That 5.3 makes a difference. I made 500rwhp on a mustang dyno with a D1 at 12psi and 12 degrees of timing.
Returnless Fuel System
- Thread starter PSD_
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Nice. A lot of untapped potential there! I guess I take back what I said earlier. The 5.3L is the best mod I did to the car. Return system and WOT box would be second.
So is the weak link after upgrading the pumps and injectors just the feed line? I have never setup a return style fuel system but im justing trying to figure out the weak links. I have a KB 2.8 only running at like 16 psi, like to switch on over to Corn and pump more boost. Since corn is safer than 93oct im just trying to see if its possible to do so with just a pump and injector upgrade and not try to run a whole new fuel setup
Yes. I would say the stock 5/16" feed line and stock filter would be the weak link after pumps and injectors. I went from 96% FPDC with GT pumps, stock feed line and stock fuel rail down to 84% FPDC by just switching to a -8 AN feed line. That was at 650RWHP on pump gas. Figure 30-35% more fuel to make same power on E85 there was no way I would have been able to run it at that level, even with a boost a pump. The volume just isn't there with that small of a feed line. If you upgrade just your feed line it will already be done if you go return down the road. The stock rails will be fine as long as you have a good reservoir (big fuel line) behind them. This is based off my experience and set ups over the years.
I was going to mention something about the 5.3 also. there's no replacement for displacement. Thats where the power is coming from on conservative everything else.
This is how I ran my returnless setup with Improved GT pumps for years without issue, supported over 600 hp on 93.
The -8AN fuel line is the ticket. A must for any reliable 600+ hp returnless system.
Is anyone else with a high hp return-less system getting a hesitation when shifting? If I shift like I’m trying to bang the gears, I’m good, but when its a little slower, I get a hesitation for a split second then the power comes back.
same thing happened to me. I did pprv delete and it did nothing. I put a return system in and it never happened again.
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It could also be a tune issue. Weirdly enough I had it happen when my 01 was N/A even though my fuel system was set up for a blower. Had to make some adjustments to fix it.
Yup PPRV has been deleted for a while and that did seem to help initially, when I was on 93 and only a SVT Focus pump. After adding a BAP and DW340 fuel pump for e85, it happens all the time. This is on an 2002 GT with a KB. Don't really want to mod the car any further so Ill live with it until I decide to go return or sell the car.
It's difficult to say with certainty......but there's one way to find out: upgrade the feed line. You're at 16psi right now, so try that first with E85, check your duty cycles.....if you have headroom, swap the pulley and go for 18.
Honestly, I'd rather run 16-18psi on corn than 19psi on pump gas/torco. You can let her rip 20+ on corn later down the road once the funds are available to go full return. Lower boost corn won't be a joke at all once you see what all that extra timing does on ethanol. Way snappier low and mid range if the tuner knows what they're doing with E85. Much more fun street light to street light. And you still have the ultra safety margin of the corn brew.
Talk to your tuner. He should be able to fix it. You shouldn't have to live with an issue like this.
Reason i want to run more boost is people were telling me with my KB 2.8 being at 16psi is too low that i should run the 2.8 at like 19-20psi
I had my tuner do the attached which seemed to help but it's not gone. He recommended going to return to resolve this issue totally.
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Oh for sure that's scenario A......but you're on the fence right now because you don't want to go full return $$$ at the moment and are trying to stretch out the returnless capability with minimal expense. That leaves you in a conundrum and you can only go so far by throwing a couple parts at it and run E85 lower boost.
Not on mine. I'm high boost (22psi), E85 and returnless.....no hesitation at all on any shift or throttle position. 04sleeper tuned.
The way I see it is: no boost is to low. It's more than the atmosphere can provide you so it's ALL good. Yeah the 2.8L will be more in its efficiency range at 19-20 psi but then you have all the other parts and mods to go with it which is mo' money. If you have the fuel and intake tract for it, let it rip.
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