without further ado



as you can see, with both the y-pipe and headers, there is a huge gain at redline over stock. about 35 whp!!! The butt dyno definitely agrees. I think i'm soundly into the 100mph+ traps now. The stock run was not my own, but borrowed from another member as i had no access to the runfiles for my own baseline. However I used it just to illustrate the differences in the power curves.

A few notes:

Peak power is still at 5800rpm. To move this upwards I still need some kind of intake manifold. The car now seems to want to continue making power at 3700 rpm, but the VI switchover interupts that then jumps upwards again after switchover.

I think I am running EXTREMELY rich over 5000 rpm. Although I didn't have A/F for my runs, there is a theory going around that the vq35 ecu severely overcompensates for increased air volume. This is evidenced by my gas mileage going to complete crap. I can SEE my fuel guage dropping whenever I floor it.

I only have two power mods. Berk intake + stillen filter and hotshot headers.

The conditions for my run (green line) and dave's run (red) were 89 degrees, sea level, 10% humidity


more comparisons to come.

 

good job got some nice bumbers for jus 2 mods.

 

what kind of y-pipe did he have?

 

cattman y-pipe

 

Headers only gave 8 more horses over the y-pipe.

y-pipe = $450 installed
HS headers = $800 installed

Not quit sure that 8 whp is worth it to me, but I'm sure with other mods the headers will prove their worthiness.

 

That makes me wanna

Its a difference of $350 making it $43.75/hp. I set my limit to $50/hp. You gotta think... lots of people are spending $400-$500 on a catback that will get them 7hp if they are lucky. Its worth it... especially if you know someone who will install it for cheap/free or you can do it yourself.

 

Now that's a great graph. Thanks for posting this

I'm surprised the 2k2+ y-pipe does so well in comparison to the headers. Hopefully you can tune the A/F if it's as rich as you say because the the additional power of the headers really aren't going to do much for you in the 1/4 mile because the real gains aren't seen till about 5500rpms and only last till 6200rpms. Seeing that the VQ spends very little time accelerating thru that range, the ET won't fall much (maybe .03-.04 seconds if that). Now if the whole curve was elevated a full 8-10whp then you'd definitely see some improvement in the ET/MPH.

What were your A/Fs above 5000rpms?

 

Any torque numbers?

 

Why didn't you incorporate your stock dyno of 205whp to show an even better comparison?

 

I would have, but that would require some photoshop magic because stillen didn't give me the runviewer files. Thus I used someone else's stock dyno.

All in all, I believe it was worth it, it wasn't only an 8hp peak gain, it was a sustained gain over the y-pipe for a good rpm range.

I paid nothing for install as I did it myself. As Jime put it, all it cost was one weekend, some bruised knuckles and a few new tools.

dave, I'd really like to know what my A/F's were, but they didn't put a sensor into the tailpipe. I will know when I get it dyno tuned with the ECU and keep you informed.

as far as ET gains, who knows. But I shift at redline and I spend a good deal of time up in the higher rev's when racing. Combined with the shorter gearing of the 6-speed and my lower final drive from smaller overall diameter tires (225/45/17) i think there are at least a couple tenths to be seen. Past 4800 rpm I'm well over 200 hp and stay above it till redline. On the stock dyno as you can see, by the time i'm at redline i'm only making about 180 whp. Maybe I'm being overly optimistic, but we'll know soon.

keep in mind, i'm running a stock exhaust from the cat back. no b-pipe or anything.

 

Can you post the TORQUE graphs please?

 

I'm just going by what we've seen with our MEVI intakes. Look at the poor graph I made below comparing my MEVI (without the JWT ECU) vs the stock intake manifold.



From 3200-4700rpms, the MEVI causes a loss of ~10whp/tq in certain parts of the graph. However from 5800-6500rpms my car gained 10-50whp over the stock manifold. I would have thought for sure the massive topend increase in power would have easily overcome the small decrease in midrange power especially considering that the only gear you use 3500-4500rpms is 1st gear. I was wrong. My 1/4 mile ET/MPH didn't improve one bit. In some cases I was actually slower with just the MEVI. The issue is that an increase in power spread over a small amount of rpm is pretty meaningless in the 1/4 mile. The reason being you spend very little time accelerating through that power band. In 1st gear you might be spending a few tenths of a second accelerating thru that increased power. On each upshift you spend a little longer time accelerating thru the increased power, but the amount of time is so fractional it doesn't make a difference in such a short race. Not until I added the JWT with the 7000rpms limiter did my ETs drop a consistent .25+ and gain 3mph. The increased midrange power along with the extra 500rpms of powerband allowed me to accelerate in a far more powerband than before, especially in 3rd and 4th gears.

Hopefully what I stated above isn't terribly confusing. In a nutshell, just remember that power under the curve is what wins races, not peak numbers. I hope your ET/MPH do improve, but I think expecting .2 is bit too much. I'd say 0.04 and maybe .5mph, if that the way the car currently sits. Prove me wrong and I'll eat my words

 

Nice work chinkzilla. Definitely coming up on my list soon...great bang for the buck...

 

What the heck do you guys need the torque posted for? Do the reverse math to figure it out. You have the RPM points and the HP at those points...

 

it seems that the increased power provided by the headers arent apparent until 5k and up. the 24 extra horses is significant at first glance, but with that improvement restricted to such a narrow powerband does it make a significant impact on overall performance?

 

He needs a cat back /B pipe setup pretty bad I think...

 

the stock exhaust system holding back potential?

 

Yeah...cause I'm lazy and it's much simpler.

 

No, I think he needs SR20s "little secret" intake mod and he'd break 225whp and hold it until redline vs. dropping 10-15whp from peak.

 

its all at the high end, nothing wrong with that of course, just cant neglect the low and mid range

 

sorry, finally got around to it. not as dramatic as the hp graph, but here it is anyway.

[img]http://64.7.211.215/tqcomparison.jpg[\img]

 

k... that was lame, wouldn't let me edit

 

That's a "secret sauce" intake mod.

 

Those are some nice numbers Chinkzilla. How long did you have the headers on before you did the dyno runs?

For those that are comparing the Y pipe to the headers I'll say this. The Y pipe was sweet and simple but with the HS headers my car feels significantly faster.

 

my headers were on the car literally less than 1 1/2 hours when I dyno'ed. no ECU reset was done.

I'm pretty impressed with your hp and torque numbers, did you get your A/F tuned with an AFC?

 

No AFC yet, but that's one of my next steps which include TS Limited Spec ECU flash, SR20's secret sauce intake (hopefully), and tuning with SAFC. Right now I'm running pretty rich myself so there is some room for improvement.

BTW, I noticed that my power levels seem to increase significantly in a few days after the installation of my headers. I think the ECU needs some type to adjust. Let us know if you have the same experience.

 

Almost forgot to ask...what do your gaskets look like, particularly the ones connecting the headers to the y pipe? My original ones were very thin and quickly blew out causing a loud exhaust leak. HS replaced them with some thick copper gaskets and the car sounds so much better, even with a Greddy catback.

 

well, i feel it in my butt dyno, but i've also been known to have a healthy dose of wishful thinking. It seems to have gotten stronger in the days after the install.

the gaskets they gave me were uber crappy and paper thin. I used additional rtv on the two header to y-pipe gaskets, and tossed the crappy foam gasket between the y-pipe and the cat, and just reused the OEM one.

 

I tell ya what, I'm a firm believer in that the ECU does need time to adjust. On numerous occasions where I've reset a CEL (basically resetting the ECU), my car feels a bit sluggish for the first few hundred miles. The intake is quieter and the motor lacks is normal punchiness. I know that Nealoc187 dynoed with an ECU that had been broken in vs an ECU that had just been plugged in and he saw absolutely no difference in power. Same day, dame dyno, withing 10 minutes.

Make sure when you dyno again to have the ECU learned and maybe the SAFC tuned

 

so you're saying, that after a new mod, the ECU detects a whole bunch of air, and wigs out so it defaults to dumping a whole crapload of fuel just to be safe? An then as time goes on it gradually adjusts?

I have a feeling it's the opposite. I would think the ECU would be continually fighting your mods...

All I know is i got an indicated 16.9 mpg on the trip computer today. Not good.

 

Ts Ecu????

 

TS = Techno Square, ie http://www.technosquareinc.com/

 

I agree with you on that. My car felt like it normally did with my stock oem y-pipe I did a reset, and over time the car feels like its getting stronger.

Good job on this Chinkzilla!

 

I would like to see an overlay of like a 2 week post install dyno. It would be nice to see if there is a good increas after the ECU has had time to adjust. Just try to do it on a day with similar weather conditions.

 

unfortunately, i won't be back at the dyno until after my next mod.

I think I've figured out the cause of my extreme rich a/f. I dropped the rear bank primary o2 sensor during install and dented it, also the o2 would not thread all the way down in the bung on the header. I'm thinking the computer is getting an erroneous lean condition and dumping fuel to compensate.

Anyway I will pull the code this weekend, at which point I will know for sure. How much is a new o2 sensor typically? 50 bucks?

 

Looks good, but I would definately look into why there's that huge dip in the curve at 37-3800RPM, and another at 5300.

 

All the 02-03's have that dip at around 3800rpm. That's when the intake manifold switches runners.

 

Nice numbers with the y pipe.