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-   -   Auto tranny shift points (https://www.homemadeturbo.com/general-discussion-6/auto-tranny-shift-points-3238/)

J-SMITH69 03-31-2003 03:47 PM

Re:Auto tranny shift points
 
my car does it, but i have a secondary butterfly in the tb that opens at 3k rpm, even at WOT

turboboy 03-31-2003 08:46 PM

Re:Auto tranny shift points
 
my non-vtec accord used to do it to...made a little nois like vtec too.....someone told me it was just a resonance in the intake or something. Dont be affraid to stay on the gas...if it shifts high its meant to do it, my accord used to shift at like 7k ( i hate autos)

88crxSi 04-01-2003 09:04 AM

Re:Auto tranny shift points
 

Originally Posted by phresh_5
Ok I know this is gonna sound stupid but if anyone else that has a auto civic can back me up on this. Some where in the range of 4500-5500RPM my NON-VTEC lunges forward. Its not huge but still noticable. Anybody else notice this?

lol, every car has that point, some are more noticable then other. its called the sweet spot of the cam. Thats where the cam "comes on" to its best power and efficency spot.
thats the idea behind the VTEC system, two sweet spots, one with the normal cam and one with the secondary ;)

turboboy 04-01-2003 11:26 AM

Re:Auto tranny shift points
 
the sweet spot with vtec is the switch between the two profiles

88crxSi 04-01-2003 11:34 AM

Re:Auto tranny shift points
 
no, each cam has its own vtec.

one picks up when the other starts to fall off.

vtec switchover is where the two tourqe lines cross. to tune a vtec engine you turn the vtec point to 8000, ,get as much power as u can with the low cam, then change it to 2000 and do the same with the high came then set the point at where the dyno lines cross.

turboboy 04-01-2003 11:43 AM

Re:Auto tranny shift points
 
this was always my understanding: yes each cam has its own vtec(intake and exhaust) but the changeover is when the rockers follow a different profile on that cam...but im most likely wrong, so be it

phresh_5 04-01-2003 02:00 PM

Re:Auto tranny shift points
 
Can't wait to do my swap, then I'll feel the real VTEC :)

ONIN 04-04-2003 09:43 AM

Re:Auto tranny shift points
 
I drive a 92 civic lx automatic tranny and I know the car and tranny like the back of my hand.

ok, this guy is 80% right:

"every automatic car i;ve driven shifts like this. when your easy on it, it shifts somewhere conservative like 3000, i guess its for fuel economy and engine longevity. but when u mash the pedal to the floor, it shifts at redline."

true, exceptfor it will shift a couple 100 rpms before redline.

2. that 4500-5500 rpm range is the car's sweet spot and that is why you feel and bit more power there.

I hold the gears down and shift at 7000 rpm (mind you, my chip has been modified to 8000 but i never go there) but prior to that, I've shifted at 6700 rpm going from 1 to 2 to d3 to d4 (if necesary) with relative ease...i've never slamed the brakes and revved to 3k at launch, i always thought that that might mess up the brakes or a few parts in the drivetrain. 2k i've done...

hope i've helped you in some way.

-chris


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