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Yeller'
07-19-2005, 10:24 AM
HehHeh, Me likey. :D

cobrabitn
07-19-2005, 09:04 PM
YOU SUCK!

Great numbers though. :thumbsup:

Yeller'
07-20-2005, 12:16 PM
Good numbers, but the tune ain't quite right yet.

I bought the safest kit made (Zex), the problem is the kit is so damn safe it won't allow a tuner to tweak the A/F to lean the car out at all. To add to the problem the boost a pump I installed I believe is wacking out the situation even further.

The A/F is at 11 before the N2O kicks in, then pig rich at 10:1 @ 4500rpms, then it leans out to 12:1 @5500, then richens to 11 again through to redline. The A/F line is down-up-down everywhere between 10:1 to 12:1 throughout the RPM range.

It never goes so rich as to be a real problem (other than power loss) and it never goes so lean as to be dangerous. It's just not "right" and annoying as piss. I'm afraid it may be inherant to the Zex "brains" box... (i.e. "the way it's supposed to work").

The Zex kit is truly made for morons, it's a good, (too) safe kit. But it's made for ricers that want to half-ass throw a 50 or 75 shot on their Honda and never have it tweaked or tuned. It's made to keep you from hurting your motor by forcing a rich condition that's unable to be tuned away.

For a clueless ricer kid that's great, for someone with a half a brain that wants to tweak it and tune it, it's a pain in the ass.

If I had it to do over I would have gotten an NX kit... but it's done now and I'm just going to have to make the best of it.

tnturbo
07-20-2005, 02:02 PM
You could change the kit around REAL easy. Have you ever looked at what is inside that box? Just eliminate the Zex "brain" and use the solenoids like a normal kit. I'm sure Scott could take care of that for you.

Yeller'
07-20-2005, 03:04 PM
You could change the kit around REAL easy. Have you ever looked at what is inside that box?

One big ass solenoid with one input/2 outputs (fuel enrichment and nitrous), pretty much... and probably a computer chip. I saw a picture of one apart somewhere a few weeks ago... Corral, SVTP?

Just eliminate the Zex "brain" and use the solenoids like a normal kit.

I don't think it would be quite that easy, hell I (we) can't even get the thing to work right the way it's "supposed" to work assembled... and you want to take it apart and try and make it work? Before I go through that nightmare I'll take the whole damn thing out, sell it on EBay, and replace it with an NX kit.

Yeller'
07-20-2005, 03:18 PM
Turbo, do you think I could be maxing out my injectors? Even though the kit works by increasing fuel pressure via the FPR?

It's "supposed" to work with the stock injectors, but the stock 24's max out at 95-100% duty cycle at 350-380 Bhp, and I'm at 350-380 RWhp.

I mean, isn't that a hell of a load on those injectors regardless of other factors? (f/p, "on" time, etc.) Is that how this kit works? By cranking up the f/p and overdriving the piss out of the stock injectors?

Go to the links below on SVTPerformance.com for further discussion, we've already got the ball rolling pretty well.

http://www.svtperformance.com/forums/showthread.php?t=202532
http://www.svtperformance.com/forums/showthread.php?t=202513

tnturbo
07-21-2005, 01:57 PM
Fair chance you are at or near the limit of the 24s on a dry kit. If it were my car I would start looking into an Aviator fuel pump and some 30-42lb injectors. You have tuning software right? That BAP may be contributing to the problem as well.

Do NOT repeat DO NOT buy another kit or sell your kit. Do you have any idea how cheaply you can buy good used solenoids? You have a dry kit. All you need is the nitrous solenoid.

Did you guys try running it any on a smaller shot? When I ran the bottle in a bag kit on my car anything over a 60 shot would freeze my mass air meter after just a few seconds. If I relocated the nozzle so it didn't do that, it got dangerously lean.

tnturbo
07-21-2005, 02:14 PM
I just read all that SVTperformance stuff. You started with Scott, I would stick with him. Future work should be cheaper. I would get him to stick his wideband on your car and do some street tuning. He will help you out. You may want to talk to Robert Hindman, fwiw he had a NOS kit for sell for $250 a while back, he has run nitrous on a 4.6 a bunch.

I do not accept the fact that you can't get a pump for a 98. I have seen several 98s making HUGE power that I know have aftermarket pumps. If the 98s were really a bastard year like some people seem to think there would be a LOT more *****ing about it and a kit to switch them. Hell, just swap out the fuel tank and fuel pump wiring harness for a 96-97. You can get those parts locally for a cheap price

Yeller'
07-21-2005, 02:46 PM
Fair chance you are at or near the limit of the 24s on a dry kit.
I called Ride Revolutions (I know, I know... but since Zex is an "importy kit" I thought they might have some insight) and talked to the manager, he said that even though you would think that the stock injectors would be at their max, that the Zex kit didn't work like I was thinking, that the system added fuel by creating more fuel pressure and that the injectors aren't a factor in what's making my A/F wacky. He said that that's the way Zex kits are, they are designed to run rich as hell and they all have wacky A'F ratios.

If it were my car I would start looking into an Aviator fuel pump and some 30-42lb injectors.
The aviator fuel pump was my first thought also when I was assembling this system, and judging from the threads on the Corral and SVTP, I thought that people were having success with them, but when I went to order one the Ford mechanic I spoke to said that they are starting to fail, and the guy "that post they work" on the Corral has gone through three of them in a few months. He said he would be happy to sell me one if I insisted, but he really didn't recommend it. So now I don't know who the hell to believe.

The problem is (you probably already know this) is that the 98 Cobra is a bastard year in which the fuel system is return style, but the pump and basket are returnless style , or something like that... so Walbro doesn't make a replacement for the 98's, and supposedly people that have tried to modify the basket and make the 96-87 walbros work have had mixed results.

For my power levels a Vortech inline and the stocker would work just as well wouldn't it?

You have tuning software right? That BAP may be contributing to the problem as well.
I have the SCT flip chip.
I know, this winter the BAP is coming out of there and an inline going in.

The Zex box is controlling the FPR and thus pressure, then the BAP is doing it's own thing with the voltage to the stock pump... I believe the two are fighting each other.

Do NOT repeat DO NOT buy another kit or sell your kit. Do you have any idea how cheaply you can buy good used solenoids? You have a dry kit. All you need is the nitrous solenoid.
I came to that realization yesterday... so all I need is one solenoid from NX, hook the Zex box N2O input and output up to the new solenoid, wire the solenoid up to the same place the Zex box was on my relay, and install a WOT switch.

Could it really be that simple? At that point could the tuner completely control/tweak the A/F to exactly where he wanted it with the SCT chip?

Did you guys try running it any on a smaller shot? When I ran the bottle in a bag kit on my car anything over a 60 shot would freeze my mass air meter after just a few seconds. If I relocated the nozzle so it didn't do that, it got dangerously lean.
No, we only ran the 125 shot (100rw actual).

The nitrous jet on my intake is installed after the MAF, it's actually only about 8 inches or so from the throttle body.

I don't think my MAF was freezing up... I don't know how it could, the nitrous jet is facing completely the other direction and it's at least a foot away from it.

What I am going to do is:

1. get rid of the BAP, install an inline (if you think that'll be okay)

2. tweak the way the vaccuum and regulator hoses are set up on the Zex box (I think they may be wrong... functioning, but wrong).

3. try it one more time on the dyno, and see if that helps the A/F any.

4. If it doesn't help... at that point I'll rip that Zex box out and use an NX solenoid.

I will probably do step #4 regardless this winter anyway.

Yeller'
07-21-2005, 03:04 PM
What's your phone number already and I'll call you, the old one I have for you doesn't work anymore. PM it to me.

My fingers are bleeding.

InfamousSVT
07-22-2005, 03:10 PM
Nice numbers man........hope you get all the "bugs" worked out with it! :thumbsup:

tnturbo
07-25-2005, 02:54 PM
Just now got back from a long weekend away. I wasn't thinking your mass air was freezing. On my old kit, I sprayed on front of the mass air meter and let it adjust the fuel for me. You are right about the solenoids being that simple to change out. I'll PM you my number

You need to take a drive by Robert Hindman's shop. He is out on Tazewell pike and knows plenty about nitrous. He can look at you install and tell you right away if everything is hooked up right or not. He can also answer you questions about the fuel pump too. There are WAY too many 98 with blowers, etc for there not to be an upgrade. Seriously, call Rober 688-7890