S54 Powerband

[Ubermensch]

I've had my Z4MC for just under a week now. The motor almost seems strained above 6k rpm. I've seen the dyno graphs and it's not like a stepped variable valve timing system (ie VTEC) where there's a noticeable upkick when the profile changes above say 5k, the power actually starts to slightly level off (it's not rising as fast as it did at lower rpm)....so this feeling might be expected. I am coming from a turbo car, so I know that has affected my seat of the pants as well.

Even knowing all that, the car just doesn't feel all that quick. Doesn't push you back into the seat. The car definitely has more than expected lowend and doesn't need to be downshifted to accelerate on the highway all, but I expected the direct opposite from a car that makes its peak power at 7900rpm. I have been short-shifting at around 6k because it just doesn't feel like there's much left above that

For those of you out there that have had much faster cars in the past (yes a low/mid-13 sec car is slow for me), does this observation seem correct?

[The__J__Factor]

I think vanos is constantly variable and always active so it's not really like vtec where it kicks in at a certain rpm. The engine deffiantly starts to fall after around 7k for me.
I think new headers would be able to fix that + a tune. Would be nicer if it pulled all the way to red line. My last car revved to 8500rpm and kept making power all the way so I too feel a little frustrated, but I know the low end is also much better in the BMW.

Nothin stock is ever perfect, mods are the answer.

[MIKe86]

there is more to a z4mc than straight line runs.

[epbrown]

You hit your peak torque at ~5000rpm, so you're not going to get much pull beyond that. The extra rpms are to reduce torque drop when shifting so you can stay in the power band, and avoid over-revs when you downshift. Even driving my hardest, I'm usually revving to 7500 rpm for upshifts.

The S2000 makes its max torque higher up the rev range, but that's why it feels so gutless at lower rpms; I think the S54's torque range is a good compromise.

[mikem]

Got to be honest I think the S54 in the Z4m is superb. It`s quicker than my E46 M3 vert was with an ESS VT460 supercharger kit and the 996`s I`ve driven (GT3 MK2 and X50 TT) both weren`t as enjoyable.

[fitchesbass]

My engine pulls strong almost all the way through the band.

Maybe you got one of the 'weaker' S54s out of the production run lol.

Really not sure though. You comments are all relative to your own notion of 'fast'. Get a dyno and then we'll have some hard evidence to look at.

[Ubermensch]

Ok ok just wanted to verify that my findings were normal (ie something wasn't wrong with my motor). I have been greatly enjoying the car, just expected the powerband to be a bit different that's all. Maybe all it's missing is a nice GT42R...

[fitchesbass]

Originally Posted by The__J__Factor

I think vanos is constantly variable and always active so it's not really like vtec where it kicks in at a certain rpm. The engine deffiantly starts to fall after around 7k for me.
I think new headers would be able to fix that + a tune. Would be nicer if it pulled all the way to red line. My last car revved to 8500rpm and kept making power all the way so I too feel a little frustrated, but I know the low end is also much better in the BMW.

Nothin stock is ever perfect, mods are the answer.

bolton power mods for a street / occasional event Z4M is a waste of money imo.

Mods of importance I see: 1) driver training, 2) stickier tires, 3) coilovers.

All this CF roofs and intakes and exhausts and stuff is 95% for show/sound imo. I still have my doubts on the $$/hp gain of the RPi CAI. Seems mighty steep.

[mikem]

Shift I guess its all down to personal preference.

Personally I find the TT runs out of revs to quickly and the GT3 too fidgety and uncomfortable to inspire confidence. I`m sure on a track the GT3 would feel more at home but I think it would need a very skilled driver to get the best out of it and for me the novelty of driving a near race car would soon wear thin and become irritating. 997`s maybe different but then thats a whole different price level.

Here`s a G Tech graph that plots my std M3 vert(Blue) Vs VT460(Green) Vs VT600(Black) Vs std Z4M(Red). The Vt460 obviously had a higher power to weight ratio when using peak figures but the area under the graph isn`t enough to outweigh the 250 Kg`s extra it had to lug. In my mind the std Z4M feels "nice" I miss the straightline speed I had with the VT600 (which was on a parr with my friends TT) but throw in some corners and the Z4M would be right with it.

OP, sorry for the threadjack.

[E82tt6]

7k or so is where mine starts to feel flat, and it falls on it's face at 7.5.

[mikem]

Shift, they`re all actual runs at the same deserted stretch of road, they`re not necessarily the slowest/fastest of each but what I would say are a good average.

The GT3 will for sure stay in history as one of the greatest 911`s if I could afford a stable of top end motors, I`d have one in there but not as an only "fun" car.

[Ubermensch]

Originally Posted by mikem

OP, sorry for the threadjack.

Oh no problem at all, this discussion is getting good. Kinda funny on the cars being brought up, as the 996TT and 996GT3 are 2 of my top choices for the Z4M's replacement in a year or so. The TT is the more likely bet as it will be my DD and will need to plow through snow during the winter, the GT3 would drag some expensive bits.

But yeah back to the original point all I'm trying to say is exactly what shift mentioned, the S54 just feels a tad strained at the upper RPMs. No I am not going to dump a few k into parts to rectify that (I go through vehicles so quick the mods just end up wasting too much money on N/A cars). The braking/steering/handling more than make up for that deficiency. In fact I haven't had a car as eager to take the twisties since my built 04 Evo RS. Definitely going to thoroughly enjoy her assuming I can get rid of all the rattles

[007MCoupe]

Originally Posted by shift@red

I would be very suprised if a stock z4m is faster than a near 500 hp e46 m3 vert considering the vert probably boasted a far superior power to weight.

Z4M vs Viper. Track vs Street performance. Driver Training vs "I know how to drive".

[Finnegan]

Originally Posted by Ubermensch

But yeah back to the original point all I'm trying to say is exactly what shift mentioned, the S54 just feels a tad strained at the upper RPMs. No I am not going to dump a few k into parts to rectify that (I go through vehicles so quick the mods just end up wasting too much money on N/A cars). The braking/steering/handling more than make up for that deficiency. In fact I haven't had a car as eager to take the twisties since my built 04 Evo RS. Definitely going to thoroughly enjoy her assuming I can get rid of all the rattles

I'll echo what others have said about the S54. You could dump a lot of money into it for some small returns (headers, cams--jury is out on those I think, etc.) but the cost/benefit is really not there. As a total package the car is damn good out of the box.

The S65 in my M3 is one of those engines that just runs like a bat out of hell towards the 8,400 redline and the power just keeps on coming--unlike the S54--which really does seem to run out of breath at the higher RPMs. (I notice it 5K and upwards, especially when coming from driving the E92.)

However, the E92 M3 is far less engaging, the feedback is more numb, and it's it's less fun to drive. Now a Z4M with an S65 engine--oh my--that would be unbelievable!

And, when you think about it, the S54 engine was at the end of it's planned life when put in the Z4M...and the things we're comparing it to like the S65 (the successor engine to the S54) or the GT3 or 996TT etc. are either newer or at a totally different price level. It's still a great engine especially when you consider the design is over 10 year old!

[dekaliber]

Originally Posted by Finnegan

I'll echo what others have said about the S54. You could dump a lot of money into it for some small returns (headers, cams--jury is out on those I think, etc.) but the cost/benefit is really not there. As a total package the car is damn good out of the box.

The S65 in my M3 is one of those engines that just runs like a bat out of hell towards the 8,400 redline and the power just keeps on coming--unlike the S54--which really does seem to run out of breath at the higher RPMs. (I notice it 5K and upwards, especially when coming from driving the E92.) The engine was at the end of it's planned life when put in the Z4M...and the things we're comparing it to (S65--the successor engine to the S54) or the GT3 or 996TT are either newer or at a totally different price level.

However, the E92 M3 is far less engaging, the feedback is more numb, and it's it's less fun to drive. Now a Z4M with an S65 engine--oh my--that would be unbelievable!

If they can fit an M5's V10 in there, the S65 should be no problem...

I agree that most of the NA tweaks are expensive and yield little reward. Seems like probably the best bang for the buck is a diff gear swap and better rubber, both of which I'll probably do next summer. At the same time, I can't help but be tempted once in a while by the ESS FI route...

[Shipkiller]

Read this from my website.. Reprinted with permission from the author.

S54 vs. S65

http://www.shipkiller.com/S54_vs._S65.html

[RussRamz]

Originally Posted by E82tt6

7k or so is where mine starts to feel flat, and it falls on it's face at 7.5.

This is easily fixed with a chip tune. I had the same gripes, but I chip tuned with an E46 M3 software write two years ago and the high-end drop-off went away.

[The__J__Factor]

Originally Posted by Shipkiller

Read this from my website.. Reprinted with permission from the author.

S54 vs. S65

http://www.shipkiller.com/S54_vs._S65.html

I wish they held back the Z4 M for a year or two and brought it out with the v8. That would have been a dream come true.

[Ubermensch]

Originally Posted by Shipkiller

Read this from my website.. Reprinted with permission from the author.

S54 vs. S65

http://www.shipkiller.com/S54_vs._S65.html

Great article!

[E82tt6]

Originally Posted by RussRamz

This is easily fixed with a chip tune. I had the same gripes, but I chip tuned with an E46 M3 software write two years ago and the high-end drop-off went away.

I'm planning on tossing on SS Stepped headers and getting an ESS tune this summer for that very reason. The gain of 25hp is sort of secondary, "feel" is more important to me. This will never be a truly "fast" car without FI, but it's certainly quick enough to have plenty of fun, and perform will under any circumstances. A bit more up top would take away the motor's only imperfection. More power is never a bad thing, but improving the car's performance at peak and power curve is even more important to driving enjoyment

When I can spare the money, I'll probably be going with one of the ESS SC kits, but that's still likely a year or so off.

[Finnegan]

Originally Posted by Shipkiller

S54 vs. S65

http://www.shipkiller.com/S54_vs._S65.html

Makes me feel pretty darn proud of the two power plants sitting in my garage....It's a pleasure to drive either one.

Originally Posted by RussRamz

This is easily fixed with a chip tune. I had the same gripes, but I chip tuned with an E46 M3 software write two years ago and the high-end drop-off went away.

The price of the ESS tune just dropped back to 795.00. Making it uber tempting.

Originally Posted by The__J__Factor

I wish they held back the Z4 M for a year or two and brought it out with the v8. That would have been a dream come true.

Yes, if you want to stay pure to the N/A roots, it sure would have been! But like SK says, if you're willing to go FI, the S54 can still move up several steps and be quite a beast.

[Finnegan]

Originally Posted by E82tt6

I'm planning on tossing on SS Stepped headers and getting an ESS tune this summer for that very reason. The gain of 25hp is sort of secondary, "feel" is more important to me. This will never be a truly "fast" car without FI, but it's certainly quick enough to have plenty of fun, and perform will under any circumstances. A bit more up top would take away the motor's only imperfection. More power is never a bad thing, but improving the car's performance at peak and power curve is even more important to driving enjoyment

When I can spare the money, I'll probably be going with one of the ESS SC kits, but that's still likely a year or so off.

Must have posted in just ahead of me (waiting for the block party here to start ).

Very good point here, and it makes me rethink my "cost/benefit" statement a bit. I haven't researched the stepped header + tune direction enough to comment. But if it give the S54 more of an S65-like charge to redline then that's a huge improvement. Not absolute power like you say, but rather more fun and enjoyment from the motor. So many folks (look over at M3 post) get caught up on absolute power numbers rather than looking at the "whole package" (power curve, feel).