I am not sure what brand the 2.75 is but I do know it was not cheap. I also could not find one with straight cut gears. Will have to check with my trans parts supplier on Monday to find out who the manufacturer is. The whole reason I went with the 400 was to reduce the chance of breakage, sure hope it does not break.
TH400 The real answer
- Thread starter charliep
- Start date
You did ! So far the only problem with the 400 conversion has been with the trans brake. When it gets hot under the car the brake will not work. We have wrapped the solenoid with heat wrap which helped some. Even last night at the track with temps in the 30's it got to hot and would not work until it cooled down. This is what it looks like when it works. Milan Dragway Photo Gallery :: Mike The Photo Guy thephotoguy@earthlink.net 734-502-4425 :: DOC5965
I can tell you this. I don't have any experience with the 2.75 in a high HP application. When I was putting my 400 together and researching the different parts available, while talking things over with a supplier I have gained alot of trust with, I mentioned the desire to use a 2.75 gearset in my anticipated 1,000 HP application. He quickly talked me out of it. Not strong enough. I went with a THM475 gearset.
As a race car's HP and torque level increases, the importance of having a low initial gear ratio decreases. Especially if the car is traction limited (10 inch slicks). Small turbo engine in a big car, it does help get that turbo spooled up a little quicker by getting the engine into its' optimum operating rpm band sooner. But then, that is why God gave us the juice.
I was kicking around the idea switching to a 210 first gear. Do you think this would hurt my performance?
I hold the transbrake at wide open throttle (25lbs boost) . Only have a dozen or so passes so have not experimented with any other throttle positions. It seems sometimes if the starter at the track is quick my car does not spool up fast enough. Last night the starter was slow so I was able to leave at 25lbs.
Top Gun's sig gave me a little clue into his setup. I would need to know much more about your car before I could offer a suggestion. Also, is your question the same as Top Gun's.
What times do you run?
Not very good 11.70-11.80's @ 110-111 mph with 1.50's 60 foots. I have a problem with my mph as the car has gone 117 before. I changed chips from an extender to a Red Armstrong and this did not change anything. Then changed my coil pack and this resulted in a 2mph gain, so now running 113. Something is also wrong with my port so my scan tool will not record. I am going to recheck my fuel pressure and try to get my scan tool working for one last time at the track this year. I have been running 24-25lbs of boost with 114 octane. Also changed the o2 sensor.
as power goes up closer ratios do provide better performance. #400GSC 2.10 / 1.40 custom ratio planetary gear set. $1149.00
This gear set is used to reduce torque multiplication/rotating speed in the transmission in first and second gear. This improves traction in applications that overpower the rear tires on the launch. This is common with high horsepower regardless of final drive ratio.
#400GSB 2.32 / 1.48 custom ratio planetary gear set . $499.00
This gear set is used to reduce torque multiplication/rotating speed in the transmission in first gear. This improves traction in applications that overpower the rear tires on the launch. This is common with numerically high final drive ratios. (IE: 4.10, 4.56, 4.88)
#400GSA 2.75 / 1.57 custom ratio planetary gear set. $449.00
This gear set is used to increase torque multiplication/rotating speed in the transmission in first and second gears. This improves acceleration with heavy vehicles and numerically low final drive ratios. (IE: 3.23, 3.42, 3.73)
This gear set is used to reduce torque multiplication/rotating speed in the transmission in first and second gear. This improves traction in applications that overpower the rear tires on the launch. This is common with high horsepower regardless of final drive ratio.
#400GSB 2.32 / 1.48 custom ratio planetary gear set . $499.00
This gear set is used to reduce torque multiplication/rotating speed in the transmission in first gear. This improves traction in applications that overpower the rear tires on the launch. This is common with numerically high final drive ratios. (IE: 4.10, 4.56, 4.88)
#400GSA 2.75 / 1.57 custom ratio planetary gear set. $449.00
This gear set is used to increase torque multiplication/rotating speed in the transmission in first and second gears. This improves acceleration with heavy vehicles and numerically low final drive ratios. (IE: 3.23, 3.42, 3.73)
ALEXANDAAL EXAND RZA4ai .
VCLHU T Y 7TYUTHJTUHJTTTYTHGNGN#400GSC 2.10 / 1.40 custom ratio planetary gear set. $1149.00
This gear set is used to reduce torque multiplication/rotating speed in the transmission in first and second gear. This improves traction in applications that overpower the rear tires on the launch. This is common with high horsepower regardless of final drive ratio.
#400GSB 2.32 / 1.48 custom ratio planetary gear set . $499.00
This gear set is used to reduce torque multiplication/rotating speed in the transmission in first gear. This improves traction in applications that overpower the rear tires on the launch. This is common with numerically high final drive ratios. (IE: 4.10, 4.56, 4.88)
#400GSA 2.75 / 1.57 custom ratio planetary gear set. $449.00
This gear set is used to increase torque multiplication/rotating speed in the transmission in first and second gears. This improves acceleration with heavy vehicles and numerically low final drive ratios. (IE: 3.23, 3.42, 3.73)
KO
OQ`JOW18Y4YY4EXYA
Check out your valve spring pressures. That can cause a sudden drop in MPH if everything else seems fine. Have you tried leaving a little softer to drop the 60's a little lower? I'd like to see that leave at 25psi.