Quote:
Originally Posted by PRAY
Idle rpm determines the pull on the converter. You can do lots of weird stuff with cams to determine the idle rpm. Tony's cam is actually really small. 223/23x on a 111. But the OL requires more idle rpm so it is happy at 850rpm. The cam in the blower car is 227/24x 115 and will idle happily at 750rpm but runs much better at 850rpm. The cam I just put in my car (no specs will be given) will idle at 850rpm but is a little happier at 900rpm. So all of these cams will "work" on a stock converter. The problem is the stock converter being basically locked for all of the down shifting events. They become violent on the 2/1 or 3/1.
The main issue with a cammed car and a stock converter is that they SUCK out of the hole. Take Tony's car for example. Baby cam that makes tons of tq (for a cammed car) and pulls hard up top. Couple that cam with a ported MSD that kills low end as well and the car simply can't get out of it's own way for the first 100ft or so of the track. That car ran 10.94@128.6 last weekend in +2,500 DA on a 28" Mickey R. Best 60ft all in was a 1.70. I had tow bolt on cars there that ran 11.0's@124. 60fts were in the high 1.5 bottom 1.6. Even though Tony's car had 4mph on those cars the 60ft killed us. The two FBO cars are on the stock converters, 26" tires with ported stock IM/TB's. Put a 4C in Tony's car and we would have gone 10.6's@130 pretty easily. So, all that extra power couldn't make up for the lag out of the hole. |
Is this during manual downshifting for engine breaking or when the car does it automatically and keeps it around 1000 RPM when slowing?