What RPM at 70MPH?
11-20-2010, 08:29 AM
#1
What RPM at 70MPH?
I am doing a swap into a beetle and trying to get highway speeds close to that of the stock RX8.
So my question is: What RPM will a 2004 6-port 6-speed Manual be at when going 70 MPH?
Here's the link to my build if you missed it:
https://www.rx8club.com/rx-8-multimedia-photo-gallery-6/reincarnated-rx8-193949/
Thanks,
Josh
So my question is: What RPM will a 2004 6-port 6-speed Manual be at when going 70 MPH?
Here's the link to my build if you missed it:
https://www.rx8club.com/rx-8-multimedia-photo-gallery-6/reincarnated-rx8-193949/
Thanks,
Josh
11-20-2010, 08:36 AM
#2
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3,500RPM . Plus or minus the error rate that is present.
The 6th gear is basically 500rpm per 10mph. 3rd gear is 1,000rpm per 10mph.
Of course, this is assuming that the final drive is 4.444 and the "gearing" created by the tires size is on 18inch rims with 40 sidewalls. Change either of these, and you will have to change the other to keep the effective final drive the same.
This is a much self-debated question on my plans with the Miata swap, and if I should attempt to have the same rpm/speed as an 8. The tires won't ever have the same diameter, so the rear end would have to change to bring it to match, but "do I really want to do that?" Should I get even more acceleration out of it? Should I give up some of that acceleration for low RPM cruising? etc...
Edit:
Since people have differing opinions below....
Caviate #1: There is an error rate present in the tach needle's interpretation of the analog signal from the ECU, generally the needle running high.
Caviate #2: The 500rpm per 10mph is the approximate number for the series 1 transmission and series 1 final drive of 4.444. This number changes with the Series 2 transmission, which has taller gears 1st through 5th, a shorter 6th, and a taller final drive (4.777).
The 6th gear is basically 500rpm per 10mph. 3rd gear is 1,000rpm per 10mph.
Of course, this is assuming that the final drive is 4.444 and the "gearing" created by the tires size is on 18inch rims with 40 sidewalls. Change either of these, and you will have to change the other to keep the effective final drive the same.
This is a much self-debated question on my plans with the Miata swap, and if I should attempt to have the same rpm/speed as an 8. The tires won't ever have the same diameter, so the rear end would have to change to bring it to match, but "do I really want to do that?" Should I get even more acceleration out of it? Should I give up some of that acceleration for low RPM cruising? etc...
Edit:
Since people have differing opinions below....
Caviate #1: There is an error rate present in the tach needle's interpretation of the analog signal from the ECU, generally the needle running high.
Caviate #2: The 500rpm per 10mph is the approximate number for the series 1 transmission and series 1 final drive of 4.444. This number changes with the Series 2 transmission, which has taller gears 1st through 5th, a shorter 6th, and a taller final drive (4.777).
Last edited by RIWWP; 11-20-2010 at 07:23 PM.
11-22-2010, 02:57 AM
#11
Registered
For the 6-speed automatic, 3000 RPM = almost 90 mph ( about 30 mph per 1000 rpm )
Last edited by PeteInLongBeach; 11-22-2010 at 04:08 AM.
11-22-2010, 02:09 PM
#13
2009 RX-8 Touring
Wait. Is this a new Beetle or an old Beetle? You gotta be crazy to put this engine in a new Beetle; new VW chassis have so many parts that are designed to wear out on a regular basis, it really isn't funny.
11-23-2010, 10:09 PM
#22
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