At what point (HP) do you have to get rid of the 'returnless' filter/regulator setup?
01-24-2015, 08:41 PM
#1
Racer
Thread Starter
At what point (HP) do you have to get rid of the 'returnless' filter/regulator setup?
Guessing I am going to be in the 650rwhp area. At what point do I need to use the early 97-98 filter and run a return line with regulator at rails under hood?
I have read tons of post and cannot seem to find an answer. I know some people do it at 550hp, A lot of people are 700+hp and i can see the need. When does it actually become a problem?
And I assume the problem would be pressure drop in rail due to regulator being before rails and long distance from rail?
I have been told I am ok with stock 1999 reg/filter setup at 650hp - but would like some opinions from anyone that has done it (I do have LPE pump and BAP).
Thanks!
I have read tons of post and cannot seem to find an answer. I know some people do it at 550hp, A lot of people are 700+hp and i can see the need. When does it actually become a problem?
And I assume the problem would be pressure drop in rail due to regulator being before rails and long distance from rail?
I have been told I am ok with stock 1999 reg/filter setup at 650hp - but would like some opinions from anyone that has done it (I do have LPE pump and BAP).
Thanks!
01-24-2015, 10:19 PM
#3
Race Director
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2020 Corvette of the Year Finalist (performance mods)
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I had a 255 in tank pump, 60lb injectors, bap, hotwire harness, and meth supporting over 700 just fine... I am in the process of building a boost referenced return style fuel system though just so I don't have to mess with it later on
01-25-2015, 11:40 AM
#4
Le Mans Master
So not that I suggest it but for the past, I donno, 2+ years, I've been running two 255's Y'ed together in the stock bucket (bottom cut off) (2004+ style tank) both running all the time with a hotwire harness running both. At idle it over powers the in tank regulator and makes 65# and drops to ~55# under WOT and stays there. I made 900+ on this setup along with a dual nozzle alky control system and FIC 1k injectors on 93 and/or race gas. Very cheap and easy albeit somewhat ghetto. Lately I've noticed that it's only at 60# at idle so I think one pump is on it's way out so I'm currently building a return style system.
01-26-2015, 04:24 PM
#5
Melting Slicks
Here is a post that I made back in 2012. I think it is still applicable in some ways. Interesting to note that I was recommending a 2nd pump at around 750 rwhp. I didn't follow that advice and went to about 850 rwhp and ended up blowing the engine. In hindsight, lack of proper fuel delivery probably played a factor.
Fuel delivery is one of the most important things to pay attention to when pushing for more power.
To be very conservative I would rank it like this for 93 octane fuel:
1. 500 to 525rwhp: No meth, stock fuel system, Hot wire kit, 60# injectors.
2. 525 to 550rwhp: Meth, stock fuel system, Hot wire kit, 60# injectors.
3. 550 to 575rwhp: Meth, stock fuel system, 60# injectors, Hot wire kit, BAP.
4. 575 to 650rwhp: Meth, stock fuel system, 60# injectors, Hot wire kit, BAP, return line, 1:1 regulator.
5. 650 to 700rwhp: Dual Nozzle meth, stock fuel system, 80# injectors, Hot wire kit, BAP, return line, 1:1 regulator.
6. 750+rwhp: Install a secondary fuel pump and correct size injectors.
Notice I recommend an injector change to atleast 80# when trying for 700 rwhp. I also personally wouldn't try to make over 750rwhp without a second fuel pump.
These ranges will depend on many variables such as how much meth you are using, what type of A/F ratio you are trying to achieve, supercharger vs. turbo. It also depends on what type of engine modifications are installed for more air flow.
The list above is very conservative. People have surpassed these values. I'm very conservative and tend to err on the side of too much fuel capacity. It gives you a little bit of cushion in case something happens. Fuel upgrades are usually way cheaper than replacing an engine.
To be very conservative I would rank it like this for 93 octane fuel:
1. 500 to 525rwhp: No meth, stock fuel system, Hot wire kit, 60# injectors.
2. 525 to 550rwhp: Meth, stock fuel system, Hot wire kit, 60# injectors.
3. 550 to 575rwhp: Meth, stock fuel system, 60# injectors, Hot wire kit, BAP.
4. 575 to 650rwhp: Meth, stock fuel system, 60# injectors, Hot wire kit, BAP, return line, 1:1 regulator.
5. 650 to 700rwhp: Dual Nozzle meth, stock fuel system, 80# injectors, Hot wire kit, BAP, return line, 1:1 regulator.
6. 750+rwhp: Install a secondary fuel pump and correct size injectors.
Notice I recommend an injector change to atleast 80# when trying for 700 rwhp. I also personally wouldn't try to make over 750rwhp without a second fuel pump.
These ranges will depend on many variables such as how much meth you are using, what type of A/F ratio you are trying to achieve, supercharger vs. turbo. It also depends on what type of engine modifications are installed for more air flow.
The list above is very conservative. People have surpassed these values. I'm very conservative and tend to err on the side of too much fuel capacity. It gives you a little bit of cushion in case something happens. Fuel upgrades are usually way cheaper than replacing an engine.
01-27-2015, 03:37 PM
#6
Melting Slicks
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St. Jude Donor '15-'16-'17-'18
I couldn't make it over 600 with the returnless style system. This was with a lingenfelter pump, the regulator in the filter wouldn't flow enough fuel. Went to a return style and no issues since.
I forgot to bleed the line on my secondary pump and the lingenfelter pump supported 750. Not too bad.
I forgot to bleed the line on my secondary pump and the lingenfelter pump supported 750. Not too bad.
01-27-2015, 08:49 PM
#7
Racer
Thread Starter
I couldn't make it over 600 with the returnless style system. This was with a lingenfelter pump, the regulator in the filter wouldn't flow enough fuel. Went to a return style and no issues since.
I forgot to bleed the line on my secondary pump and the lingenfelter pump supported 750. Not too bad.
I forgot to bleed the line on my secondary pump and the lingenfelter pump supported 750. Not too bad.
With the return style - do I need a check valve to prevent fuel drain back?
01-28-2015, 01:59 PM
#8
Melting Slicks
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St. Jude Donor '15-'16-'17-'18
I have the A&A kit with the twin holley pumps and on their website it says there is a check valve. I've looked it over and don't see where it is. Maybe someone with more experience will chime in. I've remember seeing something about cranking issues if a check valve isn't used, but it's been a while.
01-29-2015, 01:04 PM
#9
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Guessing I am going to be in the 650rwhp area. At what point do I need to use the early 97-98 filter and run a return line with regulator at rails under hood?
I have read tons of post and cannot seem to find an answer. I know some people do it at 550hp, A lot of people are 700+hp and i can see the need. When does it actually become a problem?
And I assume the problem would be pressure drop in rail due to regulator being before rails and long distance from rail?
I have been told I am ok with stock 1999 reg/filter setup at 650hp - but would like some opinions from anyone that has done it (I do have LPE pump and BAP).
Thanks!
I have read tons of post and cannot seem to find an answer. I know some people do it at 550hp, A lot of people are 700+hp and i can see the need. When does it actually become a problem?
And I assume the problem would be pressure drop in rail due to regulator being before rails and long distance from rail?
I have been told I am ok with stock 1999 reg/filter setup at 650hp - but would like some opinions from anyone that has done it (I do have LPE pump and BAP).
Thanks!
Regards,
Rob
01-29-2015, 09:49 PM
#10
Le Mans Master
I have the A&A kit with the twin holley pumps and on their website it says there is a check valve. I've looked it over and don't see where it is. Maybe someone with more experience will chime in. I've remember seeing something about cranking issues if a check valve isn't used, but it's been a while.
01-30-2015, 01:21 PM
#11
Race Director
I don't think all BAPs are created equal. I installed a standard A&A kit, and the Lingenfelter pump, but had to shut it down @5800 rpms. No meth and 92 oct., BTW. Added a Magnaspark BAP, and was able to have more fuel than I needed for 6800. I have a non-return system.