Pinching fuel line to help tune.....?

[Glass Bullet]

I went to my LHS when I first got my car (Exceed Forza) and he said something about when you pinch the fuel line as close as you can to the carb, the engine should stay normal for half a second and then rev up for about 3 seconds then dies and that means it's a good setting. Has anyone else heard about this and knows what this is used for?

 

[ohmygahitscoby]

If it cuts out at under 3 seconds, it's most likely too lean. Richen it up if it does. I have my Savage pulling 5 seconds before dying, so that's fine settings.

 

[MrClean]

Yes, that is a way to check your low-end tune. I don't think you have to pinch it right next to the carb though, anywhere on the fuel line should give you the same results. 3-5 seconds - any less = too lean, any more = too rich. Make sure you make a couple of high-speed passes after adjusting the LSN, to clear out any extra fuel in the carb/motor.

 

[Glass Bullet]

ok. thanks.

and just to be clear, i was right that this is for "optimum" tune, not just like a good break in setting or something like that

 

[MrClean]

You are correct, for break-in you want to try and leave the needles as they are from the factory, on the rich side.

 

[olds97_lss]

Actually, the pinch method is just to get you in the ball-park. Fine tune is determined by performance, smoke trail, temp and sound.

Give this a read, they talk about the pinch tuning method along with some pretty good tuning info:
http://www.rchobbies.org/cars_eng-tuning.htm

Here's an older PDF that my link is dead to, but I uploaded it to my ftp site so you can access it. It looks like crap, but the info is good:
http://home.comcast.net/~98gmarquee/pics/MiscDocs/ParisRacingEngineTuningTechTips.pdf

 

[TWOCANE]

That is to lean you want a good 5 seconds before cutting off.

 

[MrClean]

Actually, the pinch method is just to get you in the ball-park. Fine tune is determined by performance, smoke trail, temp and sound.

Give this a read, they talk about the pinch tuning method along with some pretty good tuning info:
http://www.rchobbies.org/cars_eng-tuning.htm

Here's an older PDF that my link is dead to, but I uploaded it to my ftp site so you can access it. It looks like crap, but the info is good:
http://home.comcast.net/~98gmarquee/pics/MiscDocs/ParisRacingEngineTuningTechTips.pdf

That's good sh** right there Olds!! Thanks for the links, I bookmarked one and downloaded the Ron Paris tips. (Thanks for the bandwidth

 

[olds97_lss]

That's good sh** right there Olds!! Thanks for the links, I bookmarked one and downloaded the Ron Paris tips. (Thanks for the bandwidth

No problem.

I copied that link that is still online to a txt file in case it ever goes down... I'll go through and reformat it and host it as well if need be.

Both of those guides contain a lot of good info about tuning and have helped me quite a bit.

 

[insutama]

Awsome info ill have to try this tomorrow thanks