Without debating why, I'm curious to know the upper limits of the stock 2008 Fit sport automatic transmission, anybody have info on modifications? A street car pushing 175/200 would be (and might remain) a dream!

 

No one has done it, at least that I recall from my eight years on the forum.

 

I would also be curious what the stock tranny can take.

 

I've never seen much past 130-140 whp.

 

felix was at ~170whp with his automatic using the t1r turbo kit.


https://www.fitfreak.net/forums/fit-...turbo-fit.html


Im roughly estimating because he was at stock kit boost level with 6psi and other members were reporting 170hp with that boost level and kit.

 

I'm curious if you know how many miles either of these examples were driven, I'd be happy with 140 knowing it will last a long time. I will have tune-ability.

 

If I was going to aggressively turbo a Auto, I'd go buy a wrecking yard tranny and dissect it. See how big the clutch packs are see what kind of bands if any it uses. The big thing in auto's is that often first gear is a band controlled planetary, there are places you can send the band to have high performance friction material put on to replace the stock material, making first gear tough is about 75% of a reliable high output automatic. Sometimes you can find high performance material for the clutch packs too which helps. There doesn't seem to be a better torque converter for the car so that limits power delivery a lot. You also want to go find a BIG and I mean the size of your radiator cooler for the transmission. IT WONT BE CHEAP! get a good threaded fitting cooler, unhook it from the radiator and use the external, that will reduce the cooling load on the engine radiator which will help with whatever power upgrade your pondering.

One of these - Setrab Oil Coolers | susa
These are the hands down best oil coolers on the market. There are similar units available out of the import market like from Aliexpress. Since the cooler is on the low pressure side of the hydraulics it shouldn't see much pressure, but I'd pressure test any new cooler to over 100PSI to make sure that its in good shape. You just cap one side and fill the cooler with 5wt oil. Then put air pressure on it. A tranny temp gauge is a good idea..

I suspect that based on the size of the Auto that it probably would take at least a 70% power upgrade but when you reach the limit it won't go quietly. The front axles are probably the true fuse in the equation like in most CV axle driven cars.

Keep us posted, your traveling in new waters..

 

That you so much! Rather than modify I will probably find the limits of the stocker and replace from the junk yard. I have determined the going price for a stock tranny is $500. (Then maybe dissect) I am installing this combo into a 1st gen Insight, paddle shifters and all. (This has caused some pretty nasty responses on other forums). Will update this post in time. While I will first run Flashpro, only a turbo would be added later. (Car needs to be quiet)

 

Paddle shifters get a bad rap, the fit they work pretty good if you expectations are right, the best thing about them is the ability to trigger down shifts in regular driving mode when decending long hills or forcing a up shit when the trans computer is not keeping up, like on a long gradual grade.. 5th gear is fine but the computer will keep it in 4th way too long.

Most cars I have driven with an Auto and paddles its not been useful but this car has been the exception for me..

 

That's good to hear, I have yet to experience paddle shifting.... I'm not looking to build a race car by any means but I'm a fast lane commuter so the downshift is desirable.

 

At minimum, simply add a transmission cooler to it. Should be fairly cheap. This I do to all my auto trannys.

All the autos that I either turbocharged and/or added nitrous too, I have a valve body job performed on them as well (to make them shift lightning quick). That'd preserves my clutchpacks. I have this work performed at Level 10 Performance.

None of my autotrannys have ever failed after those modifications. Good luck on your project.

 

Oh so many questions... What kind of long term power can I run (turbo will be the way I go). I couldn't imagine wanting more that 200hp but if I can get 150hp through a stocker (with cooler). I'd just replace with a used unit When it blows. What does it cost to get this work done? I'll never have anything but street tires and never on track. Also is LSD an option with auto?

 

No one really knows.
Dwtaylorpdx pretty much nailed it on the mods you should be doing. I didn't read his response until I posted mine. You can go to an autoparts store and tell them you are looking for a tranny cooler for the vehicle and they can usually help you out with what to get. This is the 1st thing you should do. It should be relatively cheap, quick and easy to install (if not by yourself, any auto shop should be able to do it for cheap).

The 2nd thing is to address the clutchpack as Dwtaylorpdx stated. His approach is different than mine though as I've never upgraded them in my vehicles. I simply make the tranny shift quicker so the tranny isn't building up heat in between gears shifting. You know...that lag you feel when going from 2nd to 3rd gear? With boost, a LOT of heat builds up when the tranny is slipping to make the shifts smooth. You don't want that. You will want the gear shifts to be lightning quick.

I had a Level 10 valve body job done on my Outback Sport before adding turbo and nitrous to it. Before the modification, power would be lost in between gears, while the tranny granny shifted, building up a lot of heat. After the modification, the car shifted like this --->



This is instant, neck snapping, no loss of power shifting that is a LOT of fun. The car is still turbocharged with nitrous and I've had it since 1996 (Almost 20 years now).

Get that tranny cooler and install it before anything else. Then follow Dwtaylorpdx if you wish to go further (or pursue a shift kit/valve body job from a shop if possible).

 

This is all great information thank you! I will research all the topics as I have limited slush box experience. My first project is doing a seemless swap as if Honda made it that way, make sure cruse control etc. are right, then start with the mods. If anything thanks for letting me know I have possibilities with this funky combo.

 

Any difference between the 07 auto and 08 auto trans? I've been considering doing the plug n' play parts (intake, IM, TB, headers, exhaust) and a tune to maximize power out of the little L15 without stepping up to a turbocharger, though I do have an extra Volvo k24 laying around...

 

Just another thought of something to look at, Check out a couple of the similar generation Acura autos, Honda hates re-engineering, I would not be surprised if the tranny in the Acura sedans would replace the fit trany if the auto is too light duty in the end, OR the internal parts may be exchangeable .. It would be trial and error.. Even if just the valve body were interchangeable the higher HP tranny "should" have heavier internals.

 

On that note, as much as I've messed with manual transmission this is my first AT.....

Does the ecu run the trans as well?
Why can't you rum let's say a Kpro on an automatic?
Could you make a tranny work without a factory ecu?

The tranny in my 08 element 2wd is pretty nice, I could imagine it with the smaller tires and lighter car, that would do well but again, how to control it?