jakub2000

Hi Guys,

I haven't followed up the forum for over 3 months and came back for more info=power.

Currently I do not use any head gasket and run 8psi with th LoveFab Vers.1 GT3071R

Here my calculation:

CR 11:1 Boost 8psi Effective CR 16.98

I heard that this works:

CR 9.83 (2mm HG) with 14psi of bost..this results in a ECR of 19.19

Now the big question is:

Can I run 10psi on 11:1 what results in only 18.48ECR what is lower than the one stated above (2mm+14psi) or is the benefit of a lower static CR due to the 2mm headgasket really a "magical" plus that allows you to run a higher effective CR?

I like how a high CR engine responds to the throttle input and would like to keep this "feature"..

Please give me some feedback on WHY this should or should not blow my engine

S2000_Europe

sideways is runing almost one bar, but dropped CR to 10:1 though. I think jwkim is runing one bar too with stock compression

jakub2000

^ Sideways is running a SC and dropped the CR. What does that have to do with my question of running 10psi on stock CR and with a turbo???

S2000_Europe

well..... 10 psi is 10psi it does not matter if it is turbo or SC. There are tons of 9 psi blowed engine with stock compression running in this forum.


Sideways is running one bar, 14.7 psi, with a 10.3 CR, lower than stock because the head job, he could help you in your question, since 14,7 psi and 10,3 CR is more agressive than your proposition, so PM him and will help you or maybe he will chime here soon



I was trying to help you so do not be rude

Scorpion

Boost is not boost. 9psi out of a t25 will not be the same as 9psi out of a GT35. Also with an SC you are taxing the motor for a second at 9000rpm, on a turbo you are making it suffer through the rpm range.

With that being said, I don't see why you can't run 10psi. I know of a guy that ran 30psi on a stock motor with stock headgasket (f20c though it wasn't in a S2000). He did eventually crank a cylinder wall, but I think there was like 5000 miles on the car at that point. And notice I said it was the wall, the piston, rods, and crank handled it fine.

John_Z

Boost is boost period. The point is with turbo the XXpsi comes in much earlier in the powerband like 4000rpm and stays at XXpsi all the way until redline as opposed to SC which puts it out at redline.

jakub2000

S2000 Europe don't get me wrong, but I expect feedback here from people that DO know what they are talking about. My car is boosting 8psi from 3900 to 9200rpm, a SC is seeing 8psi with a smaller pulley for those last few hundred RPMs...you had them both (SC and Turbo) so how can you come up with that BS.


Scorpion thanks for the feedback, I plan on doing more than 5000miles on the car, but knowing that the internals are ready for it is a good thing to know.

I am now thinking about 2 ways to go:

1. Get a boost controler (that GM selenoid is a bitch to solve out) and make a 10psi map for those "eat or get eaten" moments, while still keeping the CR stock (great rhrottle response, more WHP per psi ect.) and 8psi daily basis.

2. Pull the trigger&the head, get it done by Earl (port&polish bla bla), slam in a 2mm headgasket (if I get the FINAL answer if it finally works or not) and boost the living $hit out of it.(14psi)

My only concerns about plan 2 are:

1.Horror stories about 2mm HG and leakage of coolant
2. Un-driveability due to lower CR (off boost response) and wheel spin
3.I will kill my self
4.Have to change MAp sensor (what needs to be done with it?)

A question for those who KNOW:

Will a GT3070R push 14psi on a 9.83CR motor at 3800rpm as it does push the current 8psi on the stock CR? Or wil the spool up/full boost be affected?

jakub2000

please stop

Scorpion

NO it's not. Let's take a look at these two compressor maps.



Now say you are running 14psi of boost making around 350hp. Basic math says you'd need 35lbs of air (10hp per lbs of air). Look at the efficantcy lines, the first map shows you at around 68% where the second map is around 80%. What's that mean? Cooler, densor air coming out of the second charger. If you don't think that has an effect on combustion you need to trade your car in on a Saturn.

John_Z

^Point well made. I was trying to make a generalization that turbos make boost earlier and longer compared to SC's which only put out peak boost at redline.