Thicker HG theory Please Read

[ForcedFirebird]

Not to mention when using thicker gaskets, quench is compromised.

People are under the notion that you NEED lower compression to boost a motor, which isn't entirely true. When under boost you are effectively raising the compression ratio, so with higher compression comes lower boost.

I know people who (mildly) boosted a 9.6:1 motor, only to go with thinner head gaskets to get as close to 10:1 as possible with good results (actually I see 13second 3l engines with 400+ hp).

My Firebird (3.1l) has 8.9:1 now and with my new engine combination, I will be at 9.7:1 ;). With 6psig I'm seeing 275hp and went from low 17's (stock) to low 14's in the quarter. And this engine is consevative until I get some larger injectors (currently 24# Denso), but when the higher compression engine is finished, I can let you know the results.

[Borat]

The way I understand it...

--I understand a thicker HG adds displacement, thus more room for compressed air, but come on it cant be adding that much room to create a HUGE difference.

Displacement is a function of bore, stroke, an cylinders. Combustion chamber volume has nothing to do with it.

Even if compression was the same the engine at 15psi still has an extra 20% (approx) of oxygen in the cylinders, so there can be a bigger bang.

While lowering the c/r allows you to run more boost, the aim is to make power, not boost so a compromise has to be found.

Also, (This is where I get lost) a thicker HG can muck up the combustion chamber shape, or quench, which could result in detonation if its extreme enough. Camshaft timing is also affected with changes in HG thickness.

[backtrail69]

The only reason I see that people run a thicker HG is if the compression ratio is already extremely high and they are trying to drop it down in favor or less detonation and easier tuning.

[nholm325e]

The whole concept of a "thicker" HG doesent make much sense to me. It seems like your taking 3 steps back just to take 5 steps forward. i know what your thinkin please read on.

**Please dont get caught up in the actual numbers im making up(their just examples), im refering more to the concept or "theory" of things...

Using thicker HG will lower the compresssion of the engine, but if you lower your stock compression, your motor will obviously be underpowered until you can reach boost. So your underpowered from say idle-4K rpm.

So say you have a 2 engines, one with stock compression boosting 10psi, then you have another engine with a thicker HG boosting 15psi,(they have equal compression when their at their full boost levels) wouldnt it take the engines the same amount of "time" to get from say 0-100mph(thats all i care about).
**HP and Torque numbers dont mean a thing, the actual amount of time it takes you to get your car from one speed to another speed is the only thing that matters.

I see people use the thicker HG and boost say 15psi, if they just kept the stock HG size and boosted say 10psi, wouldnt it be the same??

--I understand a thicker HG adds displacement, thus more room for compressed air, but come on it cant be adding that much room to create a HUGE difference.

Please i would like to see your point of view on this "concept" becuase so far it seems like you should just put your $$ somewhere else for power gains...