Help with trans..oops

[Fbird]

Hi all,

I just bought a lightened flywheel and clutch set up for a 26 spline from Ford performance along with a 8080 bell housing from QuickTime to go in my type 65. I bought the bolts, and starter as well.I had originally planned on putting a 5 speed tko 600. I am installing a 2015 mustang coyote.The car has the 3 link with solid axle and 3.55 gears. I decided I wanted to go with a 6 speed Tremec. I thought I would just need to get the driveshaft shortened to accommodate the longer trans. I never noticed before that this is not a desired combination due to driveshaft problems with binding. Uggg! The headache is coming.

I would really like the 6 speed and the bell housing is already in route. Has anyone out there moved the engine forward or made a shorter driveshaft work? No trans purchased yet. Maybe go to the tkx if not the magnum. Might be able to give someone a deal on a bell housing.

Any advice is welcome. I am really feeling like trying to make the 6 speed work, but have not been around the block enough to know if this is possible. Otherwise , guess I will go with the five speed.

[mike223]

The coupe is 95" wheelbase, the roadster is 90" wheelbase.

I am not certain 6 speed (short) driveshaft is near the problem in the coupe that it can be in the roadster.

I am running a T56 in a roadster with a 10.5" driveshaft - but I am also IRS which makes the short driveshaft a non factor.


I have found the 6 speed to be overkill for my purposes - but I really do enjoy the .8 5th gear (as opposed to a taller 5th gear OD).

[edwardb]

Don't think you want to move the engine forward. That leads to all kinds of unintended consequences not the least of which is custom headers. It's true the T-56 is only recommended in the Roadster with IRS. Not as sure with the Coupe. Also, the Coyote is slightly shorter (an inch or so) than a SBF. So maybe that helps a little. As Mike223 said, the Coupe has a longer wheelbase. Although I'm not positive that necessarily means the engine/trans is further from the diff. Factory Five should be able to confirm whether that combination will work or not.

I have a Coyote/T-56/IRS in my Gen 3 Coupe. The Factory Five supplied driveshaft was 10.625" and fit perfectly. I don't use 6th (.63) a bunch because of the kind of driving I do. But when I do it's nice. Agree the 5th (.80) is good. But I've had TKO's (now would be a TKX) that went from 1.00 4th to .64 5th. Agree it's a pretty big gap. But honestly with these light cars and how much power they have, it's really not a problem. If you end up going that way, you won't be disappointed. I mainly went with the T-56 in my Coupe because I heard how much better they shift. And I can confirm it's true. Very nice. The TKX supposedly has a similar setup. Apparently much improved over the TKO.

[FracAG1980]

I agree 100% with edwardb. If a TKO (or TKX) will work without changing the drive shaft and using the 0.64 5th gear, do that. I have not started my build yet, but I have been working the gearing numbers hard to see what RPMs I would be turning at different speeds for track use and street use. IMO you will never be power shifting between 4th and 5th unless your on Mulsanne at Le Mans. 5th will only ever be used for cruising down the highway, so use the 0.64 5th gear ratio and cruise at the lowest RPMs possible (no need for 6 gears). If you need power at 75 mph on the highway, downshift to 3rd, but how often will that occur. (all of this using your 3.55 rear end).

[GoDadGo]

Fbird,

Like you, I am a fan of 6 forward gears and like you, I prefer the 3-Link for its simplicity and ability to plant the tires hard, especially when playing the Stoplight Game.
Just know that these cars don't need a 6-Speed, even though having one is really cool, especially at your Local Car Shows and/or Cars & Coffee Events.
Another thing to think about is the fact that your Coyote has a very broad RPM range so do you really need one more gear?
Also, please know that the only time I get into 6th gear is when I'm rolling down the Interstate at 70-80 Plus MPH.
Personally, I'd send the bell-housing back and go with a TKX 5-Speed instead.
Good Luck, Happy Wrenching & Watch Your Pinkies!

Steve
https://www.factoryfive.com/whats-ne...-mk4-roadster/

[mike223]

I have not started my build yet, but I have been working the gearing numbers hard to see what RPMs I would be turning at different speeds for track use and street use.

FWIW, I think the best (rear end gearing) figures for *most* street + track are to figure what it takes to bump the rev limiter in 3rd through the lights in the 1/8th mile (time vs weight vs HP calculator), and figure what it takes to bump the rev limiter in 4th through the lights in the 1/4 mile - somewhere in that range is going to be about right for most of these cars.

IMO you will never be power shifting between 4th and 5th unless your on Mulsanne at Le Mans.

True, I worried about 5th gear - truth is I rarely go into 4th hard, much less 5th... The first three are so much fun I rarely feel the need for more.

But even at that, I don't like dropping the RPMs that far with one gear change.

You can hear it at :17, 1:13, 2:05, and 2:26 on this car (at Le Mans, naturally enough )

This has got to be ~.6 5th gear:


https://www.youtube.com/watch?v=qW-bc8FFZ1A

I mainly went with the T-56 in my Coupe because I heard how much better they shift. And I can confirm it's true. Very nice. The TKX supposedly has a similar setup. Apparently much improved over the TKO.

Here is a very good video that shows exactly why T5s, T56s + TKXs shift better than conventional synchros (improved synchro info starting ~ 9:30):


https://www.youtube.com/watch?v=MXsRfbOiBhE&t=575s

[Bluemont]

FWIW - I have a 3.73 rear with a Tremec 3550 (.68 5th gear). On the two tracks I go to the most, I would hit 5th gear on the straights. Summit Point (but wouldn't be in 5th very long) and VIR. VIR I would be in 5th long enough to feel the difference with the tall 5th gear. So it really depends on the track you're going to be at. Since I'm not racing competitively, I never worried about it too much. But when I was near another car with the short 5th gear, I would keep up fine until we hit 5th, then he would walk away from me down the straight.

[Fbird]

Love the sound of racing in the video. Can’t beat that. I appreciate all the advice and sharing of knowledge. Gear ratios to buy for the trans are also helpful. I think I will just get rid of the QuickTime bell housing for mating coyote to the t-56 and get a new bell for a tkx. It sounds like anything that will work with the tko is good to go with the new tkx. Then I can use the driveshaft with my kit. The points raised against moving the engine could negatively impact the ride and don’t seem worthwhile...hmm anyone need a QuickTime 8080? I could return, but will probably have a restock fee of 15%. I got a good deal at $618 plus shipping. Know of anyone? It is expected to be delivered tomorrow.
Thanks again!

[David Williamson]

The drrive shaft for a Windsor block TKO 600 5 speed combination with a straight axle is just over 10 inches. So with the shorter Coyote and 6 speed and about the same drive shaft length you should be OK. Maybe check with FFR but I think you will be OK
David W

[Fbird]

Thank you much for the information. Take care all and Happy Easter. I got my QuickTime 8080. I am going to see if there is any interest in the for sale area before I try to send it back.