Just wanted to find out what does the power jet do that the main jet doesn't do. what if you didn't run a power jet what would happen, just put in a smaller main jet. the weather goes from 85's during the time in down to 50's for the main. Just haven't figure out the jetting to get the car to run right.
Is the standard .080 power jet in the carb so when it get hot out do you put a smaller jet in or a larger jet in or just run the same power jet all the time?

Thanks for your time.
Robert

Personally, I do most of my jetting via main jet and seldom change power jet size. If the temp change is that extreme, I would increase my main jet 2sizes. Just have to remember humidity as well as temp plays a role in proper jetting as well. I have been told numerous times that the power jet doesn't even come into effect if less than half throttle, thus it only adds extra fuel upon higher power demand. MEANGENE

I agree w/ meangene, i really only adjust the main and needle... The power jet is the "makeup" for running pumped gas compared to methanol... I was told running methanol, requires twice the amount of fuel compared to pumped gas.....

I have a jet chart somewhere that shows where each jet comes into play. I will see if I can find it and attach it... Its really hard to nail down, I can run one set of jet on my one motor and the same setup won't work on my other motor..........

if you find the jet chart, email it to me at robert@deroucheyracing.com

Thanks
Robert

if you find the jet chart, email it to me at robert@deroucheyracing.com

Thanks
Robert

I just posted to the Blog part of this site for everyone!

http://www.microracing.com/forum/blog.php?b=3

Yes, you can run w/o a power jet, but the idea behind power jet is to only give fuel upon high demand, thus you can go around track under caution w/o extreme fuel buildup that you have to cleanout before performance starts again!!!!!!!!! If I were going to attempt running w/o the power jet the very minimal main jet I would start @ is 118 thousandanths!!!!!!! Preferably 120 and lean as necessary!!!!!!!!!!! I did run w/o power jet first season or so of racing!!!! 118-120 thousandths you are very unlikely to burn or stick the engine, but I suggest if you go that route start @ 120!!!!!!!!!

W/O the power jet and main jet being this fat, you will have to punch the powerplant momentarilly occasionally to keep fuel from building up under caution!!!!!!

thanks for the chart. Here in Colorado I'm running an 102 main jet w/o power jet in one car and 106 main jet with 100 power jet in the other car. Just trying to figure out the best way to run the motors. We mostly run on 1/4 mile tracks dirt and asphalt.

Thanks
Robert

Normally I run no power jet or a large power jet on bigger tracks. If you're running 1/4 mile you'll need that extra methanol at the end of the straights. How does the strap look on your plug? Another thing to consider, has your tube been bored out. I don't recall standard, but even if you put a 118 power in (aka large), unless the tube is drilled to that tolerance or more, you'll be getting less fuel.

good luck

A stock tube is only .93. Most engine builders will drill this out to a .106. So if your tube is still stock .93 is the most it will flow.

When I suggested a main jet .118 > .120 to start was w/o powerjet @ all!!! And, as always climate affects what people may run in various parts of country!! Actually there are so many variables in the jetting sequence of things. For example, whether carb has been updated to alcohol or a stock carb, fuel to oil mixture, climate, etc., etc.!!!!! But normally, if running w/o a powerjet you usually have to run a larger main jet!!!!

the ignition has alot to do with it also, a stock ignition seems to like a lot less jetting, the guys i run with are ussually on 114-92-93 with aftermarket ignitions, i run a stock ignition and run 108-110 with a 83 power jet so try not to compare notes with someone with aftermarket ignitions, hope this helps

the ignition has alot to do with it also, a stock ignition seems to like a lot less jetting, the guys i run with are ussually on 114-92-93 with aftermarket ignitions, i run a stock ignition and run 108-110 with a 83 power jet so try not to compare notes with someone with aftermarket ignitions, hope this helps

The ignition will defiantly affect the burn of the plug, but I not sure on the jetting part of your response. I use a Buch programmed Vortex ignition all the time and I can run a lot leaner in the jetting then w/ my stock ignition. The performance ignition boxes only change the timing and ignition curves to have better throttle response and so on... I'm running right now 100m, 80p, and 246n (top clip) and my plug is burning really nice... But the issue I have is getting my temperature up... Most of my plug is white after the feature... To get my temperature up, I put a piece of tape across my radiator to block some of the air across it...