Ok, I know this is second grader-ish..but I just wanna make sure my info is right. High compression on a naturally aspirated engine is better to have right? And it takes better to upgrades, right? But for turbo and superchargers, you want a lower compression ratio right? Because... There's where I go blank. So..am I a freakin retard or do I know what I'm talking about...sort of... Lol.. Thanks.

-By the way..notice this is my 2nd post in the past 30 mins? I have nothing better to do...and it's Friday night..*** I'm a loser.

 

if you have too high of a compression ratio in your car then you can cause too much cyl pressure and start putting too much stress on your pistons, ring land, head, cause detonation or stuff like that as well


also you have static compression and dynamic compression

static compression what most compression ratios are based

these values or a just for instance but if you take a cyl that has a displacement of 10 ci and shrink it down to 1 ci then your compression ratio is 10:1

dynamic compression ratio is based on how much air you take in, your static compression ratio and **** like that

what a turbo,supercharger does is get that dynamic compression ratio up by shoving more air in the cyl

kinda like a motor that has a 5ci cyl that will compress to a 1ci means you have a 5:1compression motor
but b/c you have forced induction in there you shove 10ci of air into that motor and then compress it down to that same 1ci
you static compression is still 5:1 but the dynamic is now 10:1


I hope I am explaining this right


but there ya go

 

what RX7 said is true.

But this is barney style...
it all comes doen to how much PSI you want to run.
You want to run 5-6-7 PSi yeah a 9-10:1 engine can probly do it(I hope it can cause thats how much I am going to put into mine in a coupe weeks!)
You want to run 16-up get lower compression pistions or find some other way to lower the compression or else your gonna be prying your rods outta the street and finding nice melted pieces ao aluminum in your oil pan that are the reminates of your pistons...

So if you want to run 16+ go down to the 7's:1 in compression. If you have a 3.1 it actually pretty easy. Get the shorter stroke crank from a 2.8. The 2.8 actually had 2 cranks for it. 1 had a longer crank and lower comp pistons(I have been told) and another one had a shorter crank and higher comp pistions.

 

Ok, gotcha. So basically, what I was told by a worker at a speed shop that sold/installed turbos was a load of BS. He said my engine didn't have enough compression to handle a turbo! Not enough! What kind of compression am I running here? (Stock 3.1 liter) I could've sworn it was something like 10.4:1...but the tech data says it's 8.5:1. Thanks cam & rx7.

 

on your 9:1 as long as you have a good knock snsor on there and run least 92 octane, with a good boost retard you should be ok

I know you prolly do not want to spend more money then you have to but you should look into getting a haltech to work in your car

I am sure they have a kit you can use for it

this way rather then burning a prom anytim you want to change something you just hook it up to your laptop or somehow your PC and then can change things from there even when driving the car

VERY GOOD for tuning

if you want CHD I have a demo of the product you can look at to see how much stuff you can play with

 

That'll be cool to look at. Email it to me. In profile..

The 2 major things I am looking is spark curve and fuel map.. After all those are the only real things to really worry about. After I rebuild my motor to wish stand ALOT more PSI I will replace stock ignition with MSD, or the like, and put in a boost retard that will eliviate alot of problems before they appear. The watch as the 'Rocs fall.... Or until I twist my axle which ever happens first! Before I really get on that motor I need alot more suspension stuff...

 

you have aim right??
I thought I added your name to my list off one of your other post

if so just getonline sometime and I will pass it along

 

ok CHD I have a link here for ya

http://rx7speed.homestead.com/files/e6kDemo.zip

the file should only be about 700k I think

go for it and look at it