Topic: Shifting at what rpms?!?!?!?

[ur own shadow]

some of u guys are shifting at 4000 rpms? am i missreading something?
is it safe, cuz if it is, im all for it.
also, i was wondering how much thrttle body spacers or 4.0 throttlebodies really help acceleration?

[Jeffy]

It really depends on what you're doing and how your engine takes it.

The key is to keep the RPM's well into the powerband.  The stock engine lower edge of the powerband starts around 2700rpm and should feel fairly strong at 3000rpm.  When you shift the RPM's will drop.  Go up a hill and your RPM's will drop further.  To get the most out of your shifts you want to make sure the RPM's stay in the powerband when entering the next gear.  This means reving up higher then the lower edge of your powerband.  If you fall out of the powerband, you'll start losing power even faster.

With my Jeep, I've tuned it pretty well in the 3000-4600rpm range.  It will rev smoothly up to redline.  (Been there on a few occasions)  I'll let it rev up to >4000rpm so when I shift into the next gear it's at least 3300rpm while keeping the speed up.

Also, keep in mind you want parts that compliment each other.  Otherwise,  you could be bolting stuff on with no results.

[ur own shadow]

and this is a 4 cylinder we are talkin about, right?

[/dev/null]

Doesn't it also depend on whether it's a 2.5 or the 2.4? I would think the 2.4 would be happier in the upper RPM band. At least thats where I shift...  :wink:
I've only redlined it once and it didn't sound happy. 3k-4.5k, maybe a 'lil bit more is my usual highway shift points. Lower in the city.

Peter M

[ur own shadow]

well mine is a 2.5 and doesn't sound too happy at 3500 but i was wondering if it was safe?
btw i shift at around 3000

[Jeffy]

3500 is probable only half way through the power band.  If you shift at 3000rpm, then when you're in the next gear, you're well below the powerband.  If you're on a hill you'll probably have to downshift again.  Unless there is something wrong with the engine you should be able to rev higher.  Keep in mind redline is at 5400rpm.  So as long as you stay below redline you should be ok.  You probably don't want to be racing the engine ALL the time but sometimes it's necessary.

[chardrc]

i usually shift around 3k with my 2.5 if i really want to go i shift at around 3500 but after doing that it starts to smell like oil :roll: ... so needless to say i don't go that high often..


ow ya and my jeep likes to backfire sometimes if i push it also... :oops:  :roll:

[Krod]

Around town I shift around 2700 (right at the bottom of the powerband)

Going up hills, merging on the highway, or trying to move quick I shift around 3600/3800 rpms.  

If I'm correct, I think the motors torque band peaks out around 3200 rpms.  I try to keep the revs near that mark when I need to get moving.  


On certain trails and emergency manuvers (around crazy semi-drivers)  I've had it to 4500 with no problem.  It reved right up and back without a hiccup.

[Jeffy]

Around town I shift around 2700 (right at the bottom of the powerband)

Going up hills, merging on the highway, or trying to move quick I shift around 3600/3800 rpms.  

If I'm correct, I think the motors torque band peaks out around 3200 rpms.  I try to keep the revs near that mark when I need to get moving.  


On certain trails and emergency manuvers (around crazy semi-drivers)  I've had it to 4500 with no problem.  It reved right up and back without a hiccup.

Torque comes up early in the 3K range.  HP is much higher though.

[jagular7]

I've got a 3-sp auto with the 2.5L. It shifts way too early and won't downshift when I floor it. I usually have to manually shift into 2nd gear to get the powerband of power to be able to accelerate up a hill, pass someone on the road, etc.

In watching the tach at full throttle, the auto shifts near 3500rpms and drops to ~2800rpm. Part throttle, it shifts just over 3k into under 2500 resulting in no acceleration. Since adding the tbi spacer, it slows shifts with a little stall from 1st to 2nd.

Ive got 34's, 4.88 to compensate and tbi spacer.

[justin_aka_spike]

i shift at 4500 somtimes, and if im pushin real hard i do 5000,