View Full Version : engine rpm
04-17-2016, 01:37 PM
At what rpm does the cruise O matic shift out of 2nd, I was going 70 mph and the tach was at 2000 rpm but the car seems like there should be another gear not sure if the car went into 3rd ( drive ) I definitely feel 1st to 2nd and manually shifted to low and shifted up to drive and the car changed gear.......I have a new detent plate and lever installed.......also need to adjust the kick down linkage when I floor the car there is no kick down and the carb linkage needs adjusted the 4 bbl will not kick in
04-17-2016, 02:08 PM
You should be in 3rd gear way before 70 mph. I would make sure the vacuum modulator is working correctly.
04-17-2016, 02:34 PM
...I was going 70 mph and the tach was at 2000 rpm but the car seems like there should be another gear not sure if the car went into 3rd ( drive ) ...What RPM would you think the engine should be at, doing 70? 1,500? Most cars are over 3,000 RPM at that speed in top gear.
Not only were you in high gear but you have a tall rear end gear ratio. According to your numbers, your car is capable of 150 MPH (with RPMs to spare for more). - Dave
04-17-2016, 04:11 PM
At 70 mph with 225/70R15 tires and a 3.00:1 differential ration, my engine is churning at just under 2600 RPM.
Here's a good calculator for this: http://www.andysautosport.com/learning_center/calculators/#GearRatio
04-17-2016, 05:54 PM
Steve, he has you beat. "I was going 70 mph and the tach was at 2000 rpm."
If you have 15" tires, he must have 16" tires and if you have 3:1 RE, his is even taller.
His concern is, he is not sure if the car went into 3rd and I think you just proved that it certainly did. - Dave
04-18-2016, 05:40 AM
Actually running 18'' but they are the same height as the original 15" must be a weak shift from 2nd to 3rd this is the first automatic car that I have driven in years and with the Magna Flow mufflers its got a rumble compared to the Focus ( daily driver ), thanks for the info guys
04-18-2016, 09:01 AM
John I have a pair of 14" long x 9" wide Magnaflow mufflers (bought used) mounted ahead of the axle and the drone at highway speed was deafening. I recently added a pair of Flowmaster Hushpower mufflers (19" long x 6" wide) at the tail ends of the system (sides of the trunk) and it is much better.
I'd still like it quieter though. :(
04-19-2016, 04:33 AM
thanks for the muffler info.....will change mufflers sometime soon. more to worry about at the moment........I know all about the drone once installed a cat-back system on a Vette the drone was so bad the windows had to be down to ride in it....all the work just to change back to original...
04-19-2016, 08:08 AM
...all the work just to change back to original...I know, right? It's almost like the engineers who built these things knew what they were doing....
04-28-2016, 03:27 PM
Been driving the Bird around.....1-2 shift is no problem the shift from 2-3 is not happening till 55 mph, down shift is no problem, shift modulator bad I'm guessing any thoughts
04-28-2016, 07:07 PM
Change that because they are inexpensive. I don't see where you've changed the fluid and cleaned the filter. Also check that your shift down linkage is set properly. Lastly, try an additive.
04-28-2016, 08:03 PM
If it's not the modulator or vacuum to the modulator then drain the fluid and clean the filter as suggested. Also make sure you use Type F transmission fluid. Do not mix Type F and modern fluids.
04-29-2016, 03:40 PM
Got the car on a lift today, and found a small amount of fluid at the hose connected to the shift modulator, did not see that with the car on jack stands, will replace modulator and hose inexpensive as stated , fluid and filter was changed less than 500 miles.
07-17-2016, 08:36 AM
Finally had time to change the modulator........there was no pin when I removed the old modulator anyone have a source to get a new one......if it ain't one thing it's another
07-17-2016, 10:45 AM
Luck shined on me today a buddy had a few pins, installed new modulator and adjusted carb and shift linkage I now have a T Bird shifting as it should no more driving around in 2nd gear at over 50mph......now on to the hard brake pedal ( booster )
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