How dyno numbers are utilized by ITAC

[quadzjr]

John Carter drives that ITA ISC Miata very well. He's not lacking for power at all though. He could stay in my draft at Roebling. The one place on the track -- the front straight -- where I should be able to put some distance on him, I could not. The rest of it, that's Miata heaven. ITA Miatas have won the overall there several times. I was lucky to beat him once back in April and thought I had him on Sunday in July, but he made a great pass on me in 1.

I don't think an S car has officially been in the 19s at Roebling. Track record is 20.5 (Irish Mike) and I think Charbonneau and Williams have been in the 20s. Best I've done is a high 21.

Not saying that John doesn't drive the heck out of the car. That car has had some rough times. (it was rolled at the double school last year). It has a good motor, MVS puts out a good product. My point is that Mike in the BMW on a miata track was toe to toe with the best in ITS miata. Both with great drivers.

[JeffYoung]

John's car has a VERY good motor.

I am certainly not saying I'm among the best ITS cars to run at Roebling. I'm definitely one rung (at least) below Irish Mike, and Andrew, and Mike and Kip, and John Williams.

But I think I have enough time up front at the track, and in racing with the Miatas, to think that a well prepped, well driven ITS or ITA Miata is going to very, very hard to beat there. Can be done, certainly, but that track -- a big long momentum track - is perfect for that car.

The only place I have an advantage, or a Z car, is the last 1/3 of the front straight, and even there, Mike at ISC has done so well with power development that this disadvantage seems to have disappeared.

Just confirms that there is always development to be done.

[quadzjr]

John's car has a VERY good motor.

I know it has a good motor.. it is the same car/motor Andrew C. drove during the SIC race that was mentioned before. That he (Andrew) was running around significnatly faster per lap faster a few years agoan what John was doing at the last race at RRR acording to MVS while he was timing john during qualifying sessions. Although htis last weekend the track was fairly greasy IMHO.

Actually during the last race they did adjust the tune on the computer to help resolve some lean conditions they were having. Seemed to work as the plugs looked good when he came in during the middle of the saturday qualifying event.

[JeffYoung]

As you know, that track is very temp dependent.

In qual in the morning you basically got (in my car anyway) one or two laps before you couldn't get grip in 8/9, which as you also know kills your lap times.

FWIW, I think John's times in the 22 would be up there with Charbonneau's in the fall.

FWIW again, where John "beats" ITS cars is in two places. Turn 6 and 8/9. He's on the gas way earlier than us in 6, and then flat through 8/9.

I could pull him in 3, and some on the front straight if he was not right in my draft. 4/5 was a wash, as was 1/2.

[quadzjr]

Watching all of the miata that drive for MVS they have the mojo. They all seem to take the same lines and they are fast. I have seen the traqmate data for the cars and it is impressive. My favorite is the 5-6 area.. Flat... slight lift.. flat again.. I have tried to do that in my car.. not a chance.

but for the original question, Atleast one BMW in ITS was fast against a fast ITS miata at a miata track. Who knows what was done, to the car and what prep level? You can always ask Irish Mike, he is a pretty cool guy. Dan might know as well?

[gran racing]

When using drive train loss percentages to estimate flywheel HP from dyno numbers, does that percentage decrease the higher the cars HP is?

For example, we dynoed a 348 HP RWD car today. Should we use 18% to get close to the flywheel number? What if the car was only 150 HP (still RWD)?

[erlrich]

When using drive train loss percentages to estimate flywheel HP from dyno numbers, does that percentage decrease the higher the cars HP is?

For example, we dynoed a 348 HP RWD car today. Should we use 18% to get close to the flywheel number? What if the car was only 150 HP (still RWD)?

The more I think about it, the more I think that is a really good question. Why in fact do we use a % for drivetrain loss instead of a constant value? Does a 300 HP (crank) RWD car actually require 18 more HP to turn its drivetrain than a 200 HP RWD car?