IT should really think about welcoming Older SM's....... Without a new class..

[Ron Earp]

...and there are cases of cars with and without PSon different speclines due to trim or body type (think civic) with the same publsihed hp ratings, the ability to underdrive a parasitic system that is an effective gain over the cars without it, etc... no argument, and it's not the CRB. 'nuff said. you know where the letter form is.

The manufacturers did not publish two different horsepower specs based on the type of steering installed in the car and I’m sure we do not have that level of resolution in IT classing. How many cars came with manual and power steering racks? How many of those cars are racing? Wondering about ITS since I know some of those cars…

240,240,260,280Z – all manual
RX7 – manual and power available
TR8 – power only
Mustang – power only
300ZX – power only
Miata – power only I think for ITS years
240SX – power only?
E36 BMW 325 – power only?

FWIW NOTHING matches the process anyhow. E.G. all the popular ITS stuff is 5% or more above expected power, big motor cars like Jeff's TR8 and the mustangs are well above process weight and power (by how much I do not know, but they do allow that they are well over both). we're just lucky everythign has found a good relative balance due to all the hard work by the competitors

The process greatly underestimates gains for a variety of reasons:

*The level of R&D that would be done on IT cars that encompasses many, many facets of the engine development program.
*No distinction between two valve and four valve motors.
*Ignores what modern EFI can do for engine output compared to carbs, or even compared to early EFI.
*Largely ignores displacement and factors only peak power, although there is a "torque adder" that we know when to use when we see it.

With respect to the last point, earlier this week I got interested in area under the horsepower curve and performed some calculations based on my own dyno data. Back in the day, a version of my 260Z engine and a version of the Mustang engine were making the exact same peak power, 169 rwhp. However, the area under the horsepower curve in the best 2000 RPM wide power band for each motor was considerably different with the Mustang having a 16% advantage. Both of these engines exceed their IT process power. The 260Z was rated at 138hp from the factory and went on to make as much as 176-180hp at the wheel when everything was perfect. Parity with these two cars or engines was, as you say, by blind luck. The Z can make its 2480 lb process weight, the Mustang can't and races at about 13% heavier than the Z which is within spitting distance of the 16% horsepower area under the curve advantage.

As stated, most cars are above their 25% process power, but given how things shake out on track I’m not sure any “IT approved” formula or correction could improve things. I do think a new process using a max cam duration, a max lift, factoring displacement, and valve curtain area could create a very interesting and level class, but that’s another topic.

. It's time to open up the rule books for simple changes and start having deeper fields.

Back to this, so what is needed for SMs to come in droves to IT?

1. PS elimination allowance
2. Ability to run a larger torsen/rear end

[Flyinglizard]

The 1.6 SM has been legislated to the middle of the pack or less. The resulting values are now around$5K . Many are running Chump due to this. keep them from going chump would be a good start. IMHO.

Ask for member input regarding PS depower.

Please ask the people that pay the bills.
I doubt that 1 in 100 want to keep it as it is. The rack is the easy part, the lower column pieces are not and get expensive.

[gran racing]

Again, what's wrong with running them in SM2? Nothing on the cars needs to be changed, IT doesn't need to modify it's ruleset. Everything is already in place and done. Seems simple to me.

[Chip42]

The manufacturers did not publish two different horsepower specs based on the type of steering installed in the car and I’m sure we do not have that level of resolution in IT classing. How many cars came with manual and power steering racks? How many of those cars are racing? Wondering about ITS since I know some of those cars…

exactly my point. cars sold with both will have a single output number. my hunch is that would be the no PS number but we simply don't know. in some cases this is combined on one specline (ITA: NA miatas, from your example) and in others it's on different lines (ITB: civic DX 3dr, no PS. LX 4dr, only PS. same published hp, same engine designation, same weight, different speclines.) theres almost no reasonable or even nearly reaosnable way to "process" this.

...given how things shake out on track I’m not sure any “IT approved” formula or correction could improve things. I do think a new process using a max cam duration, a max lift, factoring displacement, and valve curtain area could create a very interesting and level class, but that’s another topic.

I, and I'm sure most of us, have no interest in making a new process. it's objective for the most part as it is, and an objective imperfect system is better than a completely subjective imperfect system.

Back to this, so what is needed for SMs to come in droves to IT?

1. PS elimination allowance
2. Ability to run a larger torsen/rear end

head prep allowances in SM are HUGE compared to IT (even grey area IT). read the SMCS, you'll love it. there are some other swaps that cross IT speclines the cars that share platforms (NA, NB ) like bracing and brakes aside from the rear center section on the NAs.

[Ron Earp]

The Miata example isn't a good one as that car just got a weight adjustment using the 'what we know' theory. The most fair way to do it would be to determine a % gain factor...say 1 or 2% (based on actual research, could be more, could be non-existent based on results) and simply add it to all cars with power steering, and then allow them to remove it.

The problem is that PS loss research is very hard to do. Some of it is methodology, but it's also that the loss is probably about the same absolute value as the noise of the measurement. First we'd need to establish a Limit of Detection for the dyno, LOD, which is the lowest value that can be distinguished from noise. But statistically we can't quantitate values at the LOD, we'd need to work at the Limit of Quantitation, the LOQ, which is about three times higher.

http://en.wikipedia.org/wiki/Detection_limit

Where I'm going with this is if we have two measurements, A and B, and we determine that the LOD of our measurement is 2hp, then we can't statistically say with greater than 95% confidence that A is different from B unless the difference is around 6hp (I'm estimating based on LOD = 3*stdev blank / m, compared to LOQ = 10*Stdev blank / m).

This PS stuff is going to be lost in the noise, and probably the reason why manufacturers do not consider it when stating hp numbers.

Still, I'd be happy to try and measure it and I have the skills to get it done.