JoeDirt's APS ST v. DynoJet: Part II (with nitrous!)
 

Had the car dyno'd last week during NOPI - numbers were respectable (421hp/505tq) but there was an odd loss/sudden peak of hp around 5k rpms (dyno below). Thought maybe it was pulling timing. Had the day off today, decided to put in 3 gal. of 100 octane (had about 1/2 tank of 91 already) to see if maybe it was pulling timing due to detonation.

Interestingly, still shows a loss of hp around 5k, then recovers, then levels off. No changes in boost, AFR, etc.

However, also had a chance to see if my intercooler sprayer was worth a sh*t. I had read both good and bad about sprayers: water, CO2, nitrous... and I pulled the trigger on an NX Intercooler Sprayer last month. Butt-dyno results said no improvement. On paper, however, there is a difference!

Test: Two back-to-back 5th gear pulls. Run #1 had a cooling period of 5 minutes (from prev. pull), no intercooler spraying (shown in RED on last graph). Run # 2 was immediately afterwards, spraying for 10 seconds prior to pull, and all throughout the pull until redline (shown in BLUE on last graph).

Results: a) 15.67rwhp/19.4tq improvement with intercooler sprayer, and b) smoother, more linear power output. The dyno shown is with no smoothing applied!

No nitrous cooling: 430.06rwhp/462.28tq (SAE correction * 1.02)
Nitrous-cooled IC: 445.73rwhp/481.68tq (SAE correction * 1.02)

Conclusion: $370 for an intercooler sprayer picked up 15 rwhp power and shows a smoother power distribution. JoeDirt-approved®

Dyno charts from NOPI and today as follows:

GRAPHS FROM NOPI (03/19/06):
http://img.photobucket.com/albums/v3...DynoSheet1.jpg
http://img.photobucket.com/albums/v3...DynoSheet2.jpg

GRAPH from AZDynoChip: (03/24/06):
http://img.photobucket.com/albums/v3...NOdynochip.jpg

Would just like to say thanks to the following vendors that have contributed to the Z:

Intense Motorsports
Caliente Automotive
Tokyo Speed Pros
Dyno-Comp
AZ Dyno Chip

Thoughts on how much was from NOS getting sucked into the intake?

If you're familiar with the location of the APS intake in relation to the IC - it'd be a longshot at best. The halo is placed in such a way that there'd be very little, if any, overspray onto the IC.

It should be noted that there was a remarkable discrepancy between my AF gauge and their sniffer. Previous dyno reading (incl. last week's NOPI, DynoComp, etc.) corroborate my AF gauge. AZ Dyno Chip's seemed to be off by about 1 - 1.2, so don't freak out by looking at a 13+ AFR under boost


AFR graph from today and pic of the IC cooler in mid-install:

https://img.photobucket.com/albums/v...ay/afratio.jpg
https://img.photobucket.com/albums/v...Febpics027.jpg

weird, is the blue line in your A/F the 1st or 2nd run? They seem a little different to me. The red one is leaner anyway.

edit, just read what you said how your A/F gauge and the sniffer were giving different readings

Red is first (non-spraying) run, blue is second run (spraying)

My AF is NOT around 13 - Keith and (unknown person) stated they just changed the sensor, but after showing them all the prev. dyno charts and they watched my AF gauge, they determined they must have a leak or something because it was reading nearly 1 - 1.2 higher than my gauge.

EDIT: Gauge shows around 11.6 - 11.9 from 5krpms forward

Great to hear! Man I cant wait to dyno my car! 3in test pipes and exhaust,cams,SSV,APS TT,NX sprayer. I should have numbers next week if my tuner isnt busy.

Nice-that APS IC is a beast...

Surely the reason that there is no 'butt-dyno' improvement is because of the massive amount of cold air hitting the intercooler on the highway as opposed to the lack of said air on a dyno (I'm still not convinced that those fans help that much) .....

awesome numbers Dirt!!!! hopefully after i add scotts performance cams and utec with the map selector next week i can get to where you are, and past it:p . btw, what psi are you running?

PSI is something I'm thinking about looking into further: right now it peaks at 12psi at 4000 rpm, and tapers to 7.5 at redline. One suggestion was to put a bleed-valve in the line between the restrictor pill and the wastegate; allegedly this will maintain boost in some fashion, though it's not very clear in my head how that works.

I have no observable exhaust leaks, running APS exhaust, boost controller set at 100% from 4k rpms and beyond. *shrug*

Then again, I kindof like how it runs now b/c it's suitable for daily-driving use.

something else must be going on. youve got the APS exhaust and your boost is still dropping. after i resealed all the piping before the turbo, disconnected the unichip boost solenoid and added a ebc, and got my exhaust fixed, i was making and holding 12psi. im not anymore, but thats another story.:( you should be making and holding 12psi too.

What's going on tig?

check yo PM

Tig,

More problems..... Dammmm.

no not really, just a minor setback.