ARCTICWHITE98Z28

iTrader: (1)

I have noticed a few posts stating that nozzle placement for dry shots is critical for the proper air/fuel ratio. I have a 98 Z28 with an MTI airlid. It is basically the same design as all of the other Z28/TA LS1 airlids. I am currently installing a single nozzle HSW dry kit. I will most likely be starting with the 75 shot and then possibly the 100 shot.

My question is, what is the best location on the airlid to install the nozzle? Also at what angle? Any pics would be appreciated. I was able to find some pics of Corvette airlids w/ dry kits, but that only helps so much. THANKS.

Robert56

iTrader: (2)

In the neck about 3 to 4 inches from the MAF. Point it directly at MAF. Then if it's a little rich you can just rotate the nozzle slightly to fine tune a/f. What nozzle are you using? a 90*? If you get it to far away it will have a tendancy to be lean, then computer is the way to tune.
Robert

Sneaky

Point it directly at the MAF?

That doesn't hurt the little "feelers" on the MAF?

Todd157k

iTrader: (5)

Nope.

allblacksrt4

iTrader: (3)

if you put it closer to the maf does it richen it up?

98redorangeta

iTrader: (10)

Robert if it was a 70 degree nozzel would you want to move the nozzel a little further back?

Robert56

iTrader: (2)

No actually the 70* work's well in most cases.

It will not harm the wires and will not freeze the wires. This is how you get a good cold/dense reading. The basic rule is, closer equals richer and farther away equals leaner. The close nozzles can be adjusted for a/f by simply rotating, whereas, to far away and you must go into pcm to compansate with additional fuel.
Look at my nozzles in pic below. They are about 3 inches from maf, and I have sprayed over 200 passes and all the way up to 250rwhp and have had "0" issues with MAF. A/f is stable in the 11.5:1 area on hits up to max so far on first stage of 170rwhp. This is a known spot that works well for all.

ARCTICWHITE98Z28

iTrader: (1)

The wires will not freeze with this setup, but the MAF should be descreened, correct? Thanks.

Robert56

iTrader: (2)

Yes correcto mundo. It's the screen that can freeze, or rather get a collection of frozen goods and cause issues.
Robert

Matt@HSW

iTrader: (14)

Some Picts:

http://www.harrisspeedworks.com/gall...s.php?album=36

http://www.harrisspeedworks.com/gall...s.php?album=32

Both using our 70 degree exit nozzles and good A/F ratio.

Let me know if you guys have any other questions.

Thanks,
Matt

BTLFEDSS

iTrader: (12)

This how i did mine the in th neck is 70 poited toward the MAF and the futher one is another 70 pointed toward the front of the air lid
BTLFEDSS

mrr23

iTrader: (3)

thsi is where i put mine and got 65 rwhp out of a 100 rated shot.

Robert56

iTrader: (2)

mrr23, did you index the nozzle? Also, maybe try cleaning your maf wires. At this far away it still should give the numbers, and actually should be a little high if anything from a slightly leaner condition compared to being a little closer in the optimum location. Maybe it's the nozzle? Anyway, that's a sorry gain, and something is up? Try a set of known good dual nozzles and you should be fine, as long as MAF wires aren't coated with oil/gunk. Do you run an oiled filter?
Robert

mrr23

iTrader: (3)

i had it pointed directly at the neck. hven't cleaned hte MAF in sometime. still has the screen on it as well. yes, i have a k/n filter. maybe bring the bottle pressure up some more. ican always just jet up as well. then again, might be good that it's low. can launch easier with it.

Robert56

iTrader: (2)

Well the screen just may be your problem. With the nozzle so close, the nitrous freezes up the fins and then there is a big restriction and a less flow of n2o and air. Standard proceedure to remove screen whenever spraying a dry hit. If it were me, I would clean the MAF wires, remove the screen, and then retest and watch for the improvement that I am sure you'll see. Let us know.
Robert

SSkeet

Is the MAF stock or did you mod it? I would think with a hit this big, it would have maxed the MAF way below the size shots you are running

Robert56

iTrader: (2)

Bone stock MAF, and currently am running a 250rwhp shot, which soon will be 285, then the magical 300rwhp shot in 3 stages.
Robert

Sneaky

Where is your IAT now? I see the nozzle is mounted practicaly where it usually stays.

98redorangeta

iTrader: (10)

Some corvette mafs have the iat sensor built into them.

SSkeet

So you mean to tell me your MAF is reading the full 250rwhp dry shot? You are not tricking the IAT sensor and adding fuel via the PE vs IAT enrichment adder? I thought the stock maf's only read up to maybe 500rwhp or even 500fwhp???????