Giday, just wondering has anyone tested how much power they gained at the wheels with the same setup going from Trimatic - M20-1, or Trimatic to 5spd celica/supra?
Has anyone tested with both?
Have heard rough figures saying you will gain such percentage but would like to hear it from experience.
Cheers
Power readings from auto and manual
Started by
_01dencwe_
, Feb 21 2006 02:10 PM
20 replies to this topic
#2
_holdon_
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Posted 23 February 2006 - 08:17 PM
i went from a Th700 to celica 5spd and noticed a huge increase. i think it was mainly because of the gearing tho..... this was behind a 202
#3
_01dencwe_
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Posted 26 February 2006 - 02:22 PM
How much a increase would that have been? Would it shave around a second off your 1/4 mile time?
#4
_jap-xu1_
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Posted 26 February 2006 - 02:29 PM
a second is a big ask.
maybe from a 16 second pass you may get a 15 second pass
but not from say an 11 to a 10,no way
maybe from a 16 second pass you may get a 15 second pass
but not from say an 11 to a 10,no way
#5
_devilsadvocate_
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Posted 26 February 2006 - 06:44 PM
O1dencwe: Not surprising to see no real responses to this topic. Its unlikely anyone is going to do a transmission changeover and have done a b4 and after dyno comparison. As you say, many quote figures, but these would have to be totally from heresay(but possibly not too far from the mark in this instance)
Quartermile times: a few variables here to be too conclusive..... many new car tests showed the auto was quicker over the quarter mile than the manual, basically due to the gearing and time saving of no shifting(ability to always have power going through the drive line)
An auto is definitely going to be heavier and less efficient for the same strength of gearbox, no one will argue with that? Not many(any) manual gearboxes need trans coolers(indicating that they dont use up as much power).....though some autos can be just as efficient in top gear when the convertor is "locked up".
Quartermile times: a few variables here to be too conclusive..... many new car tests showed the auto was quicker over the quarter mile than the manual, basically due to the gearing and time saving of no shifting(ability to always have power going through the drive line)
An auto is definitely going to be heavier and less efficient for the same strength of gearbox, no one will argue with that? Not many(any) manual gearboxes need trans coolers(indicating that they dont use up as much power).....though some autos can be just as efficient in top gear when the convertor is "locked up".
Edited by devilsadvocate, 26 February 2006 - 06:49 PM.
#6
_Torana482HP_
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Posted 26 February 2006 - 09:40 PM
As devil said, wasted energy is being converted into heat energy in an auto box. I think most of the power gets wasted in the converter and then theres the pump and all the hydraulics and extra clutches etc that it needs to spin around.
a good mate once told me that a powerglide sucks about 15HP, a turbo 350 sucks about 35 or 40HP and a turbo 400 sucks about 70 - 80HP. But im not sure how accurate those numbers are.
a good mate once told me that a powerglide sucks about 15HP, a turbo 350 sucks about 35 or 40HP and a turbo 400 sucks about 70 - 80HP. But im not sure how accurate those numbers are.
#7
Dr Terry
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Posted 27 February 2006 - 08:01 AM
Hi Guys.
This business about power loss thru auto transmissions is often overstated.
The heat is only generated when the converter is not coupled, at cruising speeds there is virtually no heat generated. The torque converter by the way is effectively converting revs to torque, that's why autos launch so well of the line, because the torque is down where you need it.
The so-called 'power loss' is only really being 'lost' in the pump & the friction of the geartrain & bearings/bushes etc. Figures of 70-80 hp are fairyland stuff.
I drag-raced a Monaro (Super Sedan) in the early 80s with a 350 Chev/TH400/9" combination doing 10.2 sec @ 130 MPH & if I was loosing 70-80 HP thru the auto I would have changed to a manual (god forbid). Remember manuals also have power losses, especially in the indirect gears where there is more gear face contact & their associated power losses.
To answer the original question, while I've never done a direct comparison on a dyno, I would be surprised at any more than a 15-20 hp loss for the average auto maybe 25 hp for a TH400 & probably around 10 hp for a 4 or 5 speed manual.
On another point, if you look at the specs of the current 6.0 LS2 HSV range, the auto has the same acceleration figures, a higher top speed & uses less fuel than the 6-speed manual, why would you bother with 3 pedals.
Dr Terry.
This business about power loss thru auto transmissions is often overstated.
The heat is only generated when the converter is not coupled, at cruising speeds there is virtually no heat generated. The torque converter by the way is effectively converting revs to torque, that's why autos launch so well of the line, because the torque is down where you need it.
The so-called 'power loss' is only really being 'lost' in the pump & the friction of the geartrain & bearings/bushes etc. Figures of 70-80 hp are fairyland stuff.
I drag-raced a Monaro (Super Sedan) in the early 80s with a 350 Chev/TH400/9" combination doing 10.2 sec @ 130 MPH & if I was loosing 70-80 HP thru the auto I would have changed to a manual (god forbid). Remember manuals also have power losses, especially in the indirect gears where there is more gear face contact & their associated power losses.
To answer the original question, while I've never done a direct comparison on a dyno, I would be surprised at any more than a 15-20 hp loss for the average auto maybe 25 hp for a TH400 & probably around 10 hp for a 4 or 5 speed manual.
On another point, if you look at the specs of the current 6.0 LS2 HSV range, the auto has the same acceleration figures, a higher top speed & uses less fuel than the 6-speed manual, why would you bother with 3 pedals.
Dr Terry.
#8
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Posted 27 February 2006 - 09:55 AM
Agree with Dr Terry, re huge losses like 80hp etc. The transcooler would need to be massive to get rid of that sort of load. I think perhaps the losses are more on a percentage base of the applied input power, rather than a simple deduct x horsepower. I cant imagine any combination requiring 80hp just from the engine to make the car move from stationary.
Edited by devilsadvocate, 27 February 2006 - 09:58 AM.
#9
_TORANR AMORE_
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Posted 27 February 2006 - 11:12 AM
I'm still trying to decide between TH400, TH350 and Supra 5 speed, (the TH350 I don't have yet). The car WILL be used on the quarter mile.
If I want to conserve all my power, and not waste as much as described in this thread, obviously I would us the Supra 5 speed.
The TH400 will use more power (btw 12 to 17%) just to operate, so 'they' say and is 'sluggier' and heavier than the TH350, but ultimately an auto will be best for the quarter and will give consistent times.
I'm also VERY interested in feedaback from those who actually HAVE done changeovers with various boxes (on the same engines and cars) as to the performance difference. At this point I can only guess.
If I want to conserve all my power, and not waste as much as described in this thread, obviously I would us the Supra 5 speed.
The TH400 will use more power (btw 12 to 17%) just to operate, so 'they' say and is 'sluggier' and heavier than the TH350, but ultimately an auto will be best for the quarter and will give consistent times.
I'm also VERY interested in feedaback from those who actually HAVE done changeovers with various boxes (on the same engines and cars) as to the performance difference. At this point I can only guess.
#10
_Torana482HP_
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Posted 27 February 2006 - 08:21 PM
Yeah said to me mate that 80HP sounded a bit too high too believe. but if what TORANR AMORE says is true then 18% of about 450HP would be around 70 or 80HP, he was telling me this with regards to the 450+ HP engine that ill have.
#11
_Bomber Watson_
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Posted 27 February 2006 - 08:38 PM
cause three pedals are more fun....On another point, if you look at the specs of the current 6.0 LS2 HSV range, the auto has the same acceleration figures, a higher top speed & uses less fuel than the 6-speed manual, why would you bother with 3 pedals.
that said, if i ever get around to putting an 8 into my lj i will probably go to an auto....but more cause i'ts cheaper to get an auto that will survive over a manual.
#12
_Torana482HP_
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Posted 27 February 2006 - 08:48 PM
but more cause i'ts cheaper to get an auto that will survive over a manual.
exactly what i thought too.
#13
_Bomber Watson_
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Posted 27 February 2006 - 08:52 PM
but have discovered this to be false???
or are you agreeing???
sorry, but i have been looking into tricked up auto's and the prices are comparable with a tremec tko ect...so it's debateable....
or are you agreeing???
sorry, but i have been looking into tricked up auto's and the prices are comparable with a tremec tko ect...so it's debateable....
#14
_devilsadvocate_
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Posted 27 February 2006 - 09:14 PM
Have you priced in the cost of a clutch to do the job, also Id imagine if you are giving the system plenty of 'abuse' the clutch would possibly need to be replaced quite regularly?
#15
_Bomber Watson_
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Posted 27 February 2006 - 09:21 PM
5 puck sprung center brass item should be up to it for a while.
basicaly it's a toss up between a tremec tko (or perhaps the one under it), tricked up glide or a tricked up th350...but seeing though this motor is atleast two years away i'm not to worried about it atm. current plans for motor is a stroked 253 running some stupid mods and a whole lot of nitrous.
basicaly it's a toss up between a tremec tko (or perhaps the one under it), tricked up glide or a tricked up th350...but seeing though this motor is atleast two years away i'm not to worried about it atm. current plans for motor is a stroked 253 running some stupid mods and a whole lot of nitrous.
#16
_Torana482HP_
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Posted 27 February 2006 - 09:35 PM
nah i agree, yeah tricked up autos cost a heap but i got told to just use the t 350 with a shift kit until it needs a rebuild, he said ill be suprised how much punishment they can take before giving in,
another dude i talked to from some melbourne auto trans place said that i should be right if i stay under about 480HP, after that he said it would cost a fair bit for stronger internals to handle the extra power.
another dude i talked to from some melbourne auto trans place said that i should be right if i stay under about 480HP, after that he said it would cost a fair bit for stronger internals to handle the extra power.
#17
_Bomber Watson_
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Posted 27 February 2006 - 09:55 PM
i doubt i'll make that much, even with the nitrous...will be aiming for around 450 on the silly stuff though. but yeah, i was thinking th350 with about a 4500 stall (will need it muhahaha) and eather a stage 3 kit of full manual valve bodies...eather way running through a b&m pro ratchet....
now i should stop talking about this cause it makes me want my 253....gotta build then blow up my 202 first...
now i should stop talking about this cause it makes me want my 253....gotta build then blow up my 202 first...
#18
myss427
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Posted 28 February 2006 - 08:53 AM
I spent a bit of time at Summernats talking to the Mansweto guy's about my engine with loss of power on dyno readings. My engine dynoed at 685 horses but only made 410 at the wheels, thats a big loss. They changed there transmission (Orange capri) from auto to manual for the dyno shootout and went from 31% loss to 18% loss from engine to wheels, with no other mods.
#19
_Yella SLuR_
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Posted 28 February 2006 - 10:42 AM
Auto's have great acceleration, specially when you manualise them, i.e. don't let the car do the thinking. Great for straight line work, and no clutch damage to worry about.On another point, if you look at the specs of the current 6.0 LS2 HSV range, the auto has the same acceleration figures, a higher top speed & uses less fuel than the 6-speed manual, why would you bother with 3 pedals.
On the track however, even manualised you get far too much engine braking through the transmission, destabilising the car into the corner (just when you want it to be behaving itself). Can be overcome to a degree by late downchanging.
^ I'm not talking about being lazy and leaving the auto stuck in "D" here.
So as roads have lots of corners, if your out for a fang, a manual is going to give the car lots more manners through the corners.
Horses for courses.
Edited by Yella SLuR, 28 February 2006 - 10:45 AM.
#20
_01dencwe_
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Posted 28 February 2006 - 01:54 PM
Thats some good figures right there. Will be interested if power loss percentage is similar with only mild or stock engines.I spent a bit of time at Summernats talking to the Mansweto guy's about my engine with loss of power on dyno readings. My engine dynoed at 685 horses but only made 410 at the wheels, thats a big loss. They changed there transmission (Orange capri) from auto to manual for the dyno shootout and went from 31% loss to 18% loss from engine to wheels, with no other mods.
#21
_Torana482HP_
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Posted 28 February 2006 - 04:31 PM
ive got a stage 2 b&m kit but im gonna sell it and buy a transpak, same thing but also has parts to let the trans shift down into any gear at any speed (be careful though), transpak costs $100. it also has three stages of shift valve body, stage 3 is the full competition. ive thought about getting a full manual valve body but i might not anymore, transpak should do the trick.
im goin for a 4200 stally + b&m megashifter (i think i cut the shifter hole in my new carpet too big for a pro ratchet to cover up, Dammit)
im goin for a 4200 stally + b&m megashifter (i think i cut the shifter hole in my new carpet too big for a pro ratchet to cover up, Dammit)
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