Rpm's and Shifting
 

Hello all,

Mustang newbee here.

I have a 99 cobra and I'm just wondering what's a good Rpm's to do my shifting. This car seems to want to be around 3000rpm's for shifting. Since I'm fresh from the 4 cylinder farm I'm not sure if I should be between 3000- 4000 (I thought I read 4000 to get full torque). I just don't want to over rev the engine and mess up my Trainline/POS traction.

Thanks in advance!

over revving won't hurt your tranny or your posi, it will frag a valvetrain and sometimes a bottom end.

99 cobra redlines at what 6800rpm... shift there if you want to. It'll be loud but it's totally fine. For drag racing, you'll want to shift pretty high in the range so you stay in the part of the power band where 4V motors make max power (>4500rpm).

I drive a 2V and I shift at 5K when I'm getting on it and 2500 when I'm cruising around like a grandma.

So, to sum up... you have a redline. Use it. Anything under that redline is just fine. Don't cruise at 5000rpm, that's just dumb. With a V8 you should cruise at as low an engine speed as you can without bogging... because you have enough torque to move the car if you feel the need without downshifting. So for me, I can go anywhere from 10mph to 60mph in 2nd gear but I shift into 3rd if I'm cruising above 30 and 4th if I'm cruising above 40. All of which keep me at about 2000rpm for cruising and as high as I can go for hard chargin'.

Yea I have a similar engine in my 04 Mach 1, somewhere around 4500 is the torque peak, that's where it pulls the hardest. So if you are racing you want to shift into second whereever about 4000rpms is, so you need to rev to about 6500.

good advice man :punk: that is what i do when just cruising :pepper:

you have just about said everything i woulda said except that i mean i kno this is just a different way of doing things but my theory is get the car into 5th gear as soon as possible or at least 4th if im going real slow...with 3$ a gallon gas prices i wanna save some fuel so if im doing 25-30 thats 4th gear but if im 30 or higher im throwin the beast into 5th and cruising around at like 1200 rpm or less somtimes...the car will keep itself going (like yousaid with the torque and stuff) i never keep it lower than idle speed but just a tad above it...i dunno just my way but your way is the way the cars prolly meant to be driven lol

no...you're technicallly correct. Stick shift means lower speed = lower RPM. In theory lower RPM will use less gas at a given speed than a higher RPM. The only time that's not true is when the engine is being overtaxed (bogged). Using 5th gear to do 40 on a flat road or downhill is super smart. Using 5th to do the same thing on rolling hills or really hot days or just going up hill, etc.. anything where you have to more than just nudge the pedal to keep it at speed is going to make matters a little worse.

Basically, use the gear that allows you to use the least throttle and the least RPM without losing its ability to get out of its own way.

The Ford Mustang Manual tells us for best gas mileage to shift into 2nd at 11mph and so on. It keeps going with that all the way to shifting to 5th at 50. It's intent seems to be to keep you under 2000rpm.

Anyone who's played with their mustangs throttle a bit knows that right at about 2000rpm or so the motor really starts to pick up the power generation significantly. Most of us are fully aware that to make a given amount of horsepower you have to burn a particular amount of fuel, as the two are directly related. So, if you stay under 2k RPM you'll burn dramatically less fuel than if you stay at 2200-2500.

This is where gears show their downside. The upshot is that most of us are indeed concerned about gas prices but we're not likely to be chased entirely off of the accelerator pedal because of it. We as a group (performance car drivers) generally know and accept that to get our jollies from driving, we'll have to pony up to the Shell station and pay the price in fuel cost. It's not that we don't care about fuel costs, just that we don't let it run our lives or our hobbies.

For those trying to improve gas mileage, don't get your hopes up too much. In 5 years of modularr V8 mustang driving I've always gotten about 17mpg average. Sure, I'll see 25 on the freeway and 8 in town but it all evens out.