Turbo '98 Cobra fuel system advice

Mack Verde

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So I have a T56 swapped 1998 Cobra with a forged Teksid build 9.0:1 compression with a ON3 gen 2 kit that needs some love in the fuel department. Goal is 850whp max on e85. Is the best thing to do to swap to a 99-04 tank? I found a dual 465 lethal performance kit for sale for $900 used I may go for if it's an easy application. Any advice is appreciated.
 

9397SVTs

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If you go with the used kit, get an '03-'04 Cobra tank. I would also get aftermarket fuel rails and 1200-1300cc injectors.

Feed the rails from the rear and return each rail separately to the regulator.

Feed line from tank to firewall : -10
All other lines: -8

I think it's ok to go a bit big with the fuel system to make sure you have some headroom. Since you want to run E85, you want to be sure to have enough volume in addition to the fuel pressure.
 

98 Saleen Cobra

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If you go with the used kit, get an '03-'04 Cobra tank. I would also get aftermarket fuel rails and 1200-1300cc injectors.

Feed the rails from the rear and return each rail separately to the regulator.

Feed line from tank to firewall : -10
All other lines: -8

I think it's ok to go a bit big with the fuel system to make sure you have some headroom. Since you want to run E85, you want to be sure to have enough volume in addition to the fuel pressure.
that's pretty overkill man. We don't even run that size line in some of the 1400-1500hp cars on E85..

My personal car.

-10 from tank to weldon filter. Pre-pump-post all all connected.. -8 from post to a Y-block, -8 to back of rails. -6 from end of rail 180* back to the regulator. -8 return.

I'm making probably around 1000rwhp with zero issues. Again we've ran this setup at 14-1500hp with no issues.
 

9397SVTs

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Everybody has their own way of doing things.
 

Tabres

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that's pretty overkill man. We don't even run that size line in some of the 1400-1500hp cars on E85..

My personal car.

-10 from tank to weldon filter. Pre-pump-post all all connected.. -8 from post to a Y-block, -8 to back of rails. -6 from end of rail 180* back to the regulator. -8 return.

I'm making probably around 1000rwhp with zero issues. Again we've ran this setup at 14-1500hp with no issues.

In his defense, that was the recommended recipe for years and years on here. It's exactly how mine is built except I have a -6 return from the rails to the regulator and regulator to the tank. There really is very little cost difference between the -8 and -10 stuff. Becomes one of those 'why not...' sort of situations.


My addition to the conversation, don't use fittings and hoses that are on the cheaper side. While they may be rated for E85, they'll harden up like a son-of-a-gun with that fuel. The fittings won't want to swivel or thread well, becomes a real nuisance. Spend they money on nice hoses and fittings.
 

98 Saleen Cobra

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In his defense, that was the recommended recipe for years and years on here. It's exactly how mine is built except I have a -6 return from the rails to the regulator and regulator to the tank. There really is very little cost difference between the -8 and -10 stuff. Becomes one of those 'why not...' sort of situations.


My addition to the conversation, don't use fittings and hoses that are on the cheaper side. While they may be rated for E85, they'll harden up like a son-of-a-gun with that fuel. The fittings won't want to swivel or thread well, becomes a real nuisance. Spend they money on nice hoses and fittings.

Yea that's true. +1 on the hoses and fittings. I use XRP stuff Super light weight, but super stupid expensive lol. But really easy to bend and stuff.
 

Mack Verde

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10-4 on all the advice which I appreciate. So my plan is as follows:

1) acquire 03/04 tank
2) acquire 03/04 style fuel system

that leaves me with wondering will my OEM wiring hook into the 03/04 hat or will I need to solder in a new pugtal? what about rails? the lethal system says it works only with stock 03/04 rails for some reason.

my car is a 1998 and has the return style system...would the Glen's performance pick up hat work for me if I choce to go external?
 
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96dreamer

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Not sure what price you consider gold, but here's an option:

2003-2004 Mustang Cobra fuel tank.
Seems like that's about what guys around me are asking for used tanks with a stock hat which would be no use to me. ON3 also sells a 03/04 style for under $300 I believe. I'm not sure what direction I'll end up going at this point. I'm still street tuning on low boost and hopefully will find out what it makes on e85 maxing out the 80 lb injectors and stock lines later this year.
 

mlackke

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Hmm, why you would need to swap the tank, why original would not be suffiect?

Where more powerful pump, bigger injectors are obvious upgrade, but what comes fuel lines and rails of 98, is there even number how much they support as stock? I would not waste any dollar on those unless mandatory.
 

96dreamer

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The 03/04 tank is nice because it has the integrated baffles and the ability to run multiple in tank pumps. I like the idea of multiple in tank pumps for a street car because of noise.

I've been under the impression the stock lines and rails start to become a restriction around 600 rwhp. My car on e85 with the 80lb injectors should be somewhere around that on lowish boost so well at what happens.



Sent from my SM-G950U using the svtperformance.com mobile app
 

98 Saleen Cobra

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here is what I don't like about the 03/04 Cobra tanks.. Multiple pumps.. Real life story right here..

My buddies 850rwhp E85 burning cobra, we are driving around floor it and car falls on its face. Thank god for E85.. Turned out a pump went out.. Car ran fine all the time cruising around.. Had that had been on pump gas? bye bye motor. I run a big single external. Maintenance is super easy. 1 pump and pre and post filters are all right there. If the pump goes out? guess what you know it right away. You get into running 3 pumps and when you need that pump the most it might be dead and you wouldn't know. Especially on stock ECU cars.. My dominator I have safeties enabled for fuel pressure, AFR, oil pressure, etc. It reaches a threshold it cuts ignition and let me know something is wrong before something melts.. Something to consider when building a fuel system guys.

03/04 Cobra guys I can see because they already have a tank.. For us though? Where you need to either buy a tank or run a pick up, I highly recommend you really think about it. the external pumps are not a big deal. I've been running one for 12yrs. A1000 no controller, and a Weldon 2525A and now a 2345 with a controller. Even though my controller is turned all the way up there are ways around things being noisy.

Food for thought.
 

9397SVTs

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I have a triple pump set-up with an 03/04 tank. I don't recall which Walbro's I have, I can check later, but they are quite loud. Two run all the time and the third is on a Hobbs switch. My car has 3" exhaust coming off each turbo with Dynomax Bullets that dump at the axle and you can definitely hear the pumps over the exhaust.
 

9397SVTs

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Any 5/8" id rail, that is application specific, will work.

If this is a street car and not a dedicated track car, I recommend the -10 feed and all other lines -8 as stated earlier. If you use the Glenn's pick-up, you'll want to get the -12/-8.

Typically, external pumps should be mounted so that they are gravity fed.

Why such "overkill"? If this is a street car, your pump will constantly be providing way too much fuel during normal driving. More fuel will be circulating through the fuel lines than going into the engine. I think the slightly oversized lines will reduce some strain on the pump and the lines will have a bit more surface area to help reduce heat build up in the fuel.
 

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