Hyper4mance2k

iTrader: (40)

as th etopic says where do you allshift at when drag racing?

riffraff

7600, or somewhere around there. all depends on who i am racing

mperformance

at what RPMS do you guys rev the motor while at take off?

Pedestrian X

doesent your car have a "shifting buzzer" hehe just rev untill the buzzer goes off it lets ya kwon when ya shoudl shift :]

mperformance

Pedestrian when you hear that buzzer you have gone too far...unless it's like second to third at least in my case...

BTW I take my car out like at 3000 rpms minimal wheelspin anything above that and the car stays in one place burning both tires.

riffraff

disconnect the overrev buzzer.. it is just an annoyance.

Zulu

heh, if I launch at 1,700rpm I take off best. Below that and I'll bog, above that and I'll nuke the tires. And I'll shift at 7~7,500, usually at 7 tho.

peejay

For best acceleration, 6500, with everything stock.

If not stock, you have to experiment at the drag strip and figure out what's best for you.

jeremy

iTrader: (1)

did the 79's have over rev buzzers? if so mine isn't working.

mperformance

peejay, revs at take off?

Zulu

Stock carb'd 12A - completely stock car: optimum launch: 5,900rpm

Stock EFI 13B - completely stock car: optimum launch: 2,300rpm

according to my little vehicle acceleration calculation program. "cartest"


I go at 1,700 personally, but, I'm not stock, so best bet is to try a few and just stay above the bog point

Pedestrian X

hehe im assumign it would depend on your tires??

Pedestrian X

hehe sorry, i was joking. guess i shoudla made it a bit more obvious :] but anyways even if ya do hear the buzzer dont mean ya gone to far. once in awhile its even good for the engine to go that high.

Sterling

...There is a little doodad that makes a Huge difference between the stock and an aftermarket carb...
The decelleration dashpot!
This lil puppy is an inexpensive dampening mechanism that I believe has a usefulness in certain applications, and is often irradicated, and the potentials overlooked.
A tab on the stock carb makes contact with this unit as the return spring draws the throttle closed. But the decelleration dashpot, having a baffle and being filled with oil, dampens the return much like a shock.
If set creatively, it can play a major roll in how your engine decellerates in between shifts so that it is at optimum RPM when you let the clutch out.

It is for this reason that I would like to experiment with a fabricated, fully adjustable dashpot. As of now, the stock dashpot can only be adjusted at what point it makes contact on the return; and the adjustment is limited as it is.
I wish to build one that is adjustable in the same mannor, but that also has an adjustable valve in it so that the rate at which the throttle returns is adjustable, as well.

I believe that by having the ability to fully let off the accelerator while still having the engine maintain its power band RPMs (By coming down so much slower), the accelerator pump would be allowed to fill once again with fuel, and help when the pedal is hit again. (The AP linkage is apart from the throttle shaft, and will return as fast as it did without the dashpot in place.

The purpose of the dashpot is to keep the results of drivetrain lash to a minimum by smoothing the return, as well as to aid in decreasing backfire.

Anyone have any thoughts on this? I'm not a drag strip racer, so I may have the mechanics of the way you guys drive all wrong.

Directfreak

iTrader: (2)

Sterling,

When I drag race my stock SE, I do full throttle (power) shifts. Meaning my right foot is firmly planted on the accelerator, touching the floorpan.

The car NEVER gets to decelerate RPM's, and actually surges forward with each shift.

"I sHiFt mAd qUiK, yO!"

Now when the Turbo is finished, I will probably break things in a hurry if I do that, Even with an 8000 RPM limiter.

Your idea sounds great, but would be more applicable in a road course, with turns and twisties, so the RPM's don't drop via the "regular" shifting. In Drag racing, it might not be needed.

Just my 02 cents

peejay

Yeah, it depends on how you launch and what tires you have and what kind of surface it is and what the temperature is outside and the engine and the gearing... Can't say "You vill launch at zis RPM OR ELSE!!!!" because it's much more complicated than that.

riffraff

to give you a launce example.. on the stock tires (which were old as hell, starting to split and dry rot) the highest rpm that i could launce at was 1500... now that i got some new 205/60/13's on there, i launce anywhere between 3500 and 4k (depending on the road).

peejay

I used to clutch-drop launch at about 5000-5500 for best results.

Sterling

So it could have appeal for the autoX crowd? I'll have to play.
They (the autoX guys) must leave it on if it's a good idea, no?

Pedestrian X

or ya could just go out and practice soem double clutching :]

Directfreak

iTrader: (2)

Autocross, SCCA, IMSA, Road Racing, everything BUT drag racing and it should be worth the trouble.
I would think it's a good idea. If they are in a stock class, then they have to run a nikki, so it would be in their best interest to max out the most out of their "stock" setup.

If they are in a modified class, chances are they are running a different carb setup anyway.

Hyper4mance2k

iTrader: (40)

so back to my topic what rpm's do you all shift at when drag racing i've got a k$n directfire and an exhaust what do you all sugest?? its hard for me to tell on the street cause the torque curve is so flat its hard to tell when you start losing power unlike my old cars..(16v jetta, which was way faster then the rexy)

Defprun

Isn't double clutching for decceleration? Did we not discuss this?

FuLLsMoKe

Me still newbie at autoX, but beginning my first autoX soon (so don't laugh at me too much) =P

What's the advantage to double clutching? Maybe I'm thinking of the wrong "double declutching"--the one for worn or damaged syncro cones...

Steps (that i'm thinkin about):
When about to shift, accelerator, press clutch, shift to neutral, raise clutch, tap the accelerator, press clutch, shift, raise clutch, then go

FuLLsMoKe

Didn't see that... but i heard that it's either for deceleration or for better acceleration by going down a gear...

PS. damn my freeserver... now i can't see my sig...