T45... How much can it really take???

[F8L BYT]

Alright guys, trying to gauge an idea from people who have been down the road with the T45 and what kind of power can it really handle.

I plan on keeping my car around 700-750 about 90% of the time but occasionally turning it up to ~850-900.

The trans is completely built the the T45 source. 26 spline input etc. The only thing stock left in it is the bearings and gear set. So I guess my question is at what power level is the gear set good to? It's a turbo car.

It will see a lot of street duty and quite a bit of track time too.

 

[98cobra#1222]

No idea on the transmission's ability to take that power level but when I was looking at building my t45 vs a t56 I was told by t45source that they could build a 750 hp capable t45 but it wouldn't be a guarantee to last at that power level for a long time whereas the magnum could handle it all day and not break a sweat. Your situation is different though having already built your t45 but I would think for peace of mind I would go t56 magnum and get the extra gear to boot. Sell the build t45 to try and recoup some money.

 

[blubyu87gt]

Driving style has a lot to do with it as well.

Clutch dumping off a 2-step with slicks on a prepped track will definitely shorten time between rebuilds. Getting the thing on a dyno so you can put the graph in the window for car shows / weekend cruising and it will likely last quite a while.

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[Tabres]

No idea on the transmission's ability to take that power level but when I was looking at building my t45 vs a t56 I was told by t45source that they could build a 750 hp capable t45 but it wouldn't be a guarantee to last at that power level for a long time whereas the magnum could handle it all day and not break a sweat. Your situation is different though having already built your t45 but I would think for peace of mind I would go t56 magnum and get the extra gear to boot. Sell the build t45 to try and recoup some money.

I have no first hand experience with finding the ragged edge of a t45's durability but I had a very similar conversation as above with both T45Source and Promotion when I built my car several years ago. Walt at Promotion actually talked to me for roughly an hour on the phone about the topic. I learned a lot. At the end of the day the consensus seemed to be that a T45 could work, but a T56 will work. I ended up with a built T56 and have never had issues with it.

 

[15PSI]

Go with the Magnum. Solid tranny and built for 700 lb ft. Like stocks, your results could vary....

 

[Corbic]

Just buy a T56 Magnum and don't look back.


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[F8L BYT]

Well the t56 isn't an option, the plan is to go Th400 next winter. But I am kinda at my spending limit this winter since I bought a new short block, fuel system, and building a turbo kit.

The trans is fresh and I put maybe 250 street miles on it last year breaking it in before the engine let go. So I'm trying to see if this one will last or who has experience with one at higher power levels

 

[1996MysticSnake]

Also the clutch has alot to do with it. Don't get some puck style clutch made for 2k horsepower cause that will kill it real quick

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[98 N/A 4V]

See sig pic. 6k 2 step dump. Been doing that with the stock 4.6 and now 5.4 and no issues. Car 60's 1.49-1.52 range with 415rwhp and 4.56 gears. Car weighed 3150 in that pic.

Put the blower on the car and still ironing out the bugs it put down 564 through the T45.

Zak at T45source built it. I had walt at pro mo build me a T45 and back when it was a 320rwhp stock monster I was able to shatter the 3rd gear. Turns out it was shimmed way off.

Hope that helps.