Hooking up with nitrous and a 3200 stall
 

I have added a Zex nitrous system on my Camaro for drag racing. It really gives the car a good kick in it's heavy @ss.:thumbsup:

My car doesn't have a lot of power without the nitrous. Around 360rwhp, I'm currently using 125 jets with nitrous.

The problem is........ it's not hooking up most of the time now.:pout:

I have 18" Z06 replica's and MT ET Street R 305/45/18. This is a tall tire @ 29".

I realize if I do hook up now, the stock spider gears aren't going to handle 1.5X 60' for long until they break. I added a line lock recently as well, but still get the 1 wheel burnout most of the time from the posi.

I plan to put an eaton tru-trac in to fix that, and while the pumpkin is out, I also plan to change the gears and diff bushings.

But, I already can't hook.

With the 125 shot....... gears would just make hooking up even worse, wouldn't they? If the 327's wont hook, no way 391's or 410's will.

I normally flash the converter when launching, it gets the best 60' that way.

Any of you guys running a stalled converter with nitrous? What size DR's are you using to hook?

Here's 2 passes. One hooking, one spinning through 1st and into 2nd. Both passes made yesterday. I normally abort the pass when spinning so much, but on this pass I was running alone, so I finished it out just to see how bad it would be. It's awful.....:facepalm:

psi...

I started with nitrous on 20 psi in the MT's, almost got sideways out of the hole :bonk:, went down to 18 still spinning. I currently run them at 16. You think I need to go even lower?

Or are you talking bottle pressure? 950-1050 is where I'm usually at.

Progressive controller?

I don't think this would work with the nitrous system I have. The Zex system I have uses their active fuel control system.

It basically varies amount of nitrous/fuel based upon bottle pressure and fuel pressure, so you can't run too rich or too lean.

Sudden changes in nitrous/fuel delivery could cause this feature problems. I want this working properly every time I use it.

currently at 13 on the NT05R's...but if your posi is actin up then even psi won't help...this would...https://www.camarocentral.com/2010_2..._p/clu-595.htm

l8tr

Joe, That differential will need to be beefed up for sure, if only one tire heats up at the burnout obviously one tire will have more traction than the other. Try to make a few runs stalling up to as high as you can with the brakes on, that may help. We basically have the same setup except for the converter and tires. Faster times are in there just need to launch differently.

Yes I'm going to have to make changes in the diff for sure. Our cars do have almost the same mods. What's really surprising to me is without a stalled converter in yours, our cars run very close to the same ET. Your actually a tenth or so faster now since you switched to the race star 17's.

My car ran a best of 8.20 before the converter, and with it a 7.84. The nitrous dropped me about 4 tenths, but your car on the stock converter dropped 7 tenths with the same shot.

I tried brake stalling it with the converter in before nitrous, but the car ran slower vs. flashing it. I haven't tried brake stalling since adding nitrous. I also have considered moving the activation switch from being hidden to a spot I can reach while making a pass, to turn it on after the 60' mark and see how that works out.

I'm not going to get a chance to try anything else now until I make some changes in the differential.

The differential is definitely the weakest link on our cars for sure once you add power. The clutch pack kits are said to work up to around 600 hp. But the factory spider gears can't handle a 1.5X 60' time for too long. Ask Pro Stock John, he broke his when he began getting 1.5X 60'.

I'm going with the tru-trac instead of the clutch pack kits. I like to drag race, and it's much stronger than a clutch pack.

The tru-trac is supposed to be good to 1000 rwhp, and I'd rather spend a little more now than have to re-do it again later.

Here's a good article on the Eaton Tru-Trac for the 5th gen Camaro.
http://www.lsxmag.com/tech-stories/d...gen-camaro-ss/

The dilemma I have though is what gear to put in with it. I know everyone loves the 391's on N/A cars, but it might be too much for nitrous with a stalled converter. I was kind of hoping someone who ran nitrous with a stalled converter weighed in on what gear they run, but no one has yet.

I would consult with Janetty, PCM of NC & DynoSteve on what path to take to get the best results regarding Nitrous/Stall/Gears. Good Luck, let me know what the plan is.

Steve is on it. From what I understand so far, the RPM when crossing the 1/8th mile mark, the tire height, and the MPH are needed to figure the proper gear for my current set up.

It will be some time before I run at the strip again. The trutrac and gears need a 500 mile break in, and I drive about 4 miles each day. So probably fall of this year before I can run again.

Steve will get it right, of that I am sure. I'll just need to record a pass after the initial tune, send it to him, and he will make any necessary changes.

I don't know much at all about tuning but I do know this. A good tuner like Steve will get your car within 95-98% of best possible results with a handheld vs. what he would get on a dyno.

The dyno is basically a stationary street, where a tuner can see what is going on. With the SCTX4, the tuner needs data because that is the only way they can see what is going on after adjustments are made. It just takes some patience and realization that without data, he can't improve what the car is doing.

When this pollen subsides, I need to bring the Rupes up to your house and get that metal flake popping in your paint!:thumb:

Yeah I broke the spider gears when I started running 1.50 ish 60 foot times. Swapped out to the TT, still had my slicks on, and went 1.47 and it lives. :)

Any video of your car launching Joe? Does it weight transfer?

I don't have a video camera, Franks girlfriend Joanne got these two passes on video. The first one had a little spin. 1.70 60' 7.55 @ 94mph. The second pass I just abandoned after the launch due to so much spin. 2.0 60'.

If you don't want to watch the whole video, the passes were at 5:00 and 15:30 of the video.

I've had several 1.5X 60' passes at Shadyside here in Shelby, she squats down nice when she hooks!


https://www.youtube.com/watch?v=rwmHenSxqQM&t=1s

I have done a lot of research on the forums, and I see it is a common thing for the clutch packs to go out, making the differential open ended. I still can occasionally get the drivers side wheel to spin when burning out, and this is when I get the good 60'.

I read one thread where they did the posi-mod, and later broke the spider gears doing a 1.5X 60'. Based upon your experience with it as well, that is why the trutrac is going in. No clutches to wear out, no spider gears to break.:thumb:

It's going to cost me a good bit of $$ to get done, as I'm also adding a 3.91 gear per Dynosteve's recommendation. But I'd rather spend it now than save some by just doing the posi-mod, and then have to later on replace the factory diff anyway from the spider gears breaking.;)

Here's a really good video explaining the differences in differentials for anyone interested.
https://www.youtube.com/watch?v=x40WGUtdaLI&t=1379s

Well everything arrived today. Eaton Truetrac, Motive 3.91 gears, and Ratech install kit.

Installation will be early next week. I found a local shop, only 10 miles from my home, the guy has 35 years experience doing this type of work. $650 for installation. Seems reasonable for an 8-10 hour job.

Nice, hope to see you out making some runs soon. Those gears are going to be pretty stout.