Race gas vs pump porting

Can anyone tell me what gains there are when a motor is modified to take advantage of race gas? For example has anyone compared eric gorr race gas porting directly with his pump gas porting?


From what I understand, the only difference is in the head. The chamber volume is lower for race gas, thus increasing compression ratio due to the higher octane.

I recently talked to Pro-Circuit about doing a cylinder and head for me... They made it pretty clear that I had to choose race or pump gas which effects how they machine the head.

I doubt they set the squish clearance any tighter on race gas engines. I think you always want it as tight as you can at any given compression ratio to promote turbulence, however you need some clearance to avoid piston/head contact as the parts deform at high temp and high RPM, and as bearings wear out.

Depending on the level of development - will determine the changes.

99 percent of the time it's only head changes.

But realistically a motor that works well on the track set up with X compression will not work well with Y compression.

Often more aggressive timings can be used with race gas heads because the compression helps the early part of the curve when coming on the pipe...

I am just getting the head cut at this time anyway. But do I do it for race gas or pump? How much better is race gas combined with the higher compression?

Almost always more compression helps power...you don't run race fuel to make more power - you run race fuel to run more compression.

Almost always more compression helps power...you don't run race fuel to make more power - you run race fuel to run more compression.

if A = B, and B = C, then doesn't C = A

(sorry for the reference. I'm helping my daughter with her algebra)

Race fuel not= HP.

Compression = HP (most of the time...)

Compression = BOOM on pump gas.

Race gas + Compression = power (most of the time)

So transient laws not apply here! (or whatever they call it).

It's a symbiatic relationship.

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