What is wrong with my car? Dyno’d on Friday night, really bad results I think. The mod’s on the car are; Turner three pulley kit, AFE intake, Euro headers, SS race cats, SS mid-pipe, Borla muffler, Shark software with rear O2 sensor delete. Outside temp was about 50, raining, Dynojet, F/A probe up the exhaust pipe, runs were in 4th.

The dyno operator ran the car to center it on the drum, DSC went crazy pushed DSC button in, wouldn’t go off after that. ABS light on the whole time. Took four tries to get it to run to 8,000. All runs produced 270 at 6,500. Torque curve looked bad (not flat) every run. As you can see 288.7 max hp, 235 max torque with a bad curve. A/F about 12.5 through most of the run.

Friend ran his NSX. The NSX was 255 4 weeks ago on same dyno. Ran on Friday with a Comptech S/C installed, running 5 pds of boost. He ran a 314, 228 torque very flat torque curve. Expected to run about 325.

I expected somewhere between 300 and 310 with the mod’s I have. What do you think the issue is? Most likely candidate would seem to be the Shark software.

looks like operating error, redyno it somewhere that has experience dyno'ing e46 M3's, those numbers are low for what you have done...

Why would you think that? We got the car to run to 8k following the standard procedure. What else would the operator do differently?

just from the many problems you had running it until then I'd assume something didn't go right for that run. Also, must have been very humid. Or could be that there is something wrong with your motor or tuning.

oh, and I haven't looked at many E46 dyno curves but your torque curve looks pretty crappy.

I bet on your first run you would've made over 300rwhp. But on the 4th pull the engine must have had a lot of heat soak especially when 4 gear was used on all the pulls.

I bet on your first run you would've made over 300rwhp. But on the 4th pull the engine must have had a lot of heat soak especially when 4 gear was used on all the pulls.

Good point.. I dyno'ed my car once and did a 3-5min wait between one of the runs and the 2nd run was 13rwhp lower.

Also, the torque curve should tell you something is not right with either the car/software or the dyno facility. It should be very flat.

Good point.. I dyno'ed my car once and did a 3-5min wait between one of the runs and the 2nd run was 13rwhp lower.

Also, the torque curve should tell you something is not right with either the car/software or the dyno facility. It should be very flat.

Don't think its the Dyno the NSX's torque line was very flat.

NSX torque curve is flat as a pancake :D Same dyno, same day.

You mentioned it was raining, was it also humid?

You mentioned it was raining, was it also humid?

Not that bad.


Based on all the input here and elsewhere I am thinking a combination of heat soak and DME issues due to getting it to run to 8,000. Shut the engine off a couple of times to try to get it going again, the DME likely went into start up mod and stayed there. This all seems to be the general consensus.

At the end of the day the real test will come on the track. The season starts Wednesday. Gobble is going to kick my butt now with that blown NSX, of course if he doesn't guess that means he has a real driving skill issue...hehe.

your problem is when using a dynojet you are supposed to dyno it in 3rd thats what active autowerks told me

your problem is when using a dynojet you are supposed to dyno it in 3rd thats what active autowerks told me

You are suppose to dyno as close to 1:1 ratio as you can..which would be 5th gear. The problem is 5th gear will out spin the capability of the roller as far as MPH is concerned so we do it in 4th. Dave

My car has made it's highest numbers on the 3rd pull, Ive made 9 pulls, 3 sets of 3, the 3rd has been the best each time.
I use a GT1 to get the DME into Roller dyno mode enable 8000 rpm.
You may have had some DME Engine protection mode intervention, or bad gas.
A set of cams would compliment your current mods and put you over 300 whp.

I basically put down the same numbers with the same mods. 282hp and 235 torque to be exact with the CEL on. I'll will go back because since that dyno i have added the AFE intake and shark. I'm hoping to see at least 300.

This may be a stupid comment... but wouldnt the o2 sensor delete effect how the software instructs the engine...? If so (and I cant imagine it wouldnt) then that could be the problem.

How did you accomplish the rear O2 delete?

Jim Conforti aka "the Shark" sells software for the E46 M3 which is written for the euro headers and cats. The software deletes the reading of the post cat o2 sensors. The software is written as such and I highly doubt the post o2 sensor delete is an issue.

I don't think this is a software problem. I think it is a DME/DSC type problem with a dyno. Conforti actually has said time and again that dynoing this car without special override equipment, which is very expensive, is pointless. He says you cannot get an accurate result so don't bother. I guess I believe him now.

There is only one correct way to dyno an E46 M3 and that is using a Modic or a GT1 to force the car into dyno mode. Otherwise you won't see the full potential of the engine. I saw 15 Hp difference in the same car in just 6500. The only difference was the dyno mode during the better run.

I was at the track yesterday so I could judge real world HP. Based on the runs down the front straight at Blawkhawk Farms with my buddy Gobble in his supercharged NSX ('93 OBDI ) which was putting down 314 on the DynoJet, I am confident that the numbers on the dyno are not accurate. In addition to 314 the NSX also has 100 to 200 lbs on my M3. The front straight pull was not much different. The NSX would pull some but not much. Of course there are other factors, gearing and corner exit speed for example. None the less the modifications were very evident as I was running down most everything on the track.

:confused I say take it to somewhere else and get it re-dynoed!

What dyno was it, and heat plays a big factor in the game of dyno'ing.

Your buddy Mark has a fair amount of driving prowess. Certainly worthy of placement in the Advanced group. He was running 2:45s at RA last year w/o the supercharger. That is a good time for an NSX.

The CTSC NSXs don't run that much faster on the straights than the NA NSXs, and the CTSC is more about low-end torque than high RPM power, which limits the bump you see at high RPM conditions such as driving schools.

I know I have no trouble with E46 M3s in my NSX at Road America or Blackhawk. The straight-line speed is roughly equal with a slight nod to the M3, but the NSX is superior in the more technical portions of the track, turns 6-11 at Road America.

Your buddy Mark has a fair amount of driving prowess. Certainly worthy of placement in the Advanced group. He was running 2:45s at RA last year w/o the supercharger. That is a good time for an NSX.

The CTSC NSXs don't run that much faster on the straights than the NA NSXs, and the CTSC is more about low-end torque than high RPM power, which limits the bump you see at high RPM conditions such as driving schools.

I know I have no trouble with E46 M3s in my NSX at Road America or Blackhawk. The straight-line speed is roughly equal with a slight nod to the M3, but the NSX is superior in the more technical portions of the track, turns 6-11 at Road America.

In comparison to an E46 M3 with an unmodded suspension and equal drivers you are absolutely correct.

In comparison to an E46 M3 with an unmodded suspension and equal drivers you are absolutely correct.

I can't speak for what the many M3s I passed over the weekend were running. Some were likely modded, but most appeared stock or close thereto. Once you start modding, anything is possible. Then the comparison becomes modded vs. modded and relatively specific.

We have met before, Mark. Gobble introduced us at Oktoberfast. I believe it was 2004, perhaps 2003. Your M3 was parked by his NSX which was near mine. I may stop by the Dyno on Thursday when he goes back.

I can't speak for what the many M3s I passed over the weekend were running. Some were likely modded, but most appeared stock or close thereto. Once you start modding, anything is possible. Then the comparison becomes modded vs. modded and relatively specific.

We have met before, Mark. Gobble introduced us at Oktoberfast. I believe it was 2004, perhaps 2003. Your M3 was parked by his NSX which was near mine. I may stop by the Dyno on Thursday when he goes back.


It must have been last year if you were the person he helped with the pad swap? It will be interesting to see how much HP he can get with a safe a/f mixture.

Heard Windycity CCA event at RA wasn't all it could be. 3 runs a day and the motorcycle turn before the Kink.

what kinda fan did they stick infront of ur car?

Wow, with your mods i would assume at least 305rwhp. Must have been something screwy. I would check everything out and try and dyno somewhere else.

I was at the dyno last night with Mark (Gobble). The dyno appears to be running fine. He put down virtually the same numbers he did in his prior dynos, as tuning the Fuel pressure is tricky and the stock injectors appear to be maxxed out with the CTSC. The dyno is used for a variety of cars, many making well over 500 hp.

I had excellent results for my car. It dynoed stronger than Gobble's car pre-CTSC, despite having only exhaust and a Cantrell AIS. My best guess is that the head flows better following the top end rebuild that was done in 2003, and that is where the extra 10-15 hp is coming from.

http://img.photobucket.com/albums/v291/brahtw8/113_1314.jpg

Here are a couple of shots of the dyno facility, including the fan . . .

http://img.photobucket.com/albums/v291/brahtw8/113_1307.jpg

http://img.photobucket.com/albums/v291/brahtw8/113_1308.jpg