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Why does my car stumble in the air?
#454577
08/30/09 02:26 PM
08/30/09 02:26 PM
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Joined: Aug 2003
Posts: 4,055
Salina ks
572_dup2
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Salina ks
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Would it help to put jet extenstions on? Carbs are sideways. Fuel pressure is 6 1/2 an use 4 port magna fuel. Or just maybe set the floats little higher? An thoughts?
Thanks
Shawn Jennings
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Re: Why does my car stumble in the air?
[Re: 408strokerdart]
#454579
08/30/09 02:45 PM
08/30/09 02:45 PM
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Joined: Aug 2003
Posts: 4,055
Salina ks
572_dup2
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It does it on every pass just before i shift into 2nd. If it did it once or twice maybe think its a fluck. Do you think fuel pressure needs turned up too?
Shawn Jennings
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Re: Why does my car stumble in the air?
[Re: Al_Alguire]
#454582
08/30/09 03:12 PM
08/30/09 03:12 PM
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Joined: Aug 2003
Posts: 4,055
Salina ks
572_dup2
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Best 60's ever all 1.28s. Got the bump stops set as tight as im gunna set them. Leaves the best around 2000rpm. Sounds like an feels like its starved for fuel right before 2nd an then after i shift it takes it a little time to recover.
I have video i will show as soon as the get it to me.
Shawn Jennings
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Post deleted by Defbob
[Re: 572_dup2]
#454583
08/30/09 03:36 PM
08/30/09 03:36 PM
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Anonymous
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Anonymous
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Re: Why does my car stumble in the air?
#454584
08/30/09 03:39 PM
08/30/09 03:39 PM
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Joined: Jun 2004
Posts: 1,217
Wellington, FL
cudabunch
pro stock
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pro stock
Joined: Jun 2004
Posts: 1,217
Wellington, FL
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What fuel pump are you using and is there a air filter on the carbs ?
Last edited by cudabunch; 08/30/09 03:40 PM.
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Post deleted by Defbob
[Re: 572_dup2]
#454585
08/30/09 03:59 PM
08/30/09 03:59 PM
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Anonymous
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Re: Why does my car stumble in the air?
[Re: 572_dup2]
#454587
08/30/09 04:13 PM
08/30/09 04:13 PM
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Joined: Jun 2003
Posts: 9,225
Charleston
sixpackgut
Drag Week Mod Champion
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Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
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standard floats will close the needle and seat when fuel sloshes back
Gen 3 power 6.22@110, 9.85@135
Follow @g3hemiswap on instagram
performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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Re: Why does my car stumble in the air?
[Re: MegaDart]
#454589
08/30/09 04:29 PM
08/30/09 04:29 PM
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Joined: Jan 2003
Posts: 19,363
Las Vegas
Al_Alguire
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 19,363
Las Vegas
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How long and high is it in the air? Maybe it is possible you are up long and high enough to uncover the front jets in carb long enough to cause and issue. Maybe some sort of modified jet extensions are in order? Have you watched the fuel pressure to see what it is doing? I know that is easier said than done while driving a car in the air but might take a peak.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Why does my car stumble in the air?
[Re: Al_Alguire]
#454590
08/30/09 04:58 PM
08/30/09 04:58 PM
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Joined: Aug 2003
Posts: 4,055
Salina ks
572_dup2
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Dont think its a voltage thing. Im back to 2 battires now.
Fuel pressure in high gear is around 6 61/4. But it dont now what fuel pressure is off the line?
Im going to cut 2 holes in the front of the cowl to let some air in. Its a piece of trash in high gear. Runs less MPH than it did before, but the 60' is best 1/8 mph is up some an 1/8 et is getting better. This should fell like afterburners kicking in!
Shawn Jennings
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Re: Why does my car stumble in the air?
[Re: 572_dup2]
#454592
08/30/09 05:17 PM
08/30/09 05:17 PM
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Joined: Feb 2005
Posts: 20,169
PA.
pittsburghracer
"Little"John
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"Little"John
Joined: Feb 2005
Posts: 20,169
PA.
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Shawn how close are your carbs to the top of your hood scoop? I had to take my tunnel ram off because mine were to close and would shut off air flow to the carbs.
1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
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Re: Why does my car stumble in the air?
[Re: Cab_Burge]
#454593
08/30/09 05:17 PM
08/30/09 05:17 PM
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Joined: Aug 2003
Posts: 4,055
Salina ks
572_dup2
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could be possible? But we didnt see any sign of fuel coming out? It fells like it starts this when the car is at its highest. But it happens so fast sometimes i forget. LOL
Im hoping the video shows signs of whats happening.
Shawn Jennings
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Re: Why does my car stumble in the air?
[Re: 572_dup2]
#454597
08/30/09 08:55 PM
08/30/09 08:55 PM
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Anonymous
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Anonymous
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Quote:
Best 60's ever all 1.28s. Got the bump stops set as tight as im gunna set them. Leaves the best around 2000rpm. Sounds like an feels like its starved for fuel right before 2nd an then after i shift it takes it a little time to recover.
I have video i will show as soon as the get it to me.
had the same problem today, my car was leaving hard and pulling up the frontend causing my jets to be uncovered causing a lean condition.
i raised my floats up on both carbs a bunch with a drill bit and problem solved. got my best et ever in bad air.
dont touch your fuel psi, thats not your problem.
Last edited by SUPERSTOCKRACER; 08/30/09 08:59 PM.
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Re: Why does my car stumble in the air?
#454598
08/30/09 09:00 PM
08/30/09 09:00 PM
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Anonymous
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Anonymous
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jet extentions wont help with sideways carbs.
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Re: Why does my car stumble in the air?
#454599
08/30/09 09:21 PM
08/30/09 09:21 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
jet extentions wont help with sideways carbs.
A set of 90% bent tubes would so the ends are at the
rear of the carb(what is the rear now)... might be
able to use a short piece of fuel hose to connect
them to the jets.... I'd do all of the jets to make
sure they are all getting fuel. This should work for
a test and if it corrects the problem then I'd make up
something that would be a little more permanent.
Also the comment of being slower in high gear...
it could be a air issue... put a air pan on first
that may knock out some of the hot air thats up in
the cowl(thats where its trying to escape to)
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Re: Why does my car stumble in the air?
[Re: hemi-itis]
#454602
08/30/09 09:39 PM
08/30/09 09:39 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
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Master
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Romeo MI
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Quote:
To eliminate the hood as an issue,make a pass without the hood on  
I believe he did(in his hood post) and really slowed
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Re: Why does my car stumble in the air?
[Re: hemi-itis]
#454603
08/30/09 09:41 PM
08/30/09 09:41 PM
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Joined: Aug 2003
Posts: 4,055
Salina ks
572_dup2
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slowed down when i took the hood off.
Shawn Jennings
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Re: Why does my car stumble in the air?
[Re: 572_dup2]
#454604
08/30/09 09:55 PM
08/30/09 09:55 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
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Master
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Romeo MI
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Shawn, you might want to try larger needle and seats on the carbs(might need to go to the alky seats for more flow
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Re: Why does my car stumble in the air?
[Re: Chris'sBarracuda]
#454609
08/30/09 11:50 PM
08/30/09 11:50 PM
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Joined: Mar 2008
Posts: 307
OH
TheBlackCar
enthusiast
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enthusiast
Joined: Mar 2008
Posts: 307
OH
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Quote:
The first thing I would do is make a pass with the hood off.. 
Chris..
Taking the hood off of something fast usually has a negative affect because fuel is pulled out of carb and ends up on the windshield. Not to mention what it does to the air...
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Re: Why does my car stumble in the air?
#454610
08/31/09 07:31 AM
08/31/09 07:31 AM
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Joined: Jan 2003
Posts: 9,994
Frostbitefalls MN (Rocky&Bullw...
gregsdart
master
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master
Joined: Jan 2003
Posts: 9,994
Frostbitefalls MN (Rocky&Bullw...
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Quote:
jet extentions wont help with sideways carbs.
They will if they are made to draw from further back in the bowl, and that was my idea, and I believe Als as well. It would take some custom work, as they would need to be flattened a little to allow for ending in the middle of the bowl instead of straight out from the jet. A little tubing, a torch, a (small!)hammer, and problem solved.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Post deleted by Defbob
[Re: Al_Alguire]
#454612
08/31/09 11:23 AM
08/31/09 11:23 AM
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Anonymous
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Post deleted by Defbob
[Re: gregsdart]
#454614
08/31/09 01:09 PM
08/31/09 01:09 PM
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Post deleted by Defbob
[Re: DJVCuda]
#454616
08/31/09 01:24 PM
08/31/09 01:24 PM
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Re: Why does my car stumble in the air?
[Re: DJVCuda]
#454618
08/31/09 03:19 PM
08/31/09 03:19 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
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Romeo MI
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I would think the front jets(front now) could uncover and its easier to suck air than it is fuel.... but then again it could be a air issue going into the carbs..... or just lack of fuel
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I used three peices of rubber hose and routed it to the rear of the air cleaner base, on my tunnel rams I'm going to use two vacume tees per carb and hook them onto the vents with a short piece of hose and connect the vents in line and leave the ends open on both ends. I should make one up and take a picture and post that instead of trynig to describe it in words 
