every time i go to the track, my car stumbles when i launch. ive tried leaving out between 3500, and 5500, and no change. i launch very hard. enough to pull both wheels off the ground, but as soon as i come up, the car stumbles for a split second, then takes off again. my carb is tuned perfect. i have a new fuel filter. is my car starving for fuel when the front end rises?

 

maybe put jet extensions on the rear jets or install a fuel pressure guage to see what's going on.

 

What kind of engine is this that pulls both tires?

 

im running the stock fuel lines from the tank to the front of the car with a mechanical fuel pump on the engine. i was thinking maybe the lines are too small. theyre only like .25 inch. the pressure gage sounds like a good idea too. that way i can check it at wot.

the engine is just a small block chevy.

 

If your running a Holley, it sounds like typical fuel slosh. Run a rubber hose from the front vent to the rear vent tube and cut a hole in the rubber line so it can vent.

Basically when you launch it's pushing fuel out of the front bowl vent and dumping it straight down the carb.

 

im actually running a speed demon carb, but i believe they share some of the same characteristics. i will check it out. that sounds like a very logical explanation IHI. thanks.

 

Like you said Demons and Holleys are prit near indentical, and after looking at the Speed Demon I see it hads the same vent design as Holley. Very cheap and easy to test out that idea anyway before digging in too deep.

Here's a pic of how I had mine many motors ago. Does'nt have to be all long like that, so long as it just arches over the carb body, and has a hole so it can still vent.

 

was your car doing the same before that trick?

ive also read alot of posts on tuning holley and demon carbs. guess i dont know as much as i thought.

 

Demon Carbs is actually in dallonega georgia so its very close to my home track. one of their employees was racing his car and noticed the trouble i was having with the carb. he gave it a good tune so it runs extremely well except when i launch hard.

 

I, as well as many others have had that same stumble off the line. This little trick took care of it. I dont have any idea why my 950HP never had this problem once I installed it-orginally I installed on the same motor I had pictured above, and I did'nt have an off idle stumble with this one.

Same thing with 2 other friends of mine, stumbled off the line, installed the hose-fixed it. Then they too bought HP series carbs and no more stumble/no more hose vent. So currently we're not running the vent hose.

 

i'm going to try that trick too IHI. thanks for the tip. also did you ever buy those rims because I remember you're looking at my pics on cardomain, just wondering if you ever did anything with it?

 

thanks IHI. ill try it and post back.

 

I have'nt bought the rims yet, took the car for a cruise the other day when it was really nice out, and the fuel pump burned up on me. A2000 not meant for S/S duty- just racing So I'm deciding on what new fuel pump set-up I'm going with. I spoke with Aeromotive about getting this pump fixed, so I sent that in, and they reccommended a pump and regulator, just dont wanna spend another $600 for a pump set-up like they reccommend. So I think I'm just going to buy their S/S pump since I've already had a Holley black on the car and 150gph will feed what I need.

So that's where I'm at, also since I'm not racing everyweekend now, car is kinda in the back of my head Much needed break mentally and financially By next spring it'll be ready as usual. I hate cars!!

 

don't worry both my holley blue pump and my mallory 3 port went out on the camaro, did i mention it hasn't even left the driveway or garage yet this year. i'm hoping mallory will warranty this thing since it shouldn't leak with only half a tank of gas through it. won't even regulate below 9psi either so i had to buy another one. if i had to do it all over again i would have just bought an already built car and saved a few thousand easily.

 

LOL, you could try to tell that to a guy just starting a project, but it wont sink in until their done Definately cheaper to buy than build!!

 

I dont know if your spraying or not,but I had the same problem
until I put a purge line on my nitrous.I was not wild about having to purge out the line before each run.kinda like showing off,but it took care of the bog...

 

Have you tried lowering the fuel level in the front bowl just a little?

 

im not spraying the car yet.

the fuel levels in the float bowls are barely visible on level ground.