Those that have an LT4 Hot Cam with an automatic tranny, what is the stall on your convertor and how smooth is your idle?

I have a TPI motor now with the ZZ4 cam, which is a bit smaller, but am building an LT4, I don't want the rough idle and have to stand on the brakes at every red light to keep from lurching forward with an 1800 stall convertor in my truck.

 

If your looking for a nice smooth idle, look else where. The cam has tons of overlap and cuase a decent rumble.

 

I wouldn't say tons of overlap. Here's a bolt-on LT1 including FLP LTs, ORP, Flowmaster and tuning idleing at 850rpm:

http://www.fbodyeurope.org/gallery/7_flpidle.MPG

Not too bad at all

 

Thats doesn't sound that bad. But is that with an automatic tranny? My ZZ4 sounds and idles great in Park, but in gear with a slight load at idle stopped at a light its a pain and starts surging...could be other problems with the motor causing this, maybe a bad combo of parts, or maybe the low stall convertor. But I want it to still drive like a truck as I does use it to haul stuff, so getting a higher stall convertor isn't something I want to do if I don't have to. The LT4 is a complete LT4 motor so no bad combo of parts there.

 

If you're not too against the stall, I think it's SLP that has a 2400 stall that will loosen up the idle a bit and won't rev to the moon when you tow stuff. Or you might consider the Crane 210/224, which idles almost exactly like stock and has GREAT low and mid-range power. There are a few LT1s running 11s with this cam too.

Why are you using it to tow stuff? The only thing these cars are meant to haul is *** LOL

 

I found the best idle for the Hotcam to be at 900 rpms at idle. Yes there is still some loping but is much smother than 800 rpms. Been there done that.
HVY SS

 

It sounds like yur not really to against the sound as your are against the surging at a light. This was part of my complaint when I did my HC as well. I am having my tranny rebuilt right now and am looking at either the B&M Torque Master 2400 stall or the B&M Hole Shot 2400 stall. I don't know the difference between the 2 other than the Hole shot is $100 more ($240 vs $340). I am calling B&M on Monday to find out but will let you know how it affected my idle and surging in a couple of weeks.

Kyle

 

Sounds like your car surges at an idle. My car did that trying to find an idle speed. Was able to adjust the air idle control thru Tunnercat Programmer and the surging stopped. So that can be adjusted thru the PCM.
HVY SS

 

Its going in my truck. Yeah, I don't have a problem with the sound/noise at all, just the surging at a stop light. I have headers with a Y to single 3" exhaust now and 2 chamber Flowmaster and about 2 ft coming off the muffs then it stops, so its pretty darn loud now.
I do my own programming now with the TPI and have TC software to flash the OBDI PCM to go with the LT4, so maybe it can be smoothed out some.

As far as cam. I'm looking to get the most low end torque out of the LT4, so any other recommendation on cam are welcomed, now the stock LT4 cam has pretty good torque on the low end already so its looks like it may be hard to beat without sacrificing idle quality, and remember the LT4 cam was designed for a manual tranny.

 

Thanks for the replies, but after reviewing some dyno sheets, I'm going with an LPE cam with more lift and wider LSA which should smooth out the idle, and it looks like it pulls harder from 2k to 6k rpms with over 365 rwhp on a basically stock LT4.
I'll let ya'll know how it works out.