I realize that people are raising the shift rpm to stay higher in the powerband, so I have a question...

Raising the boost AND the point at which the engine shifts puts the blower off the scale in terms of RPMs the rotors are turning as well as the delta T.

Has anyone considered lowering the shift point to say 5000 and cranking the boost a little more? In looking at a lot of the dyno charts on this forum, it seems like an awful lot of trucks peak somewhere around 4900-5100. I realize you go past that point to try to shift into or as close to the peak as possible, but how much is gained in shifting into a higher part of the curve vs. continuing to rev into a lower part of the curve?

What would be the result? How bad would you drop out of the powerband if you did this?

and maybe not toss a rod in the process...

Thanks

Ken

 

Thats exactly what I did. Lowered my shift points to 5200 on my street program

 

I have a post somewhere on here and showed that regardless, it's not relative and that you'll run faster times if you shift upwards of 5400 and no more than 5600. FWIW, I recommend no more than 5500. I'll find the post in a few.

 

Here it is:

https://www.f150online.com/forums/sh...threadid=34302

 

Thanks BFB

I guess you answered my question...

Mainly I was wondering if I could lower the shift point a couple of hundred w/o losing too much HP. This would take the worry out of boosting more as far as I am concerned...

did you every get a full breakdown of shift points for 1-2, 2-3, 3-od for the L engine? Given any rear end, we can calculate the numbers for the others and see where that falls on a dyno chart... just for grins


Thanks again

Ken

 

ken800 - I'll let you know in a few weeks. I'm getting to custom programs, one will be for auto-x/road course and that will have all shift points at 5000rpm, the other will basic street program with 5400rpm shift point.