lncboytre_d

After a lot of hours of trial and error tuning I finally got the N/A tune where I want it, AFR WOT 12.9-13.0 ramping from 12.6 @4400. I made my first pass with the nitrous on this tune and ran a 7.29 with 78n and 48f with a 1.65 60'.....but my AFR was at a staggering 14.9 I swapped out the fuel jet for a 52f and ran my best yet at 6.94 @ 101 mph w/ 1.61 60'. I was more than pleased with the results. Not sure what that would equate to in the 1/4, but 10's are knocking. I will go to a better track next weekend and post time slips. The print out was not working correctly at Yellowbelly tonight. Yes I went to yellowbelly dragstrip, and yes the track prep was shitty.....but effective.

Car info:
LT1 355 AFR 195cc heads
CC306
Stock suspension
3.90 gears (10 bolt)
4L60E
3900lbs full tank of fuel w/driver
Nitrous Outlet Plate Kit

lncboytre_d

AFR with the 52f was at 10.2. Next week I will drop to a 51f or 50f and see what happens. This was on 26* total timing wot

03EBZ06

probably around a 10.75-10.85 w/6.94 1/8. Are you running NANO?
An 88/52 makes more sense than a 78/52. At first thought, that would seem REALLY REALLY rich. What mph and et gain did you get w/78?

lncboytre_d

No nano here....yet. Before today the best i could get was 7.3 @ 96. But even then i was having issues with my tune and hitting the limiter. I didn't pull any plugs today, but i am willing to bet i am way rich. i will lean it out, pull plugs, and post slips next weekend.

lncboytre_d

78n 48f w/25* timing =96.6 mph
78n 52f w/26* timing =101.2mph

lncboytre_d

bottle pressure was a little high......1050-1100 psi consistently

Fbodyjunkie06

iTrader: (10)

Remember he is LT1 so he is running 43psi of fuel pressure not 58psi like we do. Fuel jet will be bigger.

lncboytre_d

Good point. I forgot about that also and was wondering if something was not accurate with the info I gave. What AFR do you guys target (along with reading the plugs)?

Fbodyjunkie06

iTrader: (10)

12.6-13.0

lncboytre_d

On Spray? I thought that was the N/A target?

Fbodyjunkie06

iTrader: (10)

Yes on spray.

Plugs will tell the true story, but from what info I have gotten from Carter01, Camscam, Shiz, ATVracr etc. all say that their plugs look like they want them to at or around 12.7-13.2 AFR. I had a tune-up in mine that should of put me at 12.9-13.1 AFR and with my bottle pressure being so far off wide band was showing 11.7-12.0 down track which is rich as ****. With correct psi I am hoping it cleans up and is near my target of 12.9-13.1.

When you get it leaned out like this the 2 degrees of timing per 50hp rule is completely thrown out the window.

The old school of thought is more fuel more timing, more fuel more timing then bam melt down and your motor is now an ashtray factory.

When you lean it out and lower the timing lower than the "rule" says, that's when you get that pretty blue flame out the exhaust. It won't light the candles on a small tune-up it takes (this is a guess) at least a true 300hp worth of nitrous if not more to really show the candles lit.

Lean is mean.

lncboytre_d

Cool. I follow you guys in the nitrous forum daily. I thought I saw where you made a post and were at 10.5 afr, therefore, I was thinking on spray I needed to be around 11.5. I will lean it out with the 50f jet this weeked and see where she is at. Hopefully I can pick up and 2-3 mph. As of now, I am pulling 9* from my N/A tune on spray. I will lean it out and pull one more degree and work from there.
Thanks for all the help.

03EBZ06

Thanks fbody. I forgot about the 43 psi making that combo way more realistic.

Fbodyjunkie06

iTrader: (10)

No problem I forget **** all the time.

LNC as you lean it out the timing will show more and more advanced even at the same value as before it was leaned out. So as you lean it out before you have an understanding of where the timing mark will be as you said pull a degree out each time you lean out the fuel jet.

Do that and you'll be fine.

I bet it picks up noticeably from leaning it out and keeping the timing mark before the bend on the strap.

lncboytre_d

Ok will do. Your advice is being applied with good results.
Thanks
Tre

ATVracr

iTrader: (5)

Thats a huge jump in A/F for a 4 jet spread.
14.9 to 10.2 with a 4 number change?
Maybe the smaller jet was partially clogged?

Go slow with changes.
Fbodyjunkie giving you solid advice.

lncboytre_d

Ok i will. I'll check the smaller jet for blockage. How much should 1 jet size change afr?

ATVracr

iTrader: (5)

Every system would be different and every fuel pressure change would aslo change that number.

It might change it that much in your system just seemed like a big swing to me. Go one jet size at a time and see what it changes.

lncboytre_d

As wide as the split is, i was thinking 1 jet =1.2 steps in afr