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Old 12-13-2008, 05:15 PM   #488
patr
Scooby Specialist
 
Member#: 97
Join Date: Jul 1999
Location: Vancouver, BC, CANADA
Default

its obvious...

there is something wrong with the car
or something wrong with the way its beng run on the dyno
or something wrong with the way the dyno is being run
or something is causing it to under perform on the second dyno (or prior to arriving)

I would stand behind the original number 100%.

a mustang will pull higher than an RR Dyno Dynamics dyno, period.

Lots of things could be in play - boost and afr graphs for the second set of pulls ? was the car running full ignition advance ? was the IC fully fanned (looking at a big fan doesn't mean it is, you need temps) ? what were the intake temps at the start of the pulls ? was the car changed since it was on the RR dyno in any way at all ? yadda yadda. So in essence, the only people who can tell you why this car pulled what it did in someone else's shop are the ones who pulled it the second time, because from the data they could tell you what the car was doing (if its the car that is the problem). But I do know what it pulled when it was on the RR dyno and I would stand behind those numbers 100%...

Ramp rate, acceleration rate, pull time, boost targets, fanning, current advance, etc. can all lead to make a pull do whatever you want it to. Or lots of other 'magic' factors. That is why you do 'normalized' pulls... or the car could just be doing what its doing.

since its all about 'posting for a friend' it would also be useful to know more about the circumstances, i.e. if your friend wants the problem with their car figured out, if there even is a problem, to get an idea of what car this is. Easiest way to get to the bottom of it is to identify said friend, and pull it again. The mustang will always pull higher... so I would say it would pull about 265 or lower on my dyno if everything remained the same...

There have been lots of interesting things happen with more dynos coming online but I will stand by my numbers 100% as do the local PCA club, the local Nissan club, the local Audi club, ICBC (!), several lower mainland car dealerships, and several manufacturers doing warranty work... etc etc
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Last edited by patr; 12-13-2008 at 05:50 PM.
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