# 1.8 auto tranny power limit



## 02SunnyB15 (Jan 22, 2004)

Ok guys just did a search and didn't find my answer,but i was wanting to know if any of you knew the limit of power a 1.8 tranny can handle?


Sorry this should have been in the 1.8 engine section,mods can you please move it thanks.


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## lshadoff (Nov 26, 2002)

Your car has the RE4FO3B transmission. My RE4FO3A trans failed (clutches burned out) in 18 months at 185WHP (6.5# boost) of mostly street driving. I had my trans rebuilt by Level 10, and it has been bulletproof to 210WHP (9# boost) for over 4 years now. I was told by Pat Garrett, the owner of Level 10, that it should be good to about 300WHP.

Lew


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## chimmike (Oct 17, 2002)

ya I'd say that sounds about right, but once you're pushing 185whp with the auto tranny, factor in the drivetrain losses on the automatic, and you're prolly putting too much stress on the engine itself......the internals.


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## 02SunnyB15 (Jan 22, 2004)

Kew,thanks for the info guys.Just trying to figur out if i want to stay auto or go manual cuz i don't want loss of drive while on one of my 300 mile trips ya know.


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## chimmike (Oct 17, 2002)

loss of drive? what are you talking about?


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## 02SunnyB15 (Jan 22, 2004)

chimmike said:


> loss of drive? what are you talking about?


Well i use to have a auto civic with 205 hp to the wheels and during the summer on higway trips if been getting on it for a while you can feel the tranny slip and watch the tch bouonce off the rev limiter so i'd have to pull over and wait till things cooled down and start back driving.


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## lshadoff (Nov 26, 2002)

02SunnyB15 said:


> Well i use to have a auto civic with 205 hp to the wheels and during the summer on higway trips if been getting on it for a while you can feel the tranny slip and watch the tch bouonce off the rev limiter so i'd have to pull over and wait till things cooled down and start back driving.


That's the symptom when the clutches are burned out.

Lew


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## 02SunnyB15 (Jan 22, 2004)

lshadoff said:


> That's the symptom when the clutches are burned out.
> 
> Lew


Yeah ii don't want that to happen again that's why i'm trying to figure out that fery fine line.


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## Zac (Mar 10, 2004)

If you go the swapping route, you can always get an aftermarket clutch. If you keep your auto, IPT and L10 are just 2 of a few companies that make autos shift just as fast as manuals and from what I have seen will prettymuch make up for the powerloss of a manual v. and auto (at least in the auto SE-Rs vs. the SE-R Spec V). All in all, building the auto is cheaper as of now since junkyard parts are still rather scarce on newer cars (the B15 in general). It will still be a couple thousand to build the auto but you are talking in the ballpark of 5-7 grand in terms of a swap (of course this is cheaper if you do the work yourself) and this is a huge project that is not something that can be done overnight. Expect to lose your car for over a month if you are getting a shop to do it. I personallty discourage a swap. If you are set on manual, buying the car in manual is the way to go. If you are set on drag, then switching to a manual is silly as built automatics as you probably know are the kings of quarter miles.


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## rmfnla (Jul 31, 2004)

02SunnyB15 said:


> Well i use to have a auto civic with 205 hp to the wheels and during the summer on higway trips if been getting on it for a while you can feel the tranny slip and watch the tch bouonce off the rev limiter so i'd have to pull over and wait till things cooled down and start back driving.


Have you tried installing a tranny cooler?


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## rmfnla (Jul 31, 2004)

lshadoff said:


> That's the symptom when the clutches are burned out.
> 
> Lew


In an auto that's the symptom of loss of fluid viscosity (from overheating).


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## lshadoff (Nov 26, 2002)

rmfnla said:


> Have you tried installing a tranny cooler?


The clutches don't burn out because the trans fluid gets too hot. They burn out because the shifts in an auto trans are purposely made to be smooth by slowly applying pressure to the clutch packs. They slip while shifting on purpose. This creates heat which the trans can handle at the stock horsepower levels. When the power is increased, a great deal more heat is generated inside the clutch pack which the trans cannot dissipate fast enough. The friction material decomposes due to this high localized heat. It becomes brittle and the coefficient of friction goes way down. It starts to slip, which creates even more heat, and soon the car becomes undrivable. 

The cure is to make the shifts more positive by modifying the valve body, replacing the clutch packs with material that can stand the higher temperatures, and installing a pump which produces more pressure to clamp the clutch packs tighter.

I had a huge trans cooler on my car, but the trans failed anyway.

Lew


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## Zac (Mar 10, 2004)

dont autos also slip for a more gentle ride? and doesnt that eplain why built transmissions seem to have a rather hard shift because they dont slip?


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## lshadoff (Nov 26, 2002)

NickZac said:


> dont autos also slip for a more gentle ride? and doesnt that eplain why built transmissions seem to have a rather hard shift because they dont slip?


I guess you didn't read my post above. I said, "the shifts in an auto trans are purposely made to be smooth". That means a 'gentle ride' to me.

I also said, "The cure is to make the shifts more positive by modifying the valve body". That means a 'rather hard shift' to me.

If that's not what you meant, let us know.

Lew


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## Zac (Mar 10, 2004)

lshadoff said:


> I guess you didn't read my post above. I said, "the shifts in an auto trans are purposely made to be smooth". That means a 'gentle ride' to me.
> 
> I also said, "The cure is to make the shifts more positive by modifying the valve body". That means a 'rather hard shift' to me.
> 
> ...


Whoops, my bad Lew. I did in fact read what you wrote but I misinterpreted smooth for something else somehow. Sorry about that.


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## 02SunnyB15 (Jan 22, 2004)

Yup i had a huge tranny cooler also but didn't help out too good ih hot ass Texas.Yup built autos are great for drag,my turbo crx is auto and runs consistent 13.9s all day.Thanks for all the helpfull info guys. :thumbup:


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## rmfnla (Jul 31, 2004)

lshadoff said:


> The clutches don't burn out because the trans fluid gets too hot. They burn out because the shifts in an auto trans are purposely made to be smooth by slowly applying pressure to the clutch packs. They slip while shifting on purpose. This creates heat which the trans can handle at the stock horsepower levels. When the power is increased, a great deal more heat is generated inside the clutch pack which the trans cannot dissipate fast enough. The friction material decomposes due to this high localized heat. It becomes brittle and the coefficient of friction goes way down. It starts to slip, which creates even more heat, and soon the car becomes undrivable.
> 
> The cure is to make the shifts more positive by modifying the valve body, replacing the clutch packs with material that can stand the higher temperatures, and installing a pump which produces more pressure to clamp the clutch packs tighter.
> 
> ...


Makes sense. 02SunnyB15 said that his Honda would run OK after the tranny cooled down, which sounded more like viscousity breakdown than clutch damage. Once the friction material gets brittle (or glazed) the tranny slips whether it is hot or cold. The only way to be sure would be to tear the thing down...


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## chimmike (Oct 17, 2002)

02SunnyB15 said:


> Yup i had a huge tranny cooler also but didn't help out too good ih hot ass Texas.Yup built autos are great for drag,my turbo crx is auto and runs consistent 13.9s all day.Thanks for all the helpfull info guys. :thumbup:



13.9's in a turbo CRX? is that thing on the stock 1.5L engine? Usually turbo hondas.....auto or manual, run better than that. Build that tranny and kick up the boost!


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## 02SunnyB15 (Jan 22, 2004)

chimmike said:


> 13.9's in a turbo CRX? is that thing on the stock 1.5L engine? Usually turbo hondas.....auto or manual, run better than that. Build that tranny and kick up the boost!


Yup still the 1.5 sohc motor.I haven't even put the car on the diet yet and still running dual point injection ha ha,that all should be changing here in the next couple weeks when turbo edit and multi point injection along with sheding over 100lbs.


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