

However, if you're with the normal turbo masses who only need less than 500 HP to have their HP tastes satiated, then a CR closer to 8.5 to 9:1 makes a whole lot more sense to me.

...And one more thing, there was a guy here who was boosting higher amounts(10+ psi) on forged +10:1 CR internals, and his engine is no longer with us. I thin khe found out that his CR was a bit higher than even 10.5:1, but in any case, instances of people with forged internals blowing are REALLY rare. His is about only one of two cases I have ever heard of someone having their upgraded engine detonate. Both cases I had heard about are in fact people with CR's higher than 9.0:1. I think the results speak for themselves.

I'm aware my opinion varyies from yours Jason (and most other in this section :-)) I think Stan had other problems besides being high compression.

I did say that it is more difficult, it is not the easiest solution. But especially being 10.5:1 already I wouldn't suggest a rebuild with lower compression. I will not even attempt to argue that lower compression on a turbo kit is not easier. But with modern day fuel systems and our well designed engine it is possible.

Una salus victus.
He will triumph, who knows when to fight, and when not to fight. - Sun Tzu

Michael J. Kulaga
e-mail: Michael_97RS@2gntDSM.zzn.com aol IM: MJKulga
http://highlander.dsmpower.com/

All motor in the making.

Injen CAI, 55mm TB, P&P Intake Manifold, Crower Stage 2 Cams, Hooker Header, GS-T Muffler, AFX UDP, S-AFC, 8.5mm Magnecor Wires, Crane Fireball HI-6DI2, FU/RU/RL STBs, TSW Blade 17x7.5, Bridgestone Potenza RE730, Front KVR Cross-Drilled Rotors & Carbon Fiber Pads

To Be Installed: P&P Milled Head, Rear Disc Brakes, Rear KVR Cross Drilled Rotors & Carbon Fiber Kevlar Pads, SS Brake Lines

10:5:1 is high enough. Turns out Vinny (Kiku) was sent 12:5:1 pistons and he just blew w/in the last month. I saw his setup, labtop and all so unless you got a lot of $ and know how to tune a car Id just stick w/ 10:5:1 or lower compression to be safe. Think whenever I do rebuild, if I do, Ill stick w/ stock forged pistons.
-Dave