- 1,274
- Chicagoland, IL USA
- oldmodelt
Reading this post
makes me glad that I just have to drive and leave the calculations to you guys. Just call me http://www.youtube.com/watch?v=NO0cvqT1tAE
By "final ratio" do you mean FD ratio or the overall ratio of the gears? I thought what we were discussing here was for say an overall ratio at the wheels of 5:1, whether you should use
5 for the gear and 1 for the FD or
2.5 for the gear and 2 for the FD?
Ah...confused...
<re-reads entire thread>
I see you define "tranny trick" as the ability to set gear ratios closer than would be possible without using the Auto Setting. Actually what I was testing was the drivetrain inertia thing. Agreed, a CF driveshaft is lighter, this will improve acceleration. However, a heavier (non CF) driveshaft should show greater difference between running high gear ratios, compared with running a high diff ratio (if the overall gearing is the same- from now on when I say "higher individual gear ratios" I also mean that the FD ratio has been adjusted to give the same ratio at the wheels). This is because the inertia is higher for higher drivetrain revs, and using higher individual gear ratios reduces driveshaft speed. But then my test found that the CF driveshaft actually increases the improvement of higher gear ratios. Then rotary_junkie's tests found the exact opposite. Much confusions...
Actually, that is what I was testing...If you meant using the same wheel speed via different gear/diff ratios then that's a bit different.
I don't think so. And it's very interesting anyway!...and makes all my testing redundant
Just wondering, are you able to get exactly the same times when launching from a specific rpm? I found (using the DS2 analogue stick) it was causing inconsistent times, so I tend to just bounce it off the limiter if I'm doing comparison testing these days.After several test runs, I found the best launch was around 3000-3500rpm so I used that as my baseline takeoff rpm.
If only the dyno graph had a rev scale on it. Then we could geek it up with spreadsheets to calculate optimum gear ratios to stay in the power band. But maybe that would take away the fun of tuning...So I've brought the car up to be 0.177 quicker over the 400m, and then continued that and been 1.23km/h faster at top speed.
Yep. I've always thought (but never tested much 400m stuff) that higher launch revs = able to run taller 1st gear without bogging = able to run tighter gearing across the board = faster acceleration. (unless there is clutch slip in GT4? I've never looked into this)With the taller first gear, the motor had to rev slightly higher (4000rpm vs 3000rpm) to keep it from bogging down at launch...
Thanks heaps! It's really impressive that after your first "tranny trick" setup you managed to increase top speed without sacrificing 400m time (in fact you actually improved it!!)That's the tranny trick (one version of it anyway).
Just wondering, are you able to get exactly the same times when launching from a specific rpm? I found (using the DS2 analogue stick) it was causing inconsistent times, so I tend to just bounce it off the limiter if I'm doing comparison testing these days.
I find that creating a gear graph that looks like a fan is opening is the best way of keeping the car in it's powerband. As you can see by the ratios I used in the 'trick' tests, I keep them close together to allow this to happen.If only the dyno graph had a rev scale on it. Then we could geek it up with spreadsheets to calculate optimum gear ratios to stay in the power band. But maybe that would take away the fun of tuning...
There is a way you can slip the clutch in GT4 on launch through throttle control that allows you to launch at high rpm without smoking the tyres on takeoff. I've been able to do this with a lot of practice.Yep. I've always thought (but never tested much 400m stuff) that higher launch revs = able to run taller 1st gear without bogging = able to run tighter gearing across the board = faster acceleration. (unless there is clutch slip in GT4? I've never looked into this)
It's because I set the first gearset to show the improvement in acceleration you can make without much effort, the next gearset was what you can do when you concentrate on both ends (acceleration and top speed). That gearset could be improved even further on the acceleration end, I know a 12.0xx is there with a slightly better 1st/2nd combination (say 2.900/2.000) and if you really really tried to maximise it I suppose you could possibly get an 11.9xx after much testing. That's while you're still maintaining that same top speed because 5th/6th would be untouched, as I only used 4 gears in the 400m.Thanks heaps! It's really impressive that after your first "tranny trick" setup you managed to increase top speed without sacrificing 400m time (in fact you actually improved it!!)