factory choked engines?

Been trying to have this discussion on a couple of BMW forums over the past year or so and nobody either knows or compleatly disagrees with me.

My 318ti has the "larger" 1.9 litre M44 with 138hp and 129 ft-lbs of torque.

The smaller 1.8 M42 engine (exactly 100ccs smaller) makes the same hp but only 127ft-lbs of torque. at the same RPMS.

It seems to me that BMW must have done something to the M44 to make so anemic compared to it's smaller sibling. (some reports actually put the 1.8 at 140hp and 133ft-lbs)

It is my belief that BMW purposely hobbled this engine to avoid it competing with the smallest of the 6 cylinder cars. A 2.0 6 producing a solid 150hp. However, I cannot get anybody to even agree that I may be right.

Opinions? Would BMW choke down the largest of the 4 cylinder engines to keep it from competing with the smallest of the 6's? I realise that a lot of the problems I have having with people not agreeing with me is that most BMW owners are in the "it's not a real BMW unless it has a straight 6" club and will look down on any 4 cylinder except for the s15 found in the E30M3.

mad_machine wrote: I realise that a lot of the problems I have having with people not agreeing with me is that most BMW owners are in the "it's not a real BMW unless it has a straight 6" club and will look down on any 4 cylinder except for the s15 found in the E30M3.

Wow, there's some irony in that statement given BMW's competition history for so many years. Heck, their headquarters is a four cylinder!

In the UK, there's a version of the MINI called the MINI One. It's not a Cooper, unlike all the US versions. When they first came out (and possibly still now), they had a lower power rating than the Cooper. But they responded really well to chipping. Why? Because it turns out that the engine was the same, but the drive-by-wire engine management didn't let the throttle open all the way on the MINI One! So BMW has purposely hobbled a "lesser" model in recent years.

Opinions? Would BMW choke down the largest of the 4 cylinder engines to keep it from competing with the smallest of the 6's?

Possibly. I have heard rumors that Mercedes detuned their SL65 becaused it was faster than SLR...

I dont know about BMWs, but some dude was telling me about his 80s Camaro and how it didnt have a rev limiter, it just couldn't flow enough air to rev past about 5000 or something. Sounds choked to me.

Camaro/Corvette anyone?

Then theres the SHO rumors of yamaha delivering engines to ford with 300 hp but ford wants/needs the Mustang GT w/ V8 to be the fastest car, so they detuned them.

LT1's install in Camaros were de-rated in 95 so they wouldn't compete with LT1's in Corvettes on paper.

It's not uncommon for a manufacturer to pull those shenanigan's to PR and profit reasons.

VW and Audi did the same with their 1.8 turbos. In the VW they made much less than the 200+ hp they did in the Audi. Computer and turbo tuning did this. Otherwise the motors were very similar if not identical.

RossD wrote: Then theres the SHO rumors of yamaha delivering engines to ford with 300 hp but ford wants/needs the Mustang GT w/ V8 to be the fastest car, so they detuned them.

I remember reading somewhere that they had to significantly lower the rev limit to keep the accessories alive, thus killing the big fat part of the powerband.

On topic, I believe the 323 simply had a computer de-tuned version of the 328 motor as well.

In addition to accessory longevity, another thing that has forced OEMs to detune a lot in the past in transmissions. If the only transmissions they have on the shelf are rated for significantly less than the engine can put out, usually the engine gets detuned rather than the transmission getting beefed up.

Bryce

skruffy wrote:

RossD wrote: Then theres the SHO rumors of yamaha delivering engines to ford with 300 hp but ford wants/needs the Mustang GT w/ V8 to be the fastest car, so they detuned them.

I remember reading somewhere that they had to significantly lower the rev limit to keep the accessories alive, thus killing the big fat part of the powerband. On topic, I believe the 323 simply had a computer de-tuned version of the 328 motor as well.

thats what i heard as well, in all the e90s...

The old VW Foxes had a steel restrictor donut in the exhaust so that the more expensive golfs and jettas were faster with pretty much the same motor.

The detuning for transmission reasons reminds me of the Cadilac Allante. When that car was built, the PCM would kill the spark on full throttle upshifts so the transmission wouldn't explode.

Then there was the whole 'Quad 4 in the Fiero' thing. Some sources said GM brass killed that idea because the two 'after hours skunk works' built test mules performed as well as a Corvette. So it came to market with the pushrod Iron Duke motor.

I know that Chrysler choked the Wrangler I-6 and the 3.5L V-6 in the LH cars. I have personally removed the restrictor and felt a few HP increase, in the 3.5L it was substantial, I'd guess 10 or so??

skruffy wrote:

RossD wrote: Then theres the SHO rumors of yamaha delivering engines to ford with 300 hp but ford wants/needs the Mustang GT w/ V8 to be the fastest car, so they detuned them.

I remember reading somewhere that they had to significantly lower the rev limit to keep the accessories alive, thus killing the big fat part of the powerband. On topic, I believe the 323 simply had a computer de-tuned version of the 328 motor as well.

The BMW 323 ('99-00 E46 chassis) was a 2.5L motor whereas the 328 was the 2.8L motor.

But what does the rest of the torque curve look like? Maybe the large engine has more torque lower in the power band, but an equal amount up top. The high-end torque could also drop off more slowly in the smaller engine.

There's also things like intake and head-flow.

It's not your peak power, it's the shape of the curve and the area underneath it.

that is what I want to play with. The M44 uses a dual stage intake.. where the M42 is a regular intake. I am thinking I might want to try the M42 intake and see what happens

I don't know, but am very interested about the 318ti.

To the posters about the Corvette, Camaro stuff. Most of the time the engine was truly very different. Corvettes had much better heads and better intakes and bigger cams. I cannot quote part numbers, but certainly no carbureted car would go long being simply "de-tuned", because they'd be a carb swap away from a Corvette. Now go and find me a carbureted Camaro that still has the stock carb on it.

At any rate, de-tuned can mean a lot. It can mean heads, it can mean compression, it can mean intake or exhaust (which the Corvette always surpassed the Camaro with). I think the OP was talking about a stupid thing like timing or cam advance on an engine that could be hidden a lot more easily with computer controlled vehicles and not immediately noticeable.

Salanis has an excellent point though, peak numbers and their location don't give you a large story. Can we get some graphs of the entire plots? Also, keep in mind a 325e/325i comparison where you'll have a gain in fuel economy that isn't normally measured (although bsfc curves are around for really big time popular stuff, I doubt you'll find one for this engine). -Brian

I also have a M44 318ti. It is my understanding that one of the reasons behind the power difference is OBD-II. The M42 (which also has nice forged internals) was OBD-I, where the M44 is OBD-II.

The problem is, judging by the "gains" from reflashing the M44, if there is a choke point, it's not electronic. Nick G can only get about a 2hp and 4 torque increase using premium fuel.

Dyno of stock and reflashed E36 M44:

The intake leading to the throttle body is restrictive, and my car responded well to both "fogging" and my cheapie intake, but that was more a "feel" than power issue. I also put a better flowing muffler on the car, but I still have the stock cat and resonator.

tuna55 wrote: To the posters about the Corvette, Camaro stuff. Most of the time the engine was truly very different.

I think the LS1 Camaros have been shown to be rated low. They have exhibited negative drivetrain loss on the dyno :)

Gimp wrote: The intake leading to the throttle body is restrictive, and my car responded well to both "fogging" and my cheapie intake, but that was more a "feel" than power issue. I also put a better flowing muffler on the car, but I still have the stock cat and resonator.

Funny how I brought that up and got laughed at how it cannot make a real difference.

that is another difference between the M44 and M42.. the intake before the TB goes UP and over the back of the radiator to an intake on the passengerside of the car. The M42 (and all 6 cylinder cars) have the intake for the filter built right into the airbox and sucking air from the driver's side instead of adding three feet of tubing.

I know cummins diesel rams with auto trans are torque limited in 1st and 2nd gear. Otherwise she'd blowed up

A lot of auto pundits believed the Cayman S was purposefully detuned by Porsche so as not to outperform the lesser 911 models. Can't have little brother beating the favored big brother, now can we? I'd still take a Cayman S over a non-GT3-or-Turbo 911.

The 88-91 Civic base hatch 4 speeds motor (d15b1) had a restrictor plate in the middle of the throttle body that made it slower than the regular Civics (d15b6). At one point, Ford had an Svt Zx2 in the works that literally blew the doors off a Mustang Gt.

Yeah, thanks. Took the restrictor plate off to give the Red Dragon a little more juice. But it's not exactly street legal, so keep it on the down low.

tuna55 wrote: To the posters about the Corvette, Camaro stuff. Most of the time the engine was truly very different. Corvettes had much better heads and better intakes and bigger cams.

If were talking LT1s, no.

LT4s, yes.