What ADA domes to run?

[LIVE2RIDE Powersports]

I'm building a bigbore 61x with 84mm pistons. What ADA domes should i run to get around 190psi?

 

[Rickster]

I'm building a bigbore 61x with 84mm pistons. What ADA domes should i run to get around 190psi?

What is your squish?

 

[LIVE2RIDE Powersports]

What is your squish?

Not sure yet. i have all the parts, and should be done within a few days. I will have my builder put the clay in it to find out. Its being ported right now. i was just trying to get a idea.

 

[Rickster]

Flattop of domes pistons?

Edit:

i have two bigbore flattop piston engines. The one with .0057 squish and 26cc domes gives me 165psi on a fresh top end. The engine with .004 squish gives me 180-185 psi with a fresh top end.

Porting, piston clearance, squish will all factor in...

 

[LIVE2RIDE Powersports]

Flattop of domes pistons?

Domes. My old 710cc motor with domes and a wc head had like 45thou clearance with stock gaskets.

 

[SUPERJET-113]

84mm 33cc w/ round top pistons
I ran that on a 61X cylinder at 84mm freestyle ported cyl. and 62T cases for a couple years.
The 33cc might get you a bit closer to 200 lbs.

 

[SUPERJET-113]

What is plan for fuel?

 

[Matt_E]

Not sure yet. i have all the parts, and should be done within a few days. I will have my builder put the clay in it to find out. Its being ported right now. i was just trying to get a idea.

So why don't you ask your builder what domes he recommends? :dunno:

 

[LIVE2RIDE Powersports]

What is plan for fuel?

Well i can get 112 pretty cheap, and if im around 190 i will prob mix 112 and 93. Will that be good enough?

 

[LIVE2RIDE Powersports]

So why don't you ask your builder what domes he recommends? :dunno:

I'm going to. I just like to get opinions from hardcore riders. He raced years ago and has a 650sx race ski with 210psi, but i like getn thoughts from guys that run the 84mm big bore and ada heads what they have luck with.

 

[Matt_E]

I have a Jetworks big bore.
I have ran 35cc domes in it - pumpgas, but very carfeul
I have ran 36cc domes in it - pure pumpgas, no worries
I now run 34cc domes and total loss, 3/2 avgas mix.

Ultimately, the builder ought to be able to tell you what domes will work best with the engine he built and that will suit your desired riding style.

 

[LIVE2RIDE Powersports]

I have a Jetworks big bore.
I have ran 35cc domes in it - pumpgas, but very carfeul
I have ran 36cc domes in it - pure pumpgas, no worries
I now run 34cc domes and total loss, 3/2 avgas mix.

Ultimately, the builder ought to be able to tell you what domes will work best with the engine he built and that will suit your desired riding style.

Thanks for the info. Ya i have a 84mm ported big bore with ada head and Total loss. Should all be built within the week so will post an update.

thanks again guys

 

[SUPERJET-113]

Well i can get 112 pretty cheap, and if im around 190 i will prob mix 112 and 93. Will that be good enough?

Ya, for sure. I was mixing 91 pump with Sunoco 110 and it was great! I had MSD T/L with aggresive curve, B pipe, Dual Brapjack 44's,etc. blah, blah... It ripped well for 2 years..
You'll like it!

 

[SUPERTUNE]

35cc to 38cc is the normal range for pump gas, what has been said all depends on the porting and engine setup.

 

[Kennay]

my jetworks BB is ported at 84mm on roundtop wiseco's with 33cc domes at ~200 psi