Power to weight ratio for each it class

[StephenB]

As the title says... I did a search and couldn't find it and I need it :)

Stephen

[erlrich]

Here you go:
ITR: 11.25 lbs/hp
ITS: 12.9 lbs/hp
ITA: 14.5 lbs/hp
ITB: 17 lbs/hp
ITC: 18.84 lbs/hp

Also, here is a link to the "Advisory Committee Addendum - IT Process" (you'll need to log onto the members area of the website): https://ams.scca.com/netForum/eweb/documenttransfer.aspx?doc=scca_postings/filecabinet/Advisory%20Committee%20Addendum-%20IT%20Process.pdf (https://ams.scca.com/netForum/eweb/documenttransfer.aspx?doc=scca_postings/filecabinet/Advisory%20Committee%20Addendum-%20IT%20Process.pdf)
It lists the figures above, and also explains the process, include what adders & subtractors are used.

[StephenB]

Looking for some more generic info on this topic... Nothing to argue about here!!

I would like to get as much info for each car in each class on power to weight ability/options.
What cars do you know that have added ballast to meet minimum weight for the class? Which ones have a hard time meeting minimum weight? Any info you have is helpful for me, if a spreadsheet already exists hook me up with who may have it! Looking more at ITR, ITS, and ITA since ITB is going through lots of changes in the next year or so but if you have the details feel free to share hem with me and I can adjust later.

Stephen

[StephenB]

Example

ITR RX8. 75lbs over, another 10-20lbs is achievable before getting creative.
ITB Audi Coupe. 50lbs under without trying.

Stephen

[Andy Bettencourt]

And remember...do NOT just take the weight of a car and divide it by that number and expect that crank HP to work out. The calculation works like this:

Stock HP x expected/estimated increase with IT prep (usually 25%)...THEN adders are used. FWD, DW, torque, etc.

[StephenB]

And remember...do NOT just take the weight of a car and divide it by that number and expect that crank HP to work out. The calculation works like this:

Stock HP x expected/estimated increase with IT prep (usually 25%)...THEN adders are used. FWD, DW, torque, etc.

I am not interested in CHANGING anything... I think that the ITAC has already done far more research and has a far better understanding than I do. I am looking more at which cars would be able to easily hit the target and which ones may struggle.

[Andy Bettencourt]

Understood. I am just trying to nip the comments coming when people just use the number to back calculate without adders.

For you, remember adders when you are estimating.

[erlrich]

Sorry - I just thought you were looking for the P/W ratios...kinda like the title says :D

The only cars I know anything about are the ITA 240SX and the ITR Camaro/Firebird. The 240SX coupe has no trouble making weight, the hatch needs a little work to get there (mine is ~ 70 lbs heavy with a 260 lb driver).

The Camaro/Firebird in ITR will not get close to weight IMO. That's only based on calculations, but I do know mine (hardtop) weighs right at 3350 w/o driver (and 1/4 tank of fuel). Add even 180 for the driver and 100 for a cage, and it would have to lose over 800 lbs to make ITR weight. Everything I've been able to dig up on the car says 450-500 lbs is doable, but not 800. Which means it is going to be at least 250, probably closer to 300 lbs heavy. In a class where it's already outclassed... :shrug:

[StephenB]

[QUOTE=erlrich;348962]Sorry - I just thought you were looking for the P/W ratios...kinda like the title says :D

T/QUOTE]

I was :). Then decided to build on that without creating a new thread...

Stephen

[Knestis]

You're looking for a metric crap-ton of data, about 7/8ths of a metric crap-ton of which is going to be wild-assed guesses.

:026:

K

[mossaidis]

^ I concur. Also question your margin of error acceptance. I usually weigh in at 2330 with 1/2 tank and the min weight is 2270. If I lost the cool suit setup, 1/4 of gas and my fat ass (190) lost 15 lbs (which I should), I would be at 2280. Is 60 lbs within margin? Are you looking for widely off cars that have 250 lbs of ballast? or with no ballast at all that still tip the scales at 250 lbs overweight?

[AE86ITA]

Perhaps a little of topic, but do usually cars with thin (180-190Lbs) drivers win their classes?? Or heavy driver win their share?

[callard]

My 1972 911E IT-S Porsche 911 weighed in at 2350 with me on board (180 lbs suited up) and I had to add 250 lbs of ballast to meet the SCCA mandated 2585 lbs based on their wild ass guess as to makeable HP. (insert frustrated emoticon here)

[Chip42]

Perhaps a little of topic, but do usually cars with thin (180-190Lbs) drivers win their classes?? Or heavy driver win their share?

both. light guys in ballasted cars have an advantage in that they can ballast more strategically, in heavy cars the light driver helps to minimize the amount of excess weight.

but I've seen plenty of big guys hammer down and win with better driving, prep, and racecraft.

[Knestis]

Given the number of factors that influence "speed" or "lap time" the difference between a 150# driver and a 200# driver isn't even repeatable lap-to-lap by a typical club racer, let alone the influence of that factor on "winning."

K

[erlrich]

What ^ said; plus I would be willing to bet if you could determine the overall proportion of XL drivers to average/thin drivers in club racing, the proportion running up front is almost the same. I know a few big boys who can wheel a car real good.

[Bill Miller]

I know a few big boys who can wheel a car real good.

Paging Kevin Ruck. Mr. Ruck to the white courtesy phone please.

[lateapex911]

Paging Kevin Ruck. Mr. Ruck to the white courtesy phone please.
Have you seen kevin recently??/