ITS cars - which are the fastest?

[gran racing]

2. Four wheel disc brakes.

Why? Testing was done at Road Atlanta (by either Peter or his brother) with rear discs versus drums. The drum brakes were good for a couple of mphs on the back straight.

Anyways, not that important to the conversation but thougtht it was interesting.

[JeffYoung]

Maintenance, reliability and pedal feel.

Drums stop just fine. For a while. Problems: at least on my car, failure mode is (a) session one, shoes look just fine; (b) session two, shoe is entirely delaminated or wheel cylinder has fallen to pieces.

With a drum brake you are CONSTANTLY working on it to get pedal feel right. And it's a trade off. You set the drum up to rotate nicely and get those mph, and you lose pedal feel. You set it up for pedal feel and you get rotational friction and lose the mph.

I hate the things honestly.

Why? Testing was done at Road Atlanta (by either Peter or his brother) with rear discs versus drums. The drum brakes were good for a couple of mphs on the back straight.

Anyways, not that important to the conversation but thougtht it was interesting.

[Andy Bettencourt]

And don't forget that test was on a FWD car where there is a ton of weight transfer under braking.

[Ron Earp]

Why? Testing was done at Road Atlanta (by either Peter or his brother) with rear discs versus drums. The drum brakes were good for a couple of mphs on the back straight.

Anyways, not that important to the conversation but thougtht it was interesting.

I don't know the players here and it is but a single data point, but what is the reasoning cited for why the drum brakes allowed a couple of mph advantage on the straight?

[JeffYoung]

I think the idea is if you set them up "loose" you get no rotational friction, meaning the shoes are backed off the drum slightly. Problem is, result is bad pedal feel.

With discs, you are always going to have some pad drag on the rotor.

[Ron Earp]

I think the idea is if you set them up "loose" you get no rotational friction, meaning the shoes are backed off the drum slightly. Problem is, result is bad pedal feel.

"Testing was done at Road Atlanta (by either Peter or his brother) with rear discs versus drums. The drum brakes were good for a couple of mphs on the back straight."

Man, that would be a really difficult test to orchestrate. I suspect the most practical way to do it would be to have a single car and convert from drums to disc brakes in the paddock and run multiple sessions back to back on the same day with the same driver with identically worn tires.

Or, maybe two cars, prepared exactly alike except for the rear brakes, and have the driver test them back to back.

However, in any of these scenarios I suspect the statistical variations in the measurement methods will result in a confidence interval that will exceed the absolute value of the measured parameter, i.e., it'll be lost in the noise.

Get yourself a car with EFI and four wheel disc brakes. Don't mess around with carbs and drums, been there and done it, a lot. It sucks.

[JeffYoung]

Absolutely. EFI and 4 wheel discs make for happy racers.

[frazer]

After thinking...I'm shopping for another 2nd Gen. Can't help it. I miss my old car and the comfort and confidence I had in it. Until I make the purchase I'll keep an open mind and my eyes out for whatever comes up.

[gran racing]

Agreed, probably not 100% perfect testing but I do think it has merrit. No matter what I've tried (new calipers included), I can't get rid of all pad drag. It's not horrible but it can be felt. Rotated an Accord with drums, and didn't have drag like mine.

[JeffYoung]

You can set them up that way (the drums) but you end up (at least on my car) with very poor pedal feel. I need the shoes out on the drums to get a good pedal.

Agreed, probably not 100% perfect testing but I do think it has merrit. No matter what I've tried (new calipers included), I can't get rid of all pad drag. It's not horrible but it can be felt. Rotated an Accord with drums, and didn't have drag like mine.

[Mazmarc63]

I've said it before and I'll say it again, the easy button is an S5 powered 2nd gen RX-7. Other cool cars to choose from for sure.

I have loved my easy button for over 15 years.

To address Mr Young's obvious envious statements about the Rx-7 - "but they have a lot of maintenance requirements and can be finicky".

I recently looked at the date of the parts bill for my last engine rebuild. March, 1997!! Not a typo. The engine in my Rx-7 was last rebuilt by Rob May when he worked at ISC over 14 years ago.

Yes, the gearboxes are the weak link but if you are smooth (= fast) you can get by with occasionally replacing synchronizers.

Yes, I am biased.

[erlrich]

I'm surprised nobody has brought this up yet, so I'll just throw it out there...


If you want the fastest ITS car, get an ITA Miata

[Ron Earp]

I recently looked at the date of the parts bill for my last engine rebuild. March, 1997!! Not a typo. The engine in my Rx-7 was last rebuilt by Rob May when he worked at ISC over 14 years ago.

I suppose the bigger question would be engine hours, not engine age. How many hours since the last rebuild? And a big Bzzzzzzztttt if you don't have an hour meter with which to check....

[Andy Bettencourt]

I'm surprised nobody has brought this up yet, so I'll just throw it out there...


If you want the fastest ITS car, get an ITA Miata

Wait until we build a 99+ for ITS!!!

[erlrich]

Wait until we build a 99+ for ITS!!!

I think it's amazing that they aren't tearing up ITS yet - given what the ITA cars are capable of, and the relatively small gap between ITA and ITS now, I would think a full-tilt, well-driven ITS Miata would be a force to be reconed with.

[JeffYoung]

I guess you haven't seen the ISC 99 ITS Miatas......

Did Kip win the ARRC one year in one?

They are basically unbeatable at momentum tracks like Roebling, and very hard to beat at a short twisty handling track like CMP.

At VIR, both Mike and Kip struggled.

[Ron Earp]

Wait until we build a 99+ for ITS!!!

Ron Munnerlyn has one here in the SE that I have driven and it is fabulous (although a bit soulless). If he scores another 15 hp with it, which I think is definitely possible, even the power rich TR8 will have to be concerned. Great balance, as always with the Miatas.

[JeffYoung]

That car and that driver with 15 more hp will be waxing us all. He was amazingly fastin the infield at Charlotte, and at Roebling (given that he was basically at SM power levels).

[Ron Earp]

I'm still going to unleash some domestic whoop ass on it. At least on the straights. For part of the straight. Well, maybe right at the beginning of the straight.

[CRallo]

I'm still going to unleash some domestic whoop ass on it. At least on the straights. For part of the straight. Well, maybe right at the beginning of the straight.

LOL (literally)