RPM Drop and Converter slip% - TEAM COTTON'S PERFORMANCE TURBO BUICK ONLINE FORUMS

trbochrgd1 · #1 12-05-2008, 01:03 PM

So I was looking over my files of that 9.56 run. My RPM drop was 400 rpm's between 1-2 (6200-5750) and 550 rpm's 2-3 (6300-5750). Is that around the norm? Or should it be a steeper drop?

Also I plugged all the #'s in on the TCI website and it came up with 6.71% of slip.

6450 rpm's, tire height 29, rear end ratio 3.42, trans ratio 1.1, mph 138.67.

I think that is pretty much right on. For the tire height I even put in 29 to compensate for tire growth. I checked M/T's website for slick growth and they stated @ 150 mph that the tires grow up to an inch to an inch and a half. My slicks are at the end of there cycle so I that's why I plugged in 29.

PaceCarTA · #2 12-07-2008, 12:50 AM

5750 is your converter , if you were to carry the shift higher it would still drop back to 5750 . with my 3600 AC9" it was at 5500 on the drops
idealy you want the converter to put you into your cams sweet spot ,

6% isnt too bad , ptc converters seems to be tigher than 5%, i was near 20% on the AC

trbochrgd1 · #3 12-07-2008, 05:00 PM

Thanks for the reply Paul. I have heard alot of good things about those converters. They seemed to be dialed in for our cars. I have a ton of money into my converter tho. I'd hate to start over again with another brand. It does seem like I am pretty close to being on the money with the Chance converter. Maybe I'll give Marty a call over there on Monday and run the #'s past him and see what he says. If what he tells me, money wise, is more than the PTC converter than I would consider switching.

JCotton1 · #4 12-09-2008, 11:03 AM

Quote:

Originally Posted by trbochrgd1

Thanks for the reply Paul. I have heard alot of good things about those converters. They seemed to be dialed in for our cars. I have a ton of money into my converter tho. I'd hate to start over again with another brand. It does seem like I am pretty close to being on the money with the Chance converter. Maybe I'll give Marty a call over there on Monday and run the #'s past him and see what he says. If what he tells me, money wise, is more than the PTC converter than I would consider switching.

Mike, looks ok for the numbers you ran, the RPM drop was consistent. Considering your shift point was 6200-6300, a 4-500rpm drop for your motor may not be bad. If you consider your motor could be shifted at 6500-6700rpm, your drop would be 7-800rpm, but then when you condider you are only running 22lbs, at 30lbs you may drive through the converter like I did when I turned the boost up 2 weeks ago. I'll be trying one of the PTC converters in my car next time out, maybe next weekend, weather permitting.. but I doubt it. More likely next spring. I'm carrying the PTC converters now, so we'll be working on data with our customers. It looks like the PTC converters are very good converters, but like any converter, sometimes a stall change may be needed. Getting them right the 1st time may not always workout..

vacuum 6 · #5 04-30-2010, 07:33 PM

Quote:

Originally Posted by JCotton1

I'll be trying one of the PTC converters in my car next time out, maybe next weekend, weather permitting.. but I doubt it. More likely next spring. I'm carrying the PTC converters now, so we'll be working on data with our customers. It looks like the PTC converters are very good converters, but like any converter, sometimes a stall change may be needed. Getting them right the 1st time may not always workout..

How did it work our for ya?