JonGTR

Ran a better 60' last night which related to better et's. I also didn't have that bogging from lack of fuel. 14.1@99.5mph I might try to put on a larger shot next time to hit 13's. It just depends on how the clutch is acting at the time.

2.27 60'
9.20 1/8
79 mph
14.1 1/4
99.5 mph

JAWS 021

WOW 14.1 CONGRATS MAN!!!

Thats a nice f-ing time


I cant wait for my NX kit...

Nice to know the stock pump can handle the 60... im hoping the eclipse turbo pump will handle the 100

Do you have an AF gauge?

email me man

JonGTR

I emailed you a few days ago. jtmccauley@hotmail.com

I'm not running on the stock pump anymore because it was bogging at higher rpms with it. I think it was just on the edge of leaning, so I went ahead and got the SX regulator and Walbro put in. I don't think I like the Walbro though, it's just too much for what I'm doing. Maybe I'll switch it out for the dsm pump until I need it later.

JAWS 021

wanna trade pumps?
tongue.gif

im hoping the eclipse pump can handle the 100... even though now im not that sure

if the stock pump maxes out at 60.. then the dsm one should handle at least a 75

Oh well..
ill find out soon enough

Anthony Thomas

Jon, there is NO such thing has having a fuel pump that TOO big. Just keep it....

You have a regulator, if you keep rail pressure in check, you won't have any problems.

JAWS 021

Actually, the way the fuel pump work is through voltage...

The stock ecu will still be sending the same pulses to the fuel pump as before... so your fuel pressure is riding sky high while your riding NA

Red posted about this once before

The fuel regulator is regulating... but its regulating thinking it has a stock pump...

BTW... thats a nice time with an almost stock neon wink

JonGTR

I will probably keep the pump in, it's just that the regulator is giving me some small problems. It's keeping it rich under throttle, even though I tune it down to 42psi at idle. I'm just too lazy right now to look into it more. poke That and having to buy a new clutch is depressing me.

Red

Well, there's some confusion here it sounds like with the stock regulator.

First off, the fuel pump gets nothing more fancy than a straight 12-volt feed. Even on my Haltech, it gets nothing more than a 12-volt feed. Unless we're talking about a returnless fuel system (I didn't see that if we were...) then the ECU doesn't control fuel pressure. In fact, even in a returnless, the ECU still doesn't control pressure, it's just regulated differently.

Anyway...

The stock fuel regulator was built to be mated to the stock fuel pump, which flows like 85 liters per hour. When you strap a Jesus Pump (Registered Trademark, 0001 AD God Industries) onto that bastage that flows uber-fuel, the poor little stock regulator isn't able to open wide enough to vent all the gasoline back to the return line.

A regulator works by a pressurized diaphragm that covers a physical hole. If you have a large enough increase in fuel flow, that little hole can actually start causing the constriction, regardless of the diaphragm opening.

In order to use a big-azz pump on these puppies while wanting to keep near-stock fuel pressure, you need to replace the stock regulator with an aftermarket static-rate one.

I'm using an Aeromotive unit, it was cheap and easy. Only problem was putting a -6AN fitting on the end of my fuel rail so I could plug it in -- but that wasn't hard. Eight dollars of parts and about two minutes of borderline sleep-inducing labor put a fitting into the rail.

EFI-specific nitrous kits also require that you run fuel pressure at 3 bar (44.1psi) for proper fuel delivery. Unfortunately I'm running 66psi in mine, which makes for some problems. That's another story smile.gif

EDIT
Jon, to cure your problem, unplug the vacuum line from the intake manifold to the Aeromotive unit. If you leave it plugged in, the unit will increase fuel pressure based on manifold vacuum (1:1 rate). You don't need that, neither do I, so rip the vacuum line off and plug the hole in the manifold with something.

Will make your life much easier smile.gif

[ April 22, 2003, 09:48 AM: Message edited by: Red ]

JonGTR

There is still a problem with that. I disconnected the vacuum line and it helped about 75%, but it's still raising the pressure about 8psi at full load. It's not a lot but it is noticeable on the *** -dyno. The regulator was used, so maybe the diaphragm is worn and needs to be replaced. I also did not seal the gauge whole 100%, but I wouldn't think that it would cause this problem.

Red

Whuuuaaa...??? poke dunno

Ok, so help me understand how you've got it laid out. You have fuel pump, fuel line, fuel filter wink , more fuel line, fuel rail, stock sized injectors, fitting at the end of the rail, fuel line, Aeromotive unit, and then return.

Did I get all of that right? (Hope it made sense, hehe)

Ok, so where do you have the nitrous tapped into? My Aeromotive unit has two "input" ports and one return port. Since the two input ports are joined, I used the second intake port to feed my fuel solenoid via reducer fitting. Is that what you did?

I'm just trying to figure out how the hell the fuel pressure raises when it's not getting a vacuum reference. If anything it should reduce pressure just slightly...

The pump should (theoretically) pump the same amount of fuel at all times. Thus at idle, you should have your highest pressure only because the fuel injectors are barely opening and the nitrous is not feeding -- all that extra fuel must be vented. At full load, your injectors are running 60%+ dutycycle and the nitrous kit is drinking it's share, so there's much less fuel to vent back.

The only thing I can think of is perhaps voltage increase... At idle, your alternator is turning slower and so (combined with perhaps an older battery) the voltage could be sagging to the mid 13's. At full load, your alternator is running at high speed and the voltage will pick up to the 14.4v level (by way of the voltage regulator unit in the alternator). It's possible that the extra voltage to the pump is causing to pump just that much more, which slightly increases your pressure... I guess? suicide

I guess the only suggestion I would have then is to lower your idle pressure by about 8psi. At idle, the car is in closed-loop mode so it will figure out the mixture on it's own. In fact, the stock regulator does the same thing: 43psi at full throttle (zero vacuum), and like 32-34psi at idle (full vacuum).

At WOT these cars run rich anyway just on the stock injectors; along with your nitrous kit being fed another 8psi, I'm sure it could be holding back another good handful of power. I'd try lowering your idle pressure a bit further and allow the closed-loop computer system to figure that part out.