150 shot doesn't feel the same up top as it does down low...
 

A couple weeks ago I put on a wet kit and it's jetted for 150 shot currently. I had it dyno tuned for a 150 shot and 91 octane (damn the desert).

So anyways If I roll into it and let the window switch activate the spray it hits pretty damn hard but lets say I switch off the nitrous at 5k+ rpms and maintain WOT there's not much of a difference in the butt dyno... Is this normal because I've already passed peak torque or is there something else going on? Any help would be appreciated! :cheers:

Normal, the lower the RPM, the more torque.

exactly. The tq basically peaks when it hits, than dies down. HP should level off.

HOWEVER, if your bottle pressure is dropping to already low pressure/no heater, or low bottle, than you will REALLY feel the drop off. What psi is your bottle?

That's the benifit of multi stage and/or progressive. A more linear torque curve. The one hit in all torque monster peaks and goes down. If you have a second stage kick in at this torque peak area then you keep pulling and even a third stage after that. A multi stg or progressive set-up will in fact win more races than a a one hit wonder.
Robert

well that makes me feel better about my setup at least :) While a multi-stage/progressive would be nice for several reasons I just don't have the scratch to drop on something like that right now.

As far as bottle pressure goes, I have a NOS bottle heater on it currently but I noticed that before I sprayed psi was roughly ~925 and then after I let off the psi ended up around 890 from just a third gear pull in an M6. I was not able to watch the gauge during the run as my gauge is attached to the bottle in the back seat. Is that kind of pressure drop normal? It was around 70deg and I had my t-tops off when i was spraying.

Dude.........I'd listen to Robert56 carefully, he has ran 11.0 on nitrous alone! :eek2: He ran that time on a basiacally stock Z06 with DR's and the bottle. :hail: Not to mention that he's a nitrous moderator!

I hope to be spraying a 150hp shot here soon.................Good luck on your situation. :)

one hit wonder..... :jest: like that one.

I have single 150 wet shot and both my tq and hp curves are very much flat so I dont know why I here all this stuff about it dropping off quick with a single shot. My curves are flat either with the nitrous or without it, so maybe it is just how my motor is. But yeah, it does feel like a hard initial hit when you activate nitrous, I think the fact that your butt feels like it died off is just a false perception.

do you have a dyno graph of this?? (your torque)...

yeah, right after the initial lean spike the torque is a bit over 450, then shortly after that hits peak at 532, then VERy gradually drops off, i mean it is a very slight curve, for the most part it is very flat, maybe like a 20-30 degree slope at the most. Sorry though i dont have the graph on the computer.

hmmm, I guess it's hard to really say anything without seeing the graph and scaling of it. Here is how mine drops off (the hp is flat, the tq drops)

http://img407.imageshack.us/img407/6356/23pb.jpg

The scaling on the two sides is different though. The rwtq is from 200-900 and the rwhp is from 0-700.

kinda like this, made it in paint so its kind of ghetto, but is similiar to what the graph looks like.
EDIT: nevermind the pic wont upload.

Sounds just like what we are talking about to me. Here's mine, you can see where 2nd stage comes on 4100rpm and when 3rd stage is done and comes on at 5100rpm I'll have a more linear torque curve. Yes some set-ups seem to maintain torque better than others, but the majority fall off at peak around 4000/4500. Conclusion, HP goes linear and torque drops off.
http://home.comcast.net/~weaver.robe...8/site1070.jpg
5.8literls1eater, that's some absolute mondo torque your putting out. Have you been able to get that to hook up? If so any times? Looks like you also broke loose on the dyno (dip in hp and torque)?
Robert

A little off subject, but have you had any problems running 91 octane? What kind of timing are you using? I live out in San Diego and 91 is the best we have here without using booster or race gas. Thanks!

I haven't brought it to the track yet, but on my 17" mt et street radials (at 15#'s) it hooks on my VHT prepped road. I think the dip in hp/tq might have been the tune, it dipped down to 10.5, than back up to 11.0 where it stays.

You know you can have your screen name changed if you want.......just thought I'd throw that to you. :)

who do I contact to do this...don't knwo who the admin is. Thanks!

If you look at my dyno you'll see a similar dip. Tuner at dyno said it was tires breaking loose when 2nd stage hit, and at my torque peak. That's why I was wondering if you had the same issue.
If you go to, User support-user name change request, they'll help ya out. Make sure you save your post count and join date.
Robert

there's is a little tire smoke back there so that definately makes sense.

And thanks for the info on name change.

Torque and HP drop off has alot to do with the combo also.Different set ups will act differently.
Dave