86 NA with nitrous, I think I met the flow limitations of my manifolds...
 

I put my car on the dyno last night. I made 142 rwhp and 120 rwtq NA. Then I put a 60 shot on it and made 179 rwhp and 171 rwtq, but when I jetted it to a 100 shot I only saw 187 rwhp and 176 rwtq. It seems as though even if I keep jetting the shot higher, I don't see any improvement. It also hesitates with the larger shot upon injection, leading me to believe that my manifolds don't flow enough air to keep the nitrous/fuel mixture to air mixture stoich (the a/f readings show this as well). We kicked the timing on the crank angle sensor back a bit when running nitrous, so the car is a dog when it's "tuned" for nitrous and not running it. I can't find anything on people running nitrous on the NAs so if anyone has any help to making more power on my kit, please let me know. You can find a video of the 60 shot run on youtube. I think it's "86 na rx7 dyno w/60 shot".

DOes the car have a cat?
What kind of nitrous kit are you using. Dry?wet?
Exhaust?

I'm running the stock exhaust manifold and all of the cat casings but all of them are hollowed. I'm also running a 3" cat back, not diameter but length (thanks sawzall). I consider it my caveman exhaust system while I'm still broke. Anyway the nitrous kit is a Cold Fusion wet kit. The motor is streetported with 3mm carbon seals and I have a Walbro 255 in the car. Do you have much experience running nitrous on NA FCs? It's been quite the learning experience for me...

stock ecu?

Yeah, I'm planning on getting an Rtek 2.1 but... I'm planning on having $1,000,000 and free hookers, that doesn't mean it's going to happen (yes, I understand if I had $1,000,000 I wouldn't need free hookers). I do have a stock ecu, but it's from an 88 vert and I don't think it's an N326. Either way...

Has anybody else run nitrous on an NA? If so, please tell me exact specifics on your setup, i.e. manifold, nitrous kit, shot size, EFI or carbed, timing... any and all details possible.

what kind of Wideband are you running...... and what sparkplugs?

I don't have a wideband in the car, I was using a probe wideband that the shop had. I'm running stock NGKs leading and trailing (9s and 7s). Do you have any experience with NA rx7 nitrous tuning?

cant wait for the hookers.

I have experience with nitrous just not on a rotary

usually on a piston motor you would run a stage colder and retard the timing abit

what kind of probe wideband what was your afr?

and if your manifolds dont flow enough air you would get a nitrous backfire through your air filter

what was your bottle pressure between runs?

i know this isnt going to fix your main problem but you should try running all 4 plugs as trailing 9. its a colder spark. your gas mileage will go down but youll get a little better response

I'm looking to run a 50 - 75 shot on my N/A. I'm at 166 rwhp and 131 torque.

I'm running 13.2 on my AFR. I currently have an S4 engine with stock ports and all S5 intake and injection. I have an RTEK 2.0 but have been unable to net any gains in two trips to the dyno. More fuel = less power. Less fuel = less power, same with timing. Every correction lost power. The outside air temp. was 20 degrees warmer during my second trip and I lost 11HP.

I race oval track against 4 cylinder cars and that port and polish and run 14:1 compression with variable valve timing and all sorts of things. I need a to get closer to the 200 rwhp mark.

I need to hide the system so I'm looking at a dry setup. Any thoughts on what kit to go with?

^^ U need to go to the normally aspirated forum. There is a thread on how to tune na's.

THey speak of the afrs which was between 13.0 and 13.7. They also speak of the timing.

YOu should go read read read.

Your intake manifold isn't holding you back at all. You'd have to double your power before it does. The stock exhaust manifold and a lack of tuning definitely aren't doing you any good though.

A 100 shot is a misnomer. A 100 shot jet isn't necessarily 100 hp. It's not that simple.

I would go with a Zex kit i had one before but you wont be able to hide a 10 pound bottle and it wont last very long

thanks

Who are you directing this at? If me well, I do read read read and the Drift Office was doing the tuning but oh well. I'm not a professional tuner...

ur tuning is off. my kids vert dynoed 239rwhp with a dry system. stock ecu,afm... 13.5@104mph on street tires..

Stock exhaust manifold? You need a real exhaust, that should help.

I didn't see a Zex kit or any other kit for an RX7. Do I just use the universal 4cylinder Import kits? What does it cost to refill a 10lb bottle? I have a large argon bottle that is empty that could be fill and setup to do my own refills but what is the cost of just refilling the 10lb bottles?

I won't have too much trouble hiding the bottle, the interior of the car is covered in aluminum sheet.

ya you would use the universal 4 cyl kit you would need to buy a few jets with it so you can tune it properly

nitrous in canada is $9 a pound wouldn't know what it is in the U.S

down the road from me it is like $20 for a 10lb nitrous refill. I wouldnt suggest filling it yourself because its a pain in the ass(i used to do paintball canisters with co2) and unless you get an expensive, quaility fill setup you will just end up wasting more n2o than you get to use.

Idk crap about nitrious. BUt i do remember my buddy speaking about one of the nitrious refill places doing it wrong.


SO there is more than one way to refill a bottle? But one propper way?

What is the bottle pressure when you spray? You DO have a viewable nitrous pressure gauge mounted in the cabin right? It should be around 1300-1400psi iirc . you really should have a bottle heater, the bottle pressure can make a huge difference depending how low it is. As the bottle runs down the pressure drops, and when it is colder out (not as much of a problem right now) the pressure will also drop.

I run my pressure at 950 (as that's what my kit recommends) and I do have a cabin mounted gauge and bottle heater. My 100 shot should yeild about 75-85 whp from everything I've checked, but only gaining a couple hp from 60-100 shot jets just doesn't make sence. Judge Ito... what is the setup on that car? Sounds like you guys are doing it how I imagined this build was going to turn out. Any info you could give would be very helpful.

maybe the motor is weak :( ....... i got 196whp on a na s4 and you got spray and your under that then something is wrong remember the stock na ecu advances timing so becareful