Big Stall Converter for S197 GT Automatics

[Five Oh Brian]

I finally got my new stall converter installed today, but it's pouring down rain so I can't really put it to the test. Ordered Fuddle Racing's street/strip "High Performance Series" converter rated to flash to approximately 3400 to 3600 rpm's on launch, while providing full lock-up at higher speeds (like the factory torque converter) for better highway fuel economy and more speed through the traps in the 1/4 mile (twice the lock-up clutch area versus the factory piece).

Just a quick drive around the block in the rain and I can easily get it to flash to about 3500 rpms. The tires break loose too easily so I can't quite tell what exact rpm it's flashing to. Come on, sunshine!!! Power-braking at a standstill, I can bring up the rpm's higher than stock, but again, it's raining so I can't really test it yet.

Most performance converter builders claim a 1/4 mile improvement of 1/2 to 3/4 second (hard to believe). Fuddle Racing claims this converter should improve my 1/4 mile time by 1/2 second - wow! If that is true, my current 13.40's should turn into 12.90's (assuming I get some drag radials). Heck, I'd be happy with 13.0's or 13.1's, but 12.9's would be incredible for such a heavy, well optioned automatic GT.

Can't wait to get back to the dragstrip to see how much harder this car launches with the higher stall speed (factory stall speed was about 2200 rpms so it bogged a bit off the line). I already have 4.10 gears, so the launch should as good (or better) than most stick shift GT's.

Anyone else have a 2005-8 Mustang GT with the automatic that has already changed converters? I'd love to hear what you think.

 

[YardSpecial]

Have not changed ours yet, waiting for the blower fairy to show up..........

 

[Five Oh Brian]

The blower fairy - that's funny. I've been working on my wife's approval for a blower for awhile. Really wanting the FRPP 400hp non-intercooled whipple supercharger, but even as an employee at a big Ford dealership, it still costs a lot more than the wife can tolerate. So until then, I'm doing the underlying mods that we can afford that still offer huge bang for the buck (tuning, gears, and stall converter). Next mod will be lightweight one-piece driveshaft. If I'm stuck with a stock motor for now, at least I'm going to get as much of its power to the ground through better driveline efficiencies!

 

[MATRIX4.6]

so what exactly does a coverter do? I never really understood that type of part.

 

[Mr_Q]

I'm still on the fence about a TC upgrade. Mainly because most the driving I do is city and traffic.

I kind of like not having to modulate the throttle to avoid breaking loose, heh. I can stomp the gas and not worry about converting my tires to smoke. I'm not being jerked around every shift, etc.

However some simple break torq'n quickly solves that issue of course, when I need to.

 

[Five Oh Brian]

I used a high rpm stall (torque) converter in my 1968 GTO for many years, so I knew I had to have one for my 07 Mustang GT.

Matrix4.6.....Essentially, the TC attaches to the flexplate (flywheel in an automatic). The engine turns the TC which has a pump that forces trans fluid against the impeller on the transmission side of the TC, so basically the TC is a fluid coupling between the engine and transmission.

In normal, low to moderate, throttle driving, a high rpm stall converter still moves the car like a stock TC. If you buy one that is a "lock-up" style (like the factory) there is a clutch that can lock up the converter (so it's not just a fluid coupling) so that you can cruise down the highway and get better fuel economy (like a stick shift car with a clutch). So far, a high rpm stall converter works just like a stock TC.

However, mash the gas pedal and instead of the rpm's blipping to about 2200 rpm's (like my stock TC did), the rpm's blip (or flash) straight to 3500 to 4000 rpm's which gets you closer to peak torque (4200 rpm's in a stock GT) so that you can launch harder. This is just like dropping a clutch in a stick shift car at a high rpm for a quicker launch.

Plus, when the trans shifts to the next gear, it stays at 3500+ rpm's instead of dropping way down like the stock TC or a stick shift would do, so you stay in the sweet spot for maximum torque. Of course, if you let off the gas, then the rpm's will drop down to normal.

Also, with a big lock-up clutch inside, the transmission will produce a more direct connection (than just fluid) at highway speeds and especially at the tall end of the drag strip to increase trap speed at the finish line. Without the lock-up feature, the stall converter would keep slipping to a higher rpm (wasting fuel and acceleration when you really need it most).

Mr_Q...A high rpm stall converter does not jerk you around during shifts. It actually smoothes out the shifts as it keeps the rpm's tighter between gears. A manual trans or stock TC drops a lot of rpm's during a shift, and would be more prone to jerking the car during a shift. I did crank up the line pressure in my transmission to offer harder shifts, but that is totally seperate from the TC.

I gotta say, with my stick shift Mustangs I liked how I could be rolling down the street in 2nd or 3rd, sidestep the clutch (like fanning the clutch on a 2-stroke motocross bike) to spin the tires. Can't really do that with a normal automatic transmission behind a stock GT as there isn't enough torque. However, with the high speed stall converter, if I mash the gas pedal while locked in 2nd or 3rd (by manually shifting the lever into either gear to hold that gear) the instant rpm flash from the converter will break the rear tires loose - talk about entertaining! Leave it in drive, and the trans will downshift and flash when you mash the gas pedal. Either way, the stall converter make the car act much more like a stick shift car with the benefit of flashing up instantly to peak torque (without having to slip a clutch).

 

[Mr_Q]

Awesome info and thanks. I think I know my next mod now.

Is the Fuddle the way to go then? You have a part number and and place to order for that?

 

[Five Oh Brian]

There are two different stall converters that I had narrowed my search down to.

I ended up buying the Fuddle Racing HP/Street 3400-3600 rpm converter. List price is $560. Click on the following link to see the different stall speeds they offer....

http://www.fuddleracing.com/05stang.html#AODe

The other converter I considered was the 3500 rpm TCI "super streetfighter" (part # TCI-456002) which the best deal I could find was $850 through rpmoutlet.com at the following link...

http://www.rpmoutlet.com/05gtjbal.htm

TCI also has a 3800 rpm "competition" converter (part # TCI-456005) that rpmoutlet.com has for $950, but that is probably too much converter for most street driven cars.

Important to note that TCI's "streetfighter" converter (part # TCI-456000) does not have the lock-up feature like their "super streetfighter," hence the reason the "streetfighter" is only $500. For a daily driver, you gotta have that lock-up feature for better fuel economy. And, at the track, you want the converter to lock up at the end of the 1/4 mile so the car charges hard by getting more power to the ground.

There are other brands out there that I looked at, but after asking around and reading how they are built and warrantied, the Fuddle Racing piece really stood out. The converter is only 9.5" in diameter, uses a billet front plate, and weighs just 28 lbs. The factory converter is much heavier. Fuddle's warranty and upgrade program is tops in the business. Customer service was excellent. All in all, I am 100% happy with my choice to use Fuddle's product and would recommend them.

 

[Jimp]

Are all 3 of those Fuddle converters lock-ups? Would you recommend a 3000-3200 or the 3400-3600 like you have for a daily driver if you don't want to hurt driveability?

 

[MATRIX4.6]

Excellent!! thanks for the insight, now with install my guess is that it is something that is really involved. Can this be done in the garage or should I have shop do the install?

 

[CobraRed_96_GT]

Excellent!! thanks for the insight, now with install my guess is that it is something that is really involved. Can this be done in the garage or should I have shop do the install?

You need to drop the tranny out of the car to drain and take out the TC from the bellhosuing. It's not exactly an novice job. I love my 3200 stall. A good way to figure out the stall you want is to subtract either 400rpm or 6-800 rpm (depending on how liberal you want your stall) from you peak torque numbers - then the TC should stall up right before you peak torque so that when you drop the hammer your glad u have slicks Dont fear the stall tho guys, those 3V modulars have pretty high torque bands.

 

[Five Oh Brian]

CobraRed_96_GT is exactly correct. Our tranny guy had to pull my trans, but left it on the tranny jack, slid the stock converter off the input shaft, slid the new one on, and reinstalled. Cost me 4 hours of labor (Ford's book time says 6-7 hours labor).

The stock 4.6L 3V makes peak torque at 4,200 rpm's, but when you start modding them (CAI, exhaust, cams, etc.), peak torque is often moved up a few hundred rpm's. CobraRed_96_GT, again, is exactly correct that you want the stall converter to flash just below the peak torque.

Also, I remember vividly from my '68 GTO that when I modded the engine and got more power, the converter would actually stall higher. I had an Art Carr 2800 rpm stall converter in the GTO, and it flashed at 2800 rpm's initially, but then I had some dyno tuning done, picked up some hp & torque, and then the stall converter flashed consistently at 3100 rpm's.

The Fuddle Racing converter I bought for my 07 GT is rated to flash to 3400 to 3600 rpm's, but I'm assuming that's for an all stock GT making 300hp at the crank. My GT is making closer to 330hp at the crank now, and this converter is flashing higher than advertised (totally fine by me!). It seems to be flashing to roughly 3800 to 4000 rpm's, depending on gear and load. That's mighty close to peak torque rpm's.

Now I just need a dry day at the local dragstrip (Pacific Raceways near Seattle) to quantify the improvement in the 1/4 mile.

 

[Five Oh Brian]

Are all 3 of those Fuddle converters lock-ups? Would you recommend a 3000-3200 or the 3400-3600 like you have for a daily driver if you don't want to hurt driveability?

Yes, all three of the Fuddle converters are lock-ups. You can call or email John at Fuddle and he'll happily recommend which stall speed will work best with your combination. I spoke with him several times before making a decision. Great customer service, and so far I'm absolutely lovin' the new converter.

 

[Five Oh Brian]

Finally got my 07 GT to the dragstrip two days ago with the new stall converter. Unfortunately, it was 93+ degrees for my first pass. The track has a weather station at the top of the tower and the density altitude (DA) was horrible (2600+ ft above sea level).

Most important thing to know about the stall converter. Stock tires don't stand a chance. My stall converter is flashing to 3800 rpm's. I either spun like crazy or I had to baby the car to launch without wheelspin. Even so, I managed to to post a best sixty foot time of 1.89 with most in the 1.90 - 1.95 range on the stock tires. With the stock converter, the best 60' time on the stock tires was 2.01 with most in the 2.05 - 2.10 range. Desperately need sticky tires (which I have on order, so hopefully next week I can get back to the track).

330 foot times and 1/8 times were also better than with the stock converter even though the weather was horrible for racing.

Best 1/4 mile this time was 13.42 @ 101.60 mph (uncorrected), but using the NHRA corrections for the horrible DA shows a 13.16 @ 104.33 mph. Corrected times averaged 13.25 @ 103.34. With the stock stall converter, best was 13.40 at 102.92 while averaging 13.49 @ 102.74. This adds up to an improvement of .25 second and .6 mph with stock tires.

Once drag radials are on the car I know I can mash the gas on launch. 60' times should drop to 1.70 to 1.75 with the 1/4 mile in the 12.9 to 13.0 range. Hopefully, the weather will be reasonable next week to get some good air to run in.

 

[Kilmar]

I have the TCI 3000 Streetfighter that is still in the box. I ordered it before my current mods. Problem is that I was told the converter may not work well with my mods, especially the Saleen.

I guess it's EBay time.

 

[Five Oh Brian]

Kilmar, you want your torque converter to flash to just a few hundred rpm's below peak torque. If your car now makes gobs of low end torque with the Saleen supercharger, then you don't likely need a higher rpm stall converter. However, if peak torque is still higher than 3,000 rpm's (which I suspect it is), then your TCI 3,000 rpm stall converter should enhance your car's performance quite noticably.