So I finished the Nismo mods on the Roadster, short of cams, and dyno'd at DSR once the Nismo headers dropped in.....

Best was about 236whp (Nismo headers, exhaust, intake)

Weird thing was the baseline started at 217whp (went to 227whp after a few back to back dynos). Mods on the baseline were the Nismo intake and exhaust. Hooked up the sniffer, and the A/F ratio was way high at around 14-15:1 at about 3800-4800rpm.

Is it me or are these pretty low numbers? Engine had about 1500 miles on it, just past breakin. Perhaps a few more breakin miles, an oil change, and more time to adapt? Dick also did the ECU technosquare reset and ran the 236hp run.

I'm just thinking the A/F ratio is looking high. Any suggestions to the cause or solution?

 

If I understand you correctly you took a baseline reading with intake and exhaust already installed and dyno'd 217. Then you added headers and went to 236? That sounds like a pretty good gain.

236 may be a little low for those mods if you have a MT. If your car is Auto then the dyno looks pretty good. DSM seems to be give the lowest numbers of any dyno I've had my car on so I wouldn't be to concerned. As long as you're seeing gains, that's what matters.

Are you running the Technosqaure ECU?

Where is the car running 15:1? Down low below 2000RPM or up high? If it's up high (above 2500RPM) then that's getting pretty lean- do you hear any pinging coming from the engine? If you're running 15:1 at high RPM's I would be careful and do something to correct it immediately.

I know when I added my cats my car leaned out to ~14:1 at about 6000 and I was getting some pretty audible pinging. I had Technosquare reflash and got it to 13:1 and it's much better now.

 

I know all of us are running 91 octane, which hurts our numbers a little bit, but I have to agree that DSR gives low numbers. I went to their website and examined what other cars were putting down. A ferrari f355 put down only 298 rwhp, when it should be about 320 considering its 375 hp rating. And ferrari usually does not overrate their cars.

Failsafe,

What was the hp difference between DSR and the other places that you have dynoed.

 

Hmmm.....more the reason the dyno's not always the most accurate tool. No audible ping heard. However....

For the best intake/exhaust baseline run (226.9whp), the A/F was 15:1 at 2500-2900rpm, dipped, then went back to 15:1 at 4100rpm-4700rpm (torque dipped/dropped at this range as well). Lowest A/F was 13.5:1, above 5000rpm.

For the headers (236whp), an ecu reset (stock ecu), and more dyno runs, the A/F ratio adjusted to 15:1 at 2500-3500rpm, dipping to 14.5:1 at about 3500-4700rpm, and then dipping again to 13:1 above 4700rpm. What's interesting is the headers seemed to fix and eliminate the torque dip previously at 4100rpm.

The Z is a 6spd. I was thinking about R/T cats as well, but am now hesitant. What gets me is how the Z picked up 10whp just by running the intake/exhaust combo on the dyno 5 times back to back (217-226.9whp). Bad gas? Driving too mellow? Just wondering what else I can do as this is really weird.

 

Very good gains for H/E/I. A gain of 19 hp is very nice. Don't worry about the base line and final numbers. It's the difference between the two after modification that matters. Your a/f sounds about right.

And, highflow cats would be a good follow up mod.

 

DSR seems to be ~10rwhp lower than my runs at ATP (which is where I usually dyno). And ~20rwhp lower than the runs I had at Stillen when I went down to SoCal.
Everyone I know who has dyno'd at DSM seems to usually get lower numbers than anywhere else. But we all know that 10 different dyno's will give 10 different numbers. The most important thing is to consistently use the same dyno to track gains.
I have a few runs at DSM and it's closer to where I live (and to StrictlyZ) so I like to dyno there (and Dick is a cool guy). But ATP has my baseline and a few more runs.

The most important thing is to listen for pinging. As mentioned my last run at DSM showed ~14:1 at high RPM. I had pinging and when Tadashi and I pulled my plugs they were white (way too lean).

But if I was running 15:1 above 2500RPM I would try and get it corrected immediately. Chances are you are getting some detonation (even if you don't hear it) and this can be extremely detrimental to the engine and it's life. Better safe than sorry. If you are running the stock ECU there is a good chance the condition will correct itself- if you're running the TS ECU or a piggyback I would correct it ASAP.

You will usually see rising gains on each successive dyno while the engine is reaching it optimal operating tempurature (usually about 3-5 runs). HP will then drop off after the optimal run.

 

The reason your baseline started at 217 is because your engine was not up to the proper temp.

Whenever we dyno a car the first 2 runs were usually just warm up runs until we get the car to proper temp.

To measure the runs on a consistent basis we would hook up to the OBD port and run the car everytime it hit a certain temperature and the fans turned off.

227 sounds right and your gains sound right. I'm really not a huge fan of the AEM/NISMO air intake. I would recommend the crawford plenum over that any day.

Unfortunately this car is hard to get power off of.

High Flow cats sounds like a good option, as Failsafe mentioned his spark plugs were lean. So make sure to do some research on the random cats in particular because it seems as if people are running a lean condition with them before you go out and invest in them

anyways i'll shut up here now

zya
Yuichi