5 speed to 6 speed swap
#1
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5 speed to 6 speed swap
I have to note that before this discussion get underway that all of you guys who just come in and say 5 speed> 6 speed will just be ignored.
So here is what I want to talk about. Recently my first gear failed on me after it was heavily abused during many autox events. TRE has a heavy duty bearing upgrade for that and regardless of which transmission I choose that will get done. I am debating having a six speed sent to TRE since he has resolved most of the issues with overheating and strength. I don't plan on making more power than what I have now which is stock turbo on E85 making 427whp/392wtq. I believe the gear ratio on the six speed is better for autox/road course events plus the overall shifter feel to me is less notchy than the five speed. I have a built five speed now with all the updates and an evo 8 3rd and 4th gear.
Basically looking for a discussion to make me pull the trigger or not. I am pretty set on this to be honest as I might have a local here who is willing to trade his perfect working six speed plus cash on his end.
So here is what I want to talk about. Recently my first gear failed on me after it was heavily abused during many autox events. TRE has a heavy duty bearing upgrade for that and regardless of which transmission I choose that will get done. I am debating having a six speed sent to TRE since he has resolved most of the issues with overheating and strength. I don't plan on making more power than what I have now which is stock turbo on E85 making 427whp/392wtq. I believe the gear ratio on the six speed is better for autox/road course events plus the overall shifter feel to me is less notchy than the five speed. I have a built five speed now with all the updates and an evo 8 3rd and 4th gear.
Basically looking for a discussion to make me pull the trigger or not. I am pretty set on this to be honest as I might have a local here who is willing to trade his perfect working six speed plus cash on his end.
#3
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The torque limits of a stock 6 speed are considerably weaker than a 5 speed. I'm assuming your 427whp/392wtq are off a dynojet? I'm making 342wtq off a mustang dyno and the shop said that I was reaching the limit of my 6 speed. Fourth and 5th are skinnier, have less oiling and cooling capabilities, and thus weaker than that of the 6 speed. On the other hand, autox usually only requires 1st and 2nd (sometimes 3rd). Tracking is a different story. It's odd how Mitsu created the MR, yet the 6 speed is weaker for track. However, my buddies 4th gear got thrashed at Laguna Seca just before New Year's--and he's got a 5 speed. So go figure, huh? I'm still running strong with my 6 speed, having 118k and monthly autox's. However, I'll probably switch to a 5 speed once the 6 speed says goodbye, just because it'll handle more power/torque, which I may or may not plan in the future. Running BSP right now but might go turbo upgrade and/or cams to run SM--but not committed.
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I run Street Modified now at the power I'm at and that is plenty to win my Region. I just think the shorter 2nd gear will help so I don't have to downshift into 1st. It is hard to tell though. Just in case I am still going to make first as strong as possible. Check out TRE's six speed rebuild as he has pretty detailed pics on what he does to enhance the cooling issue and oil problems that normally kill the transmission. I would also like to hear from the guys who have had this service done.
#5
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I ran a 6 speed for 23,xxx hard track miles with no issue. I did install a tranny cooler/pump which helps in the cooling department. I recently did a 5 speed swap/shep rebuild because I didn't want to risk blowing up a 6 speed. Overall the 6 speed feels much better on track, the 5 does feel a little sloppy. I do like the fact the 5 speeds have been proven to be more bullet proof. I travel long distances to race so eliminating weak links on the car is a big plus for me.
#6
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I ran a 6 speed for 23,xxx hard track miles with no issue. I did install a tranny cooler/pump which helps in the cooling department. I recently did a 5 speed swap/shep rebuild because I didn't want to risk blowing up a 6 speed. Overall the 6 speed feels much better on track, the 5 does feel a little sloppy. I do like the fact the 5 speeds have been proven to be more bullet proof. I travel long distances to race so eliminating weak links on the car is a big plus for me.
Kidloco, did you install a tranny cooler on the 5-spd as well? I haven't done so yet, and probably should.
To the OP, it sounds like your mind is already made up, and you already have an offer of a 6-spd trans to swap, so what exactly are you asking? It's pretty common knowledge the 5-spd is stronger, but if you prefer the ratio of the 6-spd and TRE can fortify it enough to run reliably at your power level, then its just a question of if its worth the money to you. I personally wouldn't go back to the 6-spd, but I can also think of a lot of things I would spend that money on to go faster.
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I ran my 6 speed during a couple HPDEs, but actually prefer the 5-spd. It's funny you describe the 5-spd as feeling sloppy, because thats the opposite of my experience. My 6-spd felt kind of "rubbery" when shifting, very imprecise where my Shep 5-spd feels like a bolt-action rifle. I will say different turns cause problems for me on the same track with the different transmission. At Summit Point, turn 8 was annoying with the 6 spd as I would be right on the verge of peak torque in 4th which badly unbalanced the car, but now with the 5-spd I have trouble with turn 10 because I wasn't quite able to take it fast enough in 5th to be in full boost when I straightened up. I'm hoping with the new aero/tires I'll be able to take that corner fast enough it won't be a problem.
Kidloco, did you install a tranny cooler on the 5-spd as well? I haven't done so yet, and probably should.
To the OP, it sounds like your mind is already made up, and you already have an offer of a 6-spd trans to swap, so what exactly are you asking? It's pretty common knowledge the 5-spd is stronger, but if you prefer the ratio of the 6-spd and TRE can fortify it enough to run reliably at your power level, then its just a question of if its worth the money to you. I personally wouldn't go back to the 6-spd, but I can also think of a lot of things I would spend that money on to go faster.
Kidloco, did you install a tranny cooler on the 5-spd as well? I haven't done so yet, and probably should.
To the OP, it sounds like your mind is already made up, and you already have an offer of a 6-spd trans to swap, so what exactly are you asking? It's pretty common knowledge the 5-spd is stronger, but if you prefer the ratio of the 6-spd and TRE can fortify it enough to run reliably at your power level, then its just a question of if its worth the money to you. I personally wouldn't go back to the 6-spd, but I can also think of a lot of things I would spend that money on to go faster.
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#9
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Please read my posts. My first sentence is to prevent comments like this. I didn't break a part that was common for six speeds. First gear in the six speed is just as strong as in the five speed. As noted either transmission will need to be beefed up for that gear. I want reviews from people mainly who have raced on both and better yet who have had the transmission built by either shep or tre. I don't want to hear from people who have thrown on big turbos and complain that the six speeds was ****. My car sees a lot of autox events and will get a few road course events per year. The first two gears are what see the most abuse. Rarely do I ever run out third in an event. I wouldn't exactly say I abuse my car on the street but I have from time to time.
Last edited by dangle; Jan 16, 2012 at 08:21 PM.
#11
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Please read my posts. My first sentence is to prevent comments like this. I didn't break a part that was common for six speeds. First gear in the six speed is just as strong as in the five speed. As noted either transmission will need to be beefed up for that gear. I want reviews from people mainly who have raced on both and better yet who have had the transmission built by either shep or tre. I don't want to hear from people who have thrown on big turbos and complain that the six speeds was ****. My car sees a lot of autox events and will get a few road course events per year. The first two gears are what see the most abuse. Rarely do I ever run out third in an event. I wouldn't exactly say I abuse my car on the street but I have from time to time.
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So I talked to Shep today and he convinced me to stick with my five speed. Luckily he isn't charging me for a complete rebuild and this is going to cost way less than I have expected. I am even going with the REM treatment while he's in there. To add he did say the first and second gear on the six speed are stronger but on the road course I will most likely destroy 4th gear. I really want a six speed though but what can you do.
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I do have to say one thing though. I haven't spoke to TRE yet because it is so hard to get into touch with him but he does have a heavy duty first gear bearing upgrade that I really want but when I mentioned to shep about what it was he kind of shruggled it off. Shep also believes I screwed something up with my second gear that isn't allowing me to engage first. Second gear works fine but he is almost positive so who am I to disagree with him. Both are stand up shops but for some reason I am leaning toward TRE.
#15
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Hmm, if you are mostly autocrossing, I would definitely stick with the 5-spd. I prefer the gearing of the 5-spd for autox. When Shep built mine he did Evo IX 1st/5th & Evo VIII 3rd/4th gears and I really like it. Way less unnecessary rowing in 1st-3rd gear. Good luck with whichever direction you go!
For SM though, I'd definitely want the 5 speed just because of the torques and the lighter weight.
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