M30 chips comparison - JC vs. EAT vs. Stock

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Details are below. Here're the basics:

1. JC will sound slightly louder and smoother - removes a bit of rasp from the stock exhaust. The improvement is mostly in mid-high end power and is subtle. It removes the top speed limit (unconfirmed) and runs on 93, untested with lower octanes. Noticed a marginal decrease in economy. Haven't e-tested the car with it.

2. EAT sounds rich and grumbly, especially at low-mid engine speeds and idle - doesn't remove the rasp, but adds a lot of growl. There's a top end improvement comparable to the JC, but the low/midrange boost feels considerably stronger and is quite noticable. It does not remove the top speed limit (so says its designer, but unconfirmed personally), and is confirmed to run on 91 octane. Noticed a marginal increase in economy. Haven't e-tested the car with it.

Details:

I had a Jim Conforti (JC) chip made by Turner Motorsports (TMS) in my M30B35-powered 535i/5 between 28 September and 16 January, when I traded it in for an EAT Ultrachip, installed on the 18th. I noticed a lack of factual comparison between them - and gains compared to stock, for that matter - so here's a comparison, including subjective review and acceleration times. I measured them with the OBC timer, and did 3-5 runs for the 40-60 time. All runs were done with the same 93 octane gas, probably BP since that's the only good gas in my town. Fuel amount varied (see below), but all were done with 115 pounds of driver, no cargo, no weight reduction, no other performance mods, and stock 15" basketweaves wrapped in 1/3-worn Fuzion HRi's.

Reliability? I've noticed no change. I did once find someone who said a Bavauto chip caused pinging, but that's the extent of it. Other than that, I've yet to find even a vague suspicion that some problem was caused by a chip. In any case, pinging is something you can hear clearly and fix immediately. Theoretically, a poorly-made chip could cause the engine to run so rich that the catalytic converter melts/catches fire, or not quite so rich but still damaging the cat over time, but that appears to not be the case with these.

Emissions? I have no idea. But it takes 15 minutes to swap a chip, so these could cause my car to belch cyanide for all I care (well, not really), and I'd still pass.

Jim Conforti:
When I first installed it back in September, the change could best be described as subtle. I noticed several weeks into driving with it that my car sounded somewhat louder and meatier, but I attributed that to increased muffler rot. Acceleration didn't feel a whole lot stronger, but I found myself less impatient when passing on the highway without downshifting, and there was more seat compression while accelerating in high 2nd. This chip is said to remove the top speed limiter. My car is limited to 128 (not confirmed personally), and is capable of 143 stock (officially, also unconfirmed), and apocryphally 150 or a touch more with the added power of a chip. Fuel economy went down a touch. With about 90% highway driving, I averaged 21.8 mpg. I suspect, though cannot quite confirm, that my idle was lower and thus rougher than stock. Especially in the cold, I definitely noticed it shaking the car intermittently more than the previous winter with a stock chip, even after cleaning the MAF and IACV, replacing the second intake hose, and reinforcing a vacuum line. With a nearly full tank of gas, I got the following times in seconds (the numeral is the gear):

40-60 (II) - 3.2 (the average of 3.3, 3.1, 3.2)
60-80 (III) - 4.3
60-80 (IV) - 7.8
60-80 (V) - 10.5

Stock:
After I replaced the stock ECU to ship off the JC, I realized that the louder exhaust note was just the chip doing its thing, since my car didn't rumble quite as much while accelerating, and the highway-speed drone was less noticable. I suspect that either the car didn't adapt back to the stock ECU in time, or half a tank of gas really makes a difference, because these acceleration times seem a bit fast compared to the above:

40-60 (II) - 3.2 (3.2, 3.2, 3.1)
60-80 (III) - 4.4
60-80 (IV) - 6.9
60-80 (V) - 9.9

EAT:
The first thing I noticed was that the idle got higher, more regular, louder, and changed to a more aggressive and slightly raspy burble. Even in the freezing cold, my idle doesn't fluctuate, but it is slightly rougher and feels more grumbly than stock or JC. The second thing I noticed was that it felt subtly more responsive around town at low RPM's. Definitely louder than the JC and stock, and the highway drone is more present. Highway acceleration feels at least as good as with the JC. Fuel economy is thus far where it was before, but it's supposed to increase by 1-2mpg eventually. These times were done with just under half a tank of gas and with a fair amount of snow and ice on the car:

40-60 (II) - 3.0 (2.9, 3.1, 3.0, 3.0, 3.0)
60-80 (III) - 4.3
60-80 (IV) - 6.4
60-80 (V) - 9.7

Update 23.3.2007 on EAT fuel economy: On a 1400-mile trip from Ohio to Florida, passing through DC, I averaged about 22.5 mpg. That's lower than stock, but my average speed was about 80mph including all stops except an overnight stay in DC. In South Carolina and Florida, I averaged mid-90's, with some brief runs at 120+. I don't have specific figures, but those speeds with a stock chip got me 17-19mpg.

Update 5.4.2007. According to Mark D'Sylva (the guy who makes the EAT), EAT chips do not remove the top speed limiter unless specifically stated otherwise. In other words, my car is still limited to 128, and unable to reach its true potential of at least 143, possibly as high as low 150's. I asked about getting this limiter removed, but have yet to get a reply.

Update 8.9.2007. I drove from Florida to California a couple of weeks ago. I had the stock chip until Las Vegas, and the car felt SLOOOWWW. Well, for a 535i. It was adequate overall. I replaced the EAT just before leaving Vegas, and somewhere around Modesto, CA, something must've clicked, because the car started hauling harder than ever before, even when I had the EAT earlier. And that's with 3/4 a tank of 91, and several hundred pounds of my possessions. I was getting pleasant seat compression in mid-4th, where with a stock chip, even mid-high 2nd barely felt like anything. The speedo needle definitely woke up, too, so it wasn't just the noise fooling me. The noise is wonderful, BTW. I'm going to do some more acceleration trials, but I'm hoping for mid-high 2's for 40-60, and hoping for 4 or under for 60-80.

Oh, and it runs just fine on Shell 91. 92/93 not required.

Conclusion:
For the M30B35 at least, EAT FTMFW, unless you care more about a quiet highway cruise than performance gains, or you really need that extra 15-20mph...

Useful comments on this writeup are gratefully accepted, since I want to refer any newbies with M30 chip questions here.

And does anybody know anything about Hartge, Alpina, and Venom chips for the M30?