4c vs 5c converter

i will for the life of me no matter how many threads i start or how many times i ask never truly grasp my mind around what exactly a stall converter does and how it would affect daily drivability :frusty:

A stall speed converter is smaller in diameter then the stock converter therefore it spins faster, it delays the lock up so the engine can build up rpm, in my case 4000 rpm. There is alot more power at that rpm then say 1000 rpm. So when you take off wot it feels like you have boost down low. You get a big holeshot which drops your 60 ft times dramatically. When you drive normal its almost like having a stock converter it just takes more rpm to get it to lock. These engines spin up 4000 rpm very quickly even when driving normal. Wot is where you feel the benefits of a stall speed! I have no normal driving issues with my 5c converter in fact my n/a car is quicker outta the hole then my previous paxton car which had 641 rwhp and it was a manual transmission! Lock up is defined as the direct connection between the engine and the drivetrain!

so you can basically sit at the starting line with a 4c in drive with your foot on the brake and the wheels wont break loss until you reach 4k rpm?

danny0441 said:

so you can basically sit at the starting line with a 4c in drive with your foot on the brake and the wheels wont break loss until you reach 4k rpm?

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Well, no. There is a difference between "brake stall speed" and how high a converter will flash without the brakes on. For example....

I have a 5,000 rpm stall converter and drag radials on my '14 GT. I can only hold about 2,500 rpm's against the brakes before the tires start to push the car forward despite the brakes on full.

I have found that holding about 1,800 rpm's against the brakes at the line works best for my car (after dozens of runs at differing rpm's). Then on the last amber light, I hammer the throttle as I let off the brakes. This is where the stall converter does its magic! It flashes instantly to 5,000 rpm's and maximizes the "hit." That hit is measured by an STR (static torque ratio) that effectively multiplies the torque that the engine is putting out temporarily on launch.

Whats the least aggressive setup? I would like a little help but keep daily driveability as close to stock as possible.

I'd say this one is the least aggressive. But why bother. The 4C and 5C will give you a sick launch but they are both still very easy to live with on the street.

https://www.circledspecialties.com/p-110-6r80-pro-series-stage-iii-265mm.aspx

well this thread got way bigger than i originally anticipated, and seems to have helped others along the way.

last week i ordered a 4c and some stainless power headers (thinking it will be easier to do the headers with the trans out of the way). maybe now i can drop the .05 sec i need to get 11s!!

Glad we could help u make your decision!

hawk232 said:

well this thread got way bigger than i originally anticipated, and seems to have helped others along the way.

last week i ordered a 4c and some stainless power headers (thinking it will be easier to do the headers with the trans out of the way). maybe now i can drop the .05 sec i need to get 11s!!

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My guess is you'll drop .5 instead of .05.

i went from 12.9 to 12.3 with no other changes than the 5c

What kind of 60' times are you n/a guys seeing at the track? What converter do you have?

Beefcake and Circle D both recommended the 4c so I went with that instead of the 5c I was going to go with. I don't have a lot of passes yet. But a 1.63-1.66 is the best I have gotten out of it. I tried a few passes launching at 1500 & 2000 rpm. Mods are PMAS, 2" headers, 3" exhaust, Lund tune on E85 and 20" drag radials. It is not spinning. Just seems like it needs more stall speed for a quicker 60'. So I am curious what you guys are seeing.

Thanks

Slamdcoop0428 said:

Yep i use a 4c on my car. Car launches like a damn animal!

This was when my car was averaging 9.6-9.7 and have since gone 9.47 with my 4c.

I always stall it to 1500rpm then stab it! The converter flashes so fast its hard not to let off lol

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WTF...........lol. How much power?

Rhamlinii said:

WTF...........lol. How much power?

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Now it makes a little under 800whp and has gone 9.33

86merc said:

What kind of 60' times are you n/a guys seeing at the track? What converter do you have?

Beefcake and Circle D both recommended the 4c so I went with that instead of the 5c I was going to go with. I don't have a lot of passes yet. But a 1.63-1.66 is the best I have gotten out of it. I tried a few passes launching at 1500 & 2000 rpm. Mods are PMAS, 2" headers, 3" exhaust, Lund tune on E85 and 20" drag radials. It is not spinning. Just seems like it needs more stall speed for a quicker 60'. So I am curious what you guys are seeing.

Thanks

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Best sixty is 1.58 with a 4C. Headers tune and cold air intake are the only power mods done to the car. Best timeslip has been 11.63

bluebeastsrt said:

Best sixty is 1.58 with a 4C. Headers tune and cold air intake are the only power mods done to the car. Best timeslip has been 11.63

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Stock exhaust?