IMPORTANT FOR E34 M5 OWNERS! Old M5 Messageboard Archive. Help Needed!
Within this week I will start doing a story about the trip to Germany with the E39 M5. And for have some news for the E34 M5 people here I plan to publish some "Highlights" from the old Messageboard, I have everything stored locally, since the beginning of the board.
So all "OLD" messageboard members, is there any interest to re-publish all the very good, very technical and very proffesional posts from the old MB to this and put it in a searchable archive?
To give some of you an example of the posts, here is one regarding gearing and catalythic converter. Mr M5 and Chris shines with their technical knowledge!
So, for this, if there is enough interest I need help. I have about 800 HTML pages saved from tyhe old MB on my HD. This will distributed in small portions be mailed to "voulunteers" to publish on the messageboard as an searchable archive. Note that many of these pages are just short replies with a little info, but you see quite fast which are "usable" and full of info.
So, please mail me or post here if there is an interest for this. So, have a look of the "samples" below;
OK, from Thomas;
I own a M5 latest generation with 6 gears. To make this one faster I use a rear axle 3.73. This was custom made ( The one from the older M5 can' t be used). With this modification the car is in 5.gear = 235km/h and 6.gear= Vmax=7.250 rpm = 282 km/h with 18'' wheels.I have no (!!) problems with the engine ( cooling the valves etc.). With this Vmax new brakes are necessary. the Compound brake always warped.Best is Porsche Biturbo ( no fading and brutal when hot ).
A friend of mine sold his M5. This one has 408 HP and Vmax around 292Km/h. No turbo etc. serious tuning ( expensive, no Kat etc.) His BMW dealer wanted to change this one for my M5 but I didn't.Here in Germany the engine is too close to the limit, not really faster than mine ( I tried that) and when something breaks, I know what's going on ( same with Alpina Biturbo ).
But back to the roots. The acceleration in high speed area ( from 240 to Vmax )is still amazing for me still after a few years of driving this car.I feel the speed, the road, and enjoy the engine' s sound.
No other BMW has this fascination, no M3, no 540,nothing. Why?
It's a car for a DRIVER.
:
OK, here is from Mr M5
This post is somewhat of an amalgam. Hopefully it addresses a variety of questions concerning exhaust systems, oxygen sensors, etc. These details relate specifically to tests that were performed on an unmodified E34 M5, and were determined in OFF-ROAD USE ONLY. Any inferences should be drawn with caution. Each M5 is a different.
The main question asked was what benefit, if any, would be gained by installing a freer flowing exhaust system on an unmodified car. I suspected something could be gained at full-throttle, if not in the low and mid-range portion of the power curve. Essentially, what can be bolted on for added performance during track events.
A variety of options were considered.I'll briefly detail each. The muffler was not a point of serious consideration. The M5 muffler is an excellent piece of equipment. It is effective at reducing noise while permitting good exhaust flow. If you ever have a chance to look at the internal construction of this muffler, you'll see what I mean. Installing the headers from a European 3.8L car was another option. The collectors for these headers are larger by several millimeters, and have the significant benefit of being a factory BMW part which was engineered to last for thousands of miles, something an after-market part is unlikely to provide. This was ruled out, in part because at $2,200 they were a little expensive for a simple experiment, and while larger, they are not of sufficient tube length to offer the benefit of being acoustically tuned to a motor of this displacement. Were one to replace a U.S. specification header with the European version, you would thereafter be committed to a larger catalytic converter or replacement pipe(Off-Road Only) as the header collectors are larger and would no longer be a direct bolt on assembly. (FYI, the price for the header above actually includes a reasonable discount. Welcome to the world of Motorsport). This left the catalytic converter as the focal point of the experiment. Replacing the cat with a track pipe (TP) would without doubt accomplish two things. Reduce weight and increase exhaust flow at high RPM.
The replacement piece consisted of (two) 2.5" tubes running in parallel along the path of the cat. The TP contained a cross-over several inches reward of the headers, and a fitting to accommodate the oxygen sensor. The tubes were mandrel bent, and bolted up as a direct replacement for the cat with the use of all original BMW gaskets and hardware. The functioning of the oxygen sensor was not affected by this change, when unleaded gas is used, due to it's location upstream from the cat. The oxygen sensor samples pre-catalist exhaust gasses, thus is not affected by this change. Removal of the sensor altogether will set a fault and permanently illuminate the "check engine" light.
The figures below represent wheel horsepower. With one exception, I've only related figures comparing an entirely stock car vs. the same car with the TP installed and Air-Fuel (AF) ratio corrections made to the chip. There are so many different possible chips in the market, none of which are programmed to compensate for the lean AF ratio brought on by the use of a TP, that it would be useless to include that wildly fluctuating variable here. These dynamometer tests were conducted over a two-day period. Atmospheric corrections were entered into the dyno between each series of tests, and Chevron Supreme(92 Octane R+M/2)was used throughout the dyno testing. A little tip for the uninitiated. If you have ever seen, and been inside, your M5 while it's being tested on a chassis dyno, you'd probably rather forget the experience.
These are the ultimate numbers achieved during the tests.
POWER: The results are fairly straightforward. The peak power increase at the rear wheels is a mere 13 HP. The motor revs a bit more freely, as one would expect. As you can see, the motor actually produces less power at various points below 4500 RPM where the reduction in back-pressure is a double-edge sword. *There was a suggestion in another post that a European resonator might be used in place of a cat. The low RPM power loss would likely be reduced, or eliminated altogether, if this part were used, since it is designed to maintain sufficient back-pressure for this purpose. I would suggest that the resonator is the best starting point were one interested in this sort of thing. The addition of an oxygen sensor would be the difficult part of that matter. I would want a very competent fabricator modifying a rather expensive part like the resonator. (European E34 M5 3.6L - Exhaust Pipe Front Silencer P/N 18 10 1 312 312).
NOISE: The cats used on a U.S. or European M5 are probably better than those provided with 99% of all vehicles on the road. While the TP does ultimately allow for greater flow, like the cat, it too forces compromises. Removal of the cat increases the noise level of the car, though much less so than a replacement muffler would. With a 3.73 final drive ratio, you can drive steady state at 3500-4000 RPM without intrusive levels of noise inside the car. Tests virtual identical to mine have been performed with replacement mufflers on an E34 M5 with the intent of producing an improved version for sale. In the end, no muffler was produced because no extra power was produced, only extra noise.
COST: This experiment cost approximately $1,100 from beginning to end. This included materials, dyno time, etc. The dollars to HP ratio seems a bit high.
ODOR: When your car is idling, stand next to it and give the air a little sniff. There really isn't much odor apparent with the cat in place. Remove that cat and your nose will know after a few seconds. If you turn off the car and walk to the trunk to remove something, the exhaust smell is quite apparent, and it lingers for some time. The cat may produce a rotten egg smell after extended full-throttle runs, but without it, your car will consistently be offensive smelling.
TRACK TEST: The exception to use of the stock chip for this evaluation was during a track test. In preparation for the test, a series of 6 new chips were made. These were only intended for use with racing fuel on a closed course. The gasoline used was Union 76 - 110 Octane (R+M/2) leaded racing fuel, along with a sacrificial oxygen sensor. It's important to note that racing fuel's advantages can be several. The most obvious is their ability to resist pre-ignition and detonation in high compression motors, or when extreme timing is employed. The second is that for a specific volume of fuel, leaded racing gas contains more energy, provided a motor can efficiently burn the fuel. The final example of the chips created for this test was essentially composed of timing figures 2-4 iterations above what is commonly used in performance chips sold for U.S. M5s. It was simply labeled "Race Gas +4". Some changes were also made to smooth the more erratic changes in timing values that exist in these chips, including the stock chip.
I can only relate the feel of the car with this combination of increased timing and fuel. It pulled substantially stronger than did a regular after-market chip, with either the cat or the TP installed. This is hardly a scientific way to quantify the increase in HP had by the use of advanced timing and race fuel, but it highlights an important point. Most street cars would run worse, considerably so, on this fuel. This car, with no internal modifications, and limited to removal of the cat and increasing timing and corrected air/fuel values, ran far better. This motor, initially developed 20 years ago, is quite capable. In basic terms, it's a classic racing motor design. I would speculate that in the end, the car was producing approximately 300 rear-wheel HP. Do I have the dyno results to substantiate it? No. Will I always have vivid memories of the increased acceleration? You betcha!
**Beware**
Residents of California, since 1974 it has been Explicitly Illegal to manufacture for sale a TP for use on a public roadway, or to tamper with emission control devices on your vehicle. (C.V.C. 27156) Additionally, the Federal Clean Air Act, passed in August 1990 eliminated loopholes in the federal law to extend anti-tampering prohibitions to private parties as well. It is clearly illegal to replace your cat with a TP for on-road use.
Mr. M5
OK, here is from Chris;
I couldnīt agree more.
Some points from my "emotional" side. We did a lot of things (mainly serious, sometimes stupid)in the last years at BMW cars. One of the first things to improve performance and/or sound of a car was the exhaust system. But believe me, most of these modifications costs very lot time, but the effect was nearly nothing. Mostly the people think they feel for ex. a better acceleration, but in 99% that depends on the new sound or vibrations the car produces. And if there is any performance effect, this effect ios very small compared with the work/time and money you have to invest befor. For example we modified a M3-turbo engine with a "torque X-tube", which was normally used in Motorsports in former times (before the cat. times). To produce this tube in a good quality we need around 8 hours, the effect was 5 HP from 270 HP to 275 HP and more torque between 3500 and 5000 rpm. One time we tried to replace a standard catalytic converter from a M5 with a 100cells metallic DTM-converter, normally used in Motorsports. We need 4 hours on the dynamometer to reach the normal HP and one hour more to increase power for ~ 5-7 HP. And remember, a race catalytic converter is much more difficult and sensitive against bad gasoline or something than a original BMW product.
I can also not recommend to replace the 3.6L header with the european 3.8L version because the lifetime of this part is not so long. The main problem are the small tubes on the top of the curve of the header, they will miss after using high rpm, when the header has been alive for a longer time. The vibrations let these small tubes break out and fly away, a new header is around 1700 US$. The tubes are required for the adjustment of the engine.
Generally, for ex., itīs possible to make a fine adjustement of the header to the cylinder head in the way of fine mechanical polishing and adjustement. I think nobody can measure the effect but itīs also a part of "good" tuning.
Generally if somebodey will reset the catalytic converter with a TP, it is necessary to find a total new setup for the engine and for the MOTRONIC. To reprogram the Motronic you need a lot of experience in this business and, a lot of time on the dynamometer.
For the engine setup, there are only a few people in the world which can make this "ground-setup" for an M5 engine "perfect", so stay of this step.
In reply to the 'trials' conducted below which involved removing / replacing the 'Cat' with TP and running on leaded fuel, I am in the Middle-East with my '92 M5 and these cars are spec'd for the 'Middle-East/Australia' conditions = no catalytic converter, just pipes straight to the first silencer(muffler), with tuning to run on leaded fuel 92 octane, and slight de-tuning (approx 5HP) to allow for higher ambient temperature. Locally here is averages in the high 40C+ during 6-8 months of summer, but the car does not run 'hot', even on long trips of 200Km's at 160 - 200Km/Hr (very few traffic cops, nice roads, occasional Camel!).
With the factory fitted chip still in place, my car comes alive at 4000rpm, with noticable extra pull from 4500rpm-7000rpm. If there is another chip around that is set for my conditions & car ( no cat, leaded fuel, high ambient temps, cruising speeds, long trips on average) please let me know.
Unfortunately there are no dyno-tuners / rolling-road tuners readily available to fine tune this brilliant engine.
Perhaps you could try the factory chip for the Middle-East cars and see the results?
Malcolm.
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Originally posted by Gustav: OK, three persons so far. They have each taken 100 html pages each. So there are 500 pages left. Mail me if intersted in helping.
Originally posted by Gustav: OK, three persons so far. They have each taken 100 html pages each. So there are 500 pages left. Mail me if intersted in helping.
Gustav, I think this is a very worth while project and would love to help.Please tell me what would be required. If I am not skilled enough to help with the work,I would be prepared to contribute financially to help with this project. Sorry for the accidental previous blank post.
Quote:
Originally posted by Gustav: OK, three persons so far. They have each taken 100 html pages each. So there are 500 pages left. Mail me if intersted in helping.
I have been reading at length (and loving the wealth of knowledge and ideas), but i am curious what the final outcome of this was? A lot of the posts have good information with a percentage of feedback/banter/dialog from several years ago, is there a better way to be searching the board that i am missing, besides the obvious search bar at the top right?
Does some sort of filtering/reposting need to happen again, particularly for the E34? If so, i would happily volunteer some time to streamline more of the information?
IMPORTANT FOR E34 M5 OWNERS! Old M5 Messageboard Archive. Help Needed!
It was many good posts.
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