always faster

Well well well finally had time to do some testing with my car.Got 2 main probleme so i guess ill start 2 thread.

The fact:

When cold i get 62-63 psi of fuel pressure.I do get 58+ psi when going WOT .
but...
Gradually when the engine get warm and maybe after more than an hour driving, the pressure drop 63-62-61-60-59-58 and stay between 57-58 psi in cruising/normal driving.When going WOT it drop to 52psi no less than 52 but still drop from 58 to 52.

Returnless setup less than 500 miles, Walbro 255 , Racetronix harness , KB Boost a pump.

Dynoed 681whp/580wtq @ only 8.5psi

-Suggestions: vapor lock, voltage ,anything ???

Thanks
Eric

ascastil

Does it hold pressure when you turn the car off?

Honestly, I dont think theres anything to worry about as long as its not going lean. You didnt say you were running out of fuel with the tune or anything. Probably not the best fuel pressure but if its working.....

realcanuk

Log the voltage to see if it is dropping off.

always faster

4 dyno session total and no sign of going lean.

always faster

Will install my HPT and log it.

Warp Factor

Fuel in the tank heats up significantly from heat produced by the fuel pump. Electric motor performance goes down when hot.

Just as an experiment, you could run down to about 1/4 on the gas gauge (which means the tank the fuel pump is in will be 1/2 full), fill up with fresh cool gas, and see if the fuel pressure comes back temporarily.

JoeyG

thats one of the worst things you can do to a pump, causing thermal shock. Imo convert to a return style fuel system and call it a day if you afr and plugs are within acceptable conditions.

Warp Factor

It's also a consequence of normal operation.
What would you recommend? Measuring the temperature of the fuel in your tank when you pull in for gas, and then pre-heating the new gas to match before it goes in the tank? Topping off every 30 miles? Only getting fuel when your car has been driven less than 15 minutes, before the fuel has had a chance to heat up?

And what should people be doing in winter to avoid "fuel pump thermal shock", when the fuel in the the car is 0 degrees, and the gas coming out of an underground storage tank is 50 degrees?

JoeyG

On a stock vehicle no worries to the fuel system. On a built vehicle convet to return style fuel system which will run cooler and better sustainability, imo.

always faster

Looking at the ecs stage 2 fuel upgrade right now.
But probably got ring problem to fix first ...

schpenxel

No worries IMO. Not a big deal.

ysb02

Seems like you're getting the hp almost into the dual pump range. When does a boosted 255 run out?

always faster

Well 700whp ish with a return style setup...im returnless

PEETYZ

Mine does the exact same thing. I have the same fuel system as you. No worries just keep it over 1/4 tank so you don't overwork the pump. 715/605 here

always faster

I normally dont go under 1/4 tank so good info to know
So if it keep a steady 52 psi during WOT run i should be fine ?

PEETYZ

Yep you are perfectly fine man.

always faster

This is the perfect way on how to save 1600$ with the help of forum member

Now i need to ge see if my oil consumption is only due by some bad valve seal (would be really great ) or bad rings...

Thanks

PEETYZ

lol no problem man. How much oil are you consuming? You have a catch can etc?

always faster

I got 1/2 quart in my CC setup with 4 dyno run and less than 300miles

Thread is here:
https://www.corvetteforum.com/forums...n-sad-day.html

stevieturbo

If it was tuned like this, and it consistently does this...then yes.