At the track Friday night, my son was running the Camaro. We got to the track kind of late, and during the first time trial soon after arriving, the car sputtered and bogged down bad as soon as he shifted to 2nd. He babied it down the track and came back to the pits. I was still putting the slicks on the '57, so I didn't see the run. We thought it might have gotten a slug of hot fuel, so we sprayed down all of the fuel lines, pump, & carb, got the car cooled down, and he went for his second pass.

This time I was down at the starting line, and sure enough, as soon as he shifted to 2nd it bogged down again. Babied it down again for a nice little 18-sec pass. I figured it was a fuel delivery problem, so when he got back to the pits I pulled the fuel filter, there was plenty of residual fuel pressure on the line, the filter was hard to blow through. Called the wife, she picked up a new filter and brought it out to the track, by this time the old filter had dried out and it was easier to blow through, but still not as easy as the new one. Put it in, took it out to the street outside the track (me driving), ran it up to 5500 RPMs in 1st, shifted, it bogged down but recovered after a second when I kept it floored. Slowed to a stop, tried another run but let it shift itself at 5000 RPMs, ran just fine. So, he added half a second to his dial-in, went down for the first round of eliminations, kept it in D, and it pulled smoothly through the whole 1/4 mile for a double break-out win. Then the rain started, so that was the last pass of the night.

While waiting for the fuel filter, I idly pressed open the AV - seemed to open much easier than I remembered. Wondering if there's any way a too-loose AV could cause a 1-2 shift bog-down. At launch, the choke pull-off keeps it from opening too soon, but at WOT and 5500 RPMs, ??? Not sure why it wouldn't at 5000 RPMs though.

But, could be a weak fuel pump (need to get a gage on it and check under the conditions, but I doubt it because it's fine until you shift), collapsed rubber feed line (kind of doubt that, too), or ???

I'll have to admit, that 6210 Holley sitting on the work bench is looking more and more attractive. . .

 

aww, leave that holley for now

I think checking your fuel pressure would probably be a good first step, as that would eliminate a handful of problems if its good.

Your secondary AV spring could be wearing out..? Hence loosening up.. Or if you didn't tighten the setscrew up real tight, it may have let out a bit... Try tightening it back up?

oh yea, no bog on the 2-3 shift?

 

I didn't get it going that fast on the street, and my son didn't stay in it to figure that out. I'm about to take it out this morning, I guess I'll find out. . .

 

Well, had one on-ramp opportunity. Took it up to 6000 RPMs in 1st before shifting to 2nd, 5500 RPMs in 2nd before shifting to 3rd, then had to back off (I was doing 85 in a 65 by then ). Never missed a beat.

Go figure.

 

did you check the rubber lines at the back of the car by the fuel tank to see if they where collapsing? just throwin' out ideas...

 

I checked the one by the engine, it seemed fine but it probably wouldn't hurt to replace it. I would think that would cause it to bog down at max power/RPMs before the shift due to fuel starvation, rather than just after the shift.

 

build it to a 335 or 340 stroker

 

It's a 350 already (that's what a ZZ3 is. . .).

 

even so, how did that answer the question at hand?

 

WTF?

But years ago, when i had my eldbrook carb, i had a similar problem. On the street it ran fine, at the track it would bog really badly. Never figured the problem out, i really just figured it was in the carb, and switched to a Holley DP carb and never had the problem again. Of course, i did get a stubble in the Holley later, i could never figure out what it was. We pulled the motor out around 3-4 months ago to change the oil pan, and decided to check the cam and 6 lobes were wore almost flat. I assume that was most of my problem, just trying to give you some ideas. I know how fuel problems give me grief

 

hmmm, maybe somethings a bit crazy on these edel carbs...

Mine runs pretty good (crappy warm starts) it will perform good when im just out cruisin beatin on the rice burners. But as soon as i start to really work it i get all sorts of stumbling and sputtering...

When it starts to go to crap i will get a sputter off the line then it picks up good (not as good as usual) then at around 3500RPM it starts stumbling and i cant accelerate anymore...

I think my problem is fuel supply related though. Its just an old beater OEM mechanical pump on there and for all i know its the original 84 pump!