real quick i found out my final drive ratio is 3.18 just wondering if that was a good thing or a bad thing its the 3t40 3spd on the 2200 ohv sunfire any ifno would help im going to build up the motor but what should i change the gears to im going with a turbo setup?
That's more of a fuel economy ratio, not great for performance.
If you're going to turbocharge your engine, I'd swap in another transmission. The 3T40 is pretty weak.
1997 Pontiac Sunfire
1993 Lexus ES300
1982 Kawasaki KZ550 LTD
James Cahill wrote:Kevin Dennis wrote:The 3T40 is pretty weak.
Says who?
Anybody who has ever owned a 125C/3T40E - equipped Lumina, Cutlass Supreme, or other W-car
1997 Pontiac Sunfire
1993 Lexus ES300
1982 Kawasaki KZ550 LTD
Since when is there a 3T40E?
All these guys must be doing something wrong, there are more than a handful of guys running a 3400/3T40 combo with power adders (turbo, nitrous) with no problems.
jon thompson wrote:real quick i found out my final drive ratio is 3.18 just wondering if that was a good thing or a bad thing its the 3t40 3spd on the 2200 ohv sunfire any ifno would help im going to build up the motor but what should i change the gears to im going with a turbo setup?
The first thing you want to do is get a shift kit. The stock tranny is set up for a "comfortable" shift, which means a slow, soft shift with allot of slippage. This is very bad, especially for boosted cars.
There are three shift kits that I know of personally, Superior (simplest kit, slightly firmer than stock), Trans-Go (slightly firmer than the Superior kit) and JBP's kit (looks identical to the Trans-Go, though I haven't dealt with it,
JBP Shift Kit).
I know the Superior and Trans-Go kits can be had and installed by any tranny shop that deals with TranStar Industries parts, and probably cheaper than the JBP kit. There are also rebuild kits that have the heavy duty clutches (yes autos have them too) and bands that would help with longevity in a boosted car.
As far as the gearing goes, that all depends on the mostly camshaft and then the type of turbo used. Talk to the camshaft manufacturer and the turbo company.
You will need a well built torque converter (TC), talk to custom performance TC companies such as Yank Converters, TCS, or Performance Torque Converters. Each company can build a you a top quality TC, don't skimp on a mass re-manufactured TC! The TCs used on the 3T40/TH125Cs have durable cores (the 245mm), that is often used as the cores for many racing converters.
With all these things done, heat will be the biggest problem. As with any other automatic transmission, heat will kill the tranny. For every 10* over normal operating temps, you cut the tranny life in half! Get a transmission temp gauge and a tranny cooler and watch the fluid temps.
Don't be tricked in to believing that these are weak transmissions. They are very durable, if, as with any other auto, they are properly maintained.
Yes, in stock form they don't have allot of performance potential, but with a little work, they can be as good as any performance transmission.
So a shift kit isn't going to hurt the trans like the 3 shops in town have told me? Any idea as to why they would think this?
They tell you that because they are lazy bums and do not want to install a shift kit in a FWD trans.
If you're half-way mechanically inclined and have the basic tools, a drill and a jack w/ stands you can do it yourself. If you can change the tranny fluid and filter, your 1/4 of the way there. Just get the kit and read the instructions.
Since writting that post above, Ive also found the best rebuild kit available,
Alto-Red Eagle. Look under the catalog button for the kit. You can't get anything better than the Alto-Red Eagle Frictions and the Kolein Steels. Combined with the TransGo shift kit, the appropriate gearing and a good TC, you can keep up with the best of the manuals. Irregardless of what the uninformed say.
I was going to do it myself until I discovered I had the wrong kit. So it just ended up being a pan drop/filter change. I think its already on its way out though so I will just rebuild it myself with high quality shtuff.
Well, I already have the kit (JBP), its been sitting here for about 4 months. They didn't say that they wouldn't install it, just said they woulnd't reccomend it. I will take a look at the link too, since I'm doing something to the trans should go all the way...it has 140k on it. Plus my buddy just got a header to go along with his intake and exhaust. Now I'll be back to playing catch up.
So what exactlly would I be getting? The master kit? I'm not quite understanding the table...and where are the prices? Must be a call to find out thing?
The Master kit is a complete rebuild kit, with the Red Eagle frictions(cltches and band) and Kolene steels. Look into a good synthetic Trans fluid, such as Red Line, Royal Purple or B&M Synthetic Trck Shift.The synthetic will hold up to the temprature extremes better.
Alto isn't a retailer, they are just the manufacturer. You will probably have to do a web search for a retailer. If you call them, I'm sure they could tell you who sells the kits though.
