1996 Mr.Pink

[3X00-Modified]

In CO and Last year it was enough to overpower my evap system and caused the fuel tank to be pressurized... I don't actually have a temp sensor on the fuel to check that.

[woody90gtz]

Its not shielding that's the issue... Fuel running through the fuel rails under the intake where it's hot it absorbs the heat and is dumped back into the tank... The way I have it setup now it comes from the feed to the regulator and goes directly back to the tank... The other inlet of the regulator feeds the rails so all of the fuel that is sent to the rail is used and not returned to the tank.

And you're running a Walbro 255HP right?

I've never had any issues with mine, even on long trips but that is still a stock flow pump. IIRC it's actually the original 95Z pump. I've seen reports of this happening on Power Tour and the like with cars running big fuel pumps (like Aeromotive A1000s) but never heard of it with a 255. That's the same pump I have for my Camaro...and I thought I would be ok by going conservative on the pump...because the big pumps just circulate the tank way too quickly...especially as the tank level drops. Although my rails may now get as hot since there is not a UIM over them.

Is there a way for you to use a pressure damper? LS engines running the regulator before the rails use a damper to keep the fuel pressure more consistent. The further away the regulator is, the more it will pulse with the firing of the injectors.

I have seen people actually run fuel line coolers on the return. Basically just a finned heat sink put in an area that will naturally get airflow as you drive.

[Money pit Beretta]

I see, thought you were worried about the engine compartment heating the fuel before the rails. LOL something I always wanted to do was "port" the outside of the intakes for better air flow around the rails. Also taper that rectangle on the bottom of the upper. The flow would still be low and the rear rail would eat a lot of heat. Always wished GM had put the rails on the outside in the first place. Or at least aimed the cooling fins the correct way.

[3X00-Modified]

I've thought about a fuel cooler and that will probably be my second option if this runs funky as well as moving back to return type... I mean it can't be that bad if it's the same configuration used for the 3500. And I believe their regulator is in the tank... Mine is less than 12" from the rail, line wise.

I can easily switch it's function back to a return type rail with just eliminating my Y and running a direct line from the feed to the rail then back to the regulator.

And yes its a Walbro 255lph. Switched back to an older pump that I had from the red car this year that fits the bucket perfectly vs the style I had since 08 where I had to cut up the bucket... Was never fond of that seeing how the pump doesn't get the cooling effects of the fuel around it and you can starve the pump easier under hard acceleration. And as I said I don't think its the pump or anything heating the fuel I think it's just because the fuel is running through the rails where it's hot and the hot fuel being returned is over whelming the system and the tank can't expel the heat quick enough. It mostly happened when I was in traffic or when we were going up the mountains in CO... so heavier load not fast driving. I initially though it was heat from the exhaust pipe heating the bottom of the tank but shielding that didn't help and the original exhaust never had a shield so I don't think that was the only thing causing it.

[Slinky]

I believe I'm going to put heat tape on the side of my tank that my exhaust runs and nearly touches, I was never happy about that.

[woody90gtz]

255LPH or 255LPH HP? The HP is rated 255lph at I think 80psi, so at 43-55 it is actually more than 255lph.

And you're right, big fuel pumps don't heat the fuel, they just recirculate the fuel up to the hot rails faster and it compounds the problem.

[3X00-Modified]

It's the hp version... Maybe. Not sure what I bought years ago.

It's a F20000169 which is listed as a high pressure 255

[3X00-Modified]

Ok so if ANYONE needs custom axles... gently caress DSS and RCV... Just talk to Jon a CVsource... He got my axles on Monday and had them completed and ready to ship by Wednesday night... I unfortunately did not get his emails on Wed night and Thursday morning for some unknown e-fukup but when I got a hold of him Thursday evening I got him a shipping tag and they are going out the door today. Hopefully I will have them by Wednesday.

And only $265 later... Never mind that he straightened one of the axle shafts because it was slightly bent... and he also upgraded the drivers side inner CV joint which was the quality of light duty aka 4-cylinder applications even though I bought that axle back in 09 for a V6 auto application... Damn cheese ass re-man companies not paying attention.

Quickest custom axle turn around I've ever seen...

Jon Roberts
CV-Source
678-889-4118

[heavywoody]

Definitely good info to have. Thanks for the legwork!

[3X00-Modified]

Well today is the day... Axles are on the truck to be delivered to my house this afternoon. If all goes well I hope to be posting a success or video of the car running later tonight or tomorrow morning. I feel as though I've gone over everything 50 times so I'm expecting this to be rather uneventful but there is always a chance I forgot something so I'm still very nervous or cautious of how tonight will go.

Plan of attack,
Drool over axles
Re-install rear trans bracket
Install axles
Fill transmission
Mount subframes for good and align knuckles with ball joints. (only major issue with the new rear bushings, the control arm will not bend down far enough to insert the ball joint into the knuckle... )
Set control arms at ride height, tighten outer CV bolt
Prime motor
Install oil pump drive shaft
Install oil pump drive gear assy
Install front header
Install upper intake
Fit short Intake with MAF
Route plug wires
then hope for the best.

[Red_Bra_Black_GTZ]

Lots to do for 1 nights work

[3X00-Modified]

They are all like 15 min jobs...

[3X00-Modified]

It's alive

[CorvetteBeretta]

That sounds killer! Love the exhaust tips too.. What muffler are you running?

[3X00-Modified]

Photos from 08