Volumetric Efficency (VE) for Crossfire and the goal

[elkabong]

Does anyone have a guess or WAG as to the VE for a crossfire manifold? I have been doing some basic calculations for airflow to determine if I need to work on the throttle bodies. I have been using a VE value of 82% for the calcs - is this in the ballpark?

I believe in planning, but one first needs the goal so here is mine. I would like to get as close to 300 hp as possible with the crossfire to reach mid to high 13's. My platform is 84.

My thinking is.

Port/Match the heads (maybe increase the TB to 2" - not sure)
GM Hot Cam (I am open to suggestions)
Headers (not sure which ones yet)
Flowmasters with hiflow cat
747 ECM with the proper tuning

That should pretty much do it. Am I off the mark?


elkabong

 

[kmcewan]

VE?

Ask the guys at the Crossfire Injection Vault.


www.crossfire.webhop.net


The guys at this site can write books on Crossfire performance.

Ken

 

[Ken]

Volumetric Efficiency -- Calculating your cars volumetric efficiency

_ken

 

[elkabong]

WOW! I am going to have to read that when my brain is a little fresher. Thanks - the first read was insightful (no sarcasim it really was).

Thanks

 

[WhalePirot]

I am not the type to take NO for an answer!

I believe you'll find the major issue to be the intake ports. They are quite small and cannot be enlarged. There is also a 'puddling' problem with the manifold, due to nice valleys for slow moving fuel to fall into, ut the airflow restriction is the big issue.

That makes modifications frustrating. Many cams move the peak torque and HP numbers to higher RPM, where the manifold is restricted. Also, the ECM is limited, but workable. It just takes a lot of trial and error. My car ran quite rich after repeated attempts to adjust for my 'hotter' cam.

I'd heard of guys using a double quad manifold with the throttle bodies, or getting a similar, but better manifold. I gave up in favor of TPI (huge project!). Good thing I liked my car, which is in great shape. Else, all this time would not have been worth it!

I was happy with the Flowmasters and the TRACO headers; nice improvement. The stock cat flows quite well, if in decent shape. A 'test' pipe gave me no noticeable kick in the pants (and is illegal as hell).

Search teh site for more comments on the '84. Good luck in your quest (which never ended for me).

Mike


<Need any used X-fire parts or exhaust? TBs are enlarged and teh TRACOs are cleanable and coatable. The Flowmasters have very slight rust. Worth the experiment at a low cost.>