4.10s with a4 woes
08-08-2009, 04:17 PM
#1
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4.10s with a4 woes Im sure someone has been in these shoes before. Has anyone ever had any problems with their auto wanting to shift way late and not even shifting to 4th at all and sometimes even third when hot. I know the tranny is prolly tired but when it shifts it shifts pretty snappy. And its only at WOT. I just had it at the track lastnite and it refused to shift to 4th. I went through the quarter trapping 116 and it was turning 6700 rpms in third. I just wish it would go forth so it would run some 11s. Any ideas.
08-08-2009, 11:03 PM
#5
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08-08-2009, 11:35 PM
#6
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last time i heard you cant shift into 4th at WOT. i tried on my car and i had to let off to get it to shift. sucked too because i was hauling ***** to get 3rd gear redline to 4th shift.
i think i remember reading something about the overdrive gear being so small that if it did shift it would destroy the gear so i think its a precautionary measure in the pcm
i think i remember reading something about the overdrive gear being so small that if it did shift it would destroy the gear so i think its a precautionary measure in the pcm
08-09-2009, 01:11 AM
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Yes had this samething but it was 2/3 hitting rev about 3 times had my tuner working on it took alot times jacking with it you have to get about 500 rpms away from the shift points and now it works
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08-09-2009, 09:31 AM
#8
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I think the shifts are based off of MPH. That being said then the more speed the later the shift point, which is how its doing. 1-2 normally shifts around 6300 2-3 when car is cool will go around 6500 and wont shift from lack of power in those RPM's when hot, but when i spray it hot it shifts 2-3 at 6700 and ive never seen it go to forth yet. Im getting about ready to ditch the 4.10s and go back to 3.73s. I know they work fine.
08-09-2009, 09:57 AM
#9
My car had 3.73s, shift points at 6200 and was shifting WOT into 4th before the end of the quarter, trust me you dont want that. The car drops way to many rpm and lays right over. I would be looking at going with a slightly larger diameter rear wheel and a retune.
08-09-2009, 10:13 AM
#10
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what were your kickdown mode mph tables set at for the 3-4 shift?
08-09-2009, 11:08 AM
#12
Your tire and gear setup should be as correct as possible.
However, to get the best results if you have a stall what you want to do is back the kickdown mph settings off and use the shift rpm setting to trigger the shift. BOTH settings have to be met before the shift will occur (rpm and mph). You will not get a shift when you command it either, it usually happens anywhere from 300-500rpm later depending on which shift it is (1-2 is faster than 2-3 etc because the rpm is changing quicker) so 1-2 has to be triggered at earlier rpm to get it where you want.
You do not want to shift into 4th before the end of the quarter. It will load your engine down very hard because you basically cut your torque output by 30%. It is also hard on your 3/4 clutch pack and some of the hard parts in the trans. You also should verify with a datalog what exactly the pcm says the rpm's are, the stock tach is junk in these cars. This is also why most do not go with a 4.10 rear gear, with a stall you are going to have some extra rpm from slippage which usually puts the rpm higher than most want to go which seems to be your problem.
However, to get the best results if you have a stall what you want to do is back the kickdown mph settings off and use the shift rpm setting to trigger the shift. BOTH settings have to be met before the shift will occur (rpm and mph). You will not get a shift when you command it either, it usually happens anywhere from 300-500rpm later depending on which shift it is (1-2 is faster than 2-3 etc because the rpm is changing quicker) so 1-2 has to be triggered at earlier rpm to get it where you want.
You do not want to shift into 4th before the end of the quarter. It will load your engine down very hard because you basically cut your torque output by 30%. It is also hard on your 3/4 clutch pack and some of the hard parts in the trans. You also should verify with a datalog what exactly the pcm says the rpm's are, the stock tach is junk in these cars. This is also why most do not go with a 4.10 rear gear, with a stall you are going to have some extra rpm from slippage which usually puts the rpm higher than most want to go which seems to be your problem.
08-09-2009, 11:30 AM
#13
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Your tire and gear setup should be as correct as possible.
However, to get the best results if you have a stall what you want to do is back the kickdown mph settings off and use the shift rpm setting to trigger the shift. BOTH settings have to be met before the shift will occur (rpm and mph). You will not get a shift when you command it either, it usually happens anywhere from 300-500rpm later depending on which shift it is (1-2 is faster than 2-3 etc because the rpm is changing quicker) so 1-2 has to be triggered at earlier rpm to get it where you want.
You do not want to shift into 4th before the end of the quarter. It will load your engine down very hard because you basically cut your torque output by 30%. It is also hard on your 3/4 clutch pack and some of the hard parts in the trans. You also should verify with a datalog what exactly the pcm says the rpm's are, the stock tach is junk in these cars. This is also why most do not go with a 4.10 rear gear, with a stall you are going to have some extra rpm from slippage which usually puts the rpm higher than most want to go which seems to be your problem.
However, to get the best results if you have a stall what you want to do is back the kickdown mph settings off and use the shift rpm setting to trigger the shift. BOTH settings have to be met before the shift will occur (rpm and mph). You will not get a shift when you command it either, it usually happens anywhere from 300-500rpm later depending on which shift it is (1-2 is faster than 2-3 etc because the rpm is changing quicker) so 1-2 has to be triggered at earlier rpm to get it where you want.
You do not want to shift into 4th before the end of the quarter. It will load your engine down very hard because you basically cut your torque output by 30%. It is also hard on your 3/4 clutch pack and some of the hard parts in the trans. You also should verify with a datalog what exactly the pcm says the rpm's are, the stock tach is junk in these cars. This is also why most do not go with a 4.10 rear gear, with a stall you are going to have some extra rpm from slippage which usually puts the rpm higher than most want to go which seems to be your problem.
08-09-2009, 11:49 AM
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You don't want to go threw the traps in forth like stated above it will be to much of a drop in rpms which will kill your et's. If your running a 26 in tall tire in back go to a 28 that will be like having your 3:73 gears back.
08-09-2009, 02:19 PM
#18
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Im still on the 275-40/17 street tires. Hadnt got around to buying some stickys. Im pretty sure the tires on it are around 26'' tall. Im bout to just say to heck wid the 4.10s and buy somemore 3.73s.
08-09-2009, 02:27 PM
#19
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Yea couldnt be much worse than those high 1.90's sixties i was cutting friday night. I think they prepped the track with cake iceing. Thats the beauty of the M6's its got no choice when you slam it in the next gear.
08-09-2009, 07:29 PM
#20
Well given that information one of a few things is happening to you.
1. you are getting a line of crap from the stock tach (likely)
2. your converter is taking a dump
3. your trans is taking a dump
There is no way you should be at that high of an rpm at those speeds unless your tires are seriously short or you have a bunch of slip. Also again 4rth gear is not a good idea to go through the lights. I think probably the reason your car feels like it pulls so hard in 4rth compared to third is you are just winding it too far and it doesn't have the lungs for it at all. Ie if you had less gear more h/c you would probably be faster because its better suited. Either way the combo is mismatched as it sits. A lot of times if you are spraying, less gear is more, slow moving pistons can get a nice big gulp of nitrous compared to really fast moving ones especially with stock style heads. I have had done it numerous times where moving shift and launch rpm down sped the car up a bunch on the nitrous.
1. you are getting a line of crap from the stock tach (likely)
2. your converter is taking a dump
3. your trans is taking a dump
There is no way you should be at that high of an rpm at those speeds unless your tires are seriously short or you have a bunch of slip. Also again 4rth gear is not a good idea to go through the lights. I think probably the reason your car feels like it pulls so hard in 4rth compared to third is you are just winding it too far and it doesn't have the lungs for it at all. Ie if you had less gear more h/c you would probably be faster because its better suited. Either way the combo is mismatched as it sits. A lot of times if you are spraying, less gear is more, slow moving pistons can get a nice big gulp of nitrous compared to really fast moving ones especially with stock style heads. I have had done it numerous times where moving shift and launch rpm down sped the car up a bunch on the nitrous.