Rpm vs mph
11-22-04, 11:46 PM
#6
Aoohh!!!
Thread Starter
Join Date: Jul 2001
Location: Pacific Beach, CA
Posts: 542
Likes: 0
Received 0 Likes
on
0 Posts
Alright, I just got the car. Im gonna most likely to pull the rear end out and check it out. It may
be a bigger gear or just out of wacked! Its also a little nosier that it should be. But thankz
for the quick replys guys! Muchly Appreciated!
JP
be a bigger gear or just out of wacked! Its also a little nosier that it should be. But thankz
for the quick replys guys! Muchly Appreciated!
JP
Last edited by RX-Racer; 11-22-04 at 11:49 PM.
11-22-04, 11:50 PM
#7
"By the beard of Zeus!"
Join Date: Mar 2001
Location: Huntsville, Alabama / Atlanta, Georgia
Posts: 867
Likes: 0
Received 0 Likes
on
0 Posts
WOT has nothing to do with speed at a certain RPM. It's fixed based on your gear ratios and RPM. Anyway, those RPMs seem low to me...
FS
FS
Trending Topics
11-23-04, 01:02 PM
#10
Senior Member
Join Date: Feb 2004
Location: East Tenn (Tri-Cities Area)
Posts: 352
Likes: 0
Received 0 Likes
on
0 Posts
I believe the GSL-SE (and rare GTU or whatevers) have 4:10 rear ends. The rest of us have 3:90. The noise is more that likely a bearing. I have a noise too. It's been going on over a year now and never got worse so I never bothered to fix it yet.
Wouldn't think it's rear end problem with the rpm-mph situation. Most likely, if you car is not running the right rpm's for mph, then it's a power issue with the motor.
All I can say about mine is that I can do this around 6-7k (before redline), never really payed that close attention but have been meaning to chart it all down...
1st-30(mph)
2nd-60
3rd-70
4th-90
5th-120?
Wouldn't think it's rear end problem with the rpm-mph situation. Most likely, if you car is not running the right rpm's for mph, then it's a power issue with the motor.
All I can say about mine is that I can do this around 6-7k (before redline), never really payed that close attention but have been meaning to chart it all down...
1st-30(mph)
2nd-60
3rd-70
4th-90
5th-120?
11-23-04, 02:23 PM
#14
Senior Member
iTrader: (4)
Join Date: Apr 2004
Location: Dorr, Michigan
Posts: 393
Likes: 0
Received 0 Likes
on
0 Posts
This relationship will not be effected at all by how well the car is running (except if there is clutch slipage) or where the throttle is.
If the car is at higher revs for a given speed than is should be there are really on two possibilities.
1. extreme clutch slipage. You would notice this problem at other times than just cruising so I doubt that is it.
2. your gear ratio isn't what it was from the factory. This could be that you have different size (shorter in this case) tires or a different rear end gear ratio. These would cause you speedo to read too high.
It isn't very hard to figure out what it should be given a certain ratio and tire size.
If the car is at higher revs for a given speed than is should be there are really on two possibilities.
1. extreme clutch slipage. You would notice this problem at other times than just cruising so I doubt that is it.
2. your gear ratio isn't what it was from the factory. This could be that you have different size (shorter in this case) tires or a different rear end gear ratio. These would cause you speedo to read too high.
It isn't very hard to figure out what it should be given a certain ratio and tire size.
11-23-04, 05:20 PM
#15
Originally Posted by RotaryAXer
This relationship will not be effected at all by how well the car is running (except if there is clutch slipage) or where the throttle is.
If the car is at higher revs for a given speed than is should be there are really on two possibilities.
1. extreme clutch slipage. You would notice this problem at other times than just cruising so I doubt that is it.
2. your gear ratio isn't what it was from the factory. This could be that you have different size (shorter in this case) tires or a different rear end gear ratio. These would cause you speedo to read too high.
It isn't very hard to figure out what it should be given a certain ratio and tire size.
If the car is at higher revs for a given speed than is should be there are really on two possibilities.
1. extreme clutch slipage. You would notice this problem at other times than just cruising so I doubt that is it.
2. your gear ratio isn't what it was from the factory. This could be that you have different size (shorter in this case) tires or a different rear end gear ratio. These would cause you speedo to read too high.
It isn't very hard to figure out what it should be given a certain ratio and tire size.
11-23-04, 06:55 PM
#16
How About A Cup Of STFU
Join Date: Sep 2004
Location: ALBANY, GA
Posts: 1,552
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by 1stgen_tn
Wouldn't think it's rear end problem with the rpm-mph situation. Most likely, if you car is not running the right rpm's for mph, then it's a power issue with the motor.
1st-30(mph)
2nd-60
3rd-70
4th-90
5th-120?
You must have a shitty 3rd gear if you only get another 10 mph out of it. Maybe every other tooth is missing or something !?!
11-23-04, 08:19 PM
#17
PIMP
Join Date: Feb 2004
Location: Greensboro, NC
Posts: 1,012
Likes: 0
Received 0 Likes
on
0 Posts
yea my 3rd is good for like 90 and well over 100 in 4th,
anyway my 85 GS does 4k rpms at 70 mph. How much speed is 5700 rpms?
Didn't Road & Track say the stock 12a 1st gen goes 122 mph in 4th and 5th gears.
Also how big is the difference in 175/70/R13 and the factory 185/70/R13. I have 175's so maybe that's why my rpms seem higher than all of you.
anyway my 85 GS does 4k rpms at 70 mph. How much speed is 5700 rpms?
Didn't Road & Track say the stock 12a 1st gen goes 122 mph in 4th and 5th gears.
Also how big is the difference in 175/70/R13 and the factory 185/70/R13. I have 175's so maybe that's why my rpms seem higher than all of you.
11-24-04, 06:42 AM
#18
Drifting Is Fun
Join Date: Aug 2004
Location: Houston,Tx
Posts: 142
Likes: 0
Received 0 Likes
on
0 Posts
Uh I shift at 8k I think I pull about 4k at 70mph not exactly sure though. I know at the track my trap speed was 88.9 and I was pulling a few hundred shy of 8k and getting on the freewy is a 3rd gear affair I go straight the fast lane and pull 90mph before I go straight to 5th from 3rd lol.
11-24-04, 12:16 PM
#19
Damnedknowitall
Join Date: Jul 2002
Location: Under the hood...
Posts: 154
Likes: 0
Received 0 Likes
on
0 Posts
if you are running 175 tires, your speedo is 6% off, however unless someone changed out your speedo gear in the tranny, your car can't tell the difference. I vote for clutch slippage if there is anything wrong at all.
11-24-04, 12:39 PM
#20
Senior Member
Join Date: Feb 2004
Location: East Tenn (Tri-Cities Area)
Posts: 352
Likes: 0
Received 0 Likes
on
0 Posts
I was simply going from memory. It's been awhile since I've drove it but I will make a point to take it out this weekend and write down what I get at 7k rpm.
The reason I said something might be wrong with the power of the engine is b/c I was assuming that if you were low on compression, the motor would have to work harder (highter rpms) to reach the same speed as a motor in A+ shape. Maybe that's an incorrect assumption, but it made since to me.
The reason I said something might be wrong with the power of the engine is b/c I was assuming that if you were low on compression, the motor would have to work harder (highter rpms) to reach the same speed as a motor in A+ shape. Maybe that's an incorrect assumption, but it made since to me.
11-24-04, 02:51 PM
#21
SA all the Way!
Originally Posted by 1stgen_tn
I was simply going from memory. It's been awhile since I've drove it but I will make a point to take it out this weekend and write down what I get at 7k rpm.
The reason I said something might be wrong with the power of the engine is b/c I was assuming that if you were low on compression, the motor would have to work harder (highter rpms) to reach the same speed as a motor in A+ shape. Maybe that's an incorrect assumption, but it made since to me.
The reason I said something might be wrong with the power of the engine is b/c I was assuming that if you were low on compression, the motor would have to work harder (highter rpms) to reach the same speed as a motor in A+ shape. Maybe that's an incorrect assumption, but it made since to me.
with a manual transmission car, the speed the motor spins is ALWAYS a direct relation to speed depending on gear (and assuming no clutch slippage), for the motor to be turning higher rpms because it wasnt making enough power, he would simply have to be going faster, or have to downshift to 4th to bring the revs up to make more power.
11-24-04, 03:14 PM
#22
Senior Member
Join Date: Feb 2004
Location: East Tenn (Tri-Cities Area)
Posts: 352
Likes: 0
Received 0 Likes
on
0 Posts
Alright now, the more I think about it make sense to me know.
I guess I was just being stupid as to how it all comes together.
The motor is connected to the transmission (with clutch assembly) which would be doing the EXACT same rpms as the engine (common sense) Now, with the gears in the tranny, the rpms are reduced from the rpms of the motor through the reduction gear (1st, 2nd, 3rd, 4th, or 5th-all different ratios) then, whatever THAT rpm turns out to be is what the driveshaft is going to spin at which is then connected to the diff which is reduced by gears and then goes to the wheels. I wasn't looking at it this way before......
Guess that's why you don't wanna accidently go from doing 100mph in 5th and put it in like 1st or 2nd. The rpms would immediately go to like >10,000rpm eh? ...and your foot not even on the gas.
I guess I was just being stupid as to how it all comes together.
The motor is connected to the transmission (with clutch assembly) which would be doing the EXACT same rpms as the engine (common sense) Now, with the gears in the tranny, the rpms are reduced from the rpms of the motor through the reduction gear (1st, 2nd, 3rd, 4th, or 5th-all different ratios) then, whatever THAT rpm turns out to be is what the driveshaft is going to spin at which is then connected to the diff which is reduced by gears and then goes to the wheels. I wasn't looking at it this way before......
Guess that's why you don't wanna accidently go from doing 100mph in 5th and put it in like 1st or 2nd. The rpms would immediately go to like >10,000rpm eh? ...and your foot not even on the gas.
11-24-04, 03:31 PM
#23
Senior Member
Join Date: Sep 2002
Location: SC
Posts: 325
Likes: 0
Received 0 Likes
on
0 Posts
i didnt' feel like reading all of it, but here is my 2 cents.
the rpms seem kind of high for that mph.
i have the 85 12a tranny (which has higher gear ratio (5th)than the se tranny) and the se rear (4.09), maybe my speedo is off,
im thinking your speedo needs recalibrating. or you have the same setup as me and im wrong.
carl.
the rpms seem kind of high for that mph.
i have the 85 12a tranny (which has higher gear ratio (5th)than the se tranny) and the se rear (4.09), maybe my speedo is off,
im thinking your speedo needs recalibrating. or you have the same setup as me and im wrong.
carl.
11-26-04, 10:42 PM
#24
Senior Member
Join Date: Feb 2004
Location: East Tenn (Tri-Cities Area)
Posts: 352
Likes: 0
Received 0 Likes
on
0 Posts
Maybe one of these days I will learn to just keep my mouth shut on here and let one of you guys do the advise giving...
To correct my previous statement, I took my seven out the day before Thanksgiving and made a point to watch my tach while driving it. Never got a chance to go faster than 80 where I was driving but here is what I got:
(All @ 7k rpm in a stock drive-train 83 GSL)
1st.....30mph
2nd....50mph
3rd.....80mph
4th.....100mph(close estimate)
5th......120mph(again, should be a close estimate)
Selfishly, I didn't think to check what rpms @ 60 and 70 were in 5th. If no one else posts it, I will next time I take the seven out.
To correct my previous statement, I took my seven out the day before Thanksgiving and made a point to watch my tach while driving it. Never got a chance to go faster than 80 where I was driving but here is what I got:
(All @ 7k rpm in a stock drive-train 83 GSL)
1st.....30mph
2nd....50mph
3rd.....80mph
4th.....100mph(close estimate)
5th......120mph(again, should be a close estimate)
Selfishly, I didn't think to check what rpms @ 60 and 70 were in 5th. If no one else posts it, I will next time I take the seven out.
Last edited by 1stgen_tn; 11-26-04 at 10:44 PM.
Thread
Thread Starter
Forum
Replies
Last Post
LongDuck
1st Generation Specific (1979-1985)
12
10-07-15 08:12 PM
eplusz
General Rotary Tech Support
15
10-07-15 04:04 PM
