33cc ADA domes

[x2ryder]

I just ordered a set of 33cc ada domes for my ported 701 sj. With the current 35cc domes it reads 170psi with my snap on guage. What should it read with the 33cc domes? Also can I still get away with pump fuel?
Thanks

 

[Matt_E]

About 25-30psi more would be my guess. If you run a stock ignition, or anything non-programmable, I wouldn't run that on pumpgas.

 

[ANT]

you will be fine with the 33cc domes. porting changes the compression. I ran my motor all last summer on 33's with pump gas.

 

[x2ryder]

That is what I was also told. What was your compression?

 

[njfl]

I just ordered a set of 33cc ada domes for my ported 701 sj. With the current 35cc domes it reads 170psi with my snap on guage. What should it read with the 33cc domes? Also can I still get away with pump fuel?
Thanks

Looking at ADA's website, they state 185psi with 35cc domes and 200psi with 33cc domes for a 701. That's a 15psi increase, so therefore, I would expect yours with 33cc domes to measure about 185cc.

 

[SJBrit]

My ported 701 runs 185 with 35cc domes....

 

[Matt_E]

Depends on the porting.

 

[x2ryder]

I put the 33cc domes on. It reads 190psi. I should be fine mixing half 93 half 110 shouldn't I?

 

[tor*p*do]

the Hot Products catalog shows the 33cc domes at 200#/105 octane.
I would go heavy on the 110 and light on the 93

 

[x2ryder]

200 non ported. Mine is ported. That is why it is reading 190 on the snap on guage.

 

[Matt_E]

Bah. You're fine on pumpgas with throttle control.

For peace of mind, mix 3:1 with 110.

 

[x2ryder]

Matt are you saying 3 gallons of 110 and 2 gallons of 93? I like to give it some long wide open runs.
Thanks

 

[Matt_E]

No, I am saying 3 gallons of 92 and 1 gallon 110. That's 96.5 octane. More than enough for you.

 

[x2ryder]

How did yu come up with that?

 

[Matt_E]

(3x92 + 1x110)/4

3 gallons at 92 plus 1 gallon at 110, makes four gallons total. Average the octane for the four gallons.

 

[x2ryder]

So if I want to use my 5 gallon can I can go lets say (4x93 1x110) /5. That would give me 96.4 corect?

 

[Matt_E]

A cautious yes.....but you just changed the pumpgas from 92 to 93. Are you sure about that?

Also, the 110 race gas may not necessarily be an actual 110.

Who ported your motor? That person ought to tell you a bit about what you can/should run.
Do you run a stock ignition? Any static advance?
Single or dual cooling?
What's your squish?

What's your riding style?

It's your motor....don't play guess work with it.

 

[x2ryder]

Yes, we have 93 octane here in Illinois.