8" versus 10" convertor

[Andy Lappin]

Can anybody explain to me the differences in using an 8 " convertor or a 10" convertor? My 99T/A has Precision Industries 8" 2800 stall convertor in it. I have had people tell me I should be using a 10" on the street but they can't seem to tell me why. The one I have dropped my et by a full 3 10ths so it must be doing something right. Any experts on convertors out there?
Thanks
Andy

[12secSS]

Chances are you do not have an 8" stall in your 99 T/A. A couple of questions, does your converter still have a lock up? Who did the install? All 8" stalls (or better yet every aftermarket converter) is made from V6 or I4 applications, just modified to work in different platforms. an 8" converter is too small to utilize a TCC. and also thse small converters in stock form will stall to above 3800 in a mild V8. Which converter is it, is it the Vigilante 2800, that is a 9.5" converter. And if this is the converter you have, it is one of the best for street cars. The only other thing you can do is go to a higher stall speed from your current 2800 to a 3200 or even a 3600.

Not a "converter expert", but I do work with converters every day.

[Andy Lappin]

It does have a lock up, they have it set to lock at 45mph. A local shop did the install, I have the box with my old convertor and it has a precision part number of 279015 on it. It does not say vigilante on it. I just remember the shop owner telling me it was an 8" convertor and I got on a website and could not find an 8" convertor that was a precision industries for a f body. I just got on the precision site and emailed them the part number to see what exactly I have. I know it was expensive when I purchased it, somewhere in the high 700.00 dollar range.

Thanks for any info,
andy

[12secSS]

Yup, that is a 9.5" Vig2800 converter. This converter compares to 10" based cores ... sounds to me like the people that isntalled it don't know how to measure converters.

www.converter.com

19-279015 Vigilante LS1 9.5" Torque Converter, Approx 2800 Stall

Vigilante Torque Converters
9.5" GM TORQUE CONVERTER
FOR STREET, STRIP, AND RACE
.5 sec QUICKER ET'S!

The Vigilante is Precision Industries top of the line converter; it is only for those who demand the best! It is individually made for each specific application. The 9.5" diameter converter is a very versatile size capable of providing a wide range of stalls to handle muscle cars with many performance enhancements. The 9.5" is excellent for the high end street and strip car, and is strong enough to handle all out race cars.

Unique One Piece Billet Mounting Cover - The customized billet mounting cover has no welded brackets. This smooth one-piece design reduces the rotation mass, eliminates wobble for less run-out, and keeps the converter perpendicular.
4130 CNC Machine Turbine Hub - High quality 4230 alloy prevents premature wear.
Fully Enclosed Torrington Thrust Bearings - Holds the lube oil at stall for better lubrication.
Fully Furnace Brazed Impeller and Turbine - Adds strength, increases efficiency and eliminates oil leaks.
Anti-Ballooning Plate - Keeps the converter for ballooning at high RPM's
Reinforced Turbine Vanes
Heat Treated Precision Hubs
Electronically Balanced
Pressure Tested

[Andy Lappin]

Thank you george for your expertise, sounds like I got what I paid for. I know the bitch works awesome, I did not get .5 seconds increase but a solid .3500. But hey I am still trying to figure out how to come out of the hole with this thing. any suggestions? I got drag radials and it seems to stick hard. I have been playing around power braking until 1400 and then nail it at the last yellow light, then I actually power breaked up to 1600+ and I could not keep the car still and hit the gas at the yellow. Did not seem to make a whole lot of difference though. What is your professional opinion?
Thanks
andy
,

[12secSS]

From my experience using a Vig3200 (one step up from the Vig2800 that you have), my best results came from using ET Streets and stalling it up to 3000. Now granted you are on Drag Radials (which brand?) and your stall is lower, but you should be able to go as high as 2200 ... if your tires can hold it. That is one method, but you may also see how it likes being flashed, which is going from a dead stop at idle and just mashing the throttle. The current converter I have (a B&M 3000) like to be flashed from idle and has layed down some mid 1.8 60' times on street tires. If I brake stall this converter, it just spins the tires like crazy. Just experiment with different techniques, but try one thing at a time. You will find your sweet spot. Try also removing your front sway bar end links ... or completely remove the front sway bar if you can. Good luck!

[Andy Lappin]

Yea, my drag radials are t/a , g force radials. I have not tried just a idle and mash attempt. I don't have a line lock so when I power brake past about 16-1700 rpm the brakes don't hold but the tires aren't spinning. My best 60' times are in the 1.93 range. I will keep playing with the convertor and see where I end up. When I had the stock convertor I did an idle /throttle mash and that worked with the exception of wheel spin depending on how the track was prepped etc. I think if I can get the 60' foot times to a solid 1.89 or so I would be doing a better elapsed time. I still do not have headers as my car is a 30th anniversary t/a convertible and I am trying to not do to much outside of the originality of it. Not only that but from reading this form it seems most people have y pipe bangin on the floor issues and I don't want to bugger up my car unless it can be done correctly.
Thanks for all your input,
andy