Super Jet ADA dome question

[NVJAY775]

My motor is kind of beat, but am hoping it will make it through this summer. Anyways...

61x cyl bored to 84.5 / 760 31cc domes 140 psi in front cyl and 148 in rear cyl @ 5,000' elevation. I had a slight piston meltdown over Memorial weekend, then re-honed and put in a new set of pro-x pistons and rings.

I'd like to get some more compression out of it, but noticed on the ADA site that the 29cc domes are for race gas. ??

What's my best option, or am I just going to have to run it as is this summer?

Thanks guys

Jay

 

[NVJAY775]

Where's the love bump?

 

[tor*p*do]

29 cc should give you like 210 psi (at sea level) which makes race gas necessary
at 5000 feet you will see less compression
which may be why you seeing lower compression
is the motor ported?
that also lowers compression.
how does it run?

 

[Matt_E]

29 cc should giuve you like 210 psi which makes race gas necessary

Not at 5000ft.
It should still be a lot more than what he's getting, though.

 

[SXIPro]

Was the 140 and 148 before or after the new pistons and rings? If it was measured after, something seems fishy. I'd think you'd be much higher with the 31 cc domes. (of course I know nothing about elevation's effect on compression)

 

[NVJAY775]

29 cc should give you like 210 psi (at sea level) which makes race gas necessary
at 5000 feet you will see less compression
which may be why you seeing lower compression
is the motor ported?
that also lowers compression.
how does it run?

It is ported, but I don't know who did the work. It actually runs pretty good... Weird.

Not at 5000ft.
It should still be a lot more than what he's getting, though.

You're right. I think with 31cc domes I should be close to 170 to 180 psi ish at my elevation.

Was the 140 and 148 before or after the new pistons and rings? If it was measured after, something seems fishy. I'd think you'd be much higher with the 31 cc domes. (of course I know nothing about elevation's effect on compression)

Compression was measured after new pistons and rings.

40:1 quicksilver tcw3 also. I might give the 29cc domes a shot and see how it does. But then again it is running pretty descent and not sure I want to chance anything going wrong, but I think even if I do put in the 29cc domes I will maybe only come up to around 160 ish. I just thought the 29cc domes may be cut for race fuel, or something. It's unfamiliar ground for me.

Thanks for the input. Add to it if there's more.