I loaded in two fresh identical bottles into the cradle, heated them up at home, then went out to the local NHRA track for an evening of Test-n-Tune/Grudge racing. Temps around 80* at 6PM, sunny and still. I made a total of 6 passes, three of these single runs for varoius reasons, had one slugfest with a Camaro which I barely lost, and had power drop off drastically on the last two runs, but not for the reasons I expected. I got PLX logs on four of the six runs, the first, third, fifth and sixth runs. The quickest was the third pass at 12.557 / 110.95 MPH. Track prep was - disappointing...

EDIT: I forgot to mention that I kept the tire pressure at 11 1/2 psi for every run....

I'll present these in order, with the PLX log (if there is one) just afterwards.

#1
http://i48.photobucket.com/albums/f2...8/DSCN0538.jpg
PLX
http://i48.photobucket.com/albums/f2...8/HPT0925A.jpg

#2:
http://i48.photobucket.com/albums/f2...8/DSCN0539.jpg

#3:
http://i48.photobucket.com/albums/f2...8/DSCN0540.jpg
The PLX log:
http://i48.photobucket.com/albums/f2...8/HPT0925C.jpg

#4:
http://i48.photobucket.com/albums/f2...8/DSCN0541.jpg

#5
http://i48.photobucket.com/albums/f2...8/DSCN0542.jpg
PLX log:
http://i48.photobucket.com/albums/f2...8/HPT0925E.jpg

#6:
http://i48.photobucket.com/albums/f2...8/DSCN0543.jpg
PLX log:
http://i48.photobucket.com/albums/f2...8/HPT0925G.jpg


Run #4 was against a hot Camaro - he beat me at launch and I spent the rest of the run catching him! Lost by .0598 sec , even with a better ET and trap speed. His reaction time and 60' was way better than me, and that's where he won it. It was great when I began pulling up on him through the 1/4 - a Maxima out-pulling a serious street Camaro. Daymn it felt good.

Runs #5 and #6 started dropping power - I figured the nitrous well was running dry. When I looked at the PLX logs, I saw something different, though. You look at them - especially the A/F at the end of third gear - and tell me what you see. I was running way low on fuel at that point (#5 and #6). Oh yeah, notice how well my Tune-by-tape A/F worked on runs #1 -> #4. Run #3 shows I had about 350 RPMs left before fuel cut with the 24.5" M&Hs just like I hoped.

Both 15lb bottles went in weighing 33.6lb total (identical NX bottles) and the right-hand bottle came out weighing 26.8 lb for a usage of -6.8lbs, and the left bottle went from 33.6lb down to 28.2lb, a drop of 5.4lb - total N2O consumption = 12.2 lb for the evening. I had plenty left for a run or two. That was a hair over 2lbs for each pass.

I'm sure I was running very lean at the end of #5 and #6 because of a fuel shortage in the tank, which slowed me down. It's way below an 1/8 tank now, right off the trailer.

 

That's somewhat disappointing, but I'm sure you had fun with it anyway!

 

grey great consistency! hopefully i'll be mid 12's when i come up to kansas city to race ya!!

i'm a little curious about your times and traps though....i figured it would be faster? didn't you run a 12.3 at 113 or somehting like that a few weeks ago? is there anything different from that time that might cause it to run slower?

 

Always..... If you look hard at the PLX logs, you'll find a couple of tenths just waiting there to be harvested...

What's to be disappointed about? A consistent mid-12s Maxima with A/C and sound system is ... nice....

 

After you've done this a while, you will discover that

1. A PB cannot be repeated at will. How you doing with that?
2. Every track day will be different - even it's the same track.
3. A list of equipment does not determine how quick a car can be.
4. Mysteries keep popping up, to confuse and confound you.
5. When you run me, I will beat you so badly......

For instance, looking back at my last four track days, all running the 75+75-shot setup, I have varying ETs but MPHs very close together. Look at the last one I just posted - I ran on this track Sep. 4 and saw 113 MPHs - on the 25th I saw 110 MPHs on several runs. Crappy prep?

Yeah, come on up to KCIR and have some street noobs for dinner - it's fun.

 

forgive me grey.....haha

i see i see. i forget about all those different circumstances. i just figured 3mph is a bigger deal. i'm wrong

hahaha....yes yes...i know. you will own me at this point in time. but hopefully i'll be a little bit closer to you when i come up there. i hope to be spraying 125 or 150...we shall see

i guess i'm easy to flip out when my car doesn't run close to usual...

 

Talk to the Shark... and relax, if you lose, no one dies. If you go too slow, no one dies. When that 35psi turboed AWD Eagle Talon sleeper that lives at KCIR beats up on you, well, your blood pressure will go up.

 

It looks like to me that you are not leaving hard enough. Or spinning on the launch. You should have 1.7x to low 1.8x 60' time. You need more traction up front. Did you do the zip tie trick so that the front would not lift? Or lower the front some more and raise the back.

 

My *** end is way up in the air, with help from rubber blocks, and the nose is lowered so far I can't stage, so it's up a bit on rubber blocks. Illuminas are set to "5". I don't use zip ties or cables - I have a bunch of monster ties, for a quiet day.

I'm smacking the warmed slicks with a real purged 75-shot at WOT - and I'm spinning like a **** when I leave - so to make it worse, I hit a second 75-shot right away in first gear. The more I launch with, the quicker I go.

What do you think?

 

Well if you are spinning try to lower the first stage to 50 shot and see if you can hook that and then bring in more juice once moving. Your other option is taller slicks.

 

I looked back to a previous posting where I was launching with a 50-shot. This gave me 2.1xx and 2.2xx 60' times. A 75-shot proves to be faster off the line. I went from 23/8.5/15 M&Hs to 24.5/8.5/15 M&Hs already.

???

 

Something is very wrong if you can only get 2.1x with a 50 shot. Are you dead hooking and then bogging with 50 shot or spinning? You should be at 2.0-2.1 60' NA on slicks in stock car. Have you thought about moving the bottles to the front seat like Jime has done. It will move extra weight to the front to help with traction. I know it wont be much but should help.

 

With 50-shot on launch, no bogging... not much spin, either. I'm not moving the bottles - I'd have to take out the front passenger seat to get two 15lb bottles in there - and I don't think they would fit even then. Remember, with a 75-shot launch I have gotten into the 1.8xx 60' range. Besides, I don't scr*w around with my interior much - just a gauge or two and a SHift_Fast_3 hanging on the console.

What engine/trans combos are you basing your information on? I'm running an VLSD automatic hooked to a cammed 3.5 that has no power until 4500 - hence the 75-shot - or higher - to launch with. Stall is 2800-2900, depending on how well my HPS pads hold that day.

 

Still a 3.5 with cams should have more power down low then a 3.0. And 3.0 on slicks are able to hit 2.0 with slicks.

 

It is what it is - a mid-12s 3.5 automatic with 1.9 60's...

In Jime's thread about his new 11.65 ET, "best 60' was a 1.85" for that day..... so "should have" may not apply here.

My old 3.0 PB time slip shows a 1.918 60' - go figure - and my PB 3.5 60' is a 1.893.

 

I think you guys need taller slicks. But I can be wrong.

 

is 12.0 a little lean for Nitrous? What kind of gas in the tank?

Also, what size shot?

 

what size shot, the larger the shot the richer I like to run

 

I don't think so. Read this:

http://www.hotrod.com/garage/113_0411_n2o/index2.html

The fuel is VP Racing Motorsport - wait for it -109.....

The thread mentions the shots I've been running lately..

 

It's up in this thread - at least what I'm running lately. There is much more to come...

But first I've got to work out the nitrous-cut issues I see in the PLX logs. See if you can find the problem.

 

Regardless of what the experts say we know that you have to find your own happy place. All the experts in the world don't matter as much as the "I just blew another one" or "another PB that I wasn't expecting" can do for you.

We are all learning and there is no exact a/f or perfect shot off the line.

Keep up the good work Grey. The only losers are those that don't try.

Remember "If you aren't living on the edge you are taking up way too much room."

Give'er **** Bro.

PS I will have a look at your logs but I have some of my own that don't make much sense either.

 

Hi, Jim - glad to see you're tearing up the track once again. Yup, I'm back to trying stuff again, and documenting all of it, finally. Still too much unknown happening, but I'm getting a handle on it. Oh, 11 psi sure worked out well... thanks...

In my last few PLX logs, I have the transmission-shifting and the nitrous switch voltages on Analog #1 and #2. I was hoping that the nitrous would switch off - and stay off -while the tranny shifted, but the logs say different. I'm building another electronic thing tonight to take care of that problem, and change out a flaky AERO fpr and change the 300ZXTT fuel filter for good luck.

Rev the engine to shift-point, turn off the nitrous, shift the tranny, turn the nitrous back on -while WOT and spraying a bunch. It seems so simple...


.

 

Sunday was my first day at really playing seriously with the spray. I tried the progressive controller's window switch so as to not spray through the shift but after 6 hrs of experimenting I am discarding the whole window switch and spraying through the shifts. That's the way I did it when I first started and I am beginning to believe its still the best way.

I hear ya on the "rev to shift point, turn off the nitrous, shift the trans, turn the nitrous back on" simple but it doesn't seem to work as "advertised". I ended up spraying 100 through the 1-2 shift and 200 through the 2-3 with no hiccups. So I'm a thinkin that the trans is not as fragile as I thought and I'm planning on spraying a 200 shot through both shifts on Sat. Its not like the tranny owes me anything, I got it for $400 and it has been flawless for 3 years under tons of abuse that everyone said it wouldn't take.

After last Sunday I now think window switches are for pussies and don't even plan on trying it again. Part of the problem is the shift points, it takes longer for the 2-3 vs the 1-2 so 2 window switches are required to get them right. Even though my controller has 2 window switches built in it feels like its falling on its face during shifts and I think that may be part of your issue.

 

OH, I hear you - but if you get it right, it's a great shift. I agree that the tranny is rugged, and I've sprayed a 150-shot through the shifts, but I built yet another shifting box which works perfectly- really. My problem is that the shift is controlled by one MSD 8969 and the nitrous cut is controlled by another MSD. The tranny shifts, the nitrous cuts off, the RPMs drop below threshhold on the nitrous MSD and it sprays again, while trying to shift. Woops.. I'm going to add a simple one-shot timer to the transmission controller so there is an controlled OFF time for nitrous triggered just after the shift begins. This time I've got it. I hope. I'll publish the final version.

I wish you luck on Saturday - automatic Maximas with tons of nitrous RULE!!

 

From that link:
you can run the same as the engine's air/fuel ratio. But at 450-500 hp I run 11.5:1 as a safety factor. Nitrous injection is not sequential like EFI, so when the valves are closed, the nitrous stacks up in the ports, runners, and plenum. The mixture may no longer be totally homogeneous."


Subsequently, I tune for 11.5:1 on my turbo setup.

 

I agree with the safety factor concept, but my safety factor is the 109 Motor Octane racing fuel. This really "knocks" the problems with preignition and detonation. Do you have pixs of your plugs after a hard run? Nitrous A/F and gasoline A/Fs aren't completely comparable... but I would like to see a couple of plugs.

As far as homogenous goes, I think that the N2O/fuel fog that travels through the TB then the 3.5 intake elbow then into the SSIMed intake chamber would be pretty homogenous before going down the intake runners. Maybe not...

I can easily raise my HP from 380 WHP to the 450-500 WHP level by upping the two shots - and when I do, I'll aim for an A/F lower than 12:1 - but I've lost power by going too rich, so the sweet spot very well may be 11.5:1. Only time will tell.

 

I think I have a solution for shifting under nitrous power - I built and installed a one-shot timer circuit that is adjustable and triggers off the MSD 8969 that is used to signal the Shift_Fast_3 to advance to the next gear - the timer interrupts the nitrous MSD window switch for an adjustable short time at the same time the transmission will be shifting. It worked last night during a short N/A drive w/o nitrous...

Hit rev limit, send shift signal and cut nitrous, re-start nitrous, repeat at next shift point.

I'm going to try this out under a nitrous load - maybe tonight - and PLX-log everything. Hopefully this will speed up shifting a bunch. Graphs will tell...


Later edit - I went out w/nitrous loaded, and the one-shot worked thru 1-2 and 2-3 but it started stuttering at 3500 in third gear. Really weird - it's not finished yet.

 

The Land Shark has a logo now, decals made in Australia:



I looked at my 24.5" M&H slicks, checking slippage, and found quite a bit.

Both sides: I re-marked the before and after marks with silver paint. I gotta fix this...

http://i48.photobucket.com/albums/f2...8/DSCN0544.jpg

http://i48.photobucket.com/albums/f2...8/DSCN0547.jpg

 

sounds like your getting there grey! i hope you get it figured out soon.

dang...that's a bunch of slippage there!



i hope the land shark doesn't eat me alive in two weeks

 

posted 11-16-2008 ... for what it's worth to selected viewers.

I have two pair of M&H Racemaster ripplewalls that I've been using. One pair is 23x8.8x15 on 8" American Racing Outlaw II rims, and the other pair is 24.5x8.5x15 on 10"x15" M/T ET drag wheels. The wear patterns are very different - looks like I need to get another pair of 8x15 rims.

Both pair are pumped up over 30 psi in these photos - that way I can get the car on the trailer.

23" http://i48.photobucket.com/albums/f2...8/DSCN0589.jpg
24.5"
http://i48.photobucket.com/albums/f2...8/DSCN0587.jpg

http://i48.photobucket.com/albums/f2...8/DSCN0585.jpg
http://i48.photobucket.com/albums/f2...8/DSCN0593.jpg
http://i48.photobucket.com/albums/f2...8/DSCN0592.jpg
http://i48.photobucket.com/albums/f2...8/DSCN0591.jpg
http://i48.photobucket.com/albums/f2...8/DSCN0590.jpg


As you can see, the new ones - the 24.5x8.5.x15 slicks are shredding on the outsides. Not a good thing.

 

weird my dr's are doing the samething, I called mickey thompson and they said it's from driving on my with the tire psi too low and putting them thur alot of heat cycles and to run them at 30psi for normal driving and 12-20psi for racing

and to put them on backward since they're directional and do a burnout to get the peeling off

 

awesome times!

 

Here's a couple of graphs that should chill the spine of anyone that can read a PLX A/F log. These are two separate nitrous stages, used one at a time. I think I have a fuel delivery problem, eh? Oh yeah, note the nitrous cut right at shift time - this works good ,at least.

Single 75-shot:



Single 125-shot



And the engine lived through it.....

 

I wonder what the plugs look like

Maybe it's something to do with your fuel solenoid??

 

Damn... I had lean issue(s) too. The first turned out to be a clogged fuel jet The second turned out to be a bad wiring job.
Im pretty sure you will find the problem.
I would try datalogging spaying with the bottle closed to isolate the fuel jet & solenoid from the n20 jet & solenoid.
Did you run lean N/A?
I know a a local org member that had similar problems a while back. Im sure he will chime in on using a temporary in cabin fuel psi gauge.
It would suck if the pump is dead but then again its only $80 compared to another motor...

Side note: I think its time to install a lean warning liight or shutdown switch or both.lol

 

agreed time for a a/r shut down switch

good your motor lived thur this, pretty sure the problem is already fixed

 

Well, there are two stages and two fuel solenoids. Both stages have the same problem, so pump, lines, filter, distribution block are all possibilites.

I haven't pulled plugs yet - it was a long day yesterday.... bet they're white, eh?

 

NA A/F at WOT was 12:1 flat across the board. I haven't dug into this yet, but the pump doesn't owe me anything......

 

10-4 on the A/F shutdown switch. After the run shown in the second graph, on the return road the engine was running pretty rough but smoothed out on the way back to the pits. Betcha it was REALLY hot inside....

The Motorsport 109 saved my azz, I also betcha...

 

I am guess firing idea's

is your pc to car usb cable thingy able to monitor voltage real time, I was thinking maybe your alternator is taking a crap and is not able to handle the load from the 2 stages, warmers, amps and etc.

Do you have the fuel and nitrous niods wired together or is the fuels niod seperate from the nitrous niods or is stage1 seperate from stage2.

Are you using the msd to provide direct ground to anything other then relays

or starting checking the fuel system for clogs