Hi, I've an RX-8 but this problem is actually of a friend of mine on the spanish club (he isn't registered here). As I've said in the subject his RX-8 (231 HP version) can't rev pass 6.900 RPMS in sixth gear. He has tried to accelerate un fifth gear and it goes until the speed of 135 MPH, then it changes to sixth gear (during the change the speed drops to about 125MPH "as if it had a parachute" in his words) and accelerate again, sloooooooooooooooooooowly, until 135, and then the car doesn't grow more speed, even in a slight slope down.

My car can get without much problems to 150MPH at 7.XXX RPMS. My friend car has it's motor replaced at 28.000 miles because of an oil and coolant leak and the clutch has to be replaced at 38.000 miles. His closest Mazda garage doesn't seem to have a clue

What do you think could be the problem? Broken cat? Fixed motor problem? ???

Thanks!

 

Rofl!

 

Alright, i'm on earth again. Most cars are government top speed limited, what makes your friend think his RX-8 isn't? That's like.. common sense, how is this a problem anyway - why would he be going 135 in the first place..

 

It isn't limited because in spain cars are not mechanichally or electronically limited. The question is not why he wants to go to over 135 but why his car can't

 

BTW most governments doesn't have laws limiting the top speed of cars (only Japan and a few more.)

 

6th gear is an overdrive gear- it has no power. he will not reach top speed in 6th gear as it does not have power enough to overcome wind resistance. he will reach top speed in 5th gear. at what rpm is it when it is going 135mph in 5th gear (yes people i could do the math i dont want to)

 

i agree with zoom44. 6th gear is not where you go hunting for top speed in.

 

Yes, that is what I told him but the fact is that my car and other cars here can rev up to 7.XXX in 6th and speed until 14.X-150 in 6 gear but him doesn't, so there is a clear difference.

 

Anyway he keeps telling me that the max speed his car can get in fifth gear is 137 MPH (I've asked him to tell me at what RPMS, but I guess that's at about 8200RPM, while mine easily get 145 in fifth gear at about 8700 RPMS as proven by this photo of my car in fifth gear (232 = 144):

 

wtf are you doing taking a photograph at that speed?

 

I wasn't, the photo was taken by a friend in the rear seat

 

easy on a rolling road !

 

That speed is much better on a mountain road, going daily to work!! This Fernando Alonso 2005 GP winner didn't came from nowhere you know.

 

tell him to get his catalytic converter checked it could be clogging.

 

He will, thanks.

 

OMG! new desktop image!!!!

 

As a desktop image this version is better :-D

http://juanjoalvarez.net/compartidos/232.jpg

 

Now I know this sounds lame, but when they replaced his engine they did put the high ouput motor in it? The top speed and rpms quoted seem pretty close to the automatic version.

 

At speeds like that, its all about wind resistance, weight, and the power you put out.

Deweight the car, reduce drag, and put out more power.

 

damn dude......what resolution was that taken at? it's too big even for my 1600x1200 desktop

 

No, because in 1th, 2nd, 3rd and 4th the car revs normally, the problem is in 5th and 6th gears.

 

1600x1200

 

yes, but this is not the problem, as you say 6th gear has "no power", but is in 6th when you can reach top speed. I mean, in 5th gear you reach 235km/h (146mph) more or less, but you insert 6th gear and you can go perfectly to 240km/h (149mph) and then more slowly reach 255km/h (155mph), so in 5th gear you can not obtani top speed.

I think it can be intake o cat problems... or maybe ECU problem, I don't know if they changed the ECU when the engine was changed... I say this because the performance of his car is similar as it was with the first engine.... strange...

 

it just barely fit. i went to center it and nothing happened