bensbaby

i have a built 383 sbc with holly stealth ram intake manifold
30lb inj

procomp fuel rail kit

what hp are the 3/8 fuel feed line?

I was gonna get some -8an line and do it nice

I don't want to overkill it if -6an will work

and what hp will the factory fuel pump stop working at?

ty

Kingtal0n

6an will support something like 700-900hp

https://www.aeromotiveinc.com/tech-h...th-fuel-pumps/
" It would be reasonable to rate the 340 Stealth to 700 flywheel HP EFI forced induction, 900 flywheel HP EFI naturally aspirated, on gasoline fuel. In this example the injector duty cycle for either V-8 or 4-Cyl would be between 80-85%. "
I used a stealth in my application and measured the outlet and its a 5/16" lol

Don't go any larger than you need to. And don't lean on or trust a factory pump at these output levels.
Also I don't recommend using long stretches of flexible hose. I would highly recommend using STEEL hardline for the majority of the system, then just -6 braided for either end, with Hose Clamps. Hose clamped braided hose is track legal and IMO far superior to 'chinese/ebay AN fittings' which tend to vary in quality and size quite a bit.

IROCZman15

iTrader: (25)

I just did a fuel system upgrade last winter. there are a few posts from myself and other notable TGO members on here, along with photos of my install.

I did this fuel upgrade so I wouldn't have to drop the tank or do much fuel system wise when I install the new engine winter 2019/2020 .

https://www.thirdgen.org/forums/tech...rior-next.html

340lph pump, wiring harness upgrade, -8 feed -6 return PTFE, anodized fittings, magnetic fuel filter, etc.

GeneralDisorder

iTrader: (1)

The fuel hard line is fine for your engine build. You don't need to upgrade it at all. For comparison, I have built 700 HP turbocharged engines running on factory 5/16" hard lines. You will need a larger pump. At least a 255 LPH. I would go with a 340 LPH. They are dirt cheap. AEM 340 LPH pumps are like $90.

GD

bensbaby

TY very much everyone

that's what I wanted to know

I just have to cut a access hole in my trunk and take put a big fuel pump in

I have a wally 400lph used from another car I had it in 5000kms on it

I will do that and keep the 3/8 lines

did you use the factory wiring for the bigger fuel pump

I always had to totally rewire them in other cars in the past

GeneralDisorder

iTrader: (1)

I have a 255 in my third gen. Wiring works just fine. But it's going to depend on it's condition in your vehicle. The wiring on these is getting old.

Drop the tank - don't cut a hole. Do it right.

Kingtal0n

always re-wire the fuel pump in performance applications. 100% of the time. Factory wiring isn't up to the demand of current draw.
My recommendation for a relay- goto the junkyard and pull a 70-80amp relay+container from a Volvo or similar. They usually come in a little stealthy box with a lid.
It beats the stand-alone 40amp relays which I have melted over and over and finally got smart about it.

IROCZman15

iTrader: (25)

RACETRONIX makes a complete wiring harness including relay, fuse, connectors, etc. its pricey, but all inclusive. If I wanted to i could have made my own and saved money, but I decided to buy the racetronix kit
- as already said, always do the wiring upgrade

also PLEASE DO NOT CUT THE ACCESS HOLE. do the job right and drop the tank. access holes are for butcher jobs

KyleF

There are cars out there with this in them from the factory. Why ours didn't have an access hole baffles me. Don't know why you think it is a butcher job to do this, while modifying other shortcomings of the factory design is OK. I think it is in the quality and method of making the access hole and line connections that determines if it is a hack job or a quality modification.

scooter

iTrader: (11)

I would second staying steel for as much of the fuel system as possible. I've read that the supported HP level on a 3/8" line is almost unlimited if you have enough pump to push fuel through the line. It is limited, but there is debate on where the limit actually is.

It's not there because it is NOT SAFE, no matter what you think. The fuel tank is in the crumple zone in these cars.

Don't do it, don't increase the risk when most accidents are front/rear impacts. This video shows that anything you think you're doing to make it "safe" is wholly inadequate.

KyleF

Again, we do many modifications that make our chassis and structure stronger. It is about the method.

A lot of members here have added sub frame connectors and new K-members that affect crumple zones as well. Is that unsafe? The answer technically is yes. As the car is designed to fold up and absorb and dissipate energy at impact. This is why new cars look like they get the worst of a crash but occupant safety has went up. The stronger structural members are not designed to do this and have not been tested by the NHTSA and certainly not individual combinations.


The trap door you put in place of what you cut out can be a stronger thicker gage plate than the sheet metal you remove and fully secured around the perimter reinforcing the structural integrity of the area. It will affect how the area folds up; I can't disagree that it affects safety. Though, without CAE of the method of attachment and material used, neither you or I can definitively say if is is more or less safe. I would say based off my background, that the area is small enough that if secured back in properly this variable is negligible in comparison to other variables involved in a crash that determine the ultimate results. Such as velocity of impact, mass of impacting object, angle of attack, the impacted objects freedom of motion, and etc. There would need to be 100's if not 1000's of simulations that would need to be ran.

My main point here is there is a large difference between this:



And this:

scooter

iTrader: (11)

The point of my video is that THIS IS NOT SAFE EITHER!! If the back end folds like the video, that is going to be a point of entry for fuel, no if's and's or but's about it fuel WILL get in the cabin.

Stop advocating a trap in the back is safe if it's done "right", you CAN'T do it right and you can't test whether what you've done is going to work.

Kingtal0n

I am a little bit confused by this debate. Don't people regularly mount fuel cells inside the trunk... you know those aluminum tanks that sit right inside the car where you can see them?

And then run giant fuel lines right from there down under the car etc... It just seems like a flimsy flap of sheet metal being MIA is negligible compared to the majority of fuel cell installations I've seen where a rear impact would undoubtedly rupture the enormous fuel hoses and that giant fuel pump would flood the car with fuel in seconds.

My opinion is that a good mechanical engineer could design a flap that is both more secure and safer than the flimsy factory sheet in place to begin with. And that I'd rather have the tank under the car than inside the car with me.

Personally I just bought a car that has a tank access hole already from the factory to avoid this whole issue. Its got a flimsy cover with 4x 10mm bolts around it. I just dont see the 'safety' as part of the cover, instead I see 'safety' as the mounting and configuration of the tank itself, which is both strapped and sealed by the factory whether I have an access hole or not.

Orr89RocZ

iTrader: (20)

scooter

iTrader: (11)

Trunk is a little different. Some trunks are sealed from the passenger compartment, we don't have a trunk. Who said fuel cells are legal for street use inside the car?

In the video I posted, what do you think is going to happen to the fuel when the hydraulic pressure in the tank gets high enough? The tank is going to burst and one weak spot is the rubber O run between the sending unit and the tank which would be directly under this access panel as the area is deforming. You don't think there is a high probability of fuel getting in the cabin? If the integrity of the solid piece of sheet metal is still in tact, there is a much lower likelihood of fuel getting into the cabin from that area. It is unlikely to tear and make it possible for fuel to get inside the car. If you have a trap door, that is not going to deform the same as the piece of sheet metal it is attached to, it is going to leave gaps in between both pieces of metal.

GeneralDisorder

iTrader: (1)

Cutting an access panel is an exceptionally stupid and lazy method of replacing the pump. Real men just drop the tank. As has been pointed out, an access panel directly behind your head and passengers is a great way to end up dead when the fuel tank is compressed and the sending unit squirts out right through your panel.

Besides that it's pure laziness. Borrow or rent a lift if you don't have one. Or pay a professional to do it. Us professionals have to eat too...

GD

KyleF

You can't test and prove that is is not and I didn't claim one way or the other. I actually agreed with you.

Again, there is a difference between using something like this that welds in a frame and bolts down a cover
https://www.detroitspeed.com/fuel-pu...nel-kit-080402

versus using silicon to glue the cut panel back in place as far as a "hack" job goes.

To be clear, I wouldn't cut mine open. Though, if someone is to go this way please use a bolt/rivet in panel in its place that is at least the same if not thicker gage material. Don't just hack out a big piece of material and then set it back in place.

Kingtal0n

Ohhh, now it makes sense. I did not know this- I am glad somewhere they spell out the rules.
Well thats where I would go with this. Look to the rule book and make a call based on how you use the vehicle I guess.

The access panel in my car is a flimy piece of sheet metal too so idk
heres a pic of a random one (same as my car)




looking at the two- comparing my tank to the thirdgen tank- it doesn't look like the panel itself is the issue. Rather, it looks like the design of the tank is the issue. Maybe you can convert the tank to be 'access panel friendly' somehow. Or maybe it is because of the location of the tank (inside the cabin as was mentioned above). Maybe add some kind of 'firewall' that locates the tank to just the rear of the car like a trunk area. just random thoughts and I do care because not having tank access is almost as bad as not having plug access. gl friends

GeneralDisorder

iTrader: (1)

It really depends on the structure of the vehicle - if it is likely or not that major deformation and/or fuel tank impingement would be the result of a rear end collision. On the F body's the fuel tank is not protected by much from the rear. On a most vehicles I can think of with access holes there is a large sub frame under the tank that is effectively a crash cage for the tank. The F body has nothing really - just a large rear differential that is free-floating.

..... Honestly this is pretty much a non-issue if you use a quality pump. You do the $hitty job one time and then you are done. So no real need for an access panel because when are you going to be back in there again anyway?

GD

scooter

iTrader: (11)

In this case, no, there isn't a difference. That will still allow gaps between the weld ring and the plate.

That being said, in my second gen, with an actual trunk, I am thinking about welding the panel between the back seat, the package tray and the trunk completely closed, so I can actually use something like the DSE door. Though I am not sure whether I will or not because it is so easy to drop the tank in that car. I'll be running dual ZL1 or CTS-V pumps in a Ricks tank, so I would have to put two DSE doors in