Last week I posted a request for engine upgrade options , the responces were focused on "camshaft" upgrades ( thank you for all of your ideas ) ;
I had a 97-540I- SPORT-6-speed , this car had a lot of lowend torque ; Is it possible to get more lowend power ? & Is there other options than "cams" to get more power ? I am going to call DINAN here in the "states" and ask if they can offer anything - I'm doughtful do to the fact that the 95 M5 was never imported into the U.S. via BMW ( ONLY gray-market ) .
Is the 3.8 engine built from the factory to the maxim power spec's already ? So there isn't a lot of options ????
My budget is 5,000. to 10,000. USD to boost the power up BUT ONLY IF I GET SOME REAL IMPROVEMENTS . OR , do I need to wait for the 2005-2007 M5 TOURING V10 to be released ( rumor has it they are going to do this car !!! HAS ANYONE ELSE HEARD THIS ? ).
Your E39 540 had more low-end torque because it was a 4.4L V8. The 3.8L straight six in the 1994-1995 M5 has higher peak HP, but you really have to wring it out. It's a high compression engine to begin with, so it might be hard to get "quick fixes" that boost low-end torque. To be honest, if you want a killer E34, get a 1995 540i Sport or a Canadian 1995 M540i. Both are six-speeds with the 4.0L V8 and almost all of the M5 trim. Though the 540i peaks with about 30 less HP than the 3.6L M5 and 60 less HP than the 3.8L M5, it has more torque at the low end. That's far more practical for daily driving.
Replacing the dual mass flywheel with a lightweight flywheel will improve acceleration and throttle response. I've been told that the 3.6L M5 flywheel should work and it weighs less than half the weight of the dual mass flywheel.
its interesting that the old 4.4 V8 crops up again
in terms of performance.
The truth is that this engine probably makes a fat 300bhp
rather than the stated 286hp, it's power rating is all down to
BMW politics, afterall, it grew from 4 to 4.4 litres with no power
increase ??...no way !!
it was rated the same to avoid treading on the shoes of other
models....this has been done many times in the past...
It's the same reason that 323i's (2.5) are rated at 170hp in the
uk yet make 183 on the dyno (seen at BMW UK's H.Q !!)
its a 325 engine with "soft" mapping.
Originally posted by Alan Archer afterall, it grew from 4 to 4.4 litres with no power
increase ??...no way !!
BMW tuned it so that the performance gains were massive at the low end of the RPM range. Seriously, look at a dyno of a 4.0L V8 M60 and a 4.4L V8 M62. They both peak at 282 HP, but the 4.4L has far more low end torque and significantly higher low-end HP.
When I used to work for a BMW dealer in the uk, I had a friend who owned a 540i A, the 4.0 litre version and wanted to have it chipped, and asked me to whom he should take it, I Sent him to AMD in oxford.
When he picked the car up, he was most pleased, the dyno showed his car was now producing 320 BHP, his only requierement was to use super plus unleaded. I drove the car before and after and you could notice the extra urge.
I am sure that if someone where to compare the specs between 4.0 litre and the 4.4 litre, you will probably find that the larger V8 had cams tuned to produce power lower down the rev range, Its quite possible, that the earlier cams could be fitted to the later engine and turn it into a bit of a monster, as I think that at this stage it should not be imposible to find the early v8 engine in a breakers yard, what I dont know for sure if they are interchangeable.
According to the M5 brochure here in the UK, the 3.8 produces 221lb-ft of torque at 1800rpm, and 295lb-ft at 4750rpm. Those figures compare well with the 4.0 V8 figures above. So I guess the theoretical answer is you probably can boost bottom end grunt with the right cams - lazy straight sixes can be very torquey - but at the expense of top-end power.
If bottom end grunt is really what you want, it may be easier to go back to a V8. I must admit that when I first thought of buying an M5, I was concerned about what I perceived to be a lack of torque between 1000rpm and 3000rpm. All I can say is I'm glad I overcame my perception...
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