Eprom Swap- does it really matter?

[honyama]

Hello Forum,

I read quite a lot of articles about the CPU/ Eproms of the engine control module. To be honest, I don´t trust all the advertising arguments, that you can read. + 20 HP + 10 N of Torque etc... but it sounds inviting...

I know that every engineer/software designer creates/writes a software with a lot of security space, eg. due to bad petrol, full-throttle mixture and so on. As a result the car runs always "good" under a different varity of conditions (snow, winter, on highway, traffic jam). Also the protection of the engine components itself is a very important topic- no car manufacturer wants to have a angry customer, whose engine died through a wrong setup.

But to be honest, is it really possible to get some more "power, torque" only with changing the CPU? Or can you increase the driving pleasure or response characteristic?

Initially you need a good running basic, so we don´t talk about "tuning" a 500.000 miles engine. I really want to know, if it makes a difference on a perfect running, powerfull and strong 3,5 L engine! (With high compression, serviced ignition, clean injection system).

I would like to "try" another CPU, but before I speend a lot of money, I would like to hear some honest experiences/feedback/comments.
I´m talking about a 1985 635 CSI Euro-Version without catalyist and 218 HP, 310NM, using high octane petrol.

Long text for a short question: Are they chips worth or classic ebay trash?
Furthermore I would like to know what they change? Do they only put in more petrol, or change the ignition timing?

Kind regards from old Germany

hony

[Brucey]

EPROM chips are of most interest to people running US-spec models with low compression and emissions-friendly characteristics.

Long text for a short question: Are they chips worth or classic ebay trash?
Furthermore I would like to know what they change? Do they only put in more petrol, or change the ignition timing?

They are not all the same, some are undoubtedly trash for sure.

They can change fuelling and ignition mapping.

Because 1985 models were designed to run on leaded fuel the mapping of a standard 635CSi is 'wrong' on contemporary unleaded fuel anyway, assuming that all the sensors and settings are working correctly....

FWIW the vast majority of these cars that I have seen have various issues that mean that they are not working quite right anyway. This being the case it is unlikely that stuffing another chip in will do any good at all.

If you want to optimise your motor, you are best off installing a mappable ECU and having a session on the rolling road to set it up, to take advantage of the characteristics of your engine when run on the fuel that you use.

cheers

[tschultz]

Brucey's right.

I haven't installed a chip and don't see the benefit. Spend that $200 on better engine management and you can actually make some gains. Of course that's not as easy, but you will be able to get measurable results.

[Da_Hose]

I can only speak for the US spec. M6. Dyno proven results are available from various tuners. Mine has Conforti. Conforti dyno'd their chipped S38B35 at 302 HP (+48HP) and 271 ft/lb (+32 ft/lb) of torque. That's a pretty serious gain for the $250 you spend. Korman matches those numbers with their chip and engine build.
Jose

[honyama]

Hello,
Thanks for the comments.
They set the iginition timing earlier and open the valves for a longer time? No further changes? Okay, our vintage cars dont have more adjustmensts, i forgot.

Does someone else have experiences with the 218 hp Euro engine?

How can you get so much more power out of a M6? Crazy!

[tschultz]

I can only speak for the US spec. M6. Dyno proven results are available from various tuners. Mine has Conforti. Conforti dyno'd their chipped S38B35 at 302 HP (+48HP) and 271 ft/lb (+32 ft/lb) of torque. That's a pretty serious gain for the $250 you spend. Korman matches those numbers with their chip and engine build.
Jose

From my experience, those numbers are total gain across the entire rev range. I haven't seen dyno proof to know for sure. But here's some relevant info regarding Miller Maf possible gain with tuning:

http://www.mye28.com/viewtopic.php?t=121764

Using MY stock ECU and airbox, he dyno'd at: 211rwhp & 209 torque
Miller MAF stock settings: 220whp & 215 torque
Miller MAF tuned on the dyno: 234whp & 226 torque

[GazM3]

An optimised chip can work for sure as the timing numbers especially for 80's bmws are very conservative especially on the low compression (unleaded) engine which was designed to run on Ron 91 fuel rather than the ron98 commonly available now. Another handy benifit is you can have a few extra rpm before the cutout. Peak power will still be at around 5300 but the m30 still makes handy power to 6800 or so. Some sporty driving in a manual it's nice to have that extra few rpm.

You can also play with the airflow meter to get much better part throttle performace but it's best done by someone who know what they are doing and with the aid of a wideband sensor with air/fuel gauge.

So the short answer is yes most chips are worthy. The eat chip from Canada seems to work nice. I used the fritz bitz chip form the uk for the m88 and it seemed to respond well to it. Not massive gains like the us m6 but gains netherless.

[wattsmonkey]

That's interesting Gaz,

I've got the Fritz chip but haven't fitted it. They told me the fuelling would need to be tweaked at the AFM to make the most of it with the Fritz headers, which sort-of makes sense to me.

Cheers,

Rob

[Dan101smith]

Hello,
Thanks for the comments.
They set the iginition timing earlier and open the valves for a longer time? No further changes? Okay, our vintage cars dont have more adjustmensts, i forgot.

Does someone else have experiences with the 218 hp Euro engine?

A chip can't open the valves for longer.

I've got experience with the 218bhp Euro engine. My experience is that it's a waste of time and money, and the Fritz chip in particular.

[BamaE24]

My car ('89 US spec) has an EAT chip in it. What I have noticed is not what I expected. The butt dyno can't give a good opinion though. The hp/tq gain may be there, but it hasn't changed agressively. What I have noticed it's done is smooth out how the engine runs/sounds and how it "feels like it delivers power", it also does better as the rpms go up than it used to. It isn't as winded up towards the top-end. It'll rev out at 6500rpm with the EAT, though I don't drive it that hard. Normal driving around town doesn't feel any different at all, lower rpms feel the same. I leave her in S mode FWIW.

[jacko]

I talked to Conforti a year ago about those gains..... He said all his records went to Turner when he sold that product line to them, but admitted 40+ hp seemed like a lot. I'd spend the $ if I had any confidence it was anywhere near that.

[francoid]

I chipped the M6 20+ years ago. My opinion is the gain is minimal on the normal rev range, it mostly comes from raising the redline (which in itself is debatable).

[earlyshark]

A few years ago I did a Conforti chip in an '85 635 USA, the owner could feel the difference. When I did the 5 speed swap (265) he liked it even more.