Launch advice needed

MilesnMiles · Post by **MilesnMiles** » Sun Sep 13, 09 10:34 am

Tried to hold the car on the footbrake yesterday and wound up the revs as if staging at the strip. The new locker in the diff started to apply traction and completely overwhelmed the brakes.
I dont have a line loc, so wondered what advice i could get on launching as the car wont hold on the line at the usual 2000rpm ish that I like to use?

Anonymous · Post by **Anonymous** » Sun Sep 13, 09 10:42 am

Fit bigger rear brake cylinders, Miles.

Pete · Post by **Pete** » Sun Sep 13, 09 10:44 am

It depends on how much traction the tyres have on the strip. It is completely different to practicing on the road.

A line lock only really helps on the burn out, and not necessarily on the line. My cars have always gone faster without loading the convertor.

My personal preference is to just cover the brake to stop the car rolling and then "flash" the convertor for a launch.

This approach depends on how sticky the tyres are and how loose the convertor is, and the carb needs to be tuned to avoid an off-idle bog.

On street tyres, my guess is that they will still spin up, regardless of the locker; and your best option will be to pedal it off the line and then nail it.

Trial and error...

MilesnMiles · Post by **MilesnMiles** » Sun Sep 13, 09 11:07 am

Ok chaps,
Live and learn it is. Last time out my fastest 60' was with it fully loaded, but at the cost of the tyres spinning to the extent that the trans flared up, i lost traction and had to let off and ended up with a 15.

at least the new set up will force a re-think!

Anonymous · Post by **Anonymous** » Sun Sep 13, 09 2:13 pm

You will probably 60ft better without loading the covertor.

AllKiller · Post by **AllKiller** » Sun Sep 13, 09 2:26 pm

Exactly...As Adams said,
do not load the convertor up, it builds heat in the trans, and does not allow the convertor to hit its stall point as quickly.

Stage the car and bring the revs up up to around 1200/1500 and then Punch it really hard and quick on whatever light you go on.
This allows the convertor to flash up to its stall speed and you will hook quicker and harder....you just have to hope the tyres will hook

What tyres and pressures are you running

MilesnMiles · Post by **MilesnMiles** » Sun Sep 13, 09 3:30 pm

Ok, thats useful. I'm running steret tyres at around 22psi. I've since read that there is little advantge in deflating street tyres, so i'll probably leave them at 28psi and pump the fronts up to 30psi and try that.

I have a nearly new set of M/T Drag Radials, but no wheels for them!
I'm too tight to fork out around £250+ for a new set of spare 4"pcd wheels .Been trying to find a set second hand for over a year now!

AllKiller · Post by **AllKiller** » Sun Sep 13, 09 7:09 pm

Miles wont the Drag radials go on your rims now ??
or cant you get the shafts redrilled to 4.5 pcd ?
Pump the fronts up to 40 PSI...makes it a little twitchy, but will help on the strip Only

MilesnMiles · Post by **MilesnMiles** » Sun Sep 13, 09 7:18 pm

Steve, its all a question of scale. I could convert the whole rear to 4.5, then I need to do the front, add disc brakes, new wheels etc...all just for a few fun passes per year.
I just wanted a pair of tatty old steels of a barracuda, but they simply aren't around

AllKiller · Post by **AllKiller** » Sun Sep 13, 09 8:49 pm

Someone must have a pair on here...shout louder Miles

Dave-R · Post by **Dave-R** » Sun Sep 13, 09 10:17 pm

On a street/strip car if you are having trouble with rear tyre grip it is better to load the converter.
If you do have grip it is better to mash the throttle from idle and get the full benefit from the pump shot and the highest possible stall speed. But, as already said, make sure they carb is tuned so you do not bog. If you don't have the grip your tyres will spin like that though.

However. In some cases a LITTLE bit of tyre spin can help. I lost two tenths by fitting slicks at first when I had the 3.91:1 gears. Sure the slicks were over 1.5" taller which would gear it slightly higher for the 60ft but I think the little tyre spin helped because it got me up on the power band of the engine faster.

AllKiller · Post by **AllKiller** » Sun Sep 13, 09 10:18 pm

MilesnMiles wrote: I just wanted a pair of tatty old steels of a barracuda, but they simply aren't around

The Small Bolt Mopars have a lot of common bolt patterns on newer cars

5 on 4" or 5 on 100 mm ....same

Offsets need to be checked of course, but plenty to chose from mate

Rear wheel drive cars would be better suited offset - wise...but check

Audi A3 + TT
BMW Mini series 3
89 Buick Skylark
Chevy 89 corsica, beretta, and cavalier

Chrysler Neon...MOPAR

Dodge 95 stratus , 94 shadow 94 daytona MOPAR.

Rover 75
Seat toledo GTI 95>
Skoda octavia
SUBARU impreza, legacy, outback Looks good plenty of wheels to choose from
Avensis, Camry >90, Carina, Celica, Corona
(NEW Beetle) Bora, Corrado VR6, Golf Mk 3 GTi & VR6, Golf Mk 4, Passat VR6, Vento VR6

HOWS that

Big Mopar are 5 on 4.5" or 5 on 114.3 MM lots of those to

Blue · Post by **Blue** » Mon Sep 14, 09 8:05 am

As has been mentioned, loading it up on the convertor very quickly generates a lot of heat. Heat kills transmissions fast, so mind how you go with that. Personally I always launch from tickover to get maximum flash stall.

MilesnMiles · Post by **MilesnMiles** » Mon Sep 14, 09 9:10 am

Thanks for al the input, very useful for anyone stepping up a bit, especially the bit about loading up the convertor which I wasnt aware of.

Allkiller, thanks for wheels info, did you have a link to a source so i can do further research on wheels options?

Blue · Post by **Blue** » Mon Sep 14, 09 9:33 am

How about this for an idea, get the rears converted to 4.5" PCD", leave the front's alone. Carry a 4.5 PCD" spare and get an adaptor turned up so you can use it on the front in an emergency. Friend of mine carries a 3.5 x15 rim with a 165 tyre on it for that purpose. You should have no problem finding used rims in 4.5 PCD". Sorted.