10secondZ

iTrader: (24)

Got a question...I am gunna run two gss340's in the tank...but the whole fuel system besides injectors is stock...would there be a problem with running dual 255 liter pumps with the stock regulator and all? Thank's,

Carter

MIGHTYMOUSE

iTrader: (59)

if you run them at the same time at idle.. i think there would be..

when i cut bot of mine on at idle (using the larger stock pressure line as return) i get this loud shhh!!! from under the car like high pressure water from a shower.. i assume it is the return line being too small to return 500lph of fuel.

if you run the second only under boost.. well racetronix does this and claims good results with stock lines.. but i wouldnt reccomend it. as the pressure line is something on the order of -4 at the crimps.. so you would be pushing it (i'd think) with just one 255 intank.

10secondZ

iTrader: (24)

Thank's for the reply man...damn i guess 1 255lph pump is gunna have to do for now..Thank's again,

Carter

MstgKillr

iTrader: (4)

I run the ARE/Racetronix setup for my setup. I have the second pump on at 0 vacum

MIGHTYMOUSE

iTrader: (59)

i cut mine on with my boost controller output

there are a precious few doing awesome on stock lines.. but wherever the limit is.. i think your goals are over it!

10secondZ

iTrader: (24)

it's for a friend of mines 427ci ls1 with a little spray on it..my fuel set up will be ***** 2 the wall

TwnTrboCE

iTrader: (43)

I'm running two 255's. One intank and one in line. Both run full time. I'm using stock lines and rails. But not a stock regulator.

Racetronix

iTrader: (2)

There are much more than a 'precious few' running the Racetronix DP system with stock lines who are making between 600-700RWHP. Keep in mind that the fuel lines are not the limiting factor here but rather the head pressure the pumps can develop. It all comes down to pressure and the volume to back it up!

2001WS6Vert

I think 600 is right near the limit on stock lines. Who is near 700?

Racetronix

iTrader: (2)

We don't keep a list of end-user names.
You would have to contact ARE and ask them this question as they sold most of the DP systems. Single systems have exceeded the 600RWHP mark. For a DP system this is a walk in the park. More Performance has some Racetronix prototype F99+ single systems in operation that are supporting apx. 600RWHP with steady pressure. You can call Wade @ ARE about DP's or Mike @ More about singles and ask.

The less capable single F-LT1 system supports apx. 550RWHP w/o a booster. There are quite a few using this system on www.camaroz28.com.

On some high HP F-LS1 cars a front mount FPR is required or modified rails but the factory feedline is fine. GN's have been running 9's with DP's and factory lines for years so I don't see why this is such a hard pill to swallow for the f-body crowd? This is old news. Don't forget a little 231CI V6's BSFC is going to be much worse to produce the same HP as a V8 because cylinder pressure is going to be much higher.

People on this forum seem to have some pretty odd ideas about the F-LS1 fuel system. It is much more capable than most people think. It's not about throwing a ton of money at something to make it work but rather about putting enough money in the right places.

ChrisB

I have 2 GSS340's in the tank running full time and no problem (but this is on a LT1)

2001WS6Vert

Racetronix, This is from my personal experience. I have run into limitations on both the stock rails and lines. When I was getting dyno tuned my car had a high rpm mis-fire. The tuner was not sure what was the cause. When data logging while racing I noticed the right bank o2 sensor was still cycling from rich to lean under WOT. I talked to SpeedInc. and they confirmed what I was suspecting, it needed high flow fuel rails. After installing them the mis-fire was gone and the data showed full rich. After this (with the relocation of the fuel pressure sender) I saw that my fuel pressure was dropping at WOT (not too much, lower 50's but still it was disturbing). I then ran the #8 feed line with an Aeromotive regulator and a #6 return line. After this the pressure does not budge south (it even rises due to the regulator). I did not want to do these mods but found that I had to. I am probably around 600hp. I would bet that most of the LS1 folks have replaced their lines due to necessity not because they thought they should. I'm sure there are some guys that overkill but I'm from the school where if it ain't broke don't fix it (thats why I still have my stock rear end). I'd like to see if some others might chime in on this because most cars that I read about on this site that are 600+ hp do not still have stock rails. I know there are some around 600rwhp and maybe a little over but I have not read of any around 700rwhp. I am just trying to set the record straight, I feel the limitations are closer to the 600rwhp range.

Racetronix

iTrader: (2)

Lines and rails are two different things.

The LS1 rails are a problem at higher HP levels.

The LS1 return-less system with tank-mounted FPR is a problem.

This is why FMFPR's are used as well as having -6 fittings welded to the end of the rails.

Aeromotive pumps are not as capable as Walbro pumps when it comes to developing higher pressures.

Gerotor pumps always outperform vane pumps in this area.



The post we made was to specifically address the issue of the factory feed-line.



re-quote "On some high HP F-LS1 cars a front mount FPR is required or modified rails but the factory feedline is fine. "



Fuel pressure, flow and volume are very similar to voltage, current and watts (power). If your source has enough flow / current at a high enough pressure / voltage to overcome / compensate for the line resistance (which equates to pressure / voltage drop) and still maintain the required volume / power and pressure / volts to satisfy the load (fuel rail) then all will work well. It is always better to regulate the pressure / voltage at the load / rail end as this will stabilize any fluctuations caused at the source, feedline or load demands.



There must always be enough pump volume at a given pressure that is above the actual load demand minus the feedline loss in order maintain stable regulation.



In other words we could supply a 1000HP though a line that is a fraction of the factory size given a fuel pump which could produce enough pressure & volume. The size of the feedline is not the only deciding factor in a fuel system's HP support capability. Line configuration, composition as well as all the other system components play a major part in this as well.

2001WS6Vert

Techno lingo aside, lets just say the dual Walbro in tank will have problems supporting 700rwhp through stock fuel lines, of course thats my opinion.

Racetronix

iTrader: (2)

Your opinion was disproved years ago.

If we can dig up the people that have achieved this through our dealers we will post the information here as obviously this is what it will take to end the debate.

smokinHawk

iTrader: (48)

ONe thing may work with someone but not another.
In my book i say better safe then sorry, if someone wants to be on the limit of there fuel system thats there choice.

Twntrboce has acheived over 600rwhp with a intank and inline pump and stock lines with his 346 though he told me his fuel pressure would start to drop off in the upper rpms which bothered him
2001ws6vert couldnt get much over 500rwhp with his stock lines and single pump on his 418

btw shouldnt this be in the fuel section

onfire

iTrader: (17)

Rob's Formula is over 600rwhp with stock lines/rails/tank regulator with a single 340 Walbro and a hotwire kit.

2001WS6Vert

Smokinhawk, I had the dual in tank with the stock lines, not a single. Yea you could run a bigger pump but I wanted to use the Racetronix dual Walbro in tank kit (the Walbro's are quiet). My fuel pressure would drop off (this is with the billet rails but still stock lines, because I was told the stock lines would do the job). After running the #8 line and #6 return (with the Aeromotive regulator) my fuel pressure problems were finally solved. How else do you interpret this except to say the problem holding back this setup was the lines?

MIGHTYMOUSE

iTrader: (59)

i think 2001ws6 is right and think that he is being truthful..

whether racetronix can get a car to do it or whatever doesnt mean avg. joe (me included) are gonna be blessed with it... or have the time/ability/understanding to tune around it.

hell incon claimed they had a 1k hp ls1 on engine dyno like 3 years ago... highest dynoing incon car by 'avg' joe to date is only something around 750hp.

Racetronix

iTrader: (2)

The key to your problem there was relocating the regulator to the front of the car NOT the feed line. How can there be compensation for line drop if the point of regulation is in the tank?