| Re: Transmission question |
Subject: Re: Transmission question by BeachBum on 2008/12/31 20:56:42 Quote:
Yes, I think mid to low 11's are very possible with that 383 set-up with the right converter. However, I am not a big fan of your chosen hyd flat tappet technology choice.... that'll probably hurt you a tenth or two as compared to a like hyd roller. I did a test years ago on the change... I improved 2 tenths with the move to hyd roller with less duration, but more lift, which at that time was probably a solid 20-30 hp with my 350. But, even so, deep 11's will be easy. Keeping your rpm's up is a good thing if accelerating.... I won't say how much it will effect your slap-back rpm, every set-up is a bit different, but it won't be too drastic is my guess. On your gearing, its not as bad as you think..... in reality, with your most important gear for happy timeslips, which is 1st gear, a 3.07 rear gear with a 700R4 is exactly equalivent as a th350 with a 3.73 gear if you do the math..... (3.06 x 3.07 = 9.39 and 2.52 x 3.73 = 9.39) Whats bad is a 2.59.... I don't know what GM was thinking on that one. As a note, with a 383 Superram motor, I did a very detailed before & after test years ago from 3.07 to 3.45.... I had zero et improvement on that investment, just wasted my money. But, it was a little funner to drive on the street, 2nd gear was much more usable around town. However, your HSR curve would probably see a small et improvement with more gear, but not sure. What we concluded on that, is that if you already have a good converter, gearing improvements on torque laden street motors, unless very poor ratio's to begin with(ie 2.59), do not really help you.....this was a well publicized test on the CF years ago...... but fast forward to 2008, and all of the tests the old timers did years ago seems to be forgotten or lost, cuz many do not believe this and continue to upgrade their gears and report back how fast they are now, albeit, they don't race, and instead base their conclusion on how it feels on the street. After I had done my 3.45 gears, it did feel faster on the street.... but the timeslip straightened me up and told otherwise. Back on your converter, I do not recommend you go out and loosen up your converter to 3600 rpm just based upon my opinion..... ask around, get some feedback as to the driveability of a looser converter. I think in late model forums, the general consensus is that as you get over 3000 rpm, the drivebility goes south pretty fast.... I won't argue with that, but will only say, each driver has their own idea of daily driver material. Whats livable for me, may not be for you..... so do your homework and make sure you'll still have an enjoyable driving experience before you do it..... but do rest assured, you'll go faster if you do loosen it up. btw, Azzoto's stall is approxmiately 5500 rpm..... not sure if he gave you a ride in it or not..... thats an A-typical dragstrip race converter. But, I know he does drive it on the street and reports back its fine on the street..... although I have a feeling many wouldn't share his thoughts on that. Well, thats my opinion anyway.... |
