'14 GT Automatic - drag racing results from a few simple mods

dre256

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I have been talking to Brian at Circle D today. I maybe looking at getting a less aggressive converter than yours, the 245mm 2c is what I am looking at currently. He has answered all my questions really well. I just need to add a little more thought to this project but seeing and hearing your results I am currently considering it.
 

Five Oh Brian

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I have been talking to Brian at Circle D today. I maybe looking at getting a less aggressive converter than yours, the 245mm 2c is what I am looking at currently. He has answered all my questions really well. I just need to add a little more thought to this project but seeing and hearing your results I am currently considering it.

Conventional wisdom is to pick a converter that flashes to just a few hundred rpm's below your engine's peak torque rpm. Coyote 5.0L peak torque is around 4500 rpm's stock, so a Circle D 4C or 5C would be great choices for a near stock daily driver that only sees occasional racing. They're all the same price, and many people here in the forums have had great success with the 5C. I fear the 2C may leave you wondering if you should have went bigger.
 

dre256

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Conventional wisdom is to pick a converter that flashes to just a few hundred rpm's below your engine's peak torque rpm. Coyote 5.0L peak torque is around 4500 rpm's stock, so a Circle D 4C or 5C would be great choices for a near stock daily driver that only sees occasional racing. They're all the same price, and many people here in the forums have had great success with the 5C. I fear the 2C may leave you wondering if you should have went bigger.

Brian at Circle D also said he feels the 2C is a little too low also and recommended the 3C to me. He said the 4C would be ideal but me being still concerned on how it would be around town, is why he said 3C.

Are you running stock transmission cooler?
 

skaarlaj

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"Loose as a goose" is my moddo, especially if it's a locking converter, the highway cruise rpm's are unchanged.
 

skaarlaj

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Brian at Circle D also said he feels the 2C is a little too low also and recommended the 3C to me. He said the 4C would be ideal but me being still concerned on how it would be around town, is why he said 3C.

Are you running stock transmission cooler?
I am with no problems at all, I've heard the stock trans cooling system is very good. Also when cruising and you're in lock-up mode, the fluid couple is "out" of the equation and no additional heat will be generated compared to the stock converter.
 

cbass

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What's the lockup strategy on these cars? Does a converter mean your tuner will just change one thing, or do they have to do a whole new tune because shit isn't lining up the way it used to?
 

kingcobra323

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My 3c with stock 3.15 gear drives really nicely around town and have been told the4c can as well. I wish would have gone with a higher stall converter for the track and lower 60ft. My best so far 1.59

Sent from my ZTE A2017U using Tapatalk
 

bunits19714

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My 3c with stock 3.15 gear drives really nicely around town and have been told the4c can as well. I wish would have gone with a higher stall converter for the track and lower 60ft. My best so far 1.59

Sent from my ZTE A2017U using Tapatalk

If your na still and with only minor weight lose from factory weight a 1.59 is a pretty decent 60' foot, if your fi then not so great-
especial with only a 3c
 

bunits19714

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that is actually pretty decent 60' then- my na weight was about 100 pounds more but I am 250+ # driver, depending on if I get my pizza before or after I make my passes at the concession stand-
 

skaarlaj

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What's the lockup strategy on these cars? Does a converter mean your tuner will just change one thing, or do they have to do a whole new tune because shit isn't lining up the way it used to?
Just going by how it "feels", I'd say my car at WOT will go into lock-up at a little under 6K rpms starting in 2nd gear staying locked until you let off the gas pedal. Under cruise and low load conditions it seems to lock up around 35+ mph. The higher the stall speed, the more pronounced the "locking" feeling will be. I'm sure the jolt of a loose converter suddenly locking at cruise instills panic to alot of people but there's really no way to tune for every condition you may put your car in, and occasionally it won't be the smothest feeling transition, but if you understand what's happening it's really no big deal. Also, going down the highway and cruising at any speed above 50 mph it will be locked 99% of the time, and you'll forget the loose converter is even in there. For that reason alone, I say get the converter that will get you the best 60' possible in a vehicle that has Lockup.
 
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dre256

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What did you guys pay for install? I got a quote today for transmission service with new fluid as has 37k miles and install of converter and will be 996. Plus quote for dyno tune of 550, then converter is 1200. Total of 2746, bit of a shock for me. Was hoping to be closer to 2000 for it all.
 

Five Oh Brian

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Brian at Circle D also said he feels the 2C is a little too low also and recommended the 3C to me. He said the 4C would be ideal but me being still concerned on how it would be around town, is why he said 3C.

Are you running stock transmission cooler?

Stock transmission cooler and my trans fluid is still nice and bright pink - no burning from running such a loose converter!
 

Five Oh Brian

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Just going by how it "feels", I'd say my car at WOT will go into lock-up at a little under 6K rpms starting in 2nd gear staying locked until you let off the gas pedal. Under cruise and low load conditions it seems to lock up around 35+ mph. The higher the stall speed, the more pronounced the "locking" feeling will be. I'm sure the jolt of a loose converter suddenly locking at cruise instills panic to alot of people but there's really no way to tune for every condition you may put your car in, and occasionally it won't be the smothest feeling transition, but if you understand what's happening it's really no big deal. Also, going down the highway and cruising at any speed above 50 mph it will be locked 99% of the time, and you'll forget the loose converter is even in there. For that reason alone, I say get the converter that will get you the best 60' possible in a vehicle that has Lockup.

In drive, the lock up is hardly noticeable, but it's very pronounced if I choose to "manually" shift my auto. At WOT my converter locks up about half way through 2nd gear and stays locked until I let off the gas - just like yours.

I live in a hilly area and in drive, the converter stays loose and revs going up hill. But, if I manually select a gear then the converter will lock so I can drive uphill at low rpm's.

Like you said, at cruising speeds the converter is locked, so no slippage and fuel economy is decent.

Big stall speed FTW !!!
 

Five Oh Brian

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My converter cost about $1150 from Circle-D. Shop charged me about $400 for install. Tune didn't cost anything as it was just an update to an existing tune that I had already paid for.
 

JEWC_Motorsports

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Brian at Circle D also said he feels the 2C is a little too low also and recommended the 3C to me. He said the 4C would be ideal but me being still concerned on how it would be around town, is why he said 3C.

Are you running stock transmission cooler?

I run a 4C. I was dailying it in all kinds of traffic at an average for 300 miles a week. Its all in the tune. 2c and 3c is a waste imo.
 

skaarlaj

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I run a 4C. I was dailying it in all kinds of traffic at an average for 300 miles a week. Its all in the tune. 2c and 3c is a waste imo.
For the money and amount of work involved I agree 100%, I'm not a bit put off with a loose converter. I might just go with a PD blower this winter, and try re-stalling my 5C to a 1, or 2c instead of going with a whole new 258mm converter and see how it does with the added low rpm torque of a twin screw or TVS
 

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