jkel1124

iTrader: (3)

When does it become necessary to modify the fuel return? Is it recommended with the Walb255 or DW300 drop in replacement pumps?

Naf

iTrader: (1)

with the walbro 255. I had LPE do it for me as its tedious

DMM

I've never heard of it being required for either. There are some who have noted problems with the DW300 overwhelming the regulator, however I believe these are isolated cases where the regulator is going bad as this is not a problem we see across the line. If you felt the regulator was going to be an issue, the cheap way to resolve the situation would be to remove the return line inside the tank from the regulator and plumb the return back into the module reservoir directly. Then install a Corvette regulated fuel filter in place of the OE filter as it is a direct swap. This would move the regulator out of the tank and the Vette regulated filters are proven.

Never heard of anyone doing a return on a 255 pump. The stock is 190. The OE regulator can handle a 35% increase no problem. A 58% increase you may see problems at idle as some have mentioned, however others (myself included) have not had any issues with the DW300.

RADEoN

iTrader: (12)

I've had a 255 for years now, and I've never even considered a fuel return.

VeryWhiteDevil

iTrader: (9)

same here. not required until you remove the FPR on the bucket and remote mount a new adjustable FPR. Otherwise just upgrading the pump in the bucket, no other modifications are necessary. Running My Denso 300LPH pump upgrade, no return, no problems.

jkel1124

iTrader: (3)

That's the info I was looking for. I was going lean up top with the 255 and recently installed the DW300. It's running fine but just wanted to make sure about about the returns and regulator. Thanks all!

VeryWhiteDevil

iTrader: (9)

you are running boost, so I would consider completing the upgrade and doing the remote mount FPR and return soon. especially if you continue having problems. you can refer to Philistine's upgrade, minus the dual pumps. IT is holding you back. I am not running boost. that in tank FPR blows.

2007V

iTrader: (2)

A dw300 or even a stock pump will overwhelm the regulator at idle with a Kenne Bell boost a pump on. If you wire the BAP on a MAP switch then it is fine.

raven154

iTrader: (14)

The corvette regulated filter and the stock FPR can not keep up with the extra flow of the DW300. That's why people have been getting 70psi at idle. I've read a lot about the guys uses the corvette filter also and they are having the same issue.

Sssnake

DW300 and BAP with MAP switch on boosted LS2 wo full return line. Typically 58 to 60 psi at idle. The most extreme variances are 53 to 63 psi (with BAP active). More variance than I would like but not impossible to tune. I am considering a full return line but haven't committed yet.

One additional point, if you are not monitoring fuel pressure electronically or with a dash mounted gauge (vice with a mechanical gauge on the fuel rail) I have no idea how you can possibly be getting accurate pressure readings. The pressure does fluctuate at tip in and decel and without an electronic gauge tied to your logging software it can cause issues you will chase for days. With electronic logging you can even see the harmonic frequency of the fuel rail as the pressure fluctuation increases greatly at specific rpms.

bmylez

iTrader: (3)

Sssnake, you just added your mods to your sig, right? I didn't realize your car was so godlike. Seriously, I am steaming in jealousy right now.

07CTS-V

iTrader: (6)

What is the correct part number for the 255?

Sssnake

Yeah just added. CS 8.8" ordered. Thanks

DMM

What ratio? I thought 3.55's were perfect with the stock Trans ratios.

Sssnake

3.55

I liked top speed in 4th and 5th a little better plus 1st was not really much use unless I was running the 1/4.

bmylez

iTrader: (3)

So back to one of the earlier questions: which Walbro 255 swaps right in? When I was looking around today, I saw the GSS340, 341, and 342. Looks like the 340 doesn't have the right fuel sock connection and 341/342 appear to have similar or the same connection, so both work, or...?

Grenade19

Ive been wondering about this..

Pray

iTrader: (7)

I would like to know as well. I have a NIB Walbro 340 PN# 11141 that was a left over from my TBSS. Not sure where the GS and GSS pn's are coming from. I will check the web site and see if they correlate. From all the searching and reading I have been doing, it seems that there is no solid answer on which one to go with though. Either they blow idle pressure or don't have the right pump jet or don't fit the bucked or burn up. Is there a bolt in replacement that will handle 650rwhp?

bmylez

iTrader: (3)

http://walbrofuelpumps.com/255lph-wa...fuel-pump.html

http://walbrofuelpumps.com/255lph-wa...fuel-pump.html

philistine

iTrader: (2)

Walbro GSS-342 is the identical geometry for the V1 factory replacement. The inlet/outlet are inline.

The GSS-341 has the inlet/outlet flipped 180 degrees - not factory for the V1s.

Ask me how I know, hehe.