I was curious about the need for better flowing heads and intake if you are running turbos. If the engine is not as reliant on it's own naturally aspirated ability to suck in air, if the air is actually getting force fed into the engine, do you still need a good aftermarket intake and heads?

It would seem to me that unless the air is moving through an exceptionally small area, that you can overcome restriction with boost.

Anyone care to educate me? FYI I was looking at using my stock TPI and L98 aluminum heads and adding turbos.

Exhaust on the other hand seems like it would be more important then ever. If your forcing more air in, then more air needs to come out, and a good flowing exhaust system would be much more important then the intake in a forced induction setup.

 

better flowing heads reduce pumping losses, therefore you'll make more power

 

Better flow (heads/cam/intake) will make more power. this combo can make the same power as the stock motor with less boost.
You will see most guys with FI around here have modded parts. Or at least some work done on the stock parts. port polish etc...

But how much boost? as you increase boost you compress the air more. Compressing the air makes the air temp go up. You end up with detonation and pop your engine. otherwise we would all be running 100psi.

Also think about this boost air as water running through a small diameter hose, and a large hose. If you turn the water pressure up, sure more water comes out. but the small hose will choke long before the large hose.

It will work. Look up the callaways L-98. SurfnSun had one and he modded it a bit and made some nice numbers.
I bought a one off twin kit from a guy who had them on his L-98. he had larger intake runners and a cam. everything else stock. Ported heads I believe. He made a tad over 600 rwhp.

It is a start I guess... Think of the whole engine as a system that effects everything. Sure if you had a stock factory turbo L-98, putting a better flowing exhuast on it would help. Now if you have an inlet restriction, you are handicaping your combo.

I guess to sum it up, you are on the right track. Putting the turbos on a stock L-98 will make more power. I guess the question is, is this all the power you want? Then you are good.

However, if you get bit by the power bug. You will want more. and then every little mod for more power will be itching at you.

 

Hi Guys, there are some "wives' tales" that just won't go away! Like too fast a water flow thru the radiator, or that a 3/8" fuel line cannot support a 1000 HP or more and that a supercharger forces the air in - just look at the name here: Forced Induction !!!
Here's a fact that is hard to grasp but true. Take a SBC that makes 400 HP @ 6K RPM flowing say 500 CFM (cubic feet per minute). Now we put a blower or turbo on it and we make 600 HP @ 6K RPM. At the throttle body (not the inlet to the blower or turbo) what is the CFM ???

Believe it or not it is still 500 CFM !!! At the blower inlet it might be 1000 or 1200 CFM or whatever but the engine's VE is determined by the combination of heads, cam, rpm etc. The difference in power comes from the increased charge density or mass flow thru but the CFM remains the same. So if you want more mass flow yes by all means improve the engine's VE by head work etc.
greg

 

Some stuff can be found here: http://speedtalk.com/forum/viewtopic...129&highlight=

 

Tisk tisk, you can't separate cfm, air density, mass flow, or engine ve! They are all related. If you increase density you increase cfm, mass flow and ve. Nothing is static they are all dynamic for the record!!!!!

The cfm changed because the density has changed! Now if you were talking intake charge velocity then yes it is the same.

Does the ideal gas law ring any bells.