Mazda MX-6 Forum banner
1 - 20 of 33 Posts

·
Registered
Joined
·
69 Posts
Discussion Starter · #1 ·
i would really like to know what the fifth gear is good till on an 88mx6gt i recently topped the car out on the highway and didnt
know how fast i was going because of a broken speedo cable.
anyone that knows this please give some info.....thanks:D
 

·
Registered
Joined
·
2,815 Posts
PeterD said:
It depends on rolling diameter of your wheels...

But at a guess, around 150mph...

Pete
That seems a little far from reality IMO unless you were running 20's or more which we all know would be next to impossible to fit or maybe if you get a gail force hurricane helping you out from the back then that may be realistic. I would think more around 130-140mph tops on an accurate speedo. Keep in mind my words here that that seems unrealistic if you have an accurate speedo.
 

·
Registered
Joined
·
111 Posts
I hit 128ish at just over 5000. figure from there
 

·
Registered
Joined
·
711 Posts
I was poking 140 at around 5200 in 205/55r15's.
 

·
Registered
Joined
·
948 Posts
i have an n/a and i hit 118 and still had some rpm's left, i didn't go any higher because i didn't want to die from the tires exploding....i went with low speed rating tires.
 

·
Registered
Joined
·
1,298 Posts
in km/h my car tops out at 220 (remember thats Km/h), not really sure of the RPM but apx. 5000-5200rpm?..

Methman
 

·
Registered
Joined
·
3,068 Posts
um, it's been calculated before, but I seem to recall that it's around 150 mph at 6,000 rpm.

Now wether that is doable, that's another question,
but with the stock gt tires/rim, and the stock gearing, and no over reving the motor, a flat surface, and no air resistance:))), that's the best you could do, change any parameter and your top speed will vary considerably.
 

·
Banned
Joined
·
4,040 Posts
1FIERCEGT said:
.....if you have an accurate speedo.
I'm presuming that all the profferred numbers in this thread are what the speedometer on the dash says. Accuracy of the speedo (they are traditionally optimistic) can be compromised by the speedometer driven gear in the transaxle or different tire circumference (and wheel slip).

The only accurate values are provided by radar, timing lights or gps.
 

·
Registered
Joined
·
1,397 Posts
SleepCounter said:
I'm presuming that all the profferred numbers in this thread are what the speedometer on the dash says. Accuracy of the speedo (they are traditionally optimistic) can be compromised by the speedometer driven gear in the transaxle or different tire circumference (and wheel slip).

The only accurate values are provided by radar, timing lights or gps.
Given this, I check mine occassionally when I pass a stationary radar machine. I don't know if every state has them, but in FL local police stick trailered radar machines on the side of the road that tell you your speed (in an attempt to get people to slow down, which doesn't work). I have verified mine up to 72mph on a highway once or twice. Not sure how accurate those radar's are though.I have 225/45/16's on my car, and before my FE DOHC I hit 141mph in 5th gear pulling somewhere between 5000-5200rpms. The car was still pulling but I was running out of straight road very quickly so I let off. I did have a slightly larger turbo and no boost cut (I had a chip in mine before I got the FE). If you have a turbo that can rev to the redline I'd say it is possible to achieve 150mph. I believe Jay hit 160+ in his, but I don't know how he got that reading. I know my speedo doesn't go that high.
 

·
Registered
Joined
·
43 Posts
this will solve ALL questions about speed limit

This link will slove any and all questions about speed limitations due to gearing, welcome :D
after clicking on link go to:
1: miscellaneous
2: calculators.
3: grear speed calc.

http://www.performanceprobe.com/index2.cgi

oh by the way since the probe and the MX6 are the same car, this web site is very informative if you didn't know about it.

P.S. I almost forgot, let me make a correction for all thoes nit pickers that like to fight about stupid mute points. The probe and 6 are Simmilar cars and with all things, execptions.
 

·
Banned
Joined
·
4,040 Posts
picking nits

1meanPGT said:
all thoes nit pickers that like to fight about stupid mute points.
stupid moot points, ya mean.

Oops, there ya go, I guess I'm one of those pickers of nits:D
 

·
Registered
Joined
·
1,231 Posts
So we have a theortical max of 156mph...

Whaddya know...i was pretty close eh.

Note, Ecoshardcore...this doesn't mean you were doing 156mph. You were doing whatever max speed your power levels let you achieve.

Pete
 

·
Registered
Joined
·
642 Posts
juat over a year ago i had my rev tachometer sitting at just under 6200rpm in 5th gear. i also looked at my speedo (it only goes to 200km/h) and the needle was where the fuel warning light was (i have an australian ford tx5 turbo). dont even ask y i was stupid enough to take my eyes off the road, but i remember the speedo and tacho position clearly. i was running 15psi upto redline, and i began going slightly down hill at ~180km/h. i tell u what, im never going to do that again, it was absolutely insane! but jebus i was hammering. oh and i have 17/215/45's on it.
 

·
Registered
Joined
·
111 Posts
has anyone ever looked into getting a longer 5th gear or redoing the final drive ratio for more top speed? I would like to get lower RPM's when cruising at 80/85
 

·
Registered
Joined
·
1,112 Posts
these cars are just begging to have a 6th gear. there was a guy in south africa that mated an Opel F28 six speed gearbox to an FE-DOHC.
 

·
Registered
Joined
·
3,055 Posts
All these figures are for an F2T right which revs to 6000 rpms. So in theroy a moded FE-DOHC (like mine:D ) could top out somewhere around 170 or more depending on redline. I hit 120 in 4th somewhere around 5800rpms. This was before I was turbo though so I think 170 is readsonable maybe higher but know why to know for sure. (dont worry guys 'm not planing on trying to do 200mph in my car, although...... never mind......*shuts door walks out with head down*)




evo
 

·
Registered
Joined
·
111 Posts
I like the F28 idea, damn if only I had mad amounts of cash...... There are tons of aftermarket parts for that tranny. I want this: F28 Getrag 6 Speed with LSD

According to Quaffe's speed calculator on 205/60R15 tires, shifting at 6000 RPM:

Top Gear gives 24.527 MPH/1000 RPM and a top speed of 147.165 MPH at 6000 RPM

Engine speeds in top gear:-
30 MPH = 1223 RPM 40 MPH = 1631 RPM 50 MPH = 2039 RPM 60 MPH = 2446 RPM
70 MPH = 2854 RPM 80 MPH = 3262 RPM 90 MPH = 3669 RPM 100 MPH = 4077 RPM

Top Speed in 1 gear = 32.195 MPH
And changes into 2 gear at 3271 RPM dropping 2729 RPM
Top Speed in 2 gear = 59.049 MPH
And changes into 3 gear at 4043 RPM dropping 1957 RPM
Top Speed in 3 gear = 87.633 MPH
And changes into 4 gear at 4653 RPM dropping 1347 RPM
Top Speed in 4 gear = 112.996 MPH
And changes into 5 gear at 4607 RPM dropping 1393 RPM
Top Speed in 5 gear = 147.165 MPH
 
1 - 20 of 33 Posts
Top