Hi all , looking for some help re fuel pumps , the motor in my vette is running a procharger D1 ,last time it went on the rollers we could only take it to 5300rpm as it started to run out of fuel so there was no point in going on, there are 2 pumps on the car ,one in the tank and one outside the tank in line , this is the pump that comes with the blower kit , i was told buy the guy who did the dyno run that i should run 2 fuel lines and a fuel pump on each. The motor is 383 and had Q/a bit of work done . Wot i would like to know is best pumps for the job ,in tank or out ??? and best place to buy them . Thanks for any help Regards paul from England

 

Your problem is volume, not pressure. IMO adding a second line, tapping the tank, routing, splicing into the rail..is a LOT of avoidable hassle. Its easier than that.

There are lots of intank hi-vol pumps that can be easily installed in the stock position. You can also buy a ZR-1 pump/sender assy that has 2 pumps in the intank assy with plumbing...stock.
I'd do some google searching and locate one of those. They can be fairly expensive but I can assure you it'll be cheaper than a bunch of plumbing....

Question:
are you positive that its running out of fuel volume from the pump?
did you check this at 5000 rpm with a fuel pressure gauge to see if the pressure was falling off as demand increased ?

Its just as likely the injectors are bottomed out...max output. You might want to consult with Jon @ FIC.

 

That is what I am using,
a 1990 ZR-1 dual fuel pump assembly.
Dropped right into my 87 Vert.
Wired both pumps hot with ignition key on all the time.
No problems with both pump motors running consent.

Bought a NOS GM spare 1990-1995 ZR-1 daul pump ***. from an ebay seller last summer for $140.00.
He had maybe 10 NOS units at the time.

BR

 

Yep, I saw that seller ! !

I was shopping for a new sender assy, (which was actually MORE than this ZR pump assy)...and almost bought it, but was'nt sure of the install and I needed the right part asap..

Good to know, might go back and get one now.
Could'nt believe that price. Best I found for the stock assy was $160 or 180 at one of the catalog stores..

 

Get on ebay & buy it.
Do not hesitate.

Its an exact copy of the factory production units used in the 1990-1995 ZR-1.

Has to flow at least what the Walbro 255lph pump flows single.

You just have to reuse your original male plug weatherpack connector.

I have a Snap On electrical terminal service kit in my toolbox.
made it a breeze to swap out each terminal to the old connector.

You can use a paperclip too.

 

Weldon external pump with -12AN line split into two (2) -8AN lines feeding each fuel rail with 120lb/hr injectors with -6AN lines to the BR AFPR and a single -8AN return.

That will feed your 383 w/D1 without issue.

 

Thanks for the help ,i do have the FAST /com 65lb FAST injectors and a lot of other stuff , john sleath raceing in the uk done the run and was pos it was running out of fuel , he insisted it was not enough pump or fuel line too small ?? . this guy is good at this and i am no expert when its tuneing a car with a laptop . i have posted all that i have done to the car in the G/section under Hi all there are some pic too again thanks for the help regards paul

 

Or a pro stock car.

 

That is exactly how many Renegade 5.0 Mustangs with a Procharger or Vortech YSi or better blowers are fuel plumbed as you described above.

I helped plumb up a few race fuel system on those cars in the past with my friend Ed.

You make it sound easy...........lol

Takes time and more time if you are a perfectionist like Ed & me.
The 2 of us working together could fuel plumb a race car in 6 or 7 hours.
Race ready in the morning.
A few were 8 second rides.

Use as little of 90 degree fittings if you can feeding the engine.
No 90's if all possible.
90 degree fittings are very fuel volume restrictive to a high powered race engine at WOT.

Brian

 

A 408 with R-series at 30lbs of boost will go quickly if not properly fueled.

 

I ran 600rwhp on my firebird with Procharger F1A blower using a Walbro single in-tank 255 and inline procharger pump. I'm almost positive that your problem is not fuel unless their is a mechanical problem with your present one. Trust noone and Question everything when it comes to aftermarket parts and so called experts.

 

Hi 93vette is the walbro pump you had in your firebird, the same as my stock pump in my 90 vette , is that 255 LPH ,as i have no idea wot my intank pump LPH is . Thanks all for your held

 

I'm not sure on a '90 but I think it is 190lph. You can go to Autozone and rent a fuel pressure guage. Attach it to the shrader valve or fuel pressure port. Then tape it to the windshield. Do a street run in 2nd gear and take it to 6000rpm and see if you see a drop in fuel pressure. It should hold 43psi all the way to redline. If you are running out of fuel it will be easy to see because it will drop down to like 20psi.

 

[QUOTE=93VettePilot;1577548675]I'm not sure on a '90 but I think it is 190lph. You can go to Autozone and rent a fuel pressure guage. Attach it to the shrader valve or fuel pressure port. Then tape it to the windshield. Do a street run in 2nd gear and take it to 6000rpm and see if you see a drop in fuel pressure. It should hold 43psi all the way to redline. If you are running out of fuel it will be easy to see because it will drop down to like 20psi.[/QUOTE 93vette i allready have a fuel /p gauge fitted to the car soon as i hit boost the presure goes up a little i have it set for 1 pound boost 2 more pounds fuel/P . when i said to the guy doing the rolling road ,i have a ajustable fuel presure ,he just said not presure , volume , the gauge i have is under the hood ,but when we did some road tests i tapped it to the screen and i have never seen it drop, when we did the rolling road run it ran great never mist a beat . i think the f/p is set at 45psi ? . we dont have Autozone here in England . Thanks for taking the time to reply to my post regards paul ps there are a few pic in the G section under Hi all

 

You would see a drop in pressure if your fuel pump was not providing adequate volume. What gap are you running on your plugs. Its best to drop it down to .030 for a boosted application. Distributor Cap in good shape?

Did your tuner get the Air/Fuel ratio at a smooth 12.5? All of these things will cause a miss at high rpm.

BTW: I'm in Pakistan on a diplomatic mission. Long live the UK!!! I was wondering why you were up so early in the morning.

 

[QUOTE=paul buckner;1577548703]
Then there is something else going on.
IF it were starving for fuel there would be a very sudden drop in pressure signaling that the demand was greater than the ability of the pump. A drop from 45 to near zero as the motor stumbled and burped. You'd know it...

If your tuner guy thinks he sees the motor running out of fuel on the computer, the other perspective is simple...
running out of fuel is the same as having too much air as far as the combustion is concerned.
The computer wants to maintain that perfect a/f ratio and its not picky...when its not correct it will say so, but from the computer point of view...
I've seen other guys go thru these types of blower issues.
65 lb/hr injectors is a bunch of fuel. To me, there is excess available as long as the 45 psi at the regulator is maintained. There are hi-press hi vol regulators available. Search the vette stores and flea-bay for dealers/sellers.

The regulator itself may be leaking past internally. They can pass fuel directly to the return and still show stable pressure. Test this by pinching off the return line and do the high speed tune/test again. If things improve, the regulator is faulty.
Its not a bad diaphram, but rather the seat portion of the plunger does not seat well from wear or damage, and leaks some precious volume back in the return to the tank...

 

Thanks for the help LEESVETT , like i said i am no expert when it comes to com/ maybe he just couldnt be botherd to tune it past 5300rpm i do know some one else was due in on the rollers maybe he was just in a rush to get me off . I did not ask him enough Q , i think i will take it to a diffrent rolling road and see wot they say , and ask a lot more Q s , like i said it ran great all the way up the rpm and has never fluffed or backfired ,if anything it runs rich . Dist is new msd and msd box, plugs are bosch plat/set at 60th i know you guys dont rate them much but thats wot myron cotrell suplied with the motor ,i can soon change them if you think i should ? i will let you know how the latest RR test goes . Thanks again fot the help re paul

 

Paul,
if it smells a bit rich, see if you can do your run at the same PSI as it was/is now, and then another at 35-40 psi.

In fluid power, when your create pressure by way of restriction, you decrease the flow. If its rich now that says that it might be possible to decrease the fuel charge slightly, while increasing the flow or available fuel volume. Its an "on demand" thing...

Regarding the plugs...
Its a judgement call. if all else fails, you might consider some more traditional Delco plugs. I have experimented with most brands and it may be placebo, but the Delco just seem to run better. I know for a fact that their wires and modules do better.

Good luck. If its any consolation, a buddy went thru the same dance getting his charger straightened out...and he started with new everything. Its trial & error tuning with mystery parts.

 

Thanks Leesvet greatfull fot the imput , wot a great site ,i will keep you posted on the numbers when i have done the dyno run ,its not that the car runs bad in fact it runs great , but i just think there is somemore power in there if we take it to 6000rpm just need to know wot i have got . allready spoken to a guy up the road with a rolling road ,who i did not know even exsited , he is not fam/ with FAST stuff ,but said he would look it up? no where near as many rolling roads over here as in the USA and even less who know how to use them thahks again for every bodys help regards paul from England DEF/ smells rich my neibours say they smell me befor the see me

 

My fuel gauge is inop and this was on my list of things to replace as I was told the sending unit was bad. So, I figured do it right while it's apart. You state the ZR-1 has a 2 pump assembly. Will that fit my stock 1988 coupe? How much more volume than stock are we talking about? (I'm considering a 383 build soon and wouldn't want to re-replace it). As far as the sending unit, will said ZR-1 pump assembly work with a replacement stock sending unit? (I know nothing about the electric stuff etc).

Also, I have a hesitation in the current motor when not in WOT. (not a miss just a kind of not putting out the right amount of push, but almost a miss). I have eliminated about all of the fuel and most of the electric possibilities and was thinking maybe I got an injector going bad. I Was wondering what kind of injectors could be used to replace the stock ones with? I was wanting to upgrade and have more fuel on demand. what would be the highest poundage injector to go with (without overkill) if I was going to be doing the 383 thing soon (500ish hp and porting)? I know I will need more fuel availability. Again, I was not wanting to re-replace them later but I am wanting to fix the hesitation and upgrade to more fuel availability and reliability without changing to a carburetor or something.

Thanks in advance Obi Wan

Perry