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**Barry** · 10-25-2002, 11:07 AM

Nice to see another 3.8 that is going to be at BB.You not coming to the Bash?

I hope to see 13's too.

See you there.

[ October 25, 2002: Message edited by: Barry ]

**andrew N.** · 10-25-2002, 12:23 PM

would those same jets be for the 3.4 as well?

im going to the track on the 1st of Nov.

**12secondv6** · 10-25-2002, 03:39 PM

Please be careful
I grenaded my engine in 1 month when I had 24 lb injectors and a 120 dry shot.

**John_D.** · 10-26-2002, 12:56 AM

<blockquote>quote:<hr>Originally posted by Barry:
Nice to see another 3.8 that is going to be at BB. You not coming to the Bash?
<hr></blockquote>

I didn't even think about the bash this time. I did go, back in the spring. It was pretty cool to see all those f-bodies in one place. But my car was slow then...

Is it Saturday too?

[ October 26, 2002: Message edited by: John_D. ]

**John_D.** · 10-26-2002, 12:58 AM

<blockquote>quote:<hr>Originally posted by andrew N.:
would those same jets be for the 3.4 as well?

im going to the track on the 1st of Nov.<hr></blockquote>

I believe the jets would be the same.

At the top end of the scale, I pulled the numbers together from a couple of different sources and did some estimating, so they are not anybody's "official" numbers. The ones that are the most suspect, are the ones above the 120 shot. The ones below that should be pretty much right on the mark.

Be sure and give us an update after your Nov 1 run!

**John_D.** · 10-26-2002, 01:08 AM

<blockquote>quote:<hr>Originally posted by 12secondv6:
Please be careful
I grenaded my engine in 1 month when I had 24 lb injectors and a 120 dry shot.<hr></blockquote>

Thanks for the concerns. I am being very cautious. I hit it a couple of times tonight, and it was lean, so I richened it up with the maft, and got the 02's back up there in the low to mid .90's when I sprayed it the third time. I'm only hitting it from about 45mph and going to about 80mph.

But....

When it winds out, around 80, it starts missing, and I just let off of it, so I'm not sure what's going on. Right after the shift. The o2's go full tilt to 1.0 which makes me think it is running hugely rich, maybe getting injector lock?

I bet I am finally going to have to take those stock platinums out, and try those NGK's I've had laying in the floorboard for the past month... I will do that in the morning, just to see what the difference is.

I autotap logged it the last time I sprayed it tonight, and am going to check the injector pulse widths in the log, to make sure I didn't go static or something.

Big plug gaps caused some top end miss for me a few months ago, before I regapped down to .045. I am hoping the ngk's at .035 will take care of it. I may finally be converted after all... [img]smile.gif[/img]

**John_D.** · 10-26-2002, 10:45 PM

Update...

I did put the new plugs in, and that seemed to help the misfire.

And after driving the car for a while, and letting the pcm settle in to the new maft settings, it was definitely running too rich at wot. That's why I was getting the 1.0 readings on the o2 sensor. So I leaned it back out some, but still don't have it quite where I want it yet.

I am also getting what seems like a short duration shutdown when I let off, probably running too rich while the fuel pressure bleeds back down, with that small bypass jet I'm running now. I may just have to live with that.

I definitely see a disadvantage of a dry kit: you get a quick rich condition when the fuel pressure first shoots up, but before then nitrous has started flowing all the way through the intake.

Then a quick lean condition when the nitrous first hits, but before the pcm kicks the fuel injectors up to match.

I saw this in miniature with the 85 shot, but it is a lot more apparent with the bigger shot I'm running now. The o2's go to .95 on initial wot, then drop to .82, before jumping back up and stabilizing in the low to mid .90's. The drop to .82 is holding for about 1.5-2.0 seconds now, according to autotap, before it recovers back up to the .90's. Which is longer than it used to take to recover.

So I did not get up to Beech Bend for times, because I was running too late, plus I want to tinker with the tuning some more. There are a couple more Saturdays in November before they close up for the season, so I'll get up there for one of those and see what it pulls now.

I know one thing, it hits a whole lot harder now... :D Very definite sotp increase, it jumps to 80mph much more quickly.

**12secondv6** · 10-27-2002, 12:42 AM

Everything you are saying is exactly what I expereinced, well kinda.
With the bigger injectors I would spray it and everything was completely fine low rpm's but top end I would run lean?!?!?!?
I knwo you said you are using the maft to comensate but I think you really need to have the computer reprogrammed for the bigger injectors.
Honestly, go back to stock ones.
I never had a problem with the stock ones on a 120 dry shot.
I only experienced problems w/ 120 dry and 24 pound injectors in a computer programmed for stock ones.

**John_D.** · 10-27-2002, 10:05 PM

I found the problem!

On the top end, the fuel requirement exceeds what the fuel pump can provide. I can see the fuel pressure start to drop off, and then the fpss must be cutting the nitrous.

By reviewing the autotap logs, the o2's also dropped at the same point that the fuel pressure drop occurred.

I guess I need to finally put that boost-a-pump on there, that has been sitting in the garage for 3 months...

**IronMan** · 10-29-2002, 04:41 PM

If I were to up my Dry Kit from 85 to 100, would I have to change the vaccuum jet as well? If so, to what number? Do you think I would need a boost a pump for a 100 shot? I would go with the 52 jet for nitrous like John has on his chart. He has been working on the chart for a while and it seems to make sense.

I have been thinking about this for a while, but I have not made a move because I would like to talk to someone who has a 100 shot-dry. Just to see what kind of things they added to "prevent" disaster. Thanks.

**John_D.** · 10-29-2002, 11:03 PM

<blockquote>quote:<hr>Originally posted by IronMan:
If I were to up my Dry Kit from 85 to 100, would I have to change the vaccuum jet as well? If so, to what number? Do you think I would need a boost a pump for a 100 shot? <hr></blockquote>

I ran a 57 jet for a while (a month) before taking the bigger plunge. I was having to set the maft to full rich, and was still a little bit light (.89-.90 or so, even at the full 14% rich.)

I put in about a 30 bypass (vacuum) jet, and was able to go back to zero on the maft.

My other variables that could affect my a/f are a p&p tb (removed entire post, added '99 maf sensor, no change to the throttle bore size itself), and a 3" exhaust off cia headers.

So my maft settings and bypass jettings may not be exactly what another engine/intake/exhaust configuration would need.

Going to the 52, you may not have to change the bypass just yet. You may be able to get what you need with the maft only. The 52 is only 5 jet sizes up, where the 57 was 10 jet sizes up, and that's where I hit the limit on using the maft.

**12secondv6** · 10-30-2002, 09:38 AM

When I ran the 120 dry shot I used the same fuel bypass as the 85, an adjustable fuel pressure regulator turned to 46 psi, kenne bell boost a pump turned to 50%, and a richened computer by superchips.
That worked fine forever w/ the 120 dry shot.
Then stupid me added bigger injectors (24) and never adjusted for them

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update - going with a bigger dry shot this weekend

update - going with a bigger dry shot this weekend

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