Why is the E9X M3 so bad on gas?

[TanDaMan]

Originally Posted by dreamspeed

I assume it is the very aggressive gearing.

High revving and "small motor" aren't really good "excuses" IMHO.

Just look at all the high revving small Honda VTEC motors

You don't see any 8 cylinder VTECs.

[pkimM3r]

Originally Posted by TanDaMan

You don't see any 8 cylinder VTECs.

True but isnt vanos just a copy of vtec? Lol. Sad but true.

[serranot]

Originally Posted by pkim1079

True but isnt vanos just a copy of vtec? Lol. Sad but true.

Nope. VTEC has alternate cam lobes. That can be another set of cams for lift and duration. But it's fixed.

VANOS alters valve timing. It's infinitely variable as opposed to fixed. But it does not change the cam profile like VTEC.

[pkimM3r]

Yeah so they just took vtec and made it variable timing. I believe vtec has that now too.

[serranot]

Originally Posted by pkim1079

Yeah so they just took vtec and made it variable timing. I believe vtec has that now too.

I don't think I explained it clearly. With VANOS, the engine management system can adjust the phase of the cams in relation to the crankshaft, but the cam profile is the same. The same lift, the same duration. It just occurs at a different time in the combustion cycle.

With VTEC, there is a whole new set of cam lobes for the valves to follow. I do think you're correct that Honda also added variable valve timing to the VTEC system. But I don't think it's accurate to say that VANOS is VTEC with variable timing. It's not that at all.

[Lerxst M4]

Originally Posted by 1MOREMOD

because the s65 doesnt let you get out of the throttle. once you take it deep to 8K land you want to every shift.

Where's that damn 'like' button.

[SYT_Shadow]

Originally Posted by thekurgan

port injection in the S65 is a GOOD thing, IMO. Agree with the gearing.

Originally Posted by apecush

for those wanting DI, do a google search for RS4, carbon, and valves

This. DI is absolute garbage, I'm extremely happy M division hasn't used it on any NA engines.

If you actually drive the car and plan to keep it for a while, carbon buildup will bite you in the ass

Originally Posted by e92zero

^off topic, I always wondered about how responsive is the 6th gear in the Corvette. How does that compare to our 6th gear? The 6th gear in the M3 is actually pretty decent in terms of power/responsiveness in my humble opinion. Probably why our highway mpg suffers also. Can't have it all.

No need to wonder. It's not responsive at all.

InsideLine had a 600hp long term Viper. The 8.4L V10. They said you could not use 6th unless you were going over 85mph because it put the engine at idle rpms.

In my opinion, although the M3 is geared slightly too low, the Corvette, Viper and other 'performance cars' are stupidly geared. I would be seriously upset to drive a brutish Viper and have to downshift several gears to pass someone up.

The E46M and E92M are all able to pass up very well in 6th gear...

My question is why the DCT doesn't have a really long 7th gear.

[SYT_Shadow]

Originally Posted by pkim1079

True but isnt vanos just a copy of vtec? Lol. Sad but true.

Huh?

Not at all alike and definitely not a copy. Look at torque curves of the S65 and compare against any other engine...

[swamp2]

Some decent replies here and some total crap as well...

It all comes down to engine character. That is the root cause.

Let's examine a steady cruising speed just to keep it simple. The primary losses (other than lost heat, which doesn't count as to the engines rated power anyway) are aerodynamic, drivetrain losses and tire losses. These all depend on speed as well. To keep the vehicle propelling forward the losses are just overcome and then you have no acceleration, i.e. velocity is constant. It is a total amount of power (cruising power) that is required to balance the losses. That power can come from high torque and low rpm or low torque and high rpm. You can guess which will offer the better fuel consumption as it is then all about rpm (of course for a given fixed displacement). It is a natural compromise in engine design one "typical" M3 type of engine is low displacement, high power, low torque, high redline, this is a racing style engine (no perhaps not at all levels of racing but surely at the elite levels such as F1), the other say a Vette is high displacement, lower power (relative to displacement), high torque, low redline. In an engine such as the latter one the power to just match all of the cruising losses as a given speed is achieved at low rpm. The rpm is even low enough to offset the fuel efficiency advantage that comes with a lower displacement. The drivetrain losses are also lower due to lower rpms (tire and aero losses are identical though if the same size tires and same body).

The gearing argument basically vanishes when you look at things from the perspective of power. Yes the two engine styles have different gearing but they do naturally to match the engines characteristic torque curve and redline.

What you get in exchange for this compromise is indeed the type of engine that "begs" to be driven hard and rewards you when youu do.

[US///M3]

Originally Posted by swamp2

Some decent replies here and some total crap as well...

It all comes down to engine character. That is the root cause.

Let's examine a steady cruising speed just to keep it simple. The primary losses (other than lost heat, which doesn't count as to the engines rated power anyway) are aerodynamic, drivetrain losses and tire losses. These all depend on speed as well. To keep the vehicle propelling forward the losses are just overcome and then you have no acceleration, i.e. velocity is constant. It is a total amount of power (cruising power) that is required to balance the losses. That power can come from high torque and low rpm or low torque and high rpm. You can guess which will offer the better fuel consumption as it is then all about rpm (of course for a given fixed displacement). It is a natural compromise in engine design one "typical" M3 type of engine is low displacement, high power, low torque, high redline, this is a racing style engine (no perhaps not at all levels of racing but surely at the elite levels such as F1), the other say a Vette is high displacement, lower power (relative to displacement), high torque, low redline. In an engine such as the latter one the power to just match all of the cruising losses as a given speed is achieved at low rpm. The rpm is even low enough to offset the fuel efficiency advantage that comes with a lower displacement. The drivetrain losses are also lower due to lower rpms (tire and aero losses are identical though if the same size tires and same body).

The gearing argument basically vanishes when you look at things from the perspective of power. Yes the two engine styles have different gearing but they do naturally to match the engines characteristic torque curve and redline.

What you get in exchange for this compromise is indeed the type of engine that "begs" to be driven hard and rewards you when youu do.

Did you know that the human head weighs 8 lbs ?

[Tomislav]

You don't buy an m3 for gas mileage

[kaiv]

Originally Posted by pkim1079

True but isnt vanos just a copy of vtec? Lol. Sad but true.

Originally Posted by pkim1079

Yeah so they just took vtec and made it variable timing. I believe vtec has that now too.

:facepalm: You obviously have no idea how either system work so please go educate yourself instead of making such retarded posts

[TVMA Doc]

Originally Posted by VMcV3y

The M3 achieves better mileage than the Toyota Prius:

Proof:

DETAILS BEGIN AT 3 min : 25 seconds

- V

.

Jeremy talked me into buying an M3 so that I too could be green.

[TVMA Doc]

Originally Posted by pkim1079

Yeah so they just took vtec and made it variable timing. I believe vtec has that now too.

VTEC (Variable Valve Timing and Lift Electronic Control)...the name itself implies that it has ALWAYS had variable timing. Even the original VTEC (if I'm not mistaken, it was on the 1990 Integra) had variable timing.

[nujabes24]

Originally Posted by Lute

Attachment 850096

Lmao

[aus]

Originally Posted by thekurgan

Agree, Mini has been problematic, but continues to sell like crazy. We'll all be glad we have port injection, nobody wants to deal with this every 40-50k miles:

It's really not a big deal anymore now that people know about it. These were first generation motors that had this issues and there's an easy "fix" which is a catch can. The walnut cleaning can be done for around $350 (LTBMW) now too. A 15% increase in power and mileage would put the S65 at 475 HP and 19mpg overall (assuming 17mpg overall). Even without a catch can, I'd pay $300 every 50,000 miles for that engine. Even if it was a 10% improvement, I'd be very happy with it.

There was a pretty good article in Road & Track last month about this and the manufactures are now aware of this issue and designing engines to take this into consideration. It's also an area where GM/Ford see to be ahead of the Europeans in since they seem to not have this issues as much and in the article, a few engineers mentioned that they took this into consideration when designing DI engines.

.

[Real Stig]

Why do you care about MPG in an M3?

[Thik]

Originally Posted by Real Stig

Why do you care about MPG in an M3?

Because gas costs money. And if heavier, more powerful cars are getting better MPG's, then why not wonder why?

[Lute__]

The way I look at it, gas guzzling is a small price to pay for such a race oriented car.

[brisance]

Is there any way for you to scan and post the relevant article online, maybe in a new thread? Don't want to go off-topic here and risk the wrath of the moderators, but I'm interested in this. Thanks.

Originally Posted by aus

It's really not a big deal anymore now that people know about it. These were first generation motors that had this issues and there's an easy "fix" which is a catch can. The walnut cleaning can be done for around $350 (LTBMW) now too. A 15% increase in power and mileage would put the S65 at 475 HP and 19mpg overall (assuming 17mpg overall). Even without a catch can, I'd pay $300 every 50,000 miles for that engine. Even if it was a 10% improvement, I'd be very happy with it.

There was a pretty good article in Road & Track last month about this and the manufactures are now aware of this issue and designing engines to take this into consideration. It's also an area where GM/Ford see to be ahead of the Europeans in since they seem to not have this issues as much and in the article, a few engineers mentioned that they took this into consideration when designing DI engines.

.

[Ezio]

Originally Posted by Thik

Because gas costs money. And if heavier, more powerful cars are getting better MPG's, then why not wonder why?

Whats hard to understand ?

Its a little N/A engine that makes a lot of power.

Theres a reason why american v8s are big. I would bet if the S65 was bigger and had more torque it would get better MPG.

[FVM3]

Originally Posted by Thik

Because gas costs money. And if heavier, more powerful cars are getting better MPG's, then why not wonder why?

Gotta pay to play. I put 2500 miles a month and never care about how much gas i pay for. It gives me so much fun