how come shift points dont happen when they are cammanded ? for example 3-4 shift cammand is 3750 rpm ... wich from logs happens at 62 mph .... cammand mph had to be lowered to 56 mph to make that shift happen and when it did it was slow and kinda drawn out , same with the 4-5 . all of them dont really match but the others are very sharp crip shifts ? wonder if i am doing something wrong ?
Shift points ?
- Thread starter TrentNell
- Start date
on my datalogs it's always appeared that both rpm and mph have to be met before it will shift. So I started just working with the rpm mostly, as that's the critical part to me.
On my truck 3453 rpm in third is 54 mph. To reach 3750 rpm that's a 6% increase, and the mph would only be 57 or so. So it appears that if you had it set at 62 mph then it would not be shifting until beyond 3750 rpm.
Of course tire size has everything to do with it, but since you said to shift at 3750 you had to put 56 mph in, it seems we're real close to the same overall diameter on mine (I have 265/60-17's).
On my 3-4 wot upshift I left the mph at 46 (which I believe was stock), but moved the shift rpm to 3425 rpm (old single turbo tune). It would hit a max of 3453 rpms or so by the time it made the shift, so very close.
I would try lowering the mph and setting the rpms maybe 50 below the max you want it to hit (to allow for shift time), and see how it works. The above numbers assume your converter is locked also.
Jody
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thanks for the advice i wil try a few of those things . the converter should be locked for the 3-4 shift but i need to log to verify . the key thing i have noticed is it will shift of rpm but mph seems to over ride the rpm , and same the other way , and also it seems that the fuel will reference them also... so if they are not close it seems to cut fuel and though it will shift its slowwww ,wich meens they need to be perfect for good shifts . i never had this issue till i crossed 3600 rpm . any other tips ?
another side note i have heard rumor that there is a speed limmiter in the 3-4 table that keeps it from revving higher . i hit it when cammanding at 62 mph anyone else ? .
that's another thing i have been curious about ... my tire hieght is claimed to be 30.5 " , isnt that the same as stock 245's ?
thats a good bit of imformation . that could be part of the mph descrepency .
i will have to play with the tire size to see if i can even it up . it would make it much easier to tune .
This is why I have been running a Neens tranny tune since 06. I have yet to figure out tranny stuff
i have no idea where to even start with tranny tunning. i have a tranny tune in know and i have the shift points raised along with the mph but have no idea weather they are set right in relation to each other. how do you figure this out.
as i stated i have never had a problem till i decided to rev her up a bit . the 3-4 is looking like it cant go higher then i am at ( 3750 ) . due to a table limmit in my hp tuners , not shure on the 4-5 , the 1-2 and 2-3 seem to really like 3900 rpm . EFI live will be in route maybe this week .
also i was just looking at the tranny tune. i noticed that for shift pattern b which is 4 lo. and the mph matches the rest of the shift patterns shouldnt it be lower since it will not be going that fast while hooked to the sled
huh i would have thought that sonce you would never actually go that fast in 4lo that you would have to adjust for the lower gearing
Sadly it would takes some trips down the track . also a time slip will tell you alot ... if you are running a fast et and slow mph , it shows your getting the most out of the power you have .slow et high mph shoes there is room for improvment .
Use the tire runout method instead of tire height or advertised height and your speedo will be correct. With my tranny tuning the different table cross reference. Wot shifting is referenced by rpm table. There are other changes that need to be changed to allow these tables to work properly.
adjust RP by a %, just keep bumping it up a % until you get the RPM you want, then adjust the speed (mph) by that %.