Quite often I take my MC into the redline.... When I am downshifting to gain speed... How bad is this for the car? Should you never enter the "red zone"?

 

Good question.

The MINI does have a rev limiter to prevent you from doing damage, HOWEVER, this doesn't help you on a downshift. If you are already near redline when you downshift, then it is possible to rev way past the limiter, and possibly do damage.

I don't know exacly how vulnerable the MINI is to this type of thing, but one thing that can happen is valve "float", which is when the valves can't close fast enough and end up getting smashed by the piston heads. Not good.

Again, I'm not sure how much safety factor has been build into the MINI's redline, but as a general rule, I would try to keep it below redline when downshifting...

 

So as long as Im not going past where the rev limiter normally hits on a downshift Im okay?

 

Keep it under 7500rpm on a MCS engine stock, 7200 on pulley modded MCS, to avoid damage to supercharger.

As for engine, I'm sure it's fine up to 8k for quick jabs, MC or MCS alike.

R

 

I would say so, but I'd wouldn't mind hearing some other opinions as well...

 

>>Quite often I take my MC into the redline.... When I am downshifting to gain speed... How bad is this for the car? Should you never enter the "red zone"?
I think that the red zone is a place which you should rarely go if you care about not overstressing your engine. If you are keeping the car 1 to 3 years then it doesn't matter as much. The car will not let you stay in the red zone for very long- just momentary. If you want to keep the car 10+ years then you might want to learn how to downshift and use your brake (tap it) to control you speed just enough to keep the car out of the redzone.

Lets think of this a moment. You're driving fast. You are in 4th gear doing a certain speed. You are at 6000+ rpm and you shift to 3rd. Your rpm will jump about 1000 more if you downshift and maintain the same speed. So the key is to make better use of your gears. Think about where you get the most torque? Not at rpms above 6000. Unless you have a modified Cooper S, most likely it will be in the 4500 to 5800 range. At any higher rpm, then it starts to fall off in torque and HP. So if you drive the car alot in the 4500 to 6000 range then there is less chance to get to redline. If you doing hard acceleration and peaking over 6000 rpm and then do an abrupt down shift you will pop over 6500.

Is it bad? Yes. read this
http://www.ndimports.com/articles/g_lader_article_2.asp
They are talking about upgrading a pulley and driving at high RPMs:

From the original design, the G-lader was never engineered to operate over 14,800 rpms. With a stock pulley, the G-lader typically has an average life of 75-100k miles before a rebuild is needed. Many people do not have them rebuilt at this time and go for 120-150k+ miles before finally having it rebuilt. The problem is that even though the car still runs ok, the wear on the displacer may cause it to be not usable in a rebuild.

When replacing the stock pulley with a smaller aftermarket pulley damage can occur because the displacer and seals can exceed the manufacturers maximum rpm limit. If you decide to upgrade to a smaller diameter pulley, it is recommended to stay away from high rpm driving as much as possible. Excessively high rpms is the most common reason for premature failure on a G-lader. Missing a shift or a continuous run at high rpm's can result in a failure. A common problem that high rpm running also can cause is when the displacer seal fails or gets dislodged. The problem was so common that the Ralleye Group A G-lader used 4 bolts on each seal to hold them in. With proper installation procedures we do not see this problem on street use G-laders.

 

I believe Randy BMC has mentioned in the performance mod section that the MINI valvetrain is good for 8000 rpm, but you'd have to do a search to find out, and I am not sure where he might have obtained that information. The valvetrain of the MCS does differ from that of the MC, in that the stems below the seats are thinner for the MCS (to enhance flow), and the twin rockers for exhaust valves are stronger to deal with greater opening force required because of boost pressures. The MCS valves are alos made of inconel for greater temperature tolerance. I believe the rev limit is - as DiD pointed out, related to the supercharger, and calculations do show a limit of 7500 rpm for MCS and 7200 for JCW / 15% pulleys. This leaves open a possibly higher limit for MC? The rev limiter actually kicks in by cutting fuel slightly above the redline. I have hit it a few times. One thing to note is that for the MCS, hp begin to drop below the redline, and you'd be better off shifting before then. The JCW on the other hand increases hp until the 7k redline.
M.

 

Please correct me if I'm wrong, but I don't think the Eaton on the MCS is a G ladder design.


G ladder supercharger internals

R

 

I doubt the CVT will let you do much damage.

 

Davbret, you're correct, no G-ladder for MCS.
The Eaton M45 blower on the MCS is a "roots" type, using twin screws to compress the air. Picture:


_________________
Wisdom is not a function of age, but a function of experience.
*The April Club *

 

And if you downshift so you're over-reving the engine, how is that allowing you to get a speed boost? Wouldn't you aready be past the peak HP range?

Rocketboy_X

 

>>Quite often I take my MC into the redline.... When I am downshifting to gain speed... How bad is this for the car? Should you never enter the "red zone"?


I think people worry to much about stuff like this. Once it is run in you can use the engine how it is designed to be used. Its not made out of brown paper. All 1.6 16V engines with a bit of power will have this power at the top of the rev band. So give it some welly

 

Ants, I'm just curious, what sorts of answers are you getting from the folks at your place of work?

(for those who don't know, Ants is a motoring advisor at a MINI dealership)

Most owners would usually go first to their dealer to ask such a question...and since you work at a dealer, I'd figure that you've definitely done this. How did the answer differ from what you've heard here?

 

If Itold you once, I told ya a thousand times.......Im a State Trooper now!

 

So a state trooper is whipping around town at the red line in his Mini??
CITIZENS ARREST--CITIZENS ARREST

Bye. Jim

 

drive it like u stole it