Is 5000rpm Stall Converter too much for 1998 Cobra with 347 engine?

will(703) · 06-07-2009

Hi ive recently put in a 5000 stall converter in my 98 cobra. its has a new 347 stroker. around 450hp an 430tq i think. anyway the 60ft is great. i managed a 1.57. but at the top end in 2nd and 3rd gear it seems like the car doesnt pull anymore. i cant hardly get the rpms to get to 6 grand. yet in the burnout and through 1st it shoots right up there. please post if you have ideas. guys at the track have told me the converter is to much for the car. i have a 3500 i saved so im thinking about putting that back in it to see if it improves.

dodgestang · 06-07-2009

Converter selection should be governed by the power curve of the car. What does the dyno chart for the motor look like?

will(703) · 06-07-2009

i have not had it on a dyno yet. what im basically looking for is does this problem sound like the converter may be sliping or my motor doesnt make enough power on the top end to pull it?

dodgestang · 06-07-2009

It sounds to me like you are way past your peak torque and the converter is dragging you down because of it. But I don't race a lot and there isn't a whole lot of information about your motor build, so I'll assume have a crate motor since you have assumptions about your power level. Probably a little off topic but in my experience crates rarely match advertised power levels for a variety of reasons (you don't use all the same top end they do, variances from build to build at the machine shop, etc...). Anyway, since you have a smaller converter it is only costing you the time to install it to confirm the theory.

There are also other possibilities though since you are shaking down a new combo. I've had a couple weird fueling problems in the past...I used to run out of gas at the top of 2rd gear going into 3rd and die (stop accelerating). I had to literally lift and then hammer it again after the fuel pump caught up. Is your fuel pump up to snuff? I changed the line out and then found a new problem when I was running 2 weeks...once the car is HOT...I literally was boiling the fuel in the line. That was a simple fix to move the lines off the block but it translated into the car basically dieing on me (no longer accelerating) just as I shifted it into 3rd again.

**RLG34750** · 06-07-2009

why a 5000 stall......

how did you come up with that.....

converters are like cams they need be specific to the car not something that is arbitrarily tossed in the car because it "sounds" like it will work....

again bigger is not better......

lilorange79 · 06-08-2009

I am running a 347 stroker with a 3500 stall converter, 3.73 gears and love it. It launches great and pulls hard all the way to 6500rpm on the top end. It was picked by the tech at TCI specifically for my setup. It is an awful lot of work to just swap a converter. How does it work on the street? It seems like the converter is locked up solid at that rpm and your performance issue would be something else.

Call a converter tech and ask about it, the only stupid question is one you don't ask.

badloser · 06-08-2009

I am runnning a 3800 stall and think it is a little to loose I might send it in and get it restalled... 5k is to high in my opinion

will(703) · 06-08-2009

thanks for the replys. the reason we went to 5000 is simply cause of inexperience. now we know better haha. but we gave tci all our specs an i think they were suppose to build the converter to the specs we gave them. were going to call an see if they can fix.

PLstang · 06-08-2009

Yeah, I would agree with everyone else. That stall is too high for the car.

Heck mine stalls at 4200 and that's too high for me. I'm having another custom built.......it still isn't done yet!

stang93mustang · 06-08-2009

Quote:

Originally Posted by RLG34750

why a 5000 stall......

how did you come up with that.....

converters are like cams they need be specific to the car not something that is arbitrarily tossed in the car because it "sounds" like it will work....

again bigger is not better......

I was one of those people!

I had a 45-5000 stall for my car in the beginning and ran out of motor @ 1/8 mile on 1/4 mile track.

will(703) · 06-08-2009

live an learn lol. i wont make the same mistake again...

will(703) · 06-11-2009

alright guys i swapped the converter. i plan on running it tommorow night at the local track. i was running 7.60-7.61 with a 1.60 consistent 60ft with the 5000. im now hoping for at least a low 7.50? does that sound reasonable? i will be sure to update you guys!

**RLG34750** · 06-12-2009

As you know it's all about the 60'

if you can get it to hook up lower times are in you future....

Good luck & be safe......

will(703) · 06-12-2009

appreciate it reggie. hopefully it dont rain tonight like its been doin. my local track has been closed for the past 3 weekends!!. ive had to travel the last 2 weeks to colonial beach