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Old 05-07-2012, 02:03 PM   #21
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Originally Posted by jboogie View Post
Just ran my 4th event in the miata yesterday. China T25/T28 + 1.6 so, I feel your pain. Many corners are a decision between bogging second or trying not to blow the tires off in first, I'm trying to avoid multiple first gear grabs. I haven't gotten good with left foot braking yet in the miata but after playing with brake boosting on the street it seems like you would need so much brake in the corner it would be nearly impossible to get the turn right.

TNTUBA, you should have been in Bristol yesterday. Hope you won some cash at the shootout!
With the 6 speed first gear is good for getting you from the stage line to the start beam and not much more Im only in it for about the first 20 feet.

Bob
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Old 05-07-2012, 02:34 PM   #22
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With the 6 speed first gear is good for getting you from the stage line to the start beam and not much more Im only in it for about the first 20 feet.

Bob
Yes. First is nearly useless. I stayed in second at my last event, but it was a pretty tight course. I fear I will have to do a lot of 2-3-2 shifting in the future. (I had a 5-speed last year so I'm still learning this 6-speed thing)
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Old 05-07-2012, 03:34 PM   #23
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Now that I'm building my car for SSM with the intent to go to Nationals this year I am torn as to wether I should go 6spd. It's a no doubt kind of thing for the track but with the torque I'm making I don't know if it would be ideal. Bob, what speeds are you seeing at redline with the 3.6 and 6spd in 2nd? I think a 3.9 with a 6spd may be good but right now the 5spd with the 4.1 is perfect. And I haven't blown it up yet with a lot of abuse. Thinking I may just pick up a spare 5sp and go with it. Thoughts?
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Old 05-07-2012, 04:27 PM   #24
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I've got the 3.9 and 6-speed, and I ran out of second gear on our really tight course at the last event. I expect I will run out of third at some of our bigger events, though I can't imagine it will be worth shifting to fourth ever.
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Old 05-07-2012, 04:53 PM   #25
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I've never run an autocross where dropping into 1st was ever a good idea, even on any slower corner.

the only time i found myself doing it, was when i had a blown motor and no rear bar so the car had zero power, zero boost, and zero nimbleness around a few hairpins...
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Old 05-07-2012, 05:56 PM   #26
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I'm running a 5speed with 3.636's and ONLY a 7800 rpm red line. I can do 75.something on the limiter in second. With the 4.10's last year it was 63ish. It's my opinion and experience that unless you are going to bang off the limiter for more that a few pops you are better off just riding the limiter. An upshift and down shift will cost you 1/2 second if executed well.....so unless you can make that 1/2 second up in RAW time it's not worth it. Only a couple times in National level competiton have I seen the need to go faster than 73-75ish. I would LOVE to run a course where shifting into 3rd for me was a good idea.

According to the math with 3.363's, a 23" tire and a 7,500 rpm redline a 6 speed will get you 61 ish mph in second and 84ish in 3rd. A five speed would net 73ish in second and 103ish in 3rd.
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Old 05-07-2012, 06:20 PM   #27
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Throttle based boost control helps about a lot with a quick spooling setup. Once you get up into the Nationally competitive range, then you have to start thinking real traction control.
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Old 05-07-2012, 09:33 PM   #28
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i've only autox'd my miata twice so far, but the two fastest turbo guys @ last week's event, both pro class, didn't do any left foot braking that i could discern. they would just get on the throttle when they were leaving the corner, although it did seem like sometimes it was a little in advance.

they were a built ~500whp S2000 and built ~500whp Evo. i know that the S2000 was hitting full boost before 3,000RPM's.

so maybe it's the driver skills for anticipating when to add the gas so as to hit the right power at the right time. could also be an engine/turbo setup that gives quick spool.

also, another plug for leaving it in gear. like i said, i'm still new, but i've chatted with a few seasoned drivers who recommend against shifting unless absolutely necessary. bbundy showed that with the 1.5seconds he trimmed.
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Old 05-07-2012, 10:10 PM   #29
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I have zero issues with my GT2560 and TPS controlled boost targeting. I don't feel any lag and need for "pre-throttle".

I have much more trouble with throttle control with my supercharged E36 M3. The problem with it is it makes a ---- ton of torque with small throttle openings. The TPS controlled boost algorithm prevents that with a turbo setup.
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Old 05-08-2012, 12:56 AM   #30
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Quote:
Originally Posted by TNTUBA View Post
If you aren't using your brakes....you just aren't going fast enough. The yellow SSM Vette that runs with your region was at the Shootout yesterday...I think I was @ 6 seconds faster than that car over a 50 second course...and my brakes got a SERIOUS workout. That Vette is no slouch and I'm just a lowly little supercharged car.
I was implying to use shift lock and handbrake turns when hard corner is needed.

That was David Ball. Me and him were always pretty close....which I don't think is all that bad for me considering my car is purely a street car with some 215/17 V710s stuck on for a little extra grip. If I were to have a real diff, 3.63s, better alignment and 15" wheels with wider tires...I would have no problem beating him. Though I know two things about David- He can't drive if the light gets low (like our "night" event) and he does not do well in the rain.

Maybe next year I'll get a new set of wheels/tires and run autoX. I'd like to get some 15x9 wheels and 225/45 Hankook C71s.
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Old 05-08-2012, 01:37 AM   #31
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Handbrake turns? Really?
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Old 05-08-2012, 07:35 AM   #32
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Shift Lock and Handbrake turns huh......at least it would be entertaining to watch.
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Old 05-08-2012, 08:23 AM   #33
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You guys waaaaay overanalyzed my initial post about not using the brakes.....and my sarcasm about such things on that post Oh well
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Old 05-08-2012, 09:12 AM   #34
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Dude....did you not know?
Autocross is SRZBIZNIZ!!!!!!
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Old 05-08-2012, 09:30 AM   #35
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If I'm autocrossing, I'm usually just trying to have fun. If I'm repetitively hot in a corner, the handbrake is generally too much for me to think about. Instead, I'll downshift from 3rd to 2nd (or even just get off the gas briefly and push the clutch in) and then drop the clutch. Voila - instant loose condition!

Now, to be any good at autocross, I would need to do it more than twice/year.
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Old 05-08-2012, 10:48 AM   #36
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Left foot braking works in tight turns but I use it more for helping the car rotate than keeping the boost up.

Never really had a problem with spool until I've switched to the 3.636 gears at the Teas Pro with the 275/35 A6s and a 5spd. But I that was partly poor line/driving and fueling issues. The car is radically different this year and I'm still trying to sort out and tune everything.
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Old 05-08-2012, 12:49 PM   #37
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Quote:
Originally Posted by fooger03 View Post
If I'm autocrossing, I'm usually just trying to have fun. If I'm repetitively hot in a corner, the handbrake is generally too much for me to think about. Instead, I'll downshift from 3rd to 2nd (or even just get off the gas briefly and push the clutch in) and then drop the clutch. Voila - instant loose condition!

Now, to be any good at autocross, I would need to do it more than twice/year.
What you have just described is what we call 'shift lock'. It can be handy at times.
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Old 05-08-2012, 01:27 PM   #38
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Now that I'm building my car for SSM with the intent to go to Nationals this year I am torn as to wether I should go 6spd. It's a no doubt kind of thing for the track but with the torque I'm making I don't know if it would be ideal. Bob, what speeds are you seeing at redline with the 3.6 and 6spd in 2nd? I think a 3.9 with a 6spd may be good but right now the 5spd with the 4.1 is perfect. And I haven't blown it up yet with a lot of abuse. Thinking I may just pick up a spare 5sp and go with it. Thoughts?
Honestly most of the national tour type courses I've driven the 6 speed with the 3.6 worked with only a mild rev limit hit at 7400 rpm. A lot of our local courses seem to end up faster. I think I still like the 5 speed best for gearing but with 310 ft-lbs of torque by 4200 rpm and 275 Hoosiers I was lucky to get two autocrosses out of a 5 speed before it popped. Quafe is the only 5 speed option for me. I liked the 5 speed with the 3.9 for gearing and only occasionally needed 3rd. with my current power curve it is completely pointless to go to 7800 rpm the torque falls off way too much past 7200.

@7400 rpm in second
5speed - 3.909 ~68.8mph
5speed – 4.10 ~65.6 mph
5speed- 3.636 ~ 74 mph
6speed – 3.636 ~61.6 mph
6speed -4:30 ~ 71.8 mph (in third)

For autocross only on a boosted Miata I think you really would like to get to 65 or 70 with just one shift. A 6 speed and a 4:30 or something might be cool and you could just start in second. That combo wouldn’t work for me on the track at Pacific though because I’d be at the rev limit in 6th for a really long way out of top end gear. Currently I’m hitting 155 mph on the front straight at Pacific ~15mph faster than a 4:30 will take me.

Bob
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Old 05-08-2012, 03:20 PM   #39
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Quote:
Originally Posted by bbundy View Post
Quafe is the only 5 speed option for me. I liked the 5 speed with the 3.9 for gearing and only occasionally needed 3rd. with my current power curve it is completely pointless to go to 7800 rpm the torque falls off way too much past 7200.

Bob
For a dedicated autox car, I'd go with a T5 or T10 type transmission. Can pick up a simple unit used from roundy round racers, easily rebuilt, lots of gear ratios available. Hardest part is getting a bell housing created. But then again once you do that, one could always upgrade to Jerico like a certain SSM RX7.
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Old 05-08-2012, 08:14 PM   #40
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At the San Diego national tour few weeks ago, the street tire STR cars have been reaching 75 mph on course. And then SSM on wide stickies is another ballgame on top of that

Quote:
Originally Posted by bbundy View Post
Honestly most of the national tour type courses I've driven the 6 speed with the 3.6 worked with only a mild rev limit hit at 7400 rpm. A lot of our local courses seem to end up faster. I think I still like the 5 speed best for gearing but with 310 ft-lbs of torque by 4200 rpm and 275 Hoosiers I was lucky to get two autocrosses out of a 5 speed before it popped. Quafe is the only 5 speed option for me. I liked the 5 speed with the 3.9 for gearing and only occasionally needed 3rd. with my current power curve it is completely pointless to go to 7800 rpm the torque falls off way too much past 7200.

@7400 rpm in second
5speed - 3.909 ~68.8mph
5speed – 4.10 ~65.6 mph
5speed- 3.636 ~ 74 mph
6speed – 3.636 ~61.6 mph
6speed -4:30 ~ 71.8 mph (in third)

For autocross only on a boosted Miata I think you really would like to get to 65 or 70 with just one shift. A 6 speed and a 4:30 or something might be cool and you could just start in second. That combo wouldn’t work for me on the track at Pacific though because I’d be at the rev limit in 6th for a really long way out of top end gear. Currently I’m hitting 155 mph on the front straight at Pacific ~15mph faster than a 4:30 will take me.

Bob
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