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 Updated fuel system and jetting 
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Joined: Sat Jun 01, 2013 8:02 pm
Posts: 356
As some of you may or may not know I upgraded my complete fuel system, going from twin holley blacks using a -6an on the out feed to tee and then to a big holley reg set at 6 psi and one line off each side of reg to each bowl, this system never seemed to have enough fuel? I was up to 95/96 jets which are 116/118 hole sizes? it seemed to get good times/ mph. In nov i ran blp 116 jets in back and left the 110's in front when i ran 10.02@132, I should say it was cooler, like maybe 50 for a high? yesterday was 65? It wasn't 65 tho in the morning.So I know that's part of it and im ok with not the best times, plus 60 was slower only 1.40-1.41.I'm more curious about the less fuel, my guess is it has the volume now, so over the winter i went to a new 16 gallon fuel cell and a Mallory 250 pump, fed with a 12 AN from cell to filter, then 10AN TO A Aeromotive fuel log with a bypass reg set at 6psi and returning to cell with a 10AN also. i went to the track yesterday and started out with 110 primary and 112 sec BLP jets, running 10.16@131.46, i looked at afr on lm1 and it showed low to mid 13's so i went back to 116's but this time front and back and it went 131.32 so slower mph, et was off by .02 but the 60ft was off a .01 i believe so that's a wash. AFR now showed in the high 12.90's, but its obvious it didn't want or need it, so then i went to 110's and dropped timing down to 27 since it made most power on dyno at 26. then mph was down some more to only 130.53, so then i upped timing to 31 n it went 131, then i dropped to 108's and it went 130.99 n left it made some more passes trying different shift points some and did go 10.18@131.37. So thats where i left it with 108 Blp's and 31 total timing for now. I'll go out and load the lm1 and see what it says with the 108's and report back soon.


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74 Firebird 3620 lbs
10.02@131.96 1.377 60 ft
Sun Apr 23, 2017 7:10 pm
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https://youtu.be/Y1dRb9YHB-k

Car's working pretty good now! 18 passes and 60ft only varied .015 from best to worse! Mostly 1.39-1.40 on
a TNT day leaving at 2100 now.

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74 Firebird 3620 lbs
10.02@131.96 1.377 60 ft


Tue May 02, 2017 7:17 am
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Joined: Fri Feb 08, 2013 5:50 pm
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Safe to say your old system wasn't supplying enough fuel?


Tue May 02, 2017 9:46 am
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Joined: Sat Jun 01, 2013 8:02 pm
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That would be my guess too Mark, or the fuel was kinda vaporizing in the lines before getting to regulator from heat created in lines being deadheaded? I'm down to 108's and pulls damn hard and clean ,no popping etc on top or thru run, hell i was into a headwind sat and still 131 mph and i think it may even like 106's... Even tho the LM1 shows its lean up in the mid 13's on top end, So I figured its either where the sensor is located or something, I just use that as my baseline more or less now, it slows down with more fuel, tried again sat with 112's in cooler weather, even tho graph shows richer, and i can feel it not pull as hard, kinda lazy building rpm once in drive..

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74 Firebird 3620 lbs
10.02@131.96 1.377 60 ft


Tue May 02, 2017 10:23 am
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Joined: Mon Oct 21, 2013 12:15 am
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Location: San Diego, CA
Sounds like you are on a roll. The bypass regulator helped you immensely, by maintaining steady pressure, and cooler fuel. I think the AFR gauge is a nice thing to have, but I quit using it for tuning a long time ago. It was way too easy to get wrapped around it, and push for numbers that either wouldn't or couldn't be produced. I simply jet for best mph, and read the timing mark on the spark plugs. You are on the right track by moving the timing around like you did, and bumping the jets around to see what it liked. If you get it tightened up enough, you will be able to have a Spring/Fall jetting combo, and a Summer jet combo. Usually one or two jets up or down is all you will need to keep it dialed through the season.

Good job for sticking it out. A lot of people give up a lot sooner.


Tue May 02, 2017 11:11 am
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Joined: Wed Jul 02, 2014 6:17 pm
Posts: 530
Once I stepped up the the Magnafuel-300 bypass pump, my fuel issues went away.............. :thumbr:


Tue May 02, 2017 4:52 pm
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Joined: Mon Oct 21, 2013 12:15 am
Posts: 196
Location: San Diego, CA
I switched to an Enderle 80A-0, and I have never been happier. The last thing on my mind is fuel delivery!! :thumbr:


Tue May 02, 2017 6:13 pm
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I never really figured i had a delivery problem as my pressure was always solid thru the run, it was just needing such huge jets, especially compared to the dyno. It just didn't have the volume i needed, I have it now! This all started this year cause i registered to do drag week and wanted a bypass system for driving that much :=D .The good thing is weather sat was similar to when i ran 10.02@132 in nov, but I had a pretty decent headwind sat and i was only 60 fting 1.39-1.40, Byron's track was like flypaper! I think my 9's will happen this year, least I'm crossing my fingers lol. I plan on trying drag radials at Brainerd in july to make sure my setup is good for drag week. Drag week being in sep, we could have some good air!

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74 Firebird 3620 lbs
10.02@131.96 1.377 60 ft


Tue May 02, 2017 7:46 pm
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Joined: Mon Oct 21, 2013 12:15 am
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Location: San Diego, CA
Good luck with Drag Week! That is something that I would love to do myself! I switched to Mickey Thompson Pro Bracket Radials last year, and I am so glad that I did. What an incredible tire. Top end stability, good hook, and you will mph more. I started at 18psi, and my magic number is 20. Those tires hook up on an ice rink. Not sure if you know this, and not insulting your intelligence, but don't use rim screws. Make sure you use burgundy high-tack to glue the bead to the rim, because they do walk a little, and could walk enough to throw the balance off. I had that happen, and that is a rough ride!

Again, good luck. It sounds like you are having fun, and that is what this is all about. A good passion keeps you centered.


Wed May 03, 2017 12:14 am
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Joined: Sat Jun 01, 2013 8:02 pm
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Yea , Its close to my area this year so I thought what the hell, and I have a friends who do it, may be a little rough with 4.10 's
lol. Just keep it down to about 3000 most the time should be ok. U have a link for that glue? My friend tried out the pro brackets this year ,
here's his result sat lol, Funny thing is he couldn't get them to hook til he got down to 12 psi! I'm sure he needs different shock adj to get it to work with more air, the car is absolutely awesome, has ran 9.07 N/A. I'll be using the ET street R since a tad more tread if i get caught in rain in drag week.


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74 Firebird 3620 lbs
10.02@131.96 1.377 60 ft
Wed May 03, 2017 8:10 am
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