Trans Am cars might use sequential transmission ala CART cars, but a sequential gearbox like a motorcycle gearbox, is a far cry from the computer controlled F1 trannys. Even in CART, I still see them blip the throttle on downshifts.

Now, explain to me why you would be able to brake harder just because you are H/T downshifting??? You said there would be time lost while taking your foot off the brake to blip the throttle, what I was talking about made no mention of a throttle blip at all. Let the synchros do their job and just feather the clutch (while braking all the time) as you downshift, no throttle blip required. You are then able to maintain much better brake control, not to mention if you were to actually have a brake problem, you are much more ready for it. Again, the ONLY thing you accomplish by H/T is less wear and tear on the drivetrain.

So explain to me again how H/T would actually be any faster?

 

I'm not sure where you got this feathering clutch idea, but find me a race book that even mentions this. Look you're a SV regular and I'm not looking to make an enemy. But "clutch feathering" sounds like something you've made up to compensate for not correctly rev-matching. Any fast driver that doesn't H/T, definately rev-matches. They do not try to drag the engine up to speed w/ the clutch they raise the revs w/ the gas pedal.

As for explaining. Look on page 1. Pedalfaster has make some nice pretty pictures and did a great job explaining it.

 

LOL, believe me. I don't take anything on the internet personal!! It's all friendly to me.

I have a lot of seat time in open wheel cars where you don't have synchros in the tranny, so you have to do the throttle blip. I am fairly proficient at it!

In my 350Z, there is a drive by wire throttle system. When the brakes are applied, the throttle response is almost cut off. Simply put, the throttle blip doesn't get you anything!! So I gave up and just learned how to make it smooth without the throttle blip.

Out of curiousity (and believing like many of you seem to), I borrowed a buddies MR2 Spyder (my previous car) for a couple of track sessions last month. I tried running laps while H/T and running laps without. The result was virtually identical lap times.

Again, people H/T because it saves a ton of wear and tear on your tranny. It is also smoother than just dumping the clutch and possibly locking up the rear wheels or transferring too much weight onto the front of the car because of engine braking. But if you run an ultralight flywheel (I changed out my 30lb one on my Z to a 14lb JWT unit) where I now have virtually NO compression braking and you don't just dump the clutch, but drag the engine up to speed instead, it will be just as smooth (albeit with a lot of wear to the sychros and some additional clutch wear.)

So again tell me: From a physics standpoint, why would H/T be faster?

 

Some Trans Am cars have sequential, like F1, but I belive they have weight penalties to have it. Most Trans Am cars have some sort mechanical dogbox that that is clutchless upshift, but I thought you still have to clutch to downshift...I will have to check with my friend's TransAm car...bastard wouldn't let me drive it. Since it is a couple years old Trans Am car...they may have all switched to F1 type sequential...

I guess you wouldn't need to HT if there is no disruption of the power transfer which effects weight transfer which effects balance of the car which effects traction of the tires to the track surface which effects your ability to get enter the corner at the maximum speed of your selected line. (phew, that was a long one) I always thought you need to make sure the power delivery is smooth, which is why you HT to match the revs.

When I am racing SpecMiata, which is a very competitve class, I will loose minimum one half of a car length if I missed matched the revs just a tad...meaning 100 rpm off where it needs to be. You can see it on data acquistion. And that is just from not smooth enough of a down shift. You will continue to loose speed/distance because you have also slightly disrupted the balance of the car, so the car you are racing with who executed perfectly can hold a line that you probably can't now due to the missed match. Trust me, there is a huge difference...when I ride a long with a smooth driver, they do it so perfectly, you never notice that the clutch has ever been touched.

For those who are having trouble with HT, practice is most important...but pedal position is almost as important. As mentioned, bending the pedal left until you feel comfortable is one...another is bending the gas pedal vertically...you want the gas pedal to be slightly above the brake pedal when it is fully depressed at maximum braking position...it will make it easier for you heel to get over to the gas pedal. Most street cars have the gas pedal too far and too high. You look at some of th race cars with Tilton pedal kits, it has a has gas pedal that pivots from the bottom rather than the top...Porsche have this setup stock...the heel is much easier to slide over to the gas pedal. (Some mentioned just bend it by force...I know the race shops typically heat them up to bend the pedals.

Finally, notice the pimp race shoes...they don't have the huge platform of the tennis shoes...they are tiny, so you can maneuver your foot freely...the sole is thin so you can feel the brake pedal pressure...and the gas pedal so you can feel the tap. I went and bought Puma shoes that is a copy of the Sparco shoes w/o fire protection, it makes practice much easier with the same feel as race shoes.

F1 tranny are fast because they don't miss downshifts...for those who have driven F355 with F1 and 360 Modena with F1, they will notice that the 360 is smoother because it has drive by wire which can precisely match the revs...F355 is not drive by wire, so the rev match is a blip of the throttle thru cheating the emmision system...smart, works good, but not perfect like the 360...and you feel it when you come to a corner, hard on the brakes, grab the paddle 2x and down shift 2 gears and the car just feels sweet...and you can get on the throttle so much earlier...but then you feel just as good in a 6-speed when you have master the HT technique...

And yes, I think the S is setup pretty good from the factory as far as pedal position...not perfect, but it is not a race car for me. I can still wear big fat shoes and drive the car around. It is comfortable for me and I am 6'1". (Asian if you must know)

Terry

 

So I'm trying to trailbrake and at the same time I'm slowly lifting off the clutch, all at the limit. I think I'll continue my efforts to perfect H/T. Maybe guys who've been racing since they were 5 can do all that smoothly but I doubt I'll ever see enough track time to perfect that technique.

 

I want to know if anyone feels abused by me and raceboy?

We had to make you all bring out the reasoning behind why you all felt H/T was so necessary.

You should go back and look at the abuse we have put on you based on the answers that had to be drawn out in the worst way.

Finally some reasoning that is almost worth while to stop and read. This is starting to turn in to a good thread on H/T vs Not To H/T.

The guy that started this thread isn't even in it anymore.

My point was that you need to go out and make yourself drive the car, get comfortable with it, make changes if you need to. Once you plateau or have a plat form to start learning on, then start learning techniques such as H/T, trail braking, rev matching and other time savings techniques.

I feel bad for new track goers that take advice from regulars and then they have a bad time at their first few events trying to H/T and do other techniques that take years to develop.

krazik and the rest of the SV regulars, I really hope that I can come out and run with you guys next year. I don't know what I will run my daily driver or the turbo S track purpose car that will be built by next summer. I would really like to see some of you guys in action.

 

I don't think you are supposed to lift off the clutch slowly...you want to engage smoothly, and quickly. I am fairly new to this...third year...my fellow racers are telling me that...when the clutch is in, you are shifting, as soon as you are done, clutch needs to be engaged...if not, all the time in between is lost because you can be accelerating.

If you get a chance to watch Japenese car videos with in car shots that has footwell video insert, you can see how quick they press/release clutch and how fast the gear is changed. I hink there are digitized videos posted somewhere on this forum...

Terry

 

[QUOTE]Originally posted by Strike

 

[QUOTE]Originally posted by fuse
I don't think you are supposed to lift off the clutch slowly...you want to engage smoothly, and quickly.

 

LOL, I don't really feel abused, I have a bit thicker skin than that!!! In actuallity, we are working to get the drive by wire throttle system tricked so a HT downshift will actually work (BTW, I am now on my 2nd replacement tranny, third tranny overall, but first of the redesigned units).

FUSE, a Spec Miata also does NOT use ABS if I am not mistaken, so it's a lot easier for you to lock up the rear brakes with the technique I am describing. In an ABS equipped car, it's a lot easier, and makes less of a difference.

To the old geezers (j/k) that hate technology, just take comfort in this; there is no ammount of technology currently available to make a slow driver faster, it will only make a fast driver faster! Hell, if I turn my stability control on, it's so aggressive, the car about 3 seconds a lap SLOWER on a 2:00 track.