Has anyone ran larger fuel lines from the back to the front or is it the school of thought here that they are not needed?

I am running a T88 on a large street port motor and a Haltech.

Thanks in advance for the help.

 

George?

Stock fuel lines have a limit. Not sure what that limit is, but I would guess about 475RWHP. That is with an upgraded pump.

More pressure helps, but you're going to run out of that at higher boost too.

The stock serial nature of the fuel rails is kinda of rude, too.

Working on a complete kit upgrade. It's going on Nocab's car as a test.

So, for high boost, high fuel requirements, high horsepower, your're going to need more fuel than the stock lines can handle.

With a T88 you should be scratching those limits. Why mess around with the most critical aspect of your performance....fuel? Spend another few bills on the insurance of not maxing out and going lean.

Tony K.

 

You say you are already running this setup. Easy test to see if you have fuel system is up to the task.
Put a fuel pressure gauge at the rail or near it, watch the fuel pressure while you are boosting/going throught the gears. If the fuel pressure follows proportionally to the boost you do not need change the fuel system. (This is assuming you are running the stock fuel rails with the stock fuel pressure regulator or a 1:1 ratio aftermarket one). If the fuel pressure can't follow the boost pressure proportionally then you need to do one or all of these:
A) change your fuel filter
B) get a bigger pump
C) change the fuel lines to something less restrictive

 

Good test. But what is the potential worst case while testing? Pop? Yes, it depends on the tester and their due diligence. Just raises a warning flag.

 

I just figured if this person was currently running this setup it probably woulden't be a issue to do the test. Maybe adjust the fuel a couple % up just to be safe while doing the test? How else are you going to know if you have to upgrade your fuel system without testing it?

 

The car is not on the street YET. It will be soon enough. I need to tune a bit but "should" have nice HP numbers. i just dont want to pop motor. I just want to make sure to get as much fuel to motor as it wants.

You never got back with me Badog about tuning either.

 

you will need Fuel Volume! Badog said it best, "Stock fuel line's have their limit" There's only so much volume they can flow, regardless of pressure.
Me personally i wouldn't want to push over 400hp on stock lines. But that's just me and im sure many people here have pushed well over that on stock lines,
NOT SMART, but it is possible.

Do it right and change your fuel lines!!! Unless you have some spare motor's. And then you can tell us the limit of the stock fuel lines from experience....LOL

 

Yes, spend the extra hundred bucks or so to ensure a safe reliable engine set up.

 

Sorry George, I'm going to shy away from HALTECH for right now. I don't want to spread myself too thin just yet. I don't consider myself experienced enough in that.

 

I'm too lazy to come up with the equation that defines the flow of the stock setup. Until that firm delineation point is defined, we all work with "fuzzy" numbers. These numbers are based on trial and error. Nothing wrong with that, unless you can't afford figuring out were cutting edge becomes bleeding edge!

 

Who said anything about equations? I was just giving a simple way to test the system on the car.

Plain and simple, if you have the fuel pressure at the rail and it doesn't drop off you DON'T need to upgrade the fuel system. But if your fuel pressure doesn't follow the same curve as the boost (assuming 1:1 FPR) then it's time to start looking at the system.

I'm just sick of people saying "man you really need to run -10 lines". Before long people are going to tell everyone to rip the sewer pipe out of their front yard and install it on their car so they will have all that VOLUME.

Ok I feel better now

 

I thought there were alot of people running 450-500rwhp on stock lines. Especially since some of the high hp "drop in" pumps are supposed to support 500rwhp+. Maybe I was wrong though.

 

I've heard of guys up to 500 rwhp on stock lines. Personally, I would not like to go over about 450 rwhp.
Replace and you KNOW you have quality components which won't leak or crack in the future. They will also be big enough for when the time comes that you want to upgrade even more.

 

I do plan to run over 500 hp. With that in mind, what size line do you guys think I should run and which pump?



BTW, I really do appreciate the help.

 

If your planning on making 500 or more, i would recommend -8 lines(minimum), fuel sump, and external fuel pump. Think of it as your foundation. Once you got a good fuel system, sky's the limit.

And for the guys who think you don't need volume, They haven't made any serious power then. I admit im semi-new to rotaries but i've been building piston motors for quite some time, and when you start to make some big numbers you will see just how important a good fuel system is. And it's even more important for a rotary!!!

 

I have ~8 feed lines and ~6 return lines run the length of my car. Perhaps a little overkill... but, who knows, may decide to put that 20B I've been wanting in the car
Best,
John

 

I also run -8 feed lines and -6 return. While on the dyno, fuel pressure was dropping over 420 rwhp (on a mustang dyno) with the stock lines.

It is possible that my lines may have had a kink somewhere which would aggravate the problem. It's true that others have achieved higher power numbers using stock lines but why chance it?

 

I said the dreaded word "equation." As in Volume, Pressure, and the Boyle assumption of Temperature.

I am sick of people being led to push their cars to the brink of popping without something more than trial and error. I don't think your response would have been as irksome if anywhere in there you said "carefully approach the limits" , or "watch your AFR while you are testing" , or anything else NOT implying it's easy and painless to test limits. You must be lucky.

Or you may be smart enough to get away with assumptions, but a good portion of the people reading may not have that luxury.

And I think AN-10 is over kill. AN-06 for single pumps seems fine. AN-08 for duals should be good. Why would you need more for <600RWHP and <30psi boost?

I don't think you mean to imply that volume and pressure are not related.

 

ok, so you guys would run a Supra or Walbro main pump with like a Peirberg secondary pump for reassurance?

The fuel lines -8 up and -6 back are not going to be a problem.

Thanks again for the brainstorming!!.

 

I agree that you need a good fuel system for a turbocharged rotary. They strive on them. But when people say you need X size of line for X hp it's ludicrous. It doesn't matter if you have -10 or even -8 lines on the car if your pump can't feed the engine the right amount of fuel pressure at the rail it. I bet it actually hurts some cars to have a -10 for the pressure line. Thats a hefty column of liquid pushing back onto the pump when the car accelerates hard.
I guess you just have to find a happy medium in between too small and too large. Too small and you start to run in too much delta P across the length of the line, too large you find the point of diminishing returns.

 

I'm sorry about not saying something about carefully approach limits or along the line, I should have. It just gets to me when people tell others to run the biggest line you can get your hands on when it's not necessary or desired.

I suppose I never said that pressure and volume were related, I guess I thought that was just a known.

I think we are getting close to the same page now

 

could it have been a fuel pump issue?
It seems most folks out there with 450-470rwhp experience no pressure loss when driven by a strong pump.

 

OK, so what intank fuel pump do you suggest and what secondary pump to use?