C4/C9 AUTO CONVERTER CHOICE

[DYNOED250]

well after killing 3 manuals and a few so called heavy duty clutches i decided to get an auto built.

So far its a C4, Extra clutches, kevlar bands, Some fancy valve body from melbourne Full manual., fully re-built. for 1000.
The engine has a revlimit of 6250, and peak torque on the dyno was 3800 ish, this may of been higher in the rev range due to the dissy not being strobed... Either way its 260 @050 of cam..

The auto guy Was dead set on a 4000 rpm TCE converter.. I was thinking it was a bit high what do u guys think.
i said but then ill only have 2250 of usuable rpm, but he said no thats wrong as even just reving it to 4200 you could do a run down the 1/4 and still pull a fast time... as its fully locked up and the engine is working against the converter which then will give u the drive down the 1/4...
Its hard to explain.. but i was convinced after our talk that the 4000 rpm stall was the way to go..

 

[xctasy]

It's very hard to get a 3500 rpm stall on a 4-cylinder becasue the lower the torque rating, the lower the stall ratio,


There is no problem getting 4000 rpm stall on a C4 V8.

What may be 4000 rpm on a 302 V8 may be only 4000 plus rpm on a 250 six becasue although sixes have more off idle torque, they produce less total torque than a really good 302 or most 351 V8's.

Unless he has to offload a 4000 rpm stallie for a knockdown price, I'd go for a 3500 rpm stall because the rule is that at 100 km/h, the converter should be close to locking up or coming onto the converter. With 600 mm tall bags, and 3.7:1 gears, it would be pulling 3270 rpm at 100 clicks.

If the converter is not close to hooking up, it'll slip and slip means heat until 120 km/h with a 4000 rpm stall.

And we know you wanna take it for a permit cruise sometime, dontcha?

 

[DYNOED250]

Thanks for the reply.. No the cars registed, but its never going to be used for longish cruises or trips.. Im setting it up now for drag usage and the odd sprint down to the local for some fun runs...
Ive got 2 massive trans coolers for it all ready..

THe converter is a Custom 8.5 inch job i think he said. The converter desigend for a 250..
I was just wondering if its possible to over stall an engine and go backwards performance wise.. But with the cam im running im kinda thinking mabie for 1/4 performance the 4000 stall speed might be pretty spot on.. im just not sure as the cost is pretty substantal

 

[Anonymous]

What convertor did you end up getting? You state you have 240rwhp have you ever raced it? Keen to no what sort of times a corty would do with that sort of power.

 

[DYNOED250]

im ordering the 4000 stall.... i havnt raced it yet... hoping for a high 12... if i can get the grip...