Information On Variables In Dyno Testing

**JetBlue** · 07-12-2004 02:05 PM

This has been a hot topic lately and I was wondering if anyone else read the article by Steve Dinan recently. Basically he showed that he could have different numbers on the SAME dyno based on the air velocity over the front bumper. He had four different ratings from ~350 HP to ~410 HP for the same car on the same day using different fan systems.

The two main point of the article were that cars a getting even more sophisticated and different cars are affected by different variables in testing. The second was that unless there is a sophisticated controlled environment then there is really no comparison between dynos in different facilities. Here is a link to the White Paper:

http://dinancars.com/whitepapersFile.asp?ID=6

I thought that Villain's dyno runs were very impressive since there were stock EVO's and STI's there. No dyno facility is going to have as good of a setup as the manufacturer's, but this demonstrated the real world comparison of what they have been able to achieve with the 1.8t motor.

Overall those dyno runs added with the M3 video lately have shown the versatility of these cars with a relatively small investment.

Any other thoughts?

MO

**neoprufrok** · 07-12-2004 02:42 PM

Taht's a good paper. I'm glad you posted it. It just goes to show you that dyno results are hardly the end all and be all of mod performance. In my mind, the best test of a mod is how it feels to the consumer.

For me, I autox my car and the results lie in how much faster I get around the course and how the car feels doing it.

For power testing, longer real track courses would probably answer how much power a car truly makes.

That being said, I do think that there is a place for dynos. Specifically as you have said, when in comparison to the same conditions on the same car or in reference to other cars present on teh same day. Thus, if I dyno'd my car now at Dyno Locale 1 in the morning at 78degrees with fan speed 2, I need to dynot my future mods at teh same conditions. Or, if I don't have a baseline mod, I need to dyno with another stock car with a KNOWN output (easiest being stock) like Derrick did with the Sti's.

**Villains** · 07-12-2004 02:47 PM

Dynos should be used as a reference point of what a mod can do. If you go back to same dyno again after getting some mods you can get an idea of what the mod did for you if anything. For instance, I will be adding a FMIC this week then I will go back to the same dyno to see if there is an improvement. Track testing isn't as accurate because you have a human factor which to too unreliable. I might have a great day and run good numbers then go back the very next day with the same conditions and get bad numbers. The driver is too great of a variable to use as a measuring stick. It will however give you an overall feel of how you and your car are progressing.

**Saturnine** · 07-12-2004 02:57 PM

I agree kind sir!

Originally posted by Villains
Dynos should be used as a reference point of what a mod can do. If you go back to same dyno again after getting some mods you can get an idea of what the mod did for you if anything. For instance, I will be adding a FMIC this week then I will go back to the same dyno to see if there is an improvement. Track testing isn't as accurate because you have a human factor which to too unreliable. I might have a great day and run good numbers then go back the very next day with the same conditions and get bad numbers. The driver is too great of a variable to use as a measuring stick. It will however give you an overall feel of how you and your car are progressing.

**neoprufrok** · 07-12-2004 03:36 PM

Originally posted by Villains
Dynos should be used as a reference point of what a mod can do. If you go back to same dyno again after getting some mods you can get an idea of what the mod did for you if anything. For instance, I will be adding a FMIC this week then I will go back to the same dyno to see if there is an improvement. Track testing isn't as accurate because you have a human factor which to too unreliable. I might have a great day and run good numbers then go back the very next day with the same conditions and get bad numbers. The driver is too great of a variable to use as a measuring stick. It will however give you an overall feel of how you and your car are progressing.

Well, this is what I'm getting at. I'm saying that the dyno plots are important to give you an idea as to how much more hp/tq your car is making and under what rpm.

Tracking a car is the ultimate use of that mod, thus the ultimate test of that mod is how it performs at 10/10ths driving - tracking. That's all I'm saying.