Ford Forums banner

1 - 20 of 22 Posts

·
Chasing 500rwkw
Joined
·
3,176 Posts
Discussion Starter #1
This has come up in a few other threads and instead of leading the original posts off topic it was suggested the topic be relocated.

As the original 4 speed auto is fairly weak and extremely costly to beef up, us I6ers after high horsepower dont have many ford options when it comes to better, stronger transmissions unless we want to sacrifice a gear and use a C4 or one of its derivatives.
We could import an AOD 4 speed Im led to beleive but this would be extremely expensive.
It has been suggested that we could use the Turbo700 transmission from the commodore/ chev engines using a castlemaine rod shop adapter, I think these sell for around $650-$700 recalling a post GM destroyer made a while back about bellhousings.
What is everyones opinion? Is it sacrilege to use a chev product in a ford regardless they are easy to modify to handle substantial horsepower, not to mention a hell of a lot cheaper than upgrading the electronic 4 speed we are used to.

Is there any other alternatives?
Thoughts, suggestions all welcome.

Cheers
dan
 

·
Registered
Joined
·
1,134 Posts
DansEdgli said:
....It has been suggested that we could use the Turbo700 transmission from the commodore.....
What is everyones opinion? Is it sacrilege to use a chev product in a ford regardless they are easy to modify to handle substantial horsepower,....
Is there any other alternatives?
Thoughts, suggestions all welcome.
Cheers
dan
Can't offer any alternatives, but in my experience the T700 is VERY prone to frying the 3/4 clutch pack, in V8 and V6, and are not particularly cheap to fix. All I know is that if I pull out a T700, it doesn't go back in.
 

·
Looking in YOUR bathroom.
Joined
·
3,287 Posts
There has been whispers that the BTR 4speed box isnt as flakey as we are lead to believe. I mean they were behind 250kw TS50's. 290kw GT's and now days 10.35sec XR6T utes.
 

·
Hanging Around
Joined
·
1,209 Posts
The BTR will take 300hp easy.
Mine hasnt missed a beat at 220,000kms.
Walkinshaw is right, they have used them behind some fairly high powered engines,
They were also used behind a 335hp engine in Maserati's so they cant be all that bad.

If you are set on changing it, then contact castlemaine rod shop, they have bellhousings to fit C4's and a few others into E-series.
Also check the application guide on their website.
 

·
Looking in YOUR bathroom.
Joined
·
3,287 Posts
300hp.....what about 300+RWkw, so say 530bhp? i hope so.

Does anyone know what was actualy done to strengthen the box for the Tseries, and BA XR/GT's
 

·
400 kg ego
Joined
·
6,188 Posts
I was quoted well over a grand for the TH700 kit (not including the transmission). But because the TH700s are so cheap secondhand it still makes better sense then stuffing around with trying to install the electronic BT-R into an X series or EA, then paying another $250 just to make the damn speedo accurate with the ultra-short diff you need to match the TH700's take off, then suffering with higher rpm than the TH700 on the highway after all that! No thanks.
 

·
Looking in YOUR bathroom.
Joined
·
3,287 Posts
when you have a bucketload of torque an ultra low 1st gear (ala TH700R) isnt neaded. The BTR has very similar 1-3 ratios to the AOD and C4,6,9,10 bboxes which are used in a bucket load of BIG bhp drag cars. The BTR box would have better ratios for drag racing than the TH700R i would say, as the 700 has a huge drop between 1st and 2nd.
 

·
400 kg ego
Joined
·
6,188 Posts
That's very true Walkinshaw, but I was also thinking that the close-ratio nature of the BT-R would be a disadvantage for cars with lots of torque.

In my case, for example, I'm choosing between a BT-R with 3.9s or a TH700 with 3.45s - both have a similar effective 1st ratio.
 

·
Looking in YOUR bathroom.
Joined
·
3,287 Posts
That is true and the 700+3.45 will have better cruising speeds.

Its not that the BTR's gears are stacked close, its rather the sever jump from 1st to 2nd on the TH700R's.

TH700+4R
1st 3.06
2nd 1.62
3rd 1.00
4th 0.70

BTR LE85/93/95/97M
1st 2.39
2nd 1.45
3rd 1.00
4th 0.68

If reving to 5500rpm, the 1-2 change in the boxes will result in this

TH700+4R
5500 (1st) ==> 2900 (2nd)

BTR 4speed
5500 (1st) ==> 3350 (2nd)

Doesnt seem much but it could be the diffrence of being on full boost and boging down.

It gets worse as you lower the shift rpm, as is the case in day to day thrashing/driving.
 

·
BOFH
Joined
·
7,560 Posts
Well, I will say that Mal (HOTDBZ) has an auto in his car that has 275rwkw with more to come! He's had it strenghtened a bit but I think it shows the Auto box is very much stronger than given credit for.
As said, keep it cool with a decent Trans cooler and it should do the trick.
 

·
Looking in YOUR bathroom.
Joined
·
3,287 Posts
lol. nice call.

the stock converter (1800-2000) is about perfect. With boost the stall will flash to arround 2500, which is pretty damn good for a turbo EA-L street car.
 

·
400 kg ego
Joined
·
6,188 Posts
Well you know something weird, I have always been told that 3rd gear rather than 2nd is the weakness of the TH700. My friend had a Powerdyne supercharged V6 Commodore with 3.7s etc and it went like a rocket up to 3rd gear but then hit a flat spot. That supercharger relied on revs for boost.

I guess both have their pros and cons... I haven't had any luck selling my BT-R so will probably end up using it. What really pisses me off is the need to spend $250 to get the speedo accurate with the 3.9s. :sb:
 

·
400 kg ego
Joined
·
6,188 Posts
I was asking $450/500 but I'm really not sure if I want to sell.
 

·
Registered
Joined
·
289 Posts
The BTR boxes are very strong, stronger than T700's stock.

All you need is a good shift kit and a tranny cooler, and the ratio's are much better.

I have heard a good rumor that the new model commodore about to be released without the T700, but rather the BTR in its place.

I personally believe that a good working order stock box, with the right type of electronic shift kit on it would handle 600hp. The box is physically strong enough, even the 85le's, and as for the later model transmissions they haven't changed anything to do with physical strengh in the box, all they have changed is the valve body, which has a different shift feel, has a different lock up circuit enabling it to be used in 1st and 2nd and redisigned check balls to stop the lose of 4th and 3rd that would happen to the earlier 85le's.

I have a stock standard BTR transmission in my car that i picked up from pick a part for $117 with warranty and its got very nice hard tyre spinning changes with my own shift kit in place. and i would be now putting out close to 300fwkw's.
 

·
Looking in YOUR bathroom.
Joined
·
3,287 Posts
this makes me quite happy ;)

The shift kit you talk about (using S3/4 not S5) does this make low throttle shifts rough?
 

·
Registered
Joined
·
289 Posts
not really on cruise throttle because S6 is still working. on about a quarter throttle it shifts hard, but at a quarter throttle im on boost, and require it to shift hard.

The more power you are putting down and the greater the change in engine speed the harder the shift will feel, therefore driving the car around normally in economy mode it changes nice and firm, not with a hard thump.
 
1 - 20 of 22 Posts
Top