After reviewing a lot of my EFI logs, it looks like my conveter is not close to the advertised shift extension it is supposed to have. The converter is a Yank SS3800, 2.55 STR. Car has 3.23 gears. Shift extension is supposed to be in the 4800-4900 range. My car is consistently in the 4150-4200 range. Any suggestions why it's 700rpm off? Thanks.

 

I would also like to know.

 

What are your shift points? Just curious.

 

Obviously not enough torque applied

Just like rated stall the extension depends on
how much slip you can make happen by the torque
it's up against at that RPM.

 

35th:
Wasn't there a thread where we started this discussion? Please find it and copy the relevant portions into this thread so it is all in one place.

 

Here is the info from a previous thread:
SS3600 Track Results

The shift extension is listed between 4900-5000. Using EFI Live, my peak rpm (before it drops) is between 5900-6050. It consistently drops to 4200-4300 depending on where the car shifts. After I installed a custom Predator tune, it showing higher shift extension, but below advertised. Here's the info:

From EFI Logs:
Shift 6052rpm drops to 4316rpm

Shift 6042rpm drops to 4264rpm

New Predator tune
Shift 6072rpm drops to 4525rpm
Shift 5981rpm drops to 4444rpm

Maybe with a better tune, the shift extension would improve. Still it's still 400-500rpms below what is listed for this converter. What's the best way to know what the shift extension is. I'm looking at the highest point the rpm reachs for shift rpm, and then the lowest rpm that is achieved after the rpms drop. Also, I tired adding the gear to the graph and it is way behind the rpm. For example, the graph shows the car in 3rd gear, while the rpms are still rising to redline (what I assume is still 2nd). Is that just the efi lagging with the data? I'm logging the default efi setings (about 15). Is this part of the problem. I saw that you logged only rpm and mph, to get more data points for stall info.


It's no longer on the Yank site. When the Yank SS line first came out, it was on there. On Tbyrne Motorsports' site, they have the orginial info from Yank's site in their converter section. It states that the SS3600 has a 4700-4800 shift extension and the SS3800 has a 4900-5000. It also shows the YPT4000 extension 5500-5600 range. It doesn't mention what mods, etc. Maybe I should be happy that I don't have any other issues. It just seemed that some of the other SS3600/3800's have a better shift extension than I do. I'll raise the shift points to 6200 and go from there. Thanks for all the info and help.

I recently changed my shift points to 6200 and now the shift extension is around 4700. Still seems a little low, but not sure what else I can do.

 

Your shift points were pretty low to start off with. My heavyweight Tahoe has 6000 rpm shift points...an F-body with mods should be higher. Keep raising your shift points until you ET starts to fall off. Check the Yank Website. The link to the SS converters is in the toolbar on the left.

 

I moved my shift points up to 6200 and will try that. I'm just afraid to keep raising the shift points with a stock valvetrain. With a 6200rpm shift point, the car should shift somewhere between 6200-6300. Which from what I've read is about as high as you want to shift with a stock valvetrain.

 

Just to add what had been previously mentioned...

Shift RPM has some influence on the extension becuase the output shaft speed is increased if you have higher shift points.

When I was full bolt-ons my ST 3500 shift extension was 4800 (6200 rpm shift). It was a looser design with a longer extension. The SS series is a tighter converter and will have a shorter extension. I would have expected a 4400 - 4600 shift extension from that converter on an '02 with headers, exhaust & Lid.

FWIW, You might try 6200 rpm shifts; with headers, LS6 intake, & exhaust you HP curve probably carries pretty well.

6200 is fine on a stock valve train. I know people who have used 6400, but I never used over 6300.