johnc Posted October 19, 2012 Share Posted October 19, 2012 Why is everyone so worried about first gear? Quote Link to comment Share on other sites More sharing options...
letitsnow Posted October 20, 2012 Share Posted October 20, 2012 1st is really a non issue for me, except at the drag strip. What was your car's trim level letitsnow? My '75 was fairly gutted, and will now be completely gutted. I'm not even running side glass. Before, I was at 2560lbs and I could easily just let the clutch out in 2nd gear (not pop, just minor slip) and be rolling just fine. I really don't see the point in having a 1st gear if I'll spend as much time shifting out of it than I will in it. I'm still not certain what exact clutch I have in my car as I've never pulled the tranny, but I DO know that it grabs PLENTY hard at ANY rpm without noticeable slip, but is still very streetable and easy enough to feather. I'd assume it's just an aggressive organic clutch. Having very little weight in the car with a stock flywheel helps though. And as any drag car should exemplify for all of us, is that the more power/weight you have, the less you need your shorter gears to go fast. Most of the 1,000+hp cars I've seen in person either had two or three speeds in them. Of course most were auto, but some were manual still. And never once have I seen a quad digit car (in person) that had rear gears over 4.00. Maybe once I get my car back up and running I'll take some video of 2nd gear pulls, both racing launches, and tame driving roll offs. Mine weighs 2700lbs with me in it and 1/4 tank of gas. I can take off in 2nd, but it's universally slower in my car. I don't make 1000hp, so in order to get off the line effectively I need to use 1st. Quote Link to comment Share on other sites More sharing options...
Gollum Posted October 20, 2012 Share Posted October 20, 2012 Why is everyone so worried about first gear? Because it's the only bad thing we can say about the 3.9/turbo combo. Otherwise the only "issue" I see is 5th gear cruising RPM, which I personally see no issues with as long as you don't mind INSTANT boost when you stab the throttle. Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 20, 2012 Share Posted October 20, 2012 I'll mention Jeff P tried taking off in his car in second.... it's hard on the clutch and when the wrinklies gripped, the clutch slipped. For the hell of how short first is, it works. You want to be fast at the drag strip, put an autobox into it! Quote Link to comment Share on other sites More sharing options...
Gollum Posted October 20, 2012 Share Posted October 20, 2012 You want to be fast at the drag strip, put an autobox into it! Truer words are hard to come by. Quote Link to comment Share on other sites More sharing options...
s30red240z Posted October 23, 2012 Share Posted October 23, 2012 With 3.7 LSD, 4 gear 240z trans and 24.5x8 tires i end 1/4 in 3rd gear at 7000rpm on my L24E+T Quote Link to comment Share on other sites More sharing options...
brianZortiz Posted October 23, 2012 Share Posted October 23, 2012 Ok, so I have a 3.9lsd with close ratio. Stock l26. So I have a question within this question. If we have same size tires and wheels and same trans and diff, but a different engine (turbo, NA, high hp, low hp, etc)will the rpm across speed be the same? Quote Link to comment Share on other sites More sharing options...
Gollum Posted October 24, 2012 Share Posted October 24, 2012 brian ~ yes If you had a 5.0 v8 versus a L28 RPM for a given speed and gear would be identical if the same trans, diff, and wheel size were used. Quote Link to comment Share on other sites More sharing options...
brianZortiz Posted October 24, 2012 Share Posted October 24, 2012 Thanks Gollum! Quote Link to comment Share on other sites More sharing options...
s30red240z Posted October 24, 2012 Share Posted October 24, 2012 brian ~ yes If you had a 5.0 v8 versus a L28 RPM for a given speed and gear would be identical if the same trans, diff, and wheel size were used. If the tires don't slip, big engines have a lot of torque Quote Link to comment Share on other sites More sharing options...
m1ghtymaxXx Posted October 30, 2012 Share Posted October 30, 2012 A lot of talk here about street and drag strip, anyone have any insight on this combo for autocross? I'll be swapping an L28ET into my 77 this winter, and I planning on swapping in my 3.90 and trans from my old (now parts car) 83 280ZX NA. The 83 got a lot of autocross use, and I found my 2nd gear near perfect for autocross speeds (~30-110 km/h). However I'm also now running shorter wheels (currently 205/45 lightly stretched on 16x8's vs the old 225/60 stretched the other way on the stock 14x6's) Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted October 30, 2012 Share Posted October 30, 2012 (edited) I remember my RX-2 with a heavy flywheel that ran too low a gear (high numerically) and the mass of the flywheel acted similar to traction control because the engine could not accelerate the mass of the flywheel fast enough to cause it to break traction through first gear. It was pure chance (or being too cheap for a light flywheel) that allowed the car with tiny 205/60-13 yokohama A001R to run 11.5 in the quarter mile. I changed some things with a much more powerful engine and a more highway friendly gearing and it took smoking the clutch to even get near it's previous best time. There is a sweet spot concerning flywheel weight and gearing where this can be harnessed but it might not apply to most Z car configurations. Edited October 30, 2012 by HowlerMonkey Quote Link to comment Share on other sites More sharing options...
letitsnow Posted November 2, 2012 Share Posted November 2, 2012 A lot of talk here about street and drag strip, anyone have any insight on this combo for autocross? I'll be swapping an L28ET into my 77 this winter, and I planning on swapping in my 3.90 and trans from my old (now parts car) 83 280ZX NA. The 83 got a lot of autocross use, and I found my 2nd gear near perfect for autocross speeds (~30-110 km/h). However I'm also now running shorter wheels (currently 205/45 lightly stretched on 16x8's vs the old 225/60 stretched the other way on the stock 14x6's) I have 225/50r16's and the 3.54 was good, the 3.70 is better, but all the local courses are very tight, both took right foot discipline, the 3.70lsd was considerably better in this regard though. I used most of the speed available, and I would have been on the limiter a lot if I had some camber and hoosiers, on the street tires I would hit the limiter occasionally and be in the 5500rpm range pretty often(6k limit). The turbo felt like it responded a little better with the 3.70, likely because it was always at a little higher rpm. Really it's going to depend on the course designs and how fast you can exit the corners. Quote Link to comment Share on other sites More sharing options...
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