Help choosing a transmission (not Z related)

[Xnke]

I am in the planning and parts gathering phase for another project, but am having some trouble filling out the plans. Here's what is set so far:

 

Ford 300 Inline Six, destroked to 240 cubic inches. Assume crankshaft is indestructable. (really, if I had a photo you'd believe it!)

 

Custom aluminum cylinder head flows 290cfm intakes and 195cfm exhausts at 28" of water and .530 lift. (Garage Built)

 

225*/218* .530"/.525" hydraulic-flat camshaft, aggressive lobe profile. (Crower supplied)

 

Holset HX52 turbocharger, at 14-18lbs of boost.

 

Ford 8.8 rear, 31 spline axles, with LSD. Probably as delivered in '96 explorers, 3.73 gears. Possibly (only if I can find one reasonable) the Cobra 8.8 IRS if it looks like it can be fitted in a near-stock configuration.

 

Vehicle weight should be not more than 3000lbs, with an empty tank and no driver. Target chassis is Ford Maverick or (ugh!) Mustang II...Or Ford Granada...(heee hee hee! kinda busting the weight there...)

 

The car WILL be launched on slicks at least a few times. The whole point is to build a silly-fast-in-one-direction machine that can keep time with the big V-8's and still only have six cylinders, and to showcase the custom aluminum head. It would be highly desirable to have the ability to turn the boost down to 4-6lbs and street drive it with a little civility.

 

The 300 six uses a 302 Windsor bellhousing, starter, and clutch assembly.

 

I have NO IDEA what kinds of manual transmissions I could use with this. I would not at all be surprised to make 700ft-lbs of torque peak, although the target is 500ft-lbs for as wide an RPM band as I can manage. The engine will not be revved over 7500RPM...there simply won't be a need to do so.

 

Mopar A-833? TKO600? TR6060? Z32 5SFR30A?

 

IS there a manual transmission that can handle that kind of torque without falling to it's knees and begging for mercy? I am not against the automagic if I can't have a manual...but it will be a C6. Everybody trashes the C6, but witnessed them being used for terribly abusive service for years and they don't complain as long as the shift timing is set correctly.

[JSM]

Being American I would think you should be able to find someone making bell housings to be used with a tremec 6 speed.

 

The other day on the "gears" show they were swapping a mustang automatic for a tremec 6 speed and there was an American company that sold an entire kit for the swap. They mentioned the company but I don't recall it. You may want to see if you can find the episode and at least get the name for a starting point.

 

Edit:

Here it is http://staceydavid.com/episodes/puttin-stick-mustang-v8-interceptor-paint-body-s6-ep13-1

 

Has the company names listed too!

Edited September 20, 2012 by JSM

[Six_Shooter]

If you decide to Autotragic, take a look at the GM 4L80E, yes it's an electronic trans, but there are controllers available for them, from OEM controllers, to Megasquirt with trans code to aftermarket controllers. It is a very strong trans, that will take a beating.

 

A friend of mine has a '71 Cutlass, that weighs over 4600lbs with him and half a tank of fuel, that makes over 600 ft/lbs in it's current configuration, and he is not easy on the car, it sees many hard miles every year, usually in the 10 to 15 thousand range, if not more.

 

Running a lighter car, even with more torque input will be a little easier on the trans, so it will have an easier time standing up.

 

For myself, I'm planning to run an RS5R30A, which is an early '90s 300ZX (Z32) 5-speed manual trans, since many stories claim they are extremely strong and can handle many hundreds of HP and ft/lbs of torque. I'm planning to use it in my S30, that should weigh around 2500 to 2600 lbs when it's done.

 

To be honest though, if I was building a straight line only car, especially if it was going to be a class specific car, I would go Autotragic, especially where a turbocharger is involved. You can put a load on the engine on the line, bringing in boost, before launch, without the use of spool up devices that are hard on the exhaust valves, and the Autotragic in many cases will provide much quicker shifts than most people shifting manual tansmissions.

[Xnke]

The 4L80E is right out. I'd have to get a conversion bellhousing, figure out a converter, absorb the extra expense of the transmission controller, ect. If I was going with an electronically controlled unit, it'd be an E4OD. Per dollar spent, there is no cheaper automatic box for the 289-302-351W or 240/300 six than a C4 or C6, and the E4OD is basically a C6 with a locking converter. The 4R100 gains an extra overdrive gear, but is getting into the extra-huge category. The C6 will handle enormous power in the factory configuration, and the big block versions (differences in number of pinion gears per planetary, SB had 3, and the BB got four, in general) can handle 1000HP if they are in good condition. One of our trucks at work was a 400M with a C6, in a 3/4 ton truck...we rebuilt it with a set of 4v 351C heads, aluminum intake with some spacer plates to make it fit, aftermarket pulling cam, and a holley...all stuff that the boss had laying around for a long time and we just finally put it all together. I've personally pulled a 16ft trailer with a wooden box built on it the full 16x8x4ft, full of sand, up and down through the appalachians with no issues other than tire grip. Prior to the C6 going in, it had a C4 built by a local shop to "hold 600ft-lbs and never have a hiccup!", that they had to replace twice due to it failing in similiar towing tortures. I'm not saying the truck made that much...it was geared wrong for anything but towing and we never dynoed it. But two built C4's died and the used C6 we put behind it for a stopgap is still running strong today...with all the flat-out heavy load abuse that truck gets, I am quite impressed with how well it's working out so far.

 

I know I can kill anything with a shock load on the driveline, and best I can tell the hardest part to get right in this combination of car/engine/driveline is going to be the transmission.

 

I'd really like to put in a manual, but going to the trouble to adapt a box to fit, make mounts to fit it in the car, get a driveshaft made, work out the clutch solution, I'm afraid I'll end up with 10K$ in a transmission and STILL break it regularly. A 100$ C6 core could be used to mock up, test drive, and check fitment with Even with full-power loading and a proper converter, a junkyard C6 should hold up to abusive torque levels for a few minutes. I figure a 900-1400$ budget could be enough to get it to the competition level, surely not more than about 2200$.

 

So, back to topic...there are several tremec 6-speeds, the T56, T56 Magnum, TKO, TKOII, TKO500, TKO600, ect. I'm sure there is a bellhousing made to fit the 302...the T56 for sure. Even though the TKO600 is rated for the 600ft-lbs I hope to make, it's rated on a non-slick, no-launch basis, according to the person I spoke with at Tremec. The ratings and the warrenty are only for street-driven cars, and they will not warrenty breakage caused by "racing of any kind". That last bit has me shook on buying a new one from them.