mooty

when i had 7 cup, it had no blipper. i had no issue heel and toe or blipping. it's much easier done then said (no, i didn't type it wrong). it's the lack of abs that i struggled with, not the blipping or shifting.

KaiB

RE Upestting the chassis. So, I lost sleep thinking about this last night.

The only thing I came up with which made sense is this: Mike (and others) is downshifting (w.o. the clutch) late enough and under hard enough braking that the engine speed/road speed match becomes less critical (and that the very close ratios of the gearbox help here also).

yes?

Leigh2

And I've installed a KMP Paddle shifter so I can left foot brake and still downshift in the hopes of extending the gearbox life.

mklaskin

How's the KMP kit working?

Leigh2

Haven't driven the car yet since the installation but will try it out next week at the Miller NASA race. I'll report back after I've tried it..

fleadh

I'm not sure what the problem is that you're trying to figure out? You mean the chassis being upset by not using the clutch? If that's the case, it doesn't upset it any more than a normal full-speed downshift with the clutch, in most cases. If you look at the clutch pressure graph for anyone who's fast (from my experience anyway), even when the clutch is used it's an instant in/out basically as fast as the foot can move. The later you do the downshifts the worse it is in terms of losing longitudinal G force (ie: deceleration) in my experience as the blip tends to "push" the rear of the car forward against the front brakes.

I try to time my downshifts early enough (in a normal threshold braking zone) to get the red shift lights to come on. Work up to that if you want to try it though as it's very easy to overrev the motor while practicing. :-)

-mike

KaiB

Thanks for coming back Mike, even though it might seem frustrating.

What I can't figure out is the rev-matching (engine speed v. road speed) during the downshift without the clutch. If there is no neutral btw gears, then no blip can occur if the clutch isn't used.

At least in my experience, a blipless downshift leads to an unhappy chassis.

In an H box, without the clutch is easy enough as the blip occurs as we pass the shifter though the neutral gate - tranny slides right into the lower gear and engine/road speed are equal. I just can't see how this happens with the sequential.

Would you take the time to help me work out why this (i.e. the upest rear end) is not happening and excuse the persistence...I hate not knowing.

autometrics

There is a very small period of time where a sequential is in neutral on the downshift. As the drum rotates, the slider goes past a neutral just before it engages the next gear. The blip just has to be timed very well. It's a little harder on the dogs but is very possible.

Leigh2

I wondered the same thing. The KMP downshifts without the clutch so it has to cut power to the engine, blip the throttle and shift gears with the flick of a paddle. I couldn't figure out how this was done without there being a neutral between gears.
Neutral between the gears is not something you can find using the lever though. I have heard of people missing shifts (being too gentle) and ending up in neutral but only in error. The cable/rod blippers do not have the capability to time the blips properly in order to not use the clutch. Don't plan on downshifting using the lever without the clutch too many times it will tear the dogs to pieces in short order. The KMP electronics and actuator obviously have the timing perfected.

fleadh

Perhaps a data snapshot will make more sense.. Here's the braking zone for turn 1 at Lime Rock during practice in my GTC car a couple weeks ago. It's pretty heavy braking and down 2 gears in a mostly straight line:



You can see a slight loss of negative longitudinal G on the downshift as this was the first weekend I completely switched to left foot braking (i've always done it when I didn't have to downshift) and was still working on the timing.

-mike

KaiB

Says it all, thanks.

These downshifts were clutchless, but incorporated the autoblipper?

fleadh

Clutchless, no autoblipper.

-mike

KaiB

Thanks much Mike, I've learned something.