Just curious to see how robust these transmissions are. I know the 5 speeds have been known to go out with large amounts of torque but I don't hear much about the 6 speeds.

I planned on getting slicks this Summer but I wanted to hear from other boosted 6MT's in regards to how much power they can hold before I make any moves.

Has anyone actually destroyed a 6 speed from too much power? I know sparks03max blew his third gear up a while back but that was after repeated track runs.

I am currently making 374whp but only 320ft/lbs of torque so it's not crazy power...

 

Should be fine.

 

You'll be alright

 

380 is around the limits of torque

 

Nice. I figured I would be fine but I just wanted to double check.

Another question for you since you have a 6th gen...

can you fit a 15 inch wheel over your front brakes? (i have 6th gen brakes).

how about a 16 inch wheel?

i was looking at v6 mustang wheels

 

I think 1swtmax had some trouble with the syncs in his tranny with the turbo. As you know the 3rd gear crunch and syncs are garbage so amplify that with more torque and it could be possible to have a problem. I think that you will be fine just dont try to downshift into 3rd gear to hard in boost. I actually plan on doing the SPec-V swap to fix that BAD sync (crunching gear) problem. I don't want any problems, plus it takes away from the fun of driving the car. I remember one time I was on the freeway going about 60mph and I tried to downshift from 6th to 3rd and it crunched real hard and acted like it didnt want to go into gear. That's a problem to me a warning sign.

BUT...saying all that. In general the transmission will be fine. I just would not try to be too aggressive with it because it already has issues. I seen many 350z guys running 400-550whp on the stock tranny...they have upgraded clutches though and no sync issues.

where'd you get this magical number?

 

tilley broke one with power.

i'd say you are good up to around 400wtq. below that i wouldn't really worry much, above that maybe it's time to start worrying a little.

synchros issues and strength (gear torque handling capacity) don't have anything to do with one another.

 

I am at roughy at your power level ( maybe a little bit more ) and no issues to report with the 6spd trans. The only problem is actually making that power stick and not have massive amount of wheel spin. 1st and 2nd gear are pretty much useless on street tires at least in my case.

Out of curiosity did you want 100% slicks or something like an R-compound tire?

 

I'm looking at the Nitto 555r's. They make a 245/45/17 that would fit on the stock 7.5" wide 17's.

I forgot to mention that I have a 2006 HLSD transmission, so it has slightly better synchros.

I do not think power level has much to do with the synchros though. I was more worried about the actual gears shearing when dumping the clutch off the line, or even the axles.

As far as traction, I actually don't have a problem with first gear, because it doesn't make boost until almost redline. The real problem comes with second gear which spins to the limiter.

 

if you are looking to use the tires at the track only there is no reason to go with anything other than a real slick. if you want to be able to use them both on the street and at the track then drag radials are a good option.

 

Yea the car will be on the street 99% of the time

 

I had to grind the calipers to fit 16" wheels. The 15" v6 mustang wheels have a lot of clearance and with some grinding they might fit.
Nitto 555r's suck. Just saying.

 

I don't know much about tires honestly I'm just looking for a sticky tire that will fit on my stock wheel or a 17x8 Mustang GT wheel. Any suggestions?

 

i cut 1.9s on nitto 555 DRs and they lasted like 15,000 miles. They are way stickier than any non drag radial is. I was very happy with them for street use and occasional track use. they did a pretty good job of making 2nd gear more manageable.

 

What size were you running ?

 

235 45 17

 

Lets say the two 6mts I have took the same abuse my 5mt did and still had a tight bearings.
Only one or two missing teef on the synchros, all of the teeth on the gears, while the same abuse towards my 5mt.... well may that transmission rest in piece, it's only a bellhousing and a case now, maybe parts of the diff and 5th gear are still use able but that's it...

My 3.0 was N/A, I know this is the FI section. Just helping w/ mah 2 cents.

 

This. I run Mickey Thompson's on my Z which makes 500 RWTQ. 40 rolls brake boosting spins for a second then Yanks.

 

that's what i wanted to hear

 

I also think you will be just fine.