Hey my friend 1ftss is running 10:1 compression pistons and that thing hauls ass now and he is running pumped gas like 93

 

It was because of way to much of that type of attitude, that I choose to no longer participate on the redlineforums.

 

Blown.. I'm leaving for tempe on thursday.


How much boost is he running and i imagine he's using the stock eaton. If i tried to run 10:1 and 20psi from a 1.6L whipple on shitty az 91 octane the engine would explode within minutes.

 

lol, your funny

obtw, would you kinda point me in the direction of a post where I say I HAVE 300whp, I'm roundabouts but never said 100% that I was anything beside what my last dyno said and that was with a 2.7", no timing & a 10.4 A/F so me saying I have more than I did then is more than acceptable.

Also, your blower porting is asinine

 

I try to be.

 

You *MAY* be able to get away with 94 octane using 10.5 pictons, but you will have to run stock boost or less to avoid getting knock though.

 

stick with stock compression or lower and go turbo... best way to make power plain and simple on the these motors.... no arguments about it. Unless you want to stay s/c'd... then well... we've had this argument before.

 

whats the stock LSJ compression ratio?

 

I believe 9.5:1

 

We dont know he is waiting for it to get tuned so as he does i am sure he will post a thread on here about it

 

You are correct. The pistons are a Mahle hypereutectic alloy.

You can get away running 14:1 pistons it just depends on how much boost you wanna run.

 

Also timing.

You are going to run into ignition trouble with too much compression. Richer than rich best torque and high compression and you substantially increase your chances of spark issues.

 

Which in that case would be zero. Not even race cars use that high compression with boost. The 1450 hp ecotec motor uses 10.8:1 compression and over 50 psi boost. Top fuel motors run a whopping 7.5:1 compression and 45 psi boost!

 

ALL my mods in my garage....please look before responding..........

sooooooo.... I just got the 10.5:1 with all coating for a good deal... a really good deal .

NOW my problem is I can only get 91 octane. Should I lower my comprerssion? I plan on starting with about 10psi. Then get the fuel and spark right. From there I'll adjust boost/fuel/spark accordingly.

My HG is the last thing to get before the engine goes back together......I could really use the imput....thanks

 

IMO, you really need to see what the cams you plan on running do for your effective compression and compensate with higher static compression pistons.

If you have too high of an effective compression you may run into spark blowout issues and might have to upgrade your ignition system. I increased my static compressiojn to 10-1 myself and my 272 cams brought my effective compression right back down to stock levels. However, increasing redline to 8k rpms brought forth new spark issues that I have solved by increasing spark dwell time, however its at a cost of significantly decreased coil life span.

All in all, its a pain in the ass no matter what you do. I'm sure no matter what, you can solve the problems with a little bit of tuning.

 

JBP don't give out there Stage 2 cam specs...... ..what do I do now???

 

Somewhere I saw a few specs listed, maybe in their old group buy thread. Try to call them and bug them, I'm sure they will give them up over the phone.

Here's what I found, everything except the lobe seperation angle, I would probably ignore the secondary intake specs as they are "milder" then the primaries, but I'm no expert in this:

PRIMARY INTAKE
ADV
264* 418L
@.050
209*

SECONDARY INTAKE
ADV
256* 417L
@.050
202*


PRIMARY EXHAUST
ADV
256* 417L
@.050
202*

 

With 91 octane, you will not be able to run boost. That compression ratio is way way to high for any kind of boost with THAT shitty gas.

 

Witt.....I think that is for their Stage 1 cams...but IDK.....I'll call them

4-banger......so should I get the .040 HG? That should yeald me around 10.0:1

 

Lowering compression with the head gasket is never a good idea, because it messes with the quench of the piston and deck. You can do it that way, but you may have problems with knock.

 

and the timing chain

 

I don't think an extra .17 inch would do much to the timing chain, but it definatly could as well

 

I had the .040 on there last time....that's all cometic made at the time. The timing chain fit fine. I don't understand how a thicker HG produces knock. Little info please.

 

Some engines have quench style pistons and heads. Ecotecs are not that type. No more than .045" clearance is needed for proper quench, something the Ecotec lacks.

 

^^ so increasing the HG thickness won't screw up my build? I think I'm going to go with the .040" HG anyways.

This is going to sound dumb but.......I have to ask:

could I add octane booster to increase octane levels so that I can run 10.5:1 w/ a .027"??