Author Topic: 11.60, et`s but missing thru traps  (Read 2852 times)

Offline Mr.Pontiac

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11.60, et`s but missing thru traps
« on: August 03, 2021, 08:22:50 AM »
 Trying to figure it out, car is awesome off line pulling wheels and gone but within 50 ft. Of traps it’s missing and acting like I have a rev. Limiter on the car. Thinking it’s a lean out condition. 105 MPH. Running 410 gears Crower 296 flat tapped cam. Gas tank dumped, fuel pressure is 7 psi going thru my run.Qjet 800 cfm running off jets, not power piston or rods..136 needle and seat, small float.I believe I have .056 jet`Or .057,s I’ll check to be 100% sure.I may be wrong but fill I should be around 110 mph.Timing is locked out and set at 36 degrees. ANY IDEA`S

Offline Mr.Pontiac

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Re: 11.60, et`s but missing thru traps
« Reply #1 on: August 03, 2021, 08:49:57 AM »
Pulled carb. Top off this morning, running 65 jets with a G HANGER and your custom rods.I do have L,M,P Hanger, .135 needle seat.
« Last Edit: August 03, 2021, 09:05:58 AM by Mr.Pontiac »

Offline Mr.Pontiac

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Re: 11.60, et`s but missing thru traps
« Reply #2 on: August 03, 2021, 09:08:32 AM »
Trying to figure it out, car is awesome off line pulling wheels and gone but within 50 ft. Of traps it’s missing and acting like I have a rev. Limiter on the car. Thinking it’s a lean out condition. 105 MPH. Running 410 gears Crower 296 flat tapped cam. Gas tank dumped, fuel pressure is 7 psi going thru my run.Qjet 800 cfm running off jets, not power piston or rods..136 needle and seat, small float.I believe I have .062jet`Or .063  I’ll check to be 100% sure.I may be wrong but fill I should be around 110 mph.Timing is locked out and set at 36 degrees. ANY IDEA`S

Offline old cars

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Re: 11.60, et`s but missing thru traps
« Reply #3 on: August 03, 2021, 09:17:57 AM »
No air/fuel gauge? I know some guys don't like them but maybe.

Offline 77cruiser

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Re: 11.60, et`s but missing thru traps
« Reply #4 on: August 03, 2021, 10:23:35 AM »
How's the vent on the tank?
Jim

Offline Mr.Pontiac

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Re: 11.60, et`s but missing thru traps
« Reply #5 on: August 03, 2021, 07:18:22 PM »
Only thing I see at carb. Is the filler cup on left side was not there, my fault for sure. Is that slowing me down, I dought it.

Offline Cliff Ruggles

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Re: 11.60, et`s but missing thru traps
« Reply #6 on: August 04, 2021, 04:13:32 AM »
The FIRST thing to do is to install a larger .145" fuel inlet seat, no other changes and see if it helps?

If the fuel system isn't keeping the bowl full the larger seat will let you know on the next run.

Not sure why you'd "lock out" the timing.  That's pretty "old school" and a good way too loose a race if you don't have adequate time between round to cool things down.

I've seen folks try to restart their engine in later rounds in the staging lanes and kill the starter/battery with "locked out" timing and it's difficult if not near impossible to fire a compressed mixture that early in a really hot engine.  I've also seen them "kick back" and break the nose right off the starter or take out a hunk of flywheel teeth in extreme cases.  So tread softly in that area.

Anyhow, if it's not "breaking up" in 1st and 2nd it's probably not ignition or valve spring related.

Go with a larger fuel inlet seat and look at fuel delivery first.......then move on from there.

11.60's is doing getting it done pretty good but you should be running a LOT faster than 105mph thru the traps.  That's more like low 13's for MPH, not mid to high 11's........FWIW.......Cliff

Offline Mr.Pontiac

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Re: 11.60, et`s but missing thru traps
« Reply #7 on: August 04, 2021, 06:45:15 AM »
Following your book specs, just drilled out my .135 to .140, left hand corner of carb. Is a filler black cup, I call it that, it was not inside carb ( my fault) installed one , I see fuel in the void, maybe that’s where my issue is. Switched from G hanger to L also.

Offline Cliff Ruggles

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Re: 11.60, et`s but missing thru traps
« Reply #8 on: August 04, 2021, 09:08:05 AM »
The filler block has NOTHING to do with WOT drag racing performance.

At most I've had a few complaints from folks who claim leaving it out will cause flooding with hard braking.

I brake pretty hard with my car at the track on occasion, no filler block has ever been used and it's FLAWLESS.

Move up to a .145" or even .149" seat and see if you pick up some MPH or help the WOT issues at high RPM's.

They still could be engine related (valve springs), so if things aren't getting better and you've ruled out ignition, fuel delivery, etc, don't cave in a piston or bend a valve continuing to find your issue!.........

Offline tayto

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Re: 11.60, et`s but missing thru traps
« Reply #9 on: August 04, 2021, 10:35:19 AM »
is the filler block the round thing goes where the mixture control solenoid is on the CCC units? or the thing that goes above the float?

Offline Cliff Ruggles

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Re: 11.60, et`s but missing thru traps
« Reply #10 on: August 04, 2021, 01:03:05 PM »
The cup is what he's talking about that sits in the aneroid area.  It doesn't need to be there, but really hurts nothing that I've seen if you don't use it.

For sure leave the splash guard in place above the N/S assembly.....

Offline Mr.Pontiac

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Re: 11.60, et`s but missing thru traps
« Reply #11 on: August 05, 2021, 08:10:13 AM »
Ok, Thank you

Offline Mr.Pontiac

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Re: 11.60, et`s but missing thru traps
« Reply #12 on: August 07, 2021, 07:45:25 AM »
Ok, small update, cleaned my washable fuel filter out, found very little depri if any. Removed top of carb.and took out needle and seat, drilled it out to .140, from my machinist days probably went couple thousand. Bigger. From the .135.I had g hanger with your trick secondary rods and kicked ti up to L, should rich-n up secondary side. Taking car out soon, I’ll post results.

Offline Cliff Ruggles

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Re: 11.60, et`s but missing thru traps
« Reply #13 on: August 08, 2021, 05:49:32 AM »
Didn't you post above that it was already drilled to .140"?

I'd go to .145 or even .149" for what you are doing.

If that doesn't work you need to address fuel delivery to the carb.  Are you running a sumped tank already?

What pump?

Is it behind the tank? 

What size fuel lines?......

Offline Mr.Pontiac

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Re: 11.60, et`s but missing thru traps
« Reply #14 on: August 23, 2021, 07:18:37 AM »
Holley blue pump, yes tank is sumped, running no.10 lines up to pump, then no.8 up to reg.from there short  8 inch long no. 6 to carb.