Dyno results with NOS

[SNDSOUL]

Well I finally got to put my car on the dyno this past weekend and the results were about what I thought they would be. The only thing that was odd is my car is running lean when I am not spraying. Anyone know why this would be? My results were as follows:

Off the spray=255RWHP
On the first stage(50shot)300RWHP
On both stages(50 & 35)335RWHP

My mods are:
short gears
4:23 ring and pinion
RM clutch
Comptech headers
RM carbon fiber intake
Apex exhaust
Dual stage Nitrous(1st stage engages @ 3200RPM, 2nd stage engages with VTEC)

My A/F ratio was 15:2 when I wasnt spraying and 12:1 when I was. I know the reason it was better when I was spraying was b/c I am using a wet system, but why would I be running lean with just a I/H/E combo. Do I need to put a FMU in or maybe just a boost-a-pump with a fuel pressure regulator? If I can get the A/F richer I would feel much safer and I would probably gain 10-15 HP. MORE POWER=MORE SPEED!

 

[SNDSOUL]

BTW, I do not have any check engine codes showing. Here is a pic on the dyno.

 

[Factor X Motorsports]

At what point did it run 15.2? Certain points at lower RPM at WOT the AFs will read slightly lean. On the top end it should go no leaner than 13.4. Check the fuel pressure and injector spray pattern to make sure it is up to Spec. If you have any questions feel free to e-mail or call.

Speed Safely,

Factor X Motorsports www.factorxmotorsports.com

 

[SNDSOUL]

Originally posted by Factor X Motorsports:
At what point did it run 15.2? Certain points at lower RPM at WOT the AFs will read slightly lean. On the top end it should go no leaner than 13.4. Check the fuel pressure and injector spray pattern to make sure it is up to Spec. If you have any questions feel free to e-mail or call.

Speed Safely,

Factor X Motorsports www.factorxmotorsports.com

Wow, I'm impressed you guys really know your stuff. The 15.2 ratio was at the low rpm's and then it went to 13.2 at about 5000. The guy running the dyno said the ECU must have adjusted the timing to richen it up. I guess he was wrong? Then why did my car only dyno 255 off of the NOS? With I/H/E I thought I would post something a little higher than stock. My car was serviced and checked the day before the dyno to make sure everything was in tip-top shape. Mech. said the engine was in perfect running cond.

 

[Factor X Motorsports]

The ECU will not richen up under WOT, its called open loop. That’s when the 02 sensor signals are no longer being used be the ECU and the ECU refers back to the internal fuel table. In reference to your timing question, the ECU will pull out up to 10 degrees of timing at a time if it detects detonation (knock sensor). Btw, you WILL feel 10 degrees of timing missing (extreme loss of power). As far as your car publishing 255rwhp, it could be accurate even with your current mods. What year is your NSX? How many miles? We have had NA NSXs run anywhere between 232rwhp to 260rwhp.

Speed Safely,

Factor X Motorsports www.factorxmotorsports.com

 

[SNDSOUL]

my car is a 92 with a little over 70000 miles. It has had the timing and water pump service. Also new cam seals and VTEC solenoid seals. There is not a noticeable amount of power loss so I would guess that it is not taking any timing out. The car is running 11.9-12.2 in the 1/4 on the juice and feels very strong. I just thought that it had more power than that off of the Nitrous. When I installed the I/H/E the car was noticeably faster(13.7 stock,13.2 after mods), but I also had the gears done at the same time. Could it be that I am sucking too much hot air with the exposed filter? Dyno was run with the hatch open so probably not. Would a fuel pressure increase help? It seems like an easy upgrade for insurance purposes. Would an V-AFC do the trick or just go with a B&M fuel pressure riser?

Sorry for so many questions, no one in my area is an NSX specialist so to speak. Thanks again for your help.

 

[nsxlr8]

If your car only showed lean on the dyno for that short time that is typical when ANY car does that, there is not an issue with fuel. Do NOT attempt to adjust your fuel pressure. Tacking on a piggyback will SURELY just give you more headaches (There's someone else on the list who has posted a few times about his - Nothing but trouble from what I've read) Some cars just have less power. Too many variable. Car may not have been broken in properly. (Rings not properly seated, etc) It's just that way. The best possible way to have known (Which is what ALL should do in my opinion) is to dyno the car BEFORE you do any mods, then immediately after. You get a more complete picture. So, if you started out with 233 at the wheels, a 20 hp increase isn't all that bad!

 

[robr]

fwiw, 255 is not at ALL low with those mods on a 92. stock is 270 at the crank and if you look at all the dyno runs that have been posted over and over again for stock 91-96's, they *generally* tend to run in the 230's (note the *'s around generally before you start trying to respond with "look at these stock runs at 250").

fwiw i have similar mods to you (ct headers, hks exhaust, ct cf airbox and the addition of no .... um, kitties) and my 91 dynoed at 265 so given the usual location, temp, altitute variances, etc our numbers appear reasonable.

 

[SNDSOUL]

I forgot to mention that this dyno is in New Orleans(below sea level, but very humid) and it was about 95 degrees I think. I dont know if the humidity would affect it, but I'm sure the temp did.

Also ran that day was my friend Toms Comptech'd 91. Only pulled a 296??? He was very disappointed, but the big difference between our cars was the torque and powerband. I had about 50 horsepower on him from about 2000-7000, then his spiked to the 296. Mine planes out at about 6500 and carries until 8000. His torque was generally straight across, mine literally went straight up. I had over 75lbs of torque on him as soon as I sprayed. NOS is instant power!!