Jump to content

what compression do you need to have toa run race fuel?


FraireRacing

Recommended Posts

I have a stock 64mm pistons still Cherry lol. I ported the cylinders from intake and exhaust only. I have a cool head that im about to run w/ 18cc domes I had 22cc domes before. I have boyesen reeds and cages, 1/2in carb spacers, an aluminum Y w/18cc a single 39mm kehien carb with a k&n, and t5 exhaust. I also have a Ricky stator and an adjustable timing plate.

 

My question is am I going to have to run race gas or can I still get away w/ using 93 octane and an octane booster

Link to comment
Share on other sites

DO NOT put octane booster in your bike. When you install the 18cc domes you need to compression test your motor and that will tell you what type of fuel you will need to run. Just remember anything over 165-170lbs, requires higher octane fuel.

Link to comment
Share on other sites

  • 3 weeks later...

I know this is old...but you need to measure compression ratio, not cranking compression.

You get cranking compression by using a PSI gauge in the cylinder.

 

You get compression ratio by measure parts/clearances/tolerances inside the motor.

Cylinder volume and trapped head volume are just a few of the numbers you'll need.

 

I agree, this has been covered a lot, and it's easier to search the forum and Google for it rather than any of us rewrite a novel!!

Link to comment
Share on other sites

Octane boosters aren't good for Banshee's? I haven't tried it but I was just thinking about it. And thanks man I didn't know what the compression limit had to be to run pump or race fuel

I dont think it that there not good but that they dont really work. They only slightly move the octain up. I believe.

Link to comment
Share on other sites

I'd use octane boosters in an absolute pinch if I had too, otherwise, hell no.

Octane boosters are good for a point or two, and you'd have to use quite a bit to be honest.

 

Toulene is a common compound used in octane boosters, as well. It is NOT what you want for a high revving two stroke motor.

 

Buy race fuel, again...if you need it based on compression ratio, not cranking compression.

Link to comment
Share on other sites

  • 1 month later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...