gooner Posted January 12, 2007 Share Posted January 12, 2007 can you help ?? I've got a twin turbo, auto, just wanting to know how or if, I can increase the acceleration from standstill! Obviously if it was manual you could build the revs then release the clutch - but not so easy with the auto!!! It feels like when you put your foot down its got like a ...."pause" for like a tenth of a second! Quote Link to comment Share on other sites More sharing options...
Chewie Posted January 12, 2007 Share Posted January 12, 2007 Try stomping on the brake pedal. Press the accelerator to about 3000 rev/min and let go of the brake. Trouble is you'll fry the autobox if you hold it too long or revs too high. Quote Link to comment Share on other sites More sharing options...
Class One Posted January 12, 2007 Share Posted January 12, 2007 Again not really technical. Do a search on powerbreaking, it will reveal all about the pros and cons of getting a rapid getaway in an auto. Quote Link to comment Share on other sites More sharing options...
Sheefa Posted January 12, 2007 Share Posted January 12, 2007 A RLTC unit with Launch Control and a 3800 hi-stall is a nice, but expensive combination! Launching with the brake as Chewie said is your best bet mate. Personally, I just plant my foot on the woot pedal from the off and let RLTC take car of the traction. Quote Link to comment Share on other sites More sharing options...
Alex Posted January 13, 2007 Share Posted January 13, 2007 You can't use RLTC Launch Control on an Auto. Quote Link to comment Share on other sites More sharing options...
Pete Posted January 13, 2007 Share Posted January 13, 2007 You can't use RLTC Launch Control on an Auto. Even with a hi stall? Quote Link to comment Share on other sites More sharing options...
mikeyb10supra Posted January 13, 2007 Share Posted January 13, 2007 Hi Stall would be a waste on a stock twin car in my opinion.....stripping the car out and going BPU is prob as good as its gonna get to be honest, supras are not as quick as other lighter motors at launching, they make up for it after a few 100m though and as other have said, TC off, power break, dial up some revs and let fly, will put a lot of strain on the box though and fry your transmission fluid Quote Link to comment Share on other sites More sharing options...
Alex Posted January 13, 2007 Share Posted January 13, 2007 Even with a hi stall? What would be the point?? The TC limits the revs... Quote Link to comment Share on other sites More sharing options...
Pete Posted January 13, 2007 Share Posted January 13, 2007 What would be the point?? The TC limits the revs... It's probably my lack of understanding of both as I've no experience of either. How does launch control work on RLTC? Quote Link to comment Share on other sites More sharing options...
Alex Posted January 13, 2007 Share Posted January 13, 2007 Launch control limits revs on launch....think it limits it till you depress the clutch again.... Quote Link to comment Share on other sites More sharing options...
Pete Posted January 13, 2007 Share Posted January 13, 2007 Launch control limits revs on launch....think it limits it till you depress the clutch again.... You slip to neutral, press the button, the system monitors the revs input, then won't let you rev higher than that point? Ah, right..so it sits there at a relatively low revs (low power), you drop the clutch, it senses this and releases the rev limit and away you go. Better than doing it without as you're not going to high revs and therefore more likely to spin. ? Does a Hi stall work by locking the transmission somehow until a certain revs? Quote Link to comment Share on other sites More sharing options...
Sheefa Posted January 13, 2007 Share Posted January 13, 2007 You slip to neutral, press the button, the system monitors the revs input, then won't let you rev higher than that point? Ah, right..so it sits there at a relatively low revs (low power), you drop the clutch, it senses this and releases the rev limit and away you go. Better than doing it without as you're not going to high revs and therefore more likely to spin. ? Does a Hi stall work by locking the transmission somehow until a certain revs? Wez, I thought a PI hi-stall increased the revs to say 3800 on the launch system and off the brake or into drive from neutral and away you go? If this is not the case, how comes the Auto dragsters are beating the manuals time and time again mate? Are they using an entire piece of kit or what? Cheers. Greg Quote Link to comment Share on other sites More sharing options...
Jake Posted January 13, 2007 Share Posted January 13, 2007 I thought a PI hi-stall increased the revs to say 3800 on the launch system and off the brake or into drive from neutral and away you go? Off the brake yes, into drive from neutral no. If you're in neutral the engine will just rev its arse off. Whacking it from Neutral into Drive at raised revs will damage the gearbox. If this is not the case, how comes the Auto dragsters are beating the manuals time and time again mate? Are they using an entire piece of kit or what? Autos change gear a lot quicker than manuals. With an auto the revs (and therefore boost) don't drop at all while changing from one gear to another. Quote Link to comment Share on other sites More sharing options...
Sheefa Posted January 13, 2007 Share Posted January 13, 2007 Ah thanks for clearing that up Jake. Power-breaking is still the way forward then. So, what the hell is the point in a hi-stall if you can't use it with the RLTC LC mechanism? Quote Link to comment Share on other sites More sharing options...
Jake Posted January 13, 2007 Share Posted January 13, 2007 what the hell is the point in a hi-stall if you can't use it with the RLTC LC mechanism? Does a Hi stall work by locking the transmission somehow until a certain revs? It makes the bite point (aka "the stall speed") higher up the rev range. With a stock TC the car will pull away at say 2000rpm but with a high stall it won't start moving the car until higher revs - that's what allows the car to make boost more quickly. If you're power braking with the stock TC the revs won't go above 2000 rpm. So when you release the brake you still won't launch great because there's little or no boost at 2000 rpms. Do the same with a, say, 3600 Hi Stall and you'll have a good amount of boost there and the car will launch great. Fitting a hi-stall to an auto is the single biggest thing you can do to improve drag times. Quote Link to comment Share on other sites More sharing options...
Sheefa Posted January 13, 2007 Share Posted January 13, 2007 Cleared that up perfectly. Thanks Jake Greg Quote Link to comment Share on other sites More sharing options...
gooner Posted January 13, 2007 Author Share Posted January 13, 2007 Well thanks everyone for your input - I'm a tad lost on some of the points - however, if I hold my brake and rev, anything past 2000rpm just makes the tyres spin - wicked burnout - but not what I'm after LOL. I see a guy on men & Motors with a Supra doing the 1/4 mile - and his car just seemed to have so much acceleration from standstill - it was just quick pull away - mine's quick its just for that fraction of a second where you wait for it to pull. Quote Link to comment Share on other sites More sharing options...
Jake Posted January 13, 2007 Share Posted January 13, 2007 Well thanks everyone for your input - I'm a tad lost on some of the points - however, if I hold my brake and rev, anything past 2000rpm just makes the tyres spin Like I said, with the stock torque converter you can't rev it past 2000rpm (at a standstill in Drive). To get a really good launch you'll need a high stall TC. Quote Link to comment Share on other sites More sharing options...
Pete Posted January 13, 2007 Share Posted January 13, 2007 It makes much more sense when you actually remember what a Torque Converter does in an auto box. Quote Link to comment Share on other sites More sharing options...
mikeyb10supra Posted January 13, 2007 Share Posted January 13, 2007 Like I said, with the stock torque converter you can't rev it past 2000rpm (at a standstill in Drive). To get a really good launch you'll need a high stall TC. Surely a higher stall with stock twins, you would nearly lose the first turbo on take off and start to move off nearer the transition of tubby 1 to tubby 2 so would lose the boost from number 1?? I agree a higher stall is needed on a single car Quote Link to comment Share on other sites More sharing options...
paul mac Posted January 13, 2007 Share Posted January 13, 2007 a 3800 hi stall would be well over the top on a BPU, i use a 3200 on a T61, if you want to launch fast go BPU run 1.4 bar boost and fit a 3200 stall T/C, RLTC without lunch control will also help alot, oh and fit some decent tyres on the back as well Quote Link to comment Share on other sites More sharing options...
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