Realistic VE Figure for 1275/Spridget 1296/1500 Spitfire

M

March 79B

Member
Could anyone on the forum please advise as to what a realistic figure to calculate volumetric efficency for the engines listed above might be? This would be for a highly modified production race engine. Appreciate and insight and thanks for your time and consideration. Jerry
 
March 79B":1qqezz6f said:
Could anyone on the forum please advise as to what a realistic figure to calculate volumetric efficency for the engines listed above might be? This would be for a highly modified production race engine. Appreciate and insight and thanks for your time and consideration. Jerry
Click to expand...

Jerry,

Is this for PipeMax?

VE is a moving target depending on how well the engine is put together and will keep increasing as gains are made (see the progress in engine technology / understanding even within the confines of a vintage architecture like a Triumph or MG engine). See the wide disparity in trap speeds for the same make/model/engine. Not all engines are assembled / prepared equally.

Also, rules dependent as SCCA Production limits:
1) choke size
2) stock valve sizes
3) can't add material to the head,

All of which will ultimately dictate how much air can flow through the engine. Item #2 is unrestricted in GT, but you are still limited by the other two. So to start, you need to decide what kind of engine you're building, what's the rule set, and lastly, how tight are you willing to wind it?

Aaron ___?___ (AVP Heads / Engines (Saurino's engine builder)) posts on Larry Meaux's (PipeMax) private forum. Rick Parent (builds Pat Ryan's 1296cc Spitfire engines) has as well. Both have PipeMax and should be the ultimate resources for both of those engines. I pm'ed you their email addresses.

Cheers,
Bob
 
106% ? At 5900 rpm?

Wow, that is really great. Especially with two valves per cylinder, siamesed intakes and non cross flow heads.

Guess I should should have stayed with my old Bugeye instead of these new dangled motors. 8)
 
That only equates to about 105 ft lbs.
Around 1.3 ft lbs per cu. in.
I would consider 120+ at the torque peak good. And anything over 115% at the hp peak good. At least at the piston speeds I usually work with.
 
You must log in or register to reply here.
Back
Top