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Old 09-27-2016, 02:30 PM
AutoGear AutoGear is offline
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Default Is it time to change from a wide ratio gearbox to a close ratio one?

Regarding American Sedan's gearbox ratios. The spec ratios are essentially those Warner Gear supplied for the T5 transmissions current in Camaros, Firebirds and Mustangs when the class was created. At the time the T5 was ubiquitous, the parts were cheap and, conveniently, except for first, the ratios for Ford and GM were almost identical. Building American Sedan around the T5 was an easy decision.

Nevertheless, it was not ideal. Warner designed the T5 to support four cylinder, six cylinder and mildly-tuned five liter eight cylinder motors circa 1982. From almost the first, T5's in Mustangs and the third generation F-car had durability issues which were never solved; racing made things even worse.

While T5's and T5 parts were cheap the problems could be managed; eventually, the more durable Warner Gear T10, with ratios essentially unchanged, was made an option and teams began migrating. More recently, dog-ring gearboxes and Syracuse four-speeds have been added to the option list and migration continues, although the ancient T5 ratios persist.

I have never talked to an American Sedan driver who argued that the current gearbox ratios were well-selected. I have also never had a vintage road-racer, given the freedom to choose, select the American Sedan ratios. It seems clear that a consensus believes the spec ratios are too widely spread. Now the question --- 'Is it time to allow a close-ratio gearset in American Sedan?' --- is being heard again.

My experience suggests that closer ratios would reduce shock related damage throughout the driveline system and, over time, offset the expense of migration. For example, within our synchronized gearboxes, smaller rpm drops between gears would extend synchronizer ring life, anticipating the failure of which is the leading reason behind our American Sedan rebuilds.

Would migration be necessary to remain competitive? That would largely depend upon how the intermediate gears are used today and might be used with closer ratios. There would probably be more shifts, less setup braking, and less acceleration out of the corners. My guess is that the difference in times would be smaller than we think and that adding a carefully selected close-ratio would not prove to be a game-changer.

For Full Prep we're thinking a second gear move from approximately 1.93 to approximately 1.64, and a third gear move from approximately 1.34 to approximately 1.27. Dog-ring 'boxes, Warner T10's and our Syracuse four-speeds could easily make this change; we do not believe that T5's or TKO's could be converted.

Your feedback is requested and appreciated.

George E Sollish

Chief Engineer
Auto Gear Company
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Old 09-27-2016, 08:01 PM
nape nape is offline
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Don't really have a dog in this fight since I don't run AS, but coming from a class where I do have the option to run any ratio (NASA American Iron), I will give my experience.

I have AutoGear's ultra-close ratio box (2.20, 1.48, 1.18, 1.0, if I recall correctly) and it is fantastic at Road America. I reset the Track Record there earlier this year with a 2:30.245 and a paltry 304 RWHP.

That being said, at smaller tracks, I find myself shifting a lot. Every shift is a tenth and every corner you can't left foot brake, you are leaving a little on the table, plus the chance of a missed shift.

For example, Gingerman. Ran there in June with the ultra-close M22, struggling running 1.41s, felt like I was driving my ass off but couldn't really find time.

Went back in August. Threw in a 2.64/1.75/1.33/1.0 Super T10 chasing an issue. Same set of tires, worse conditions, no setup changes, car "feels" slow but the time sheet says otherwise. I ended up resetting the TR to a 1:38.4 by the end of the weekend. Only 1 up/downshift between T10-T11, run the rest of the track in 3rd gear, LFB every corner but T11, stand on the gas early and hard.

Should I have found 2-3 seconds? Hell no! Am I going to run the ultra-close there again? Hell no! While closer ratios have the ability to help performance, the driver needs to be able to take advantage of it and it still might not be a magic bullet.

Close ratio transmissions are an advantage at some tracks but a hindrance at others.
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Old 09-27-2016, 11:00 PM
fastandyracing fastandyracing is offline
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I am a fairly fast regional guy, ran at Daytona runoffs in 2015, I built my own car, engines, transmissions, rearends, etc.

What Nape just brought up is the single most compelling reason not to allow a close ratio box. As soon as you open up the ratios available to the gear box vendors then you will have to select the "best" box, or maybe even the best 2nd gear, or 3rd gear, or whatever mix of ratios is optimum for the particular track. Guess what, the regional guys who cant afford to have several boxes with different ratios in them, or have a team or test days available to change them out and figure out which is the best package for a particular track will just be further behind.

I don't remember there being any significant transmission issues lately, there seem to be multiple affordable options out there, Tremec, T10, autogear, Upgraded T5's, etc. lets not fix something that isn't broke and put the regional guys further behind the national guys.

Just my opinion.

Andy
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Old 09-28-2016, 12:59 PM
AutoGear AutoGear is offline
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Thanks for the comments. I agree that allowing 'ad lib' gearbox ratios would be madness. Bear in mind, however, that that is not what I proposed. Re Nape's comments, observe that his T10 has faster intermediate gears than those currently legal in AS and that those ratios could be used in AS if that was the will of the class. The numbers I offered (which are those used by about 2/3 of our vintage road-racers) are more cost-effective but others could be used.

George
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Old 09-28-2016, 03:00 PM
andy mcdermid andy mcdermid is offline
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I would like to switch to a more common set of gear ratios, a close ratio gear set will lesson the load on the transmission, engine, and driveline. That of course will save all of us $$$ and maintenance time. It looks like the current ratios are becoming harder to get and the support for T5 and Tremic boxes is falling off sharply.
If the close ratio gears came with a weight penalty that would keep the current ratio boxes competitive until they die off.

My .2 cents
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Old 09-28-2016, 03:14 PM
jimwheeler jimwheeler is offline
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I don't think the closer (not close) ratios are worth a weight penalty (see George's comments) except in the dog box. Maybe add 50# additional to the #50 dog box penalty for adding closer ratios.

wheel
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Old 09-28-2016, 03:56 PM
Danny"TheKid"Richardson Danny"TheKid"Richardson is offline
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Just to be clear, from what I am reading above, this is not a request to open the ratios to whatever you want but to change the spec ratios to closer? The biggest concern against trans ratios before was the fact that a wealthy driver could carry 10 different ratio boxes with him to every track. Sounds like a spec change wouldnt cause that.
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Old 09-28-2016, 04:18 PM
AutoGear AutoGear is offline
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Danny's correct --- the last thing anyone wants is to increase the cost of racing.

Nape is also correct --- it is not uncommon for our better-funded vintage teams to carry our standard close (2.199/1.640/1.274/1.000) for short courses and our ultra close (2.199/1.506/1.174/1.000) for long courses. We're actually under pressure today to build and deliver an even closer set of gears with a roughly 1.90 first for use at WGI and elsewhere, so this can obviously get out of hand.

What I'm suggesting is a new and closer destination spec for the post-T5 and post-TKO world. Andy's suggestion that weight could be used to level the field until the old 'boxes disappear is good, although I do believe that the amount needed might be too small to bother. There is a cost associated with standing still which must be balanced against that of motion.

Thanks.

George
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Old 09-28-2016, 08:15 PM
aszilagyi aszilagyi is offline
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Mabey a second shorter speck ratios with a weight penelty?
Over the current box.

Simply 2 boxes to pick from the heavy / close . And the lighter current one.

Thinking the hard part may be difficult gaining consciences. On what the ratios would be. For the heavy box .

This battle could be as difficult as the dog box was!

Would I try it if it was available today ?

If I was using a fixed gear Trans. Maybe .

If I already had a dog ring box in the car , Hell Yes !
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  #10  
Old 09-29-2016, 04:12 PM
nape nape is offline
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Quote:
Originally Posted by AutoGear View Post
...

We're actually under pressure today to build and deliver an even closer set of gears with a roughly 1.90 first for use at WGI and elsewhere, so this can obviously get out of hand.

...

Thanks.

George
As if I didn't hate driving through the paddock enough with a 2.20 1st...

It does make for bitchin' starts vs. people who are wound out in 2nd or lugging 3rd though.

Last edited by nape; 09-29-2016 at 06:10 PM.
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