Torque Converter Upgrade
 

So, I installed the stock 6R80 transmission behind the stock (sort of) 2014 Coyote engine. Seemed like a good place to start. The car ran great, and is a blast to drive.

But there were a few things about this that really bugged me:
-- the 1-2 upshift was pretty harsh. Almost like a kick in the bu tt. Some custom tuning improved it, but still pretty harsh.
-- Apparent poor brake function. In Neutral, the brakes work really well, and feel great. In Drive, not so much.
-- speaking of brakes, any little bit of sand or water, and the front tires would lock up and slide before the car stopped.
-- Shifting from Park to Drive was a bit of a bang.

Apparently, the stock torque converter has a 2,800 rpm stall speed. And that's too low for a car this light. Also, I read that the stock converter is good for about 500hp. More than that, and it will eventually be destroyed.

I purchased a new torque converter from Circle D Specialties; lock-up, triple disc, billit construction, yada, yada, yada. Stall speed 3,200-3,400. I took it to a trans shop to do the swap because I am unable to do that kind of heavy lifting at the moment.

I drove it home today. Still some snow and ice on the roads, so I didn't drive very far. But what a huge improvement! Brakes are instantly better. The 1-2 shift is significantly better. Still slid a bit on the ice, as expected. I can't wait for better weather when I can get it out for a real run.

All in all, a significant improvement, and well worth the price tag.

Bob,

Where does your engine idle, OEM or aftermarket ECU and what are you using to control the trans?



Ed

It's all stock Ford stuff. I bought a donor palate with everything included. Engine idle is right about 750, just like stock.

At the time, there were no real options for a shifter. So I used this electronic shifter.
https://www.powertraincontrolsolutio...utton_Shifter/

At your idle rpm the transition from park or neutral into gear should be relatively soft, especially with that converter. Additionally unless you are on it, the gear change from first to second should also be soft. Sometimes if the converter clutches are dragging these events will take on an impressively harsh quality.

The converter lock up is tunable in the ECU strategy. It is possible the previous owner was fiddling around there and left it in a frisky condition. There are a number of aftermarket tuning products available for that engine trans combination. The one with the worst customer service is SCT. The HP-Tuners folks are much friendlier and easier to work with.

You might want to investigate aftermarket alternatives that have support for ECU controlled transmissions. One of the best featured and best priced is MegaSwuirt through DIYAutoTune. They have a plug and play version for the SN95 cars that has all the TiVCT controls already in the software but not turned on. The ECU uses all Ford sensors or whatever you wish to use and could support your TiVCT system if you elect to keep it or it could ignore it if you chose to operate it that way.

The MS3Pro units that DIYAutoTune sells come with lifetime warranties, tuning software data logging software and cost the same (~$1K) as a tuning software only package from someone like HP-Tuners or SCT. You don't need the top of the line race unit you only need the #2 offering that comes in at ~$1K. If you want to use a Plug and Play model the price goes up to ~$1,350.

The big deal is you are in 100% control of the engine and trans tuning.


Ed

It is. Once warmed up, I shifted it in and out of park a couple of times. I could feel it, but still nice and soft. A lot like my truck, and softer than my wife's Ford. I could probably have gone a step up on stall speed, maybe 3400-3600? We'll see how it performs when I get to drive it more than around the block. At the moment, I'm thinking it's perfect for my needs.

I had a Megasquirt on my FFR. And I also use Megasquirt on my race car. I bought both of them custom built from DIY. Both were installed with a custom wiring harness that I built myself. Very simple, easy to work on, and adjust. Dead nuts reliable, too.

But this is my fun street car. I want to put gas in it and drive it. I'll do routine maint once a year, and leave it at that. I want durability over light weight. For that, the stock computer and wiring harness fits the bill perfectly. Easy to tune, set once and forget. Besides, I already own them. :)

I see I was preaching to the choir :). Apologies Bob, I didn't mean to be pedantic.


Ed

Had some nice weather this weekend - 60* and sunny (I love Colorado!). Took the car out for a couple of hours. Drove in traffic, and some open roads. Hammered the throttle a few times, but mostly gentle street driving in traffic.

A significant improvement. Shifts are gentler, especially the 1-2 upshift. Other shifts are almost imperceptible, even under hard throttle. Brakes are much improved. Car is much more predictable and easier to drive.

I think going a bit higher on the stall would be slightly better. I installed a 3,200-3,400 stall, but going one step higher to 3,400-3,600 will improve low throttle operation, and braking.

I'm going to use the engine oil temp as a trans temp gauge. When I can get time, I'll install the sensor in the cooler line. Summer time in the mountains might heat up the fluid. Or not. We'll see. :)