Opinions on this drag launch method

[jc052685]

So, I have been thinking about this hard for several months and I finaly decided I could use some other peoples opinions on this.

 

So just to start with here is the setup

 

'74 early 260z

L28e(t)

Factory 4-spd

3.7 r200

Factory axles

4 puck unsprung ACT clutch (rated 520ft/lbs)

Race weight (2460lbs)

 

 

Ok, so the car dynod 305whp / 329ft/lb. I also have a 75wet shot on the car that I have sprayed once. My problem is 1st gear is sooooooo short. I will be running 24.5x8x15 MT ET Drags. Probably going to run them at 12psi. I am thinking if I leave on the spray I can do so in second gear. I think this might also be safer on the axles. I could just be crazy, but hey.

 

6300rpm shift gives me....

 

1st - 35mph

2nd - 56mph

3rd - 89mph

4th - 126mph

 

Compared to a factory Ls1 Camaro

 

1st - 53mph

2nd - 79mph

3rd - 108mph

4th - 141mph

 

So looking at these numbers I would thonk a car that weighs 1000lbs less and is putting down nearly 100 more whp it should not be a problem useing second gear to launch. Yes I am very good a clutch control on the launch so I dont thing bogging it down to too low of an rpm will be an issue.

 

 

Thanks,

Jeff

 

.

[turboHLS30]

Ok whats the eason behind using the 4 speed???

[jc052685]

Ok whats the eason behind using the 4 speed???

 

why not?

[turboHLS30]

Idk just wondering because I wouldn't imagine using a 4 speed for drag.

[jc052685]

Idk just wondering because I wouldn't imagine using a 4 speed for drag.

 

Again why?

[datsun723]

There are a lot of guys even using the 3 speed automatic to drag. It isn't ideal for everyday driving since the gearing sucks for highway cruises but for dragging, one less gear to shift into probably isn't a bad thing

[jc052685]

Any ideas or opinoins on the topic and not about the tranny its self?

[olie05]

As I was telling you over the phone, this could have a similar effect to swapping in a 2.3 diff in place of your 3.7... at least for the first two gears.

 

for the 3.7:

1st - 35mph

2nd - 56mph

3rd - 89mph

4th - 126mph

 

with a 2.3

1st - 56mph

2nd - 90mph

3rd - 142mph

4th - 202mph

 

If you are almost at redline at your trapspeed then I would keep everything as it is and try the 2nd gear start. Otherwise you should adjust your diff ratio until you are at redline in 3rd gear, and use 1-2-3. The question is if that will actually make your car faster. (it follows your theory though.)

 

Hopefully someone with lots of drag experience can chime in and say if this is a good approach to a lower e.t.

[lazycat5]

Ok I ran your numbers on the Richmond Gear drag race calculator. You should have a trap speed of 116mph / 125mph with a recomended gear of 3.93 off the nos. and 3.66 with. That makes your 3.7 rear a good choice for both. First gear is more than likely the strongest gear in your trans I wouldn't recomend a 2nd gear launch with nos. and if you drop to much rpm that may also cost you your engine. If it were me I would launch in first and hit the nos in 2nd. This should help you have traction and keep your clutch from geting overpowerd and not letting you get into the next gear, its happend to me. Hope this helped.