Z4 3.0si coupe review

[pokeybritches]

Originally Posted by aerobod

(due to it being an over-square cylinder design), so it shouldn't be in that rev range in a higher gear anyway.

The M is an under squared engine, bore and stroke of 87.0 x 91.0 mm (had to look those up lol). I think the M54 was under squared too.

[chickdr]

Originally Posted by M_Six

I'm still amazed at the power of my 3.0si. Especially after trudging along in my 3.0 X5 for a few days. I just wish it had the ///M steering wheel. If the weather permits, I may test drive an '07 ///MR tomorrow when my si goes in for service. With the really shitty roads here, I'm not sure the ///M will suit as a DD. Concrete roads and expansion joints suck.

With its non RFT tires, you may be surprised at the M's ride vs a RFT equipped si...

[Huz-Z]

Originally Posted by M_Six

I'm still amazed at the power of my 3.0si. Especially after trudging along in my 3.0 X5 for a few days. I just wish it had the ///M steering wheel. If the weather permits, I may test drive an '07 ///MR tomorrow when my si goes in for service. With the really shitty roads here, I'm not sure the ///M will suit as a DD. Concrete roads and expansion joints suck.

Believe me - you have not seen shitty roads until you come to my town!!! Potholes on top of potholes in cracked, torn up and rutted pavement. Miserable would be an understatement.

And I drive a 3.0si over that!

[dekaliber]

Originally Posted by chickdr

With its non RFT tires, you may be surprised at the M's ride vs a RFT equipped si...

QFT.

Both cars stock, I actually think M's ride is more supple than the 3.0si. My girlfriend, who gets a good amount of seat time in shotgun, noticed this almost immediately.

[mhughett]

Originally Posted by dekaliber

QFT.

Both cars stock, I actually think M's ride is more supple than the 3.0si. My girlfriend, who gets a good amount of seat time in shotgun, noticed this almost immediately.

If the si has the RFT's, I agree with you 100%. Once I changed out the tires though, I think the si rides a little better. This is the single best mod you can make to the si. The M steering wheel is a close second.

[Huz-Z]

Originally Posted by mhughett

If the si has the RFT's, I agree with you 100%. Once I changed out the tires though, I think the si rides a little better. This is the single best mod you can make to the si. The M steering wheel is a close second.

What tires did you put on your si to replace the stock RFTs?

Cheers!

[mhughett]

Hancook's V12 EVO. I bought the slightly taller size used by the M coupe and it now made my speedometer dead-on accurate.

[vachss]

Originally Posted by mhughett

Hancook's V12 EVO. I bought the slightly taller size used by the M coupe and it now made my speedometer dead-on accurate.

That's a pretty significant change: 4% increase in tire diameter. I would imagine the increase in aspect ratio had as big an effect on handling compliance as did the change from RFT to conventional tires. I'm curious, did you also notice any decrease in acceleration and/or increase in mileage - as this is exactly the opposite of what the M guys do when they swap in 3.93 rear gears.

[mhughett]

Originally Posted by vachss

That's a pretty significant change: 4% increase in tire diameter. I would imagine the increase in aspect ratio had as big an effect on handling compliance as did the change from RFT to conventional tires. I'm curious, did you also notice any decrease in acceleration and/or increase in mileage - as this is exactly the opposite of what the M guys do when they swap in 3.93 rear gears.

No, not at all. But then I think you would need to do a "before" and "after" with a stopwatch to be able to notice the difference. I guess I effectively made each gear ever-so-slightly taller. Certainly no negative affect on handling. Only a much quieter ride and no tramlining any more. Oh, and no more "crashing" over little imperfections in the road. This and the tramlining were the main reasons I made the change to conventional tires.