Hi all,

Continuation of the tangent taken in the E46 M3 vs 993 thread, this might be interesting to all since it covers the following:

1) Real benefits from typical mods on a non varioram engine?
2) Is Varioram really better than non-vario, and by how much?
3) How fast is the 993 compared to modern fast cars (E46 M3)
4) What does short gearing do for us?
5) How does the Varioram engine respond to more significant mods (headers/RS cams/chip)?

To catch everybody up, I'm using a pretty decent car acceleration simulator called cartest.exe, programming it with various dyno curves (all from a dynojet sourced from people on this forum, so they're consistent), and changing the gearing around (haven't gotten around to playing with weight yet). Everything else on the 993 examples are exactly the same. The E46 M3 is used as the modern reference - we all agree that while it's no turbo, it's a pretty darned fast car. Runs are rolling starts from 30+ in 3rd gear, and 60+ in third gear, done that way because the simulator is most accurate with rolling starts - and yes I've done some real world timings and modeled my car in the simulator and they come out surprisingly close! So anyway check out the image attached to see the results.

Answers:
1) Typical mods make a noticable difference, but mostly over 5500 rpm. At the top of the rev scale, where the stock car would continue to fall behind the M3 at a rate of about a car length every 5 seconds, the modified car would hold.

2) Basically everything that has been said about the VR vs non-VR holds true in this simulation. The top of the HP curve (5500+) looks almost identical between the two cars. Up to about 2800 rpm, both cars are fairly identical as well. Around 3000 the VR starts to pick up and 3500-4500 it has NOTICABLY more power, which starts to trail off as the non-VR catches up at 5000+rpm. This is also assuming both cars weight the same of course (some say the 95's are lighter by a bit, who knows). In everyday situations, the VR *will* be faster than the non-vr, pretty dramatic if you're lugging the engine (the 30+ run) and not so big a deal if both cars are in the upper rev band.

3) If you lug the engine, the 993 isn't going to perform like the more refined S54 engine in the M3. It's got plenty of torque. In the upper revs, the stock 993 is slower, but not by that much. Mods and gearing help tremendously.

4) Short/close gears rock on these cars, if you can deal with the lower gas mileage/slightly higher cruising revs. I didn't do the G50/21 gears here as it's just too much stuff to sort through, I did 993RS's gears (a bit more extreme, and cheaper way to go) to show just what kind of a difference they make in rolling start situations. See the M3 destroy the stock non VR 993 when lugging? Change to these gears and you'll closely match the M3 both in the low and top end with no other mods. Wow. Change gears in a stock VR car and it's even better! Biggest bang for buck by far according to these numbers. BTW 993RS's gears go 3.82,2.25,1.68,1.30,1.10,.96 where stock goes 3.82,2.05,1.41,1.12,.92,.78

5) I was intrigued by RSRS's result in his modified 3.6 VR with headers and RS cams, so I stuck his dyno curve in and got some great results! Ok so it's a little soggy on the bottom with the stock gears, but man o man when it hits its powerband, it would pass the M3 like a cat on fire. Slap the short gears on it and you might give a stock turbo a run for it's money (maybe at least under 130).

For those of you looking for speed, you might think of trying short & close gears (maybe with a short shift kit, lwf, and clutch) to get your bang for your buck. Anxious to hear 993RS's report!!

Thanks for reading,

flat

 

Do the same cars on Cartest's "racetrack" simulator, and see how they com out in lap times on the 'ring. That would be interesting, though probably of dubious value when comparing between car models.

Chip

 

Yah I decided against that approach as I'm pretty sure the 'track time' feature is a rough estimate at best and introduces factors that will skew the accuracy of the test. Working up the rolling start figures manually keeps things simple and gives a reasonably accurate comparison between the cars.

flat

 

This may have been covered previously, but is it possible to model the 993 with a lightweight flywheel?

 

Yah I was looking at that as well, the program has some rotational mass settings but I'm not sure how much I can do with them. For now it's just gearing and power curve. Maybe next round I'll do a weight loss comparo...

flat

 

Cool, keep us posted! There's a yahoo here at work w/ a M3 that I'd love to blow away.

 

flatair,
Nice work. Just one comment: in respect to having to live with more fuel consumption and higher cruising revs: don't think so. After the conversion from g50/20 to g50/21 on my previous car, when cruising I just found myself using a higher gear...

 

bottom line is they are apples to oranges,
BMW is a true 4 seater coupe derived off a production coupe,
993 is an engineered sports car from the get go,
dont get me wrong BMW's E46 M3 is a nice car, is far more predictable at the limit than any Porshce plus is more comfortable, but.....its heavy and I have questions about the reliability of the S54 motor since they use 10-60W sythetic and they still eat rod bearings every 20K miles or so if driven hard (they extended the warranty to 6 years 100K miles on some cars) and the trans gets horrid gear lash in it if you don't know how to drive a stick properly (not to mention the self-adjusting pressure plate)

I have driven and hopped every ///M3 ever produced (never told you guys I was a master BMW tech too) , I can buy and build a 95-99 (E36) M3 to over 400hp smog legal on pump gas with a 4:10 diff that will slit an E46 M3's juggular (the most I have ever seen out of an E46 M3 was 365hp at the wheels on 100 octane but FAR from smog legal and about $20K in the hole) put the fear of god into 993TT owners for $30K

So here is my list
Sports car: 993 95 non vario ram get a chip and they scream or get a 96 up vario ram not a big enough difference IMO

Sports coupe:
E36 M3 uber evil coupe in disguise, potential to go real fast for real cheap still be daily driveable at 400 hp and be incognito to boot

E46: "I have money and have to show it off" sports coupe

 

fixnprsh,

YupI think most of us completely agree with your synopsis. I intended this thread to be more or less a tangent of the other M3 vs. 993 thread that's a 993 performance/mod analysis rather than an "a" vs. "b". The E46 just happened to be the benchmark car because they're pretty quick in a straight line. Two totally different cars (both great in their own ways too).

993RS,

Hmm maybe, but remember the G50/21 isn't quite as extreme as making 5th gear your new 6th gear. Actually I imagine your fuel economy might change due to 'new driving habits' when you get your car back

 

flatair,
I never said my fuel economy would remain the same. I just said that theoretically if I wanted to, it could remain the same... but if my priority were fuel economy I would have opted for taller gears... I expect my car to eat tires for breakfast....