what's a good shift point?

[street6]

I recently finished installing my new set up (see in sig) and I have been trying to get a rough base line tune before I go to the track. After reviewing a few powerlogger runs I noticed my WOT 1-2 shifts are between 5000-5125 rpms and the WOT 2-3 shifts are between 4900-4950 rpms while running in drive allowing the trans to shift on it's own (shifts are nice and firm but not too harsh).

My Pats Performance 9.5 n/lu converter has an advertised stall of 3000 and with my T-netics TE60 I only get to about 2600 rpms @ 0 boost. However I can build about 8-9#'s boost at the line foot braking it to 3000 rpms (at the track I was gonna try launching w/ 5-6#'s on drag radials).

My 205/222 roller cam has a 108* lobe separation with -4* of overlap. Motor has a healthy lift with 1.65 rollers and has race ported irons.

After seeing the shift points I checked my TV cable and noticed 5-6 notches showing (toward the firewall) so I'm a little hesitant on adjusting for more notches (to make the shifts later and firmer).

What would be a good shift point for my set up? If I would benefit from later shifts should I just manually shift it at the track? Or is the car shifting early b/c my converter is tight and all is ok? The car feels to run fairly strong and all I'm looking for is 11.50's to 11.80's (no cage).

Thanks in advance for any advice......

 

[JP112_89]

My $.02

I do not want to post any bad info so.... IMO, it would HELP if you had your governor modified. Especially with that big cam. I THINK the TV cable will actually adjust itself if I am not mistaken.


Mine shifted WAY too early for me when I put in the 210/210 roller and higher stall converter. Seemed once the car started pulling good, it shifted. WTF


I had my governor modded and she works much better. I think 5800rpm minimum that cam. IMO, I would go 6000-6200rpm for maximum performance. You will probably have to shift out MANUALLY. ** Because, I do not think just a governor mod will get you there.


* I did not like the idea of trying to shift manually. * SO MANY other things I HAVE TO WATCH.... So didn't want to fu ck up and over rev. I wanted it the shift out automatically.:cool

I am ready to get reamed for this post.haha

 

[street6]

Thanks for the input. I will first make a few manual shift runs up to about 5500-5600 and see how she feels. If all is good I'll go up from there.

I really don't like the idea of manually shifting either. If I decide to have the governor modified how do I know how much weight needs to be removed to get me to the desired rpm range? Is there a starting point?

 

[SSedan64]

Governor Mods

Some Info here on modifying the Gov. I think it's 150-200rpm per 1gram removed from small weight. Do a search to be sure.
http://www.turbobuick.com/forums/tr...r-higher-shift-points.html?highlight=governor

 

[bison]

I recently finished installing my new set up (see in sig) and I have been trying to get a rough base line tune before I go to the track. After reviewing a few powerlogger runs I noticed my WOT 1-2 shifts are between 5000-5125 rpms and the WOT 2-3 shifts are between 4900-4950 rpms while running in drive allowing the trans to shift on it's own (shifts are nice and firm but not too harsh).

My Pats Performance 9.5 n/lu converter has an advertised stall of 3000 and with my T-netics TE60 I only get to about 2600 rpms @ 0 boost. However I can build about 8-9#'s boost at the line foot braking it to 3000 rpms (at the track I was gonna try launching w/ 5-6#'s on drag radials).

My 205/222 roller cam has a 108* lobe separation with -4* of overlap. Motor has a healthy lift with 1.65 rollers and has race ported irons.

After seeing the shift points I checked my TV cable and noticed 5-6 notches showing (toward the firewall) so I'm a little hesitant on adjusting for more notches (to make the shifts later and firmer).

What would be a good shift point for my set up? If I would benefit from later shifts should I just manually shift it at the track? Or is the car shifting early b/c my converter is tight and all is ok? The car feels to run fairly strong and all I'm looking for is 11.50's to 11.80's (no cage).

Thanks in advance for any advice......

Post the numbers on your cam card. Your overlap is assuredly more than 4*. Soundsd like an oddball profile. Doesnt look very friendly for streetable cars either. Too much overlap and it will be aggravated by the extra exhasut duration. If you have stock heads id be shifting around 5400at 25psi. Maybe a little sooner with less boost. With a good valve job and bowl clean up then id go to 5600. Your TV should be at the setting that gives max TV the earliest. So set it tight.

 

[street6]

Roller 205/222 cam (specs from build sheet)

intake opens BTDC -2* (ATDC is -)
intake closes ABDC 27*

exh opens BBDC 42*
exh closes ATDC -2* (BTDC is -)

lobe separation 108*
degree intake lobe 104*

cam lift @ .050" intake 323
exh 345


Using a camshaft calculator (Wallaceracing.com) I entered the above cam specs and was given this info:

Your camshaft has an overlap of -4* (negative four degrees) with an intake duration of 205* and an exhaust duration of 220*.
The inlet cam has an installed centerline of 104.5* ATDC
The exhaust cam has an installed centerline of 112* BTDC


You said to set the TV cable tight. Does this mean more clicks toward the firewall? I'm currently showing 5-6 clicks toward the firewall. I read under gnttype.com that the average factory setting was approximately 4 clicks toward the firewall and that the more clicks toward the firewall gives later and firmer shift.

I was looking to run 23-25 #'s of boost w/ alky and the car has ESP Performance race ported irons w/ the larger valves and 1.65 roller rockers.

 

[street6]

Back from the track.....a long night and only got 2 runs in.

I made an attempt to manually shift (2nd run) using my laptop (powerlogger tach).....and no good, too many things to keep an eye on all at once. I guess I will have to have the tranny governor modified.

After reviewing the first run (22-23 psi w/ 21* timing 1st/2nd and 19* timing 3rd) which was in "DRIVE" it looks as though it shifted into 2nd @ 5050 rpms (approximately 28 mph) and the rpms only fell back to about 4650 on the shift. Then throughout the entire run the tach just staggers back and forth between 4700 and 4850 rpms (even during the 2/3 shift) while the mph climbs. Is this the point where the converter is coupling but not getting to it's designed rpm range? And if I have the governor modified for say 5600 shifts will it still drop back to about 4650 on shifts or will this rpm figure rise as well? Will there much to gain from the additional 500-600 rpm shift?

I left the track a little disappointed with a best of only 12.1 @ 110 mph however I did get out of it around 1000 ft. (false knock on the shift). 1/8th mile speed was 90 mph.

Thanks for the help guys........I'm SLOOOWLY learing and tuning.