Manual Launching

[groper]

just curious here, as I have a few ideas to throw around...

whilst I havnt ever raced at a competition drag strip (we dont have one near here) I have raced compettion motorcross, and owned many roadbikes, cars etc...

Take this, a standard 1000cc road bike will do 120+km/h in first gear. why? well, whats the point of gearing it any lower when you cant keep the front end down! so, you cant use the whole ~170hp in first gear or youll flip it and therfore the OEM standard gearing is very tall.

now consider a 380rwkw manual xr6t trying to get off the line... wheelstanding is not the problem but instead another limiting factor, traction. so we cant use the whole 380rwkw in first as the cars gear ratios werent designed with that much power in mind.

obviously, same applies even more to BIG HP drag cars and hence get away with 2 speed powerglides etc...

however, our street cars arnt used only for drag racing, and so we still need for the most part, close to the standard gear ratios for driveabilty, practicality etc... same goes for motorcross bikes, which need very short gears for tight tracks etc.

now what we used to do racing motorcross at a gate start on our 450`s for example, is start in 2nd or 3rd (depending on the track) and use LOTS of clutch with the engine on the revlimiter... traction and wheelstand is controlled using clutch only and you NEVER back off the gas- leave that up to the revlimiter. if you didnt launch in this way, youd never get the holeshot and end up some where near the back of the pack into the first corner.

so, I believe the key for faster manual xr6t times is launching in 2nd providing someone can come up with a clutch that will take this much punishment.-therein lies the problem... bikes use ~7 wet plates.

this would eliminate one gear shift at a critical point- near the start of the run. what you guys reckon? is it possible, and has anyone tried it?

[F6 UTE]

Won't work as it will bog down ( too tall ).. I have launched at 5500rpm in first and it has bogged down.

Just get Simon from Extreme to tune it, he has a 'fix' in his software that both Youngy and I use to run 11's. Launches well @~4200rpm.

To go 'quicker' in a manual won't require much.. Wait for the CV's to come first, the times will follow....

[Turbo6man]

No it won't work with a heavy vehicle - it all comes down to power/weight ratio. No clutch will ever be able to transmit the same torque as first gear can - as that is what you are asking it to do. The best way to launch a car is with gears, not the clutch. Theoretically, if you had a short enough first gear you would never have to ride the clutch - a la Road Rangers and such like which are used in semis and road trains. On most road cars there is the need to ride the clutch to some degree to get the engine at max torque point for fastest hole shot - then it comes back to "can the tyres give enough traction at said max torque revs?" Generally not, therefore some compromise is usually reached - it takes many practice starts to find what is exactly the right balance for each individual vehicle. But launching a car is totally different to launching a bike.

[DRTYBOOST]

  F6 UTE said:

Won't work as it will bog down ( too tall ).. I have launched at 5500rpm in first and it has bogged down.

Just get Simon from Extreme to tune it, he has a 'fix' in his software that both Youngy and I use to run 11's. Launches well @~4200rpm.

To go 'quicker' in a manual won't require much.. Wait for the CV's to come first, the times will follow....

Hey f6 ute just wondering what type of fix is it im guessing it eliminates the wheel spin to a degree?

What clutch would u recommend on most T's that have power of about 288rwkw and 800NM?

Thanks,

[Muzza]

Get the best clutch you can afford X 2. I put a ceremic clutch in 2 weeks ago then melted it on the weekend. Now I'm up for another $1500-2k to get something I won't have to replace for the next few years. It's put my engine rebuild back another 6 months........DOH!

Mal Wood has 2 options worth looking at the 11.5" single or one of the doubles plates.

Muzza.

[Buf-Phoon]

What about the MW road/race clutch, supposedly bullet proof for $2750 from memory, can't find the link If I was still driving a manual , I would certainly give it more than a consideration, looks the bikkies IMO

[F6 UTE]

It's a very nboisy clutch.. Sounds like you've busted a ring gear if you had an auto..... Pedal bite too low also.

For me, F6 clutch. With upgraded discs, it's all you'll ever need.

Although...........I'm still using factory supplied item

The 'fix' makes the car get off the line, no bogging down.. My best is a 1.61 60'..

[jetute]

what was your best 60' when you had a wog tune in the car?

[F6 UTE]

1.87 Jetter

[jetute]

so you really have the launches down pat ... takes experience to get to this level and for anyone to get even close to your times the launcehs are critical... about the hardest thing in the manual!!

well done

Edited 10/04/07 03:04 PM by Dagabond