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Fuel system for drag racing

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Mr_Roboto View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mr_Roboto Quote  Post ReplyReply Direct Link To This Post Topic: Fuel system for drag racing
    Posted: Oct/27/2022 at 8:35am
So I'm running -8 AN lines in the Eagle and I was wondering about keeping tech inspectors happy. From what I've read the regulator at the firewall is a no-no, but what about a bulkhead setup? I want to mount one either on the engine or somewhere I can get to it fairly easily, the end goal is that I want to have the ability to change lines easily as I go from carb to EFI or other engine platforms. 

Also, anything else I should know before I go in? I am planning an in tank pump setup on a fuel cell in the stock location. 
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Post Options Post Options   Thanks (1) Thanks(1)   Quote PROSTOCKTOM Quote  Post ReplyReply Direct Link To This Post Posted: Oct/28/2022 at 1:36am
Since you have this posted in the Drag Race section I am going to assume your car is a track only race car?

The hot setup is to put the fuel cell in the front of the car. I haven't used a fuel system in the rear for almost 20 years. Why try to push fuel forward when you can let gravity help push it for you. Also having the cell in the front allows for a smaller fuel pump requirement than is needed if the fuel source is in the rear. 

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Post Options Post Options   Thanks (1) Thanks(1)   Quote WesternRed Quote  Post ReplyReply Direct Link To This Post Posted: Oct/28/2022 at 10:24pm
Probably a bit more info on what level you are running at would help.

Generally no fuel system stuff within the cabin, this includes fuel lines and mechanical fuel pressure gauge lines. If the fuel cell is inside the trunk, you need to seal the trunk off from the passenger compartment.

Generally no fuel lines around the bell housing area just in case of a failure that might sever the lines, this would possibly include having the regulator mounted on the firewall. Ideally run the fuel lines down the outside of the chassis rails.

Regulator can go in plenty of locations, like inner fender, spring tower, mounted off carby or even at the tank. Most modern cars run an in-tank fuel pump and regulator combo and there are some aftermarket setups that will also do this, then you don't need to run a return line.

Depending on what EFI system you choose, if it's something like the Holley Sniper or FITECH throttle body systems, then they have a built in regulator (although it is a bit dinky), so you just need the supply and return lines from the throttle body.

EFI vs carby have very different fuel pressure requirements, 6-10 psi vs 60-80 psi, so if planning to upgrade to EFI, make sure things like hoses are rated to the higher pressure. Some regulators come with two springs that you can interchange, one for low pressure and one for high pressure, so look for something like this.

For my mid 11 second 360 Gremlin, I run the Holley Sniper EFI system, I have a fuel cell under the floor in the stock location, Bosch 044 style pump under the fuel cell the 3/8" lines from the pump to the throttle body and a return line the same size back to the fuel cell.

A fuel pressure gauge is a good idea too for diagnostic purposes, you probably don't have a lot of time to look at this during the run, so a data logger really helps here. Data logger could be as simple as a go-pro mounted somewhere to record the gauges and you can review the footage after each run. With my Sniper system, I have added a fuel pressure transducer that feeds into their digital dash so it gives me a live gauge and also data logging capability. Buy the Super Sniper if going this route as it has built in capability for additional inputs like fuel and oil pressure.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mr_Roboto Quote  Post ReplyReply Direct Link To This Post Posted: Oct/30/2022 at 3:14pm
Okay, so this is going to be a street vehicle that will be taken to the track some times. It's an Eagle SX4 so it's got the Spirit Chassis+ the complexity of the AWD too and since I want to turbocharge it the yet further complexity of all the exhaust pipes going various places (I haven't figured out if I want to go around the front or the rear of the engine to place the turbo yet either.) 

Power wise if I break 400 to the tire I'd be very pleasantly surprised. Initially I'll have a 258+cam+Turbonetics T66 Turbocharger. These days that strikes me as a pretty modest goal. Provided I can find E85 around here I'd be far more inclined to turn it up and see where it goes, after I blow up my A998. :D Not really afraid of that either, I've done a few 700R4s and have heard that they are super simple boxes. My real goal is to make something like an AMC nod to the Syclones/Typhoons. I think the concept is cool and would be a blast in an SX4.

Never really been to the track before and depending on the track you go to I've heard very mixed things about the level of hassle they give you over stuff like FPR placement. I figure it's easier to do it once and not have the hassle of doing it a few times which is about how my luck goes.

I am running PTFE 8AN line for this. I decided I wanted to do it once and not goof around in that regard. I'm going to modify the cell to accommodate up to two (initially will be one) in tank fuel pumps. That way I can be set up for any power level I ever wish to run up until the point I get something absurd like a Magnafuel or Weldon, and even that would be a fairly minor swap.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 70Xcode Quote  Post ReplyReply Direct Link To This Post Posted: Jan/25/2023 at 8:58pm
My local track doesn't mind them on the firewall if it's a unmodified firewall. 
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