i've been thinking alot about my nitrous setup and i am desiring more! haha

i have plans to save up for a turbo and a possible 3.5 at some point. but i would like to take the nitrous as far as i can without getting into two stage setup and stuff due to money. i would rather spend that money on a turbo or something. so my question...what is the most any one here has sprayed in one stage? 100 shot? is it possible to spray 125 off the line? i'm just wanting to know how far of one stage of spray can i go...and i know traction will be an issue but i have slicks and that can be delt with. so any ideas?

grey was right...once i spray a little i'll want more! haha

 

I think Jime sprayed a 150 shot off the line in his 4th gen when it ran a 12.1

 

but he used a progressive controller

 

is traction the only reason not to spray so much off the line or could there be possible damage to the engine?

from what i understand it just seems like traction is the only reason not too....

 

too much nitrous at low rpms can kill your motor
basicly you just want to make sure you do not exceed the tq limits of your rods at given rpm

 

OK - you're officially hooked on the stuff!

I sprayed a 100-shot for a while with 10" BFG DRs - found out I REALLY needed traction bars, but JClaw hadn't invented them yet. I bought a set from his first batch - and I still love them. That's when I decided to use two nitrous stages. And replaced three engines.....

 

wow! yeah i had contacted jclaw about the traction bars and i think at the time he had one left but now i'm sure its gone.

how can i find out the torque limit at a certain rpm?

 

Never heard of anyone bending a rod because of nitrous. I did break a piston top and melted the piston = dead motor. But it wasn't at low RPMs - 2nd gear, around midpoint.

"If you ain't breakin' sumthin' , you ain't racin' "

 

You will just have to guess. Here is a chart I found on the SR20 forums. You will have to know the OVERALL torque your engine is capable of. So estimating is involved.

This chart really helps you figure out how to tune your progressive controller or nitrous stages. For instance, the engine may be able to handle a 200 shot of nitrous above 5K rpm, but it may not handle the insane amounts of torque at 3K rpm.



The X/Y is rpm and the shot of nitrous. The chart figures the amount of torque that is added due to a particular shot of nitrous at a particular rpm.

Jime has sprayed a straight 150 shot without the progressive before, but of course he had traction issues with the 22" MT slicks. But, for some reason, he was still able to get 1.8 60 foots easily while just hazing the slicks through the 60 foot. At my local track (bad prep), if I sprayed the 75 shot out of the hole, I would blow the 22" slicks off the rims and just do a burnout off the line. There is small chance for any traction. I would get a 2.1 or worse. And that is with a fully locked front suspension with aircraft cables just like Jime's old setup.

In my experience, the 50 shot launch is probably the cleanest and most consistent at my local track. I would still be able to get 1.83 60s even with the 50 shot.

But I was able to somewhat hook up once on the 75 shot launch with the slicks and got my best 60 foot at 1.80. But, after that run, the track prep got worse and I never saw even a sub 1.9 ever since.

Just b/c you have slicks, doesn't mean all traction problems are solved, even with smaller shots of nitrous. Combine that with a 3.5 engine and you're in for some fun!

 

thanks Aaron for that info! i didn't realized how much nitrous affected torque at low rpms! wow!! that was very interesting! thank you!

yeah i don't know if you saw the video i posted of my car or not but in the second video you can see me spinning like crazy off the line. i still pulled 1.82 60'. numerous times. i'm not sure if i want it to hook because that's when stuff starts breaking........

now i definitely understand the benefit to progressive controllers. are SR20 motors known to be stronger than the VQ30DE? from what i'm seeing i might be able to do a 125 shot....

my bad....i didn't mean since i have slicks that my problems are solved. i just always have good track prep and i was pulling 1.82 60' without burnouts...i was just pulling up to the line...so i know that if i did burnouts and such that i still have a lot of "traction potential" haha

 

Yes, I bet you'll be able to get some 1.7s maybe. I wish my car would dead hook. I don't mind broken parts. I just want it to hook up. But you're right, the slicks need to the be the weak link. I'd definitely be happy with a 1.75-1.79 if you are able to get them somewhat consistantly.

No, the SR20 engine isn't really stronger when you are talking about how much nitrous to spray. The bigger the engine gets, the more nitrous it can usually handle. Most 4 bangers can easily handle a 50-75 shot while the VQ30 should be able to handle a 75-100 shot on pump gas if tuned correctly. And a lot of V8s can safely go over 100 shot. But, I wouldn't spray anything more than a 100 shot though without using at least 100 octane. With colder plugs and race fuel (and maybe <15* timing), you should be able to do 150 shot right around 3K rpm in first gear. I just wouldn't do the same shot at 3K in 3rd gear. Know what I mean? More engine load means better chance for detonation.

But, if properly setup, I really feel the VQ30DE on stock internals can handle a 200+ shot. But I would recommend not to spray the full shot below 5K rpm. Just a guess. I am not speaking from experience though since I have only done a 75 shot on the VE30DE and that was easy.

But Jime has done the 150 shot countless amount of times on the VQ30DE. And he will soon be doing a 200 shot on the 3.5. Can't wait for that one!

 

Just finished installing the progressive controller and my 2nd stage. Tomorrow I will install my wideband shutdown gizmo and do some testing. I won't be able to test the first stage on the street but I should be able to do the 2nd stage and next visit to the track I will program the controller for the 1st stage and then hopefully together.

I don't think I can do much more than a 50 shot off the line now and ramp that up to a 100 and see how it goes, it will take some runs to get it together but hopefully it will. Not sure if I will spray through the shifts yet, I will try the 1-2 first and then the 2-3 which may not cooperate as nice but we will see. Just hope the drivetrain holds together and the pistons maintain their integrity. This is all with a stock block and trans so testing the Nissan to the limits.

 

maybe you can cut the 2nd stage between shifts, to cut down slippage and tranny temps

and one_fast_max to be safe I would keep your total tq output(nitrous and motor) to 450 or less

 

thanks t6378tp....with the mods i have i guess i'm making around 200 hp and tq....just a guess. with 100 shot nitrous at 2800 rpm that's about 400 ft-lbs....it appears that 100 shot may be as much as i should go for launching off the line...correct?

jime.... now your car when you sprayed 150 off the line was automatic correct? i'm just curious, if you didn't have a progressive controller what rpm did the 150 shot begin??

 

Not exactly sure at what RPM it began I would guess around 1500 as soo n as the WOT activated, I have never had a window switch.

Spraying at low RPM's is a manufacturer thing. The nitrous companies say that to prevent people from spraying in 3rd or 4th gear at low RPM levels and the engine not being able to rev quickly so it blows nice holes in the pistons.

You can spray in 1st gear at any RPM level as long as you are WOT. The engine revs up so fast in 1st it can't load up and blow stuff. If you read the NX FAQ's you will see this, no other nitrous companies will touch it.

If you read below, this is from NX's FAQ's and clearly indicate that spraying from launch is no problem. This subject comes up every time a nitrous discussion takes place, not sure why folks can't get the message.

Q. Are drag racing launch techniques any different with nitrous for AT or MT's? A. Depending on the traction available the launch techniques are the same, however with the increased torque and horsepower generated by nitrous usage, sometimes is necessary to delay the nitrous onset for a brief period.

Q. How high must the RPM's before activating nitrous? A. The RPM level is not as important as is the motors ability to rev freely when the nitrous is engaged, I.E. If the vehicle is in low gear, nitrous can be engaged at any time, but if the vehicle is in a higher gear moving at a slow speed when the nitrous is engaged the engine will detonate and damage will occur.
Q. Can you powerbrake an automatic with nitrous without it blowing up? A. The answer is a qualified, yes. If your brakes can hold your engine, at full throttle, with the nitrous on, the answer is yes, but it is doubtful this would be possible.

 

I've sprayed as low as 1500rpms but that was with a 75shot, with a 100shot I just feel safer starting out at a higher rpm plus I could never get any traction

 

wow ok great! thanks jime.

i understand about the free revving part...i'm not trying to be annoying or anything but does this mean spraying a 200 shot from launch is technically ok?...besides traction of course...purely engine damage. as aaron was talking about over loading rods at a certain rpm? because it sounds like your saying that rpm and any shot of nitrous doesn't matter...its just the "free revving" part that's more important...correct??

 

I have sprayed a 200 shot off the line. Don't think you will overload the rods in 1st because the engine revs so fast it doesn't have a chance. Where I would use Aaron's chart is for the other gears after you shift, that's where you don't want to be at too low an rpm, or if you are on the street and engage in one of the higher gears at low rpm.

When my trans shifts it drops down to around 4000-4200, you can see by the chart that you will have some high torque levels there but not enough to cause problems. Besides you won 't be able to get the tires to hold unless the track is prepped well.

I know guys who won't go to the track to T&T unless there is a big race even if they only get a run or two because they know the track will be well prepped and will hold the tires. Last weekend we had a big event and saw at least 5 guys break trans/axles because of the traction. When you see cars that can pull 60' times under 1 sec you know its well prepped, of course these are 6 sec cars.

 

you've sprayed 200 off the line???? do you remember the time slip? i'd love to see it! haha dang....

wow...ok then. sounds like i'm going to start spraying alot more soon need a wide band first though! will a walbro 255 be enough for a 150 shot? i've read a little about alternate fuel systems but my original plan was to stay at 75 shot so i don't know much about what i should do with a fuel system above 100 shot....

 

I went to HPT last night for a Grudge session, and since I got there a little early, I was able to make two consecutive runs all alone. For the first run, I sprayed the primary 75-shot on launch and waited until I was in second gear before hitting the second 75-shot stage. For the second run, I launched on the 75-shot and immediately sprayed the second 75-shot in first gear. I thought this would be good to know.

I'll make a better thread in the 1/4 mile section ( with slips) but here are the numbers: "it is what it is"

Pass#______1________2______

R/T:_______.117_____.275
60':_______1.968____1.898
330':______5.438____5.310
1/8:_______8.249____8.118
MPH:______87.82____87.91
1000':_____10.679___10.549
1/4:______12.714____12.592
MPH:_____110.90____110.49

Seems like spraying more early makes a difference.

 

awesome thanks grey for that info! nice times btw

hopefully within a few weeks i'll have my fuel pump, wide band, and 100 shot.

 

Ain't no doubt 'bout it - you got the " More NAAZZZ" bug bad, really bad. Ain't it great?

 

i'm loving the NAAZZ bug hahah

grey...can a 255 fuel pump handle 150 shot? just replacing my stock fuel pump with the 255??

and also...when i get a wideband...what's the best way to tune it? 2nd gear starting at 4000 rpm?? how did you tune your nitrous to get the afr you wanted?? i know you change the fuel jets but whats the best way to tune (gear and rpm) to find which fuel jet to use?

 

Well, I've got a Walbro 255lph pump installed in place of the stock pump, and I sprayed 150-shot-combined for a year or so with a 3.0 motor. I also replaced the fuel filter with one for a 300ZX turbo car - that filter can handle much more fuel. I got mine at Advance Auto Parts for $11.00. You also will need a FPR - I use an Aeromotive adjustable one, set in bypass mode. Consider the hose from the bottle to the nozzle - if your bottle is in the trunk and the hose is about 14-16 ft long, it may not handle anything over a 100-shot. That's why I went from a 16' -4AN braided hose to the new 16' -6AN plastic race hose from NX.

A N2O reference site on A/F:
http://www.hotrod.com/garage/113_0411_n2o/index2.html

Tuning starts with setting your fuel pressure to the stock 43psi with the regulator - keep the RPMs up to 1000 or so when adjusting - and installing the stock jets for nitrous. If you have a logging A/F meter, go out for a drive with nitrous enabled and bottle warmed and nail it through the gears, go back and review logs. If a non-logging A/F meter, do the same and watch the meter. Chances are good that the A/F will be good - I shoot for 11.5:1 to 12.5:1. If you have to change jets, get a few extra fuel jets up and down in size by one step and make gradual changes - one jet size at a time. Chances are good ( if you're using NX parts) that stock jets are good. With an A/F meter and a few jets, you'll nail it - the tune is good at all RPMs.

 

ok. well i have the 300zx fuel filter. i will probably get the 6AN line before i jump to the 100 shot....

the only part to this i don't know much about is the adjustable fuel pressure regulator. i guess i need to look and read about those....

thanks grey!!

edit: ...i just looked at a picture of that afpr....that thing is crazy looking...i wouldn't know how to hook it up. i need to do some reading

what's the point of an afpr? i guess i just don't understand how they work...i figured the fuel pump was what determined the pressure.....

 

The reason you need it is that a Walbro is capable of much higher fuel volume and pressure than the stock pump. The stock 3.0 has a fpr installed on the fuel rail and connected to the return fuel line. Yes, your fuel system recirculates gas from the tank up to the engine and back again, and pressure is regulated at the fuel rail. Chances are that the Walbro will overwhelm the stock fpr and raise the injector FP too much, and also mess up your nitrous A/F seriously.

An external FPR can be installed to maintain a constant fuel pressure to the engine while providing a much higher fuel volume than stock. I use this one ( the ..105):
http://www.jegs.com/p/Aeromotive/756927/10002/-1

Connected like this: (the straight pipe comes up from the filter, the 90* one goes to the fuel rail through some 1/8"NPT brass for fuel connections)

http://i48.photobucket.com/albums/f2...3/Dscn1868.jpg

http://i48.photobucket.com/albums/f2...3/Dscn1867.jpg

http://i48.photobucket.com/albums/f2...3/Dscn1865.jpg

 

I have a question

why isn't the vac port on the afpr connected so fuel psi drops when your at idle or is this your old setup with the 3.0 and it's just used to choke down the psi enough for the stock fpr to handle

 

Read the specs - that's a pressure port, and was intended to raise the fuel pressure one psi for every lb of boost, or something like that. No boost, no care..

I never had any problems with running a solid 43 psi for all RPMs - you are in closed-loop in most normal driving, after all...

 

thanks grey for the pictures! i definitely need to look into that. i'm still a little confused but some reading will fix that

i just got back from the track....i pulled my best 60' so far...a 1.80 but i was trapping 2-3 mph slower and .2-.3 slower than two weeks ago....i'm a little confused....

i'm wondering if i got a bad nitrous fill or something...it wasn't hauling as much as last time....

 

if you connect that port the engine it will lower and raise fuel psi in relation to vac psi or not boost so if you have it set a 43 static at wot it will be 43 and at idle or around 18-20in lbs of vac you'll be around 35

It's pretty clear the car runs just fine the way it is but it will help with gas mileage alittle and thats how the 4gens come from the factory

 

It's still a Pressure port, for raising fuel pressure when boost pressures raises.

"Adjustable from 30 to 70 psi and beautifully finished with Type II bright red and black anodized coating. Fuel pressure will rise on a 1:1 ratio when referencing boost. -6AN fittings included." No mention of vacuum here..

My car runs just fine that way - it did with three 3.0s and now with a modded 3.5, all set to 43psi static pressure, and all fours motors get/got about 26-27 MPG on the highway. Closed-loop is a powerful force of nature.