New Project - Skunkwerks EM9D

gsxr

Gone to the M119 dark side

103

10-30-2010, 11:24 AM #605

(10-24-2010, 09:51 PM)Captain America Pete has a Mustang dyno first off, which is better (more accurate/ real world numbers) than a Dyno Jet. ... Oh, and if your worried about not having Dyno Jet numbers for previous comparison, he can convert the real world numbers over to the over inflated Dyno Jet numbers for ya.

LOL! I've heard exactly the opposite, that DynoJet generally tends to have lower (more realistic) numbers than Mustang. Also remember that there are multiple different types/models of each dyno, i.e. not all Dynojets are the same, nor are all Mustangs the same. If you really want to know how accurate the dyno is, get the exact model from the shop, and do some Googling on that specific model. Even then it's a gray area as the dyno has to be calibrated after installation and if they screw up the calibration, the numbers may not compare well to other dynos, even one of the same mfr / model. In summary, it's best to use the dyno as a tuning tool, and always use the same dyno. It doesn't matter if it reads 100hp or 500hp, after you make a change if it reads 110hp or 550hp, you still got a 10% power increase. The dragstrip is the final equalizer, the dyno numbers are irrelevant if you can't get the power to the ground.

About the 3rd/4th gear thing. Something is screwy there. Justin should definitely have been able to get good runs in 3rd gear with NOS activated. I'm not sure what was going on. There shouldn't have been such a discrepancy between the runs n teh diesel, either. I've done runs in two different gears on my E420 and the difference was 1-3% at most. A 10% delta is huge. Maybe that dyno has lightweight rollers (TOO light weight) and cannot properly load up higher-power cars? It might work fine on low-torque ricers but wouldn't work as well on high-torque diesels or juiced M119's.

BTW, as y'all learned the hard way, the 722.3/722.4 tranny needs both the Bowden cable AND the kickdown solenoid disconnected to keep it in 3rd gear at low RPM's. I unplug the solenoid at home and the Bowden cable at the dyno to keep things simple, while retaining driveability to & from the shop.

If anyone can locate a wire that will work with the dyno's electrical tach input, PLEASE let us know. The optical sensor is a PITA and loses signal about half the time - a real annoyance. I thought it needed a high-voltage signal from a plug wire, but if it will work with a low-voltage signal, we could try the flywheel speed sensor....

Huh

This post was last modified: 10-30-2010, 11:28 AM by gsxr.

Dave M.
Boise, ID, USA
1997 E420 - 149kmi (Bugeyes)
1994 E420 - 136kmi (Blondie)
1994 E500 - 116kmi (Q-ship)
1992 500E - 179kmi (Mach 5)
1987 300D - 330kmi (Sportline Stage 2)
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