KC valvebody question

[JDSfastGN]

I installed a KC a while back and am very happy. my only complaint is that the 3-2 downshift is a little too lively. It will still drop into 2nd at 70-75 mph. Im sure the problem has to do with the calibration and my car having 3.23s rather than 3.42s. My car just doesn't like dropping into 2nd at much over 60 or so, plus from a roll Id rather take advantage of the abundant low rpm 3rd gear torque. So my question is, do I put a stiffer or softer TV modulator downshift spring in? Thanks

 

[chris718]

Which 3/2?Wide open or modulated?

 

[JDSfastGN]

Wot downshift, does the tv modulator have no effect on this?

 

[bison]

Then have the wrong vb imo. I want my car in 2nd at 75mph for maximum acceleration and i still have 3.42 gears. That was one of the big advantages to the calibration from a highway roll. Im still in 1st at about 50mph. 2-3@92mph

 

[JDSfastGN]

well im very happy with the upshift points, my PTC is not quite as efficient as yours it would seem. But I just don't want it dropping into 2nd at 70 mph+ The car just doesn't like it for some reason, i get a lot of false knock on a big downshift when its above 65 mph and Id rather be in 3rd. Wrong VB or not what are some tweaks I can look at? My upshift on a 28" tire is 43 mph for 1-2 and 85 for 2-3 and Im very happy with these numbers and the car loves this setup at the track. Its just from a roll on the highway that it downshifts and usually falls on its face at the high mph downshifts.

 

[JDSfastGN]

Any ideas? Any tweaks I should try? The valvebody is out right now. I have added a slightly stiffer spring to the MTV downshift valve but am not sure if this will do anything but effect part throttle downshifting. The setup is pretty normal. KC valve body, dual fed, CK shift kit, 3-2 valve mod etc.... Thanks guys.

 

[chris718]

Install a tv plunger with no part throttle detent hole in it.

 

[bison]

well im very happy with the upshift points, my PTC is not quite as efficient as yours it would seem. But I just don't want it dropping into 2nd at 70 mph+ The car just doesn't like it for some reason, i get a lot of false knock on a big downshift when its above 65 mph and Id rather be in 3rd. Wrong VB or not what are some tweaks I can look at? My upshift on a 28" tire is 43 mph for 1-2 and 85 for 2-3 and Im very happy with these numbers and the car loves this setup at the track. Its just from a roll on the highway that it downshifts and usually falls on its face at the high mph downshifts.

What tires are you using? How are you getting the rpm/mph shift data? Id look into the knock thing and see if you can have it disabled for a sec or so at throttle transition if its false. My car is a bullet from an 80mph roll with a 3-2 kick down. That is why i use this vb so often in high boost applications where the engine has good heads and a cam.

 

[JDSfastGN]

What tires are you using? How are you getting the rpm/mph shift data? Id look into the knock thing and see if you can have it disabled for a sec or so at throttle transition if its false. My car is a bullet from an 80mph roll with a 3-2 kick down. That is why i use this vb so often in high boost applications where the engine has good heads and a cam.

315/35/17 nitto drag radials is my normal street setup when the problem occurs. The shift data came from my powerlogger 1/4 runs (i have the mph setup to match the trap so its pretty close) but those runs were on my 28" tall slicks. I may look into the chip/knock ignore and see if the car likes the downshift. I do have 3.23s so you would expect it to want it even more, although my mph for when it downshifts is just a guess. The speedo reads 70ish which is probably close to 75-77 mph.