1st Test and tune, any advice - Chevelle Tech
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post #1 of 20 (permalink) Old Jun 4th, 17, 1:02 AM Thread Starter
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troy
 
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1st Test and tune, any advice

first time ever on a track,,, 1/8 mile malta montana

best 2 passes 60ft 1.64 1.65
330 4.89 4.90
1/8 7.67 87.69 7.71 87.28

car ran out of fuel i think all 8 passes some times 50-100 ft before stripe, after coasting and pumping the carb motor fired up, never took it out of drive, no way i could go to 1/4 mile track right now

454 +.060 25cc dome pistons .002 in hole, .39 head gaskets, 781 heads mild pocket port, 2.25 intake, 1.88 exhaust, , cam lunati voodoo 241in 249 ex at .050 hydraulic roller, 2in headers 3.5in collectors, 850 holley dp 80 in front 88 in rear, front 3.5 pv th350 4000 freakshow converter 4.11 gears locker, and 275 60 15 mt drag radial
car weighs 3990 with driver,
i have 1/2 in fuel line from the rob mc pickup to 170 gph mechanical pump to regulator, no gauge for psi yet, 20 initial, 36 total at 2400 rpm,
some of the conversion calculators i looked at show this combo about 450 flywheel horsepower, i was hopping for 550,

shifting at 6000-6500, 6600 chip in msd box,
do i have more in this setup if so where, wonder how to diagnose running out of fuel, and how to fix, little fuel comes out of bowl screw at idle, motor makes 8in vaccum, at 900rpm

i had a great time, even let my kid make a couple passes, he is hooked,,,, would like to make full passes under power,
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post #2 of 20 (permalink) Old Jun 4th, 17, 1:39 AM
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Chris
 
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Re: 1st Test and tune, any advice

I was going to say check your floats, but by having fuel coming out of the screws it sounds like too much fuel. In any case, it sounds like they are out of adjustment.

Are you sure you have enough spring for 6500 rpm?

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post #3 of 20 (permalink) Old Jun 5th, 17, 7:12 PM
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Greg.
 
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Re: 1st Test and tune, any advice

When I had a 1/2" Line and Mech Fuel Pump on my 400ci 65 GTO in the 80s
it would nose over at the 1,200' do to lack of Fuel Flow
put on a Epump near the Tank and switch it on at the Burnout

She then ran all the way to the end no problem

My below times etc. are with a 3/8" Line and Filter half way from Tank with a
Mech Edelbrock # 1722 = Hi Vol 110gph - 3/8 NPT inlet/outlet - 6 psi - no regulator needed

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Born 283 / PG / A51
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60' = 1.756 1/8 = 7.815 et / 89 mph
1/4 = 12.253 et / 111 mph
NEW Best on M/T S/R #6641 street Tires/dress 2016/10/9
60' = 1.720 1/8 = 7.747 et / 89 mph
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post #4 of 20 (permalink) Old Jun 5th, 17, 10:57 PM
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Frank
 
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Re: 1st Test and tune, any advice

The engine is actually dying? Usually the engine will stumble enough that the fuel catches back up without dying. Sounds like something weird is wrong, could the regulator be completely blocking fuel for some reason? Why does it need a regulator, what model fuel pump is it? I just went through fuel problems and thought it was the pump, very annoying to debug!!

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post #5 of 20 (permalink) Old Jun 5th, 17, 11:25 PM Thread Starter
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troy
 
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Re: 1st Test and tune, any advice

its a holley 12-454-20 170 gph i ordered a new regulator 12-704 holley that is what they recommended the motor dies i leave in drive, keep pumping the pedal and it finally starts back up after a few seconds and i can drive back to the pits
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post #6 of 20 (permalink) Old Jun 5th, 17, 11:54 PM
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Dan
 
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Re: 1st Test and tune, any advice

What fuel tank? What fuel lines?
Tip # 1 is if you are going down track and your car gets out of shape (even a little bit out of shape) Lift and run again later. You do not want to meet Mr. K rail.

'66 SS Chevelle
565 BBC Mamofied 300cc Ovals
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Best e.t. to date 6.09 @112.45
1.391 60' 3.925 330' working at it
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post #7 of 20 (permalink) Old Jun 6th, 17, 1:33 AM
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Rod
 
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Re: 1st Test and tune, any advice

Quote:
Originally Posted by 300stw View Post
first time ever on a track,,, 1/8 mile malta montana

best 2 passes 60ft 1.64 1.65
330 4.89 4.90
1/8 7.67 87.69 7.71 87.28

car ran out of fuel i think all 8 passes some times 50-100 ft before stripe, after coasting and pumping the carb motor fired up, never took it out of drive, no way i could go to 1/4 mile track right now

454 +.060 25cc dome pistons .002 in hole, .39 head gaskets, 781 heads mild pocket port, 2.25 intake, 1.88 exhaust, , cam lunati voodoo 241in 249 ex at .050 hydraulic roller, 2in headers 3.5in collectors, 850 holley dp 80 in front 88 in rear, front 3.5 pv th350 4000 freakshow converter 4.11 gears locker, and 275 60 15 mt drag radial
car weighs 3990 with driver,
i have 1/2 in fuel line from the rob mc pickup to 170 gph mechanical pump to regulator, no gauge for psi yet, 20 initial, 36 total at 2400 rpm,
some of the conversion calculators i looked at show this combo about 450 flywheel horsepower, i was hopping for 550,

shifting at 6000-6500, 6600 chip in msd box,
do i have more in this setup if so where, wonder how to diagnose running out of fuel, and how to fix, little fuel comes out of bowl screw at idle, motor makes 8in vaccum, at 900rpm

i had a great time, even let my kid make a couple passes, he is hooked,,,, would like to make full passes under power,
Good, thorough post. I really enjoy these types of threads but I hope you don't leave us hanging like some do. I hope you are able to report back with what fixed the problem.

I think a fuel pressure gauge will help you at least eliminate that as the problem.

What calculators are you using? That combo should easily be over 500 hp, if not, 550.
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post #8 of 20 (permalink) Old Jun 6th, 17, 6:58 AM Thread Starter
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troy
 
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Re: 1st Test and tune, any advice

Quote:
Originally Posted by Stokerboats View Post
What fuel tank? What fuel lines?
Tip # 1 is if you are going down track and your car gets out of shape (even a little bit out of shape) Lift and run again later. You do not want to meet Mr. K rail.
factory new tank, 1/2in sending unit robmc setup, braided 8an fuel line from the tank to pump, mostly followed factory steel line routing,
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post #9 of 20 (permalink) Old Jun 6th, 17, 3:01 PM
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Kerry
 
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Re: 1st Test and tune, any advice

If you have a regulator, but no gauge, how do you know if you have 6-7 psi pressure? I am running -10 from RobbMcc pickup to 12-454-20 pump, -10 to aeromotive regulator, then dual -6. No fuel delivery issues. But, I did have to run my regulator set to 7 psi cold (gauge reading drops as soon as the underhood temps rise). And I had to put reflective heat tape on all the hoses under the hood, as well as holley plate heat shield. Otherwise the odd time at the track it would have a hesitation like it was running out of fuel. Float levels set to the bottom-1/4 way up the sight glass. I also run a vented gas cap, and a vent from the factory vent fitting ran through a brake booster charcoal filter.
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post #10 of 20 (permalink) Old Jun 6th, 17, 4:10 PM
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Dan
 
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Re: 1st Test and tune, any advice

Quote:
Originally Posted by 300stw View Post
factory new tank, 1/2in sending unit robmc setup, braided 8an fuel line from the tank to pump, mostly followed factory steel line routing,
Assuming your pump uses the original fuel pick up location you may have to fill your tank to 1/2 full or more to keep the pickup in the gas during acceleration. I see you posted those things earlier but I'm old and miss stuff often. Liquid filled gauges will change readings from cold to hot if they are located on or near the engine. Make sure you set pressure at rpm when the gauge is cold. Is your gas tank vented? You need an equivalent amount of air entering the tank as you have fuel exiting the tank. An example would be stick a straw in a glass of milk and then place your finger over the top of the straw and pull it out of the milk. The milk will stay in the straw until you take your finger off the top of the straw thus venting it.

'66 SS Chevelle
565 BBC Mamofied 300cc Ovals
3.73 12 bolt
Best e.t. to date 6.09 @112.45
1.391 60' 3.925 330' working at it
"seize the day", live and thrive
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post #11 of 20 (permalink) Old Jun 6th, 17, 4:40 PM
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Geoff Swanson
 
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Re: 1st Test and tune, any advice

Quote:
Originally Posted by 300stw View Post
first time ever on a track,,, 1/8 mile malta montana

best 2 passes 60ft 1.64 1.65
330 4.89 4.90
1/8 7.67 87.69 7.71 87.28

car ran out of fuel i think all 8 passes some times 50-100 ft before stripe, after coasting and pumping the carb motor fired up, never took it out of drive, no way i could go to 1/4 mile track right now

454 +.060 25cc dome pistons .002 in hole, .39 head gaskets, 781 heads mild pocket port, 2.25 intake, 1.88 exhaust, , cam lunati voodoo 241in 249 ex at .050 hydraulic roller, 2in headers 3.5in collectors, 850 holley dp 80 in front 88 in rear, front 3.5 pv th350 4000 freakshow converter 4.11 gears locker, and 275 60 15 mt drag radial
car weighs 3990 with driver,
i have 1/2 in fuel line from the rob mc pickup to 170 gph mechanical pump to regulator, no gauge for psi yet, 20 initial, 36 total at 2400 rpm,
some of the conversion calculators i looked at show this combo about 450 flywheel horsepower, i was hopping for 550,

shifting at 6000-6500, 6600 chip in msd box,
do i have more in this setup if so where, wonder how to diagnose running out of fuel, and how to fix, little fuel comes out of bowl screw at idle, motor makes 8in vaccum, at 900rpm

I had a great time, even let my kid make a couple passes, he is hooked,,,, would like to make full passes under power,

Are you sure your not putting on blinders by not looking at other possibilities ?Your set-up should deliver plenty of fuel for 450HP motor.
I'm thinking you should be looking at an possible ignition issue. I had a very similar issue that turned out to be the coil. The motor would nose over and die briefly then come back to life after getting out of the gas for a brief instance. It happened every single time in 3rd gear at 5500 RPM's. Funny thing was I could not get it to do it on the street.
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post #12 of 20 (permalink) Old Jun 6th, 17, 7:05 PM
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Re: 1st Test and tune, any advice

Quote:
Originally Posted by 300stw View Post
...
some of the conversion calculators i looked at show this combo about 450 flywheel horsepower, i was hopping for 550,

....,


That seems about right to me. According to a calculator I looked at, your times are equivalent to around 12 flat in the 1/4. I put in 3990lbs and get about 530 flywheel hp.

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post #13 of 20 (permalink) Old Jun 10th, 17, 4:40 PM Thread Starter
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troy
 
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Re: 1st Test and tune, any advice

i will change out the coil, i have the factory vent hooked to the tank no vented cap, i had 3/4 tank to full tank of fuel,

changed out the regulator to a holley 12-704, checked pressure 6psi, made a few passes down an old road where no one is around for miles, hit 125 mph a couple times held it there for 6 seconds, according to my garmin gps,,,, was pulling 6500 rpm in high gear, no misses sputters or anything,,,, hope that was the problem, headed to the track again in a week,,,,
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post #14 of 20 (permalink) Old Jun 17th, 17, 5:31 PM Thread Starter
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troy
 
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Re: 1st Test and tune, any advice

today. 1.58 60ft
7.45.
89.91 mph


lots of fun
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post #15 of 20 (permalink) Old Jun 17th, 17, 5:58 PM
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Kerry
 
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Re: 1st Test and tune, any advice

Nice job! One thing I was going to mention, do you have a lightweight fuel pump pushrod? The ARP one is 73 grams versus a factory one at 144 grams. The rod can affect your fuel flow at high rpm.

You could also up the pressure to 7 psi.
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