JHew84

Well recently my car club hosted a dyno day and since my car is out of commission at the moment I thought i'd just dyno the cummins to get a baseline for it before any modifications that may come it's way.

Well first the shop owner tried to push me to the back of the line because he didn't want me to smoke out his shop. I could see this as a legitimate reason aside from the fact that two hondas had gone before me that were burning so much oil everyone left the shop and waited outside until they were done... Plus being bone stock my truck barely blows any smoke whatsoever...

Anyway then they tell me they won't be able to get me a torque read-out because I (obviously) don't have any ignition wires for them to read the rpm's from. After my first run I heard him mutter something about having another way of doing it but didn't hear anything else about it and was rushed off the rollers after my second run. Obviously there is a way to get torque readouts on a dyno for a diesel because I see them posted EVERYWHERE, but is there something special the shop needs? I guess my main question would be is there a legitimate reason I only got 10 minutes on the dyno and two pulls, or did they just not want to mess around setting it up to get a proper readout for me?

- James

P.S. it was a dynojet

HOHN

That's why it's best to go to a diesel-only dyno day.

You can easily get an RPM readout from a diesel. They usually just spray a white paint spot on the damper and then rig up the pickup to read that spot.

Dynojets measure HP and calculate tq based on rpm.

Other dynos (load dynos) measure tq and calculate HP.

Both require engine rpm to calculate.

Justin

JHew84

Yeah, we were going to back calculate the torque (ended up being somewhere around 390ish at the peak HP rpm) but I just haven't gotten around to it at different points.

I think the part he mumbled was about something they could plug into the OBDII port to read the rpms? I'll probably search for it later but does anyone know what this is off hand and if it's cheap enough that I could just pick one up and bring it with me next time?

JD730

The places I've been to use a little piece of reflective tape on the dampener and use an optical pickup from underneath the vehicle to measure the rpms.

JHew84

I'll definitly have to remember that. I'm pretty sure they could have rigged something along those lines up but it was pretty obvious to me from the first time I asked when my slot was that they didn't really want me dynoing that day. Oh well, next time i'll be prepared and won't get blindsided last minute because they can't hook up to my spark plug wires :lol:.

So how terrible is 184whp on a stock cummins w/146K on the ticker? It has some kind of aftermarket air filter on it that will be getting replaced soon because i'm sure it's actually doing more harm than good.

skynyrd

its more or less cause he didn't want you showing up any of the ricers that were there with a stock '02 diesel!

JHew84

I definitly woulda beat out the hondas on torque but a few of them were almost at 400whp . And between the S/C Marauder, S/C 99 'maro SS, and f150 lighting with a few boltons I definitly wouldn't have taken first in the torque department, all three of them were in the 460+wtq range and the SS had a slipping blower belt . My buddy with the lightning wanted to have a competition to see who put down more torque, I told him i'd be back next year with a tuner and we could go at it on a level playing field (since he's modded and i'm not), i'm thinking I might be able to edge him out with a few more investments .