04snake

the time is here to install a Edelbrock 03 Cobra Dry kit on my #1 money pit and I need to decide if it will be a pre or post MAF setup. Being a F-Body owner as well for a short time, I know uzze guys have been doing the Nauzz forever so the problem/reasons for different setups are not real specific for the type of car more than the type of setup.

I already have a SCT 2400 oversize MAF, all the fuel upgrades so fuel won't be an issue with a Dry shot and I will be running the NOS only at the track. Will the hardest hitting most reliable way to spray be post MAF with a tune specific for it or do I try the one-tune for all method with the spray cooling the MAF and fooling it into dumping more go-juice? Is MAF freezing a big issue or is the big reason most guys seem to prefer the the post MAF squirt because it hits harder being closer to the intake?

Other things to consider is that I intend to use a jet one size larger (125 shot) than the largest on in the kit (100 shot) so I might get a decent hit from in front of the MAF. I am really squirting to help cool the IAT temps for more consistency with a highly overspun 17# ported Eaton for index racing (10.0) more than for heads up best times and will be using a heater/fan for bottle pressure control and a NXpress window switch for mostly top end rollout help.

opinions? Pre or Post MAF and most importantly WHY, thanks in advance!

dementia

iTrader: (4)

I'm under the impression that dry shots are ALWAYS supposed to go Pre maf. With the nitrous you're adding a lot of oxygen and the MAF sensor needs to read this in order to tell the computer how much fuel to add. If you're shooting dry after the maf no extra fuel will be added and you'll instantly go lean and probably blow your motor. Not sure how tuning and a post maf setup works. I've never heard of it but I'm also fairly new to the game. As far as freezing up the maf screen just descreen it. Everyone also seems to agree that aftermarket mafs aren't a good way to go.

sweetness

the maf needs to read it so it can add more fuel or else BOOM!!

pianoprodigy

iTrader: (1)

Flip chip, post MAF

Robert56

iTrader: (2)

Being a Ford kit is where the question comes from, before or after the MAF. The Fords, use an additional fuel pump to spike pressure, or voltage booster to pump to spike pressure to get additional fuel through the injectors, both ways would be nozzle after MAF. Now doing this on an lsx, it will be before the MAF, and computer will read temp/density through the MAF, and convert this to increasing the duty cycle of the injectors for more fuel. More on this in the wet vs dry thread.
Robert

04snake

both Pre and Post MAF use your fuel system to add the additional fuel required. I am a self tuner, I tuned my 99SS with HPtuners and also have an SCT license for 03-04 Cobras (they sell single model keyed databases) and all the datalogging/ WideBand tools to track every single pass at the track. Your are correct in that a single tune, if you have the available FP Duty cycles, can be used for both with and without the sauce if you spray before the MAF but many guys seem to agree that will not be as strong a hit as a dry shot plumbed after the MAF, just before the plenum. The drawback to that is that you need a special NOS tune that has taken into account the extra fuel required. You force more fuel relative to the air it sees in a certain RPM range and if you are using a window switch this can work very well. If you tune yourself, with some trial and error you can smooth out the transitions pretty well and get it dead nuts on and I don't expect that to be a problem.

Not sure about your aftermarket MAF comment, but I actaully need a larger than stock MAF to flow all the air required for 600-650HP, so there really isn't any other choice you have to replace it and then retune/recalibrate to the new larger MAF, just sumthin u need to do?

Robert56

iTrader: (2)

I am not sure if your asking about setting up your ford or your chevy? Anyway, all the lsx platform cars running dry run it before the MAF. The reason the after maf style is in existance is because not all computers are created equal. Meaning, the ltx platform and the Fords in general have had a more primitive PCM, read: algorithms. So on the lsx platform there is no need to find an alternative dry method and reling solely on the computer works and hits as hard as any other method/kit.
Robert

04snake

I am juicing my Cobra, I promised the wife not to hack the new to me 99 SS in a major way for at least a couple years or until the Cobra is gone.

I think there may be other reasons for most people using a Pre-MAF setup on LSx's, like the distance between a Pre and Post MAF setup on a LSx would not be that great, so the dimished hit from a Pre-MAF is not that great and it will require less "special" work by a tuner. If you don't tune yourself, that can get expensive but the style of PCM probably doesn't have much to do with it. the idea that a PCM from an 04 Ford is more primitive than a 98-02 GM is kinda funny, I know everyone wants to think there stuff is the shiet but after messing with both I see no evidence. The Ford tunes only with the MAF, so taking the MAF out of the equation or giving it a diminished role is a little tricky on the other hand it is simple to not use a MAF in a GM so a SD only tune would NOT care where the shot is because it is ignoring the MAF?

thanks for the link to the Wet vs Dry, I will poke around in there again but I had looked that over a couple of months ago.

I just noticed you are a NOS vendor (duhh..), what about recommendations for window switches, solenoids, bottle Heating/cooling sytems, purge kits. I have most of all that stuff ordered along with a whole array of gauges, but it is not too late to change out a few things!

Robert56

iTrader: (2)

Well maybe the lastest Ford PCMs are caught up, but in the not to distant past they were not equal and limited to about a 75 shot concerning pcm. I know of no one running a dry after the MAF on an lsx car. Now if your talking SD tune, then it's different, but still using the pcm for adding fuel.
On the kits/parts etc. We offer the PRO Dry kit, and this was spec'ed for the lsx platform, and not just generic. Great results have been had, and we have most CAI nozzle loctions mapped out for correct a/f from the get go.
Here's athread on the PRO Dry and the Ultimate PRO Dry for insight.
PRO Dry Thread
Ultimate PRO Dry Thread
Robert