Since there was some concern about my torque numbers on my OLD first Dyno run, I went to someone else with a Dynojet chassis dyno (who also happened to be about an hour closer to home).

When I explained that I was doing another baseline Dyno because of the torque numbers, guess what he said.

"Ah, Ha! This is elementary Dr. Watson! Since the HP and TQ curves do not cross at the magic (except when explained by physics) 5250rpm point, there must have been a problem with the perceived engine RPM."

I.E. The first dyno operator got the engine RPM from the wrong wire. He used some wire under that plastic shield covering the intake manifold. The second dyno operator said "that wire was probably an injector timing wire that fires every 90 degrees versus an ignition wire that fires every 270 degrees." (I don't get it but hey, I'm not a Dyno operator.)

I mentioned that I asked the first guy about using the # 1 ignition wire but he said that it was not a good signal because of the "coil on plug" ignition system. (Made sense, 12.5vdc versus ??,000vdc.) Well, the second guy was able to get a good signal from cylinder # 1 after a good deal of fiddling around and comparing the Dyno's RPM reading to my Tach reading.

After we got the Dyno RPMs matching the RPMs on my Tach, we went for a ride.

First 2 runs done in 4th gear from 2000rpm to 6300rpm.

Results:
RwHp: 218.6
RwTq: 218.4

Adjusted assuming a 20% loss via the 5AT:
FwHp: 273.25
FwTq: 273.0

Much closer to published numbers. HP a little low and TQ a little high. Well within tolerances.

When I asked why he stopped at 6300rpm he said "No need to go to redline because both curves are dropping by that point." He also explained that he preferred to use the same scale for the SAE HP and the SAE TQ graphs even though it tended to cause the graph lines to overlay the HP and TQ numbers. Note, one of the graphs he showed me (not included in this topic) showed the same blip at 3250rpm as I'd seen on my original baseline Dyno. He said, "That happens. Every engine is unique and can show behaviors unique to that engine."

The 3rd run was done by me at my request. Since I hadn't hit a rev limiter on the first dyno at 6700rpm I wanted to take a run in 5th gear to see if there was a speed limiter.

That run was different. According to my Speedometer, there is a speed limiter. And that limit is.... Ta! Da! 155mph! The speedometer stopped at 155. The dyno operator got confused about what was happening since my rpms wasn't climbing and he tried to indicate that he was going to brake the drums. I backed off of the accelerator and he hit the red button. You can see what happened to the HP and TQ at about 5380rpm.

No surprises there, others on this forum have come to the same conclusion about the top speed imposed by the speed limiter.

Now the graph of the 3rd dyno run showed my top speed as 148.4mph. Two factors involved here which account for the difference between 155mph and 148.4mph. First, my rear tires' diameters are 0.3" smaller than stock (rear tires are now 255/40R18s vs the stock 235/50R17s) resulting in a speedometer reading that is 0.8% too fast. Adjusted by this factor my top speed should have been 153.76mph according to the dyno. Second, vehicle speedometers are not that accurate. (As everyone who has had their car dynoed in order to use this fact to escape the loss of their driver's license can attest to. This "out" is no longer accepted here in NC. You can still go to the DMV and have your speedo checked but it can not be used to wiggle out of a more severe sentence.)

Actual Dyno graphs in the next posts.

Note, all runs were with the VDC turned off. It still indicated that it had detected a "slip" due to the front wheels being stopped and the rear wheels spinning.

Also, when I tried to turn the VDC back on, it would not reset. I turned off the ignition, pulled out the key, got out of the car and locked the doors. Turned the ignition back on and VDC stil indicated that it was turned "off" and that there was still a "slip" condition. I then started the car and rolled her off of the dyno thinking that the ECU might need to sense that the wheels were not in a "slip" state. Didn't work. The dyno operator crawled under the front to look for some disconnected sensors but couldn't find anything amiss. He suggested that I disconnect the battery in order to try to "reset" the ECU. That turned out not to be necessary. I just hadn't driven far enough for the "slip" sensors to detect a non "slip" state. The "slip" light went off within 100ft and I was able to turn the VDC back on. FYI. YMMV.

Screamin' Daemon - L5AT

 

Graph # 1: Two dyno runs in 4th gear.

Screamin' Daemon - L5AT


33707-Screamindaemon_DynoJet_Baseline_CAM00.jpg

 

Graph # 2: One dyno run in 5th gear.

Screamin' Daemon - L5AT

33708-Screamindaemon_DynoJet_Baseline_CAM01.jpg

 

Those numbers are more in line with what I got from my dyno run. Now I must wait for aftermarket parts companies to come to the rescue and offer power upgrades. I want another 100hp/tq.

Robert

G35 Coupe 5AT, Brilliant Silver, Tire and Wheel Pkg.
G RIFIK 1

 

Has anyone done a run with the 6MT? What are the differences in the two?

 

I have done a run on my 6MT with a B&B exhaust and the numbers are as follows.

230 rwhp
240 torque

Driveline loss is right between 19-20% on the 6MT.

I am installing an Injen CAI today and I will re-dyno next week.

By completely stock numbers where.

HP - 224
TQ - 225

TMaxG

 

19-20% drivetrain loss on a 6/MT is too much IMO. 350Z's are losing 15% through the drivetrain. Infact there is a 350Z at my350z.com that has 262 RWHP with an Injen CAI, Grouding Kit, and removed resonator.

Now do you think that 350Z is making 326 Horsepower with a 20% drivetrain loss? Or do you think that 350Z is making 306 Horsepower with a 15% drivetrain loss?

I do understand that the 350Z has a shorter wheelbase, and because of that a shorter drivetrain, but a whoping 5% differance!? Nah!

20% sounds right for an automatic.

 

Are those 350Z's the Track model? If so, doesn't the Track model have a Carbon Fiber Drive Shaft? That would greatly decrease the driveline losses... Naturally, our G35's don't have CF drive shafts...

 

Nope, its the enthusiast model with 17" rims.

 

my base run I got

240.5 hp
238 tq

BS G35C 6spd navi/aero/prem