Steve W

First of all, if you knew how a wideband worked, and the fact that it requires at least 45 seconds warm up time before starting the car, or it would be quickly ruined, you would realize that it would be an extreme inconvenience to the typical user. Second, the electronics associated with a wideband are much more complex than just trying to read the voltage off a wideband. Trying to achieve the controlled air fuel ratios such as you proposed, 12.6:1 at full throttle, 14.7:1 or whatever at cruise can be simply done by programming the chip as such and ignoring or disconnecting the stock O2 sensor. This is basically how a European chip is. The simple way to do it is program the lower load regions of the part throttle fuel maps to between 15.2 to 14.7 for good fuel economy, and progressively richen the higher load regions to the air/fuel ratio for maximum power. WOT ignores any O2 sensor or AFM inputs anyways, so that is typically programmed with the air fuel curve for maximum power. You are just making it too complex.

With respect to pinging, as long as the ignition maps are not overly aggressive and matched to the fuel octane a user used, and the fuel maps are rich enough under power, it is not typically an issue. My ignition maps are typically much more conservative than 'other' chip companies that you may know about. In addition, I implement modified ignition retard curves based on air temps, such as hot weather summers, so in effect I can dial in as much as 6 degrees or more of overall ignition retard if the ambient temps exceed 100 degrees. This is something I do not think other 'chips' implement and take advantage of. Does this mean pinging will never occur? If the customer's car has other mechanical issues such as heavily carboned pistons and valves, and clogged injectors, no, but it goes a long way towards creating an appropriate margin of saftey and why customers typically toss their old 'pinging' chips to me after replacing it with something more appropriately programmed.

Lorenfb

Right! Some more B.S. The analog to digital converter and the microprocessor
within DME max out with the engine temp data once the engine has warmed up;
about 10 to 15 minutes. After than, the microprecessor doesn't "see" any more
changes in the engine temp.

So, unless the complete DME firmware in the EPROM was re-written, I seriously
doubt that the temp is being used to set minor changes to the timing; i.e. selecting
other ignition maps. It's very easy to change the timing offsets within the
EPROM, but it's very difficult without a MAJOR redesign to add additional temp
maps especially for temp changes which aren't seen by the microprocessor.

Again, let's all wait for the hot weather and see!

Diamond Blue

Same **** from Loren again attacks and no personal (Loren, your car's tests to back up what you are talking about) stats. Again my car is in great shape 80,000 miles after 13 years with a chip in it. Steve provided data to back up what he says. All you can do is say this is B.S. Can't say we seen YOUR TESTS to prove your point yet. Well lets see it?

Steve W

Want some cheese with that whine? Frankly I'm not going to disclose with you or anyone how this is done, but I assure you, you have no idea.

Lorenfb

Based on the following quote, what can be concluded?

"In addition, I implement modified ignition retard curves based on air temps, such as hot weather summers, so in effect I can dial in as much as 6 degrees or more of overall ignition retard if the ambient temps exceed 100 degrees."

1. So during many of the summer months, don't expect any real improvements or,
2. With 6 degrees retard, expect possibly less performance than from the stock
Porsche chip, or
3. Could the DME be retarding (power loss) during unnecessary temp conditions?

How about load? Pinging not only results from temp, octane levels, but also the
key factor of engine load. There may be normal temp days when climbing a
grade causes sub-audio pinging.

This is why most shops these days no longer recommend chips as they did in the
late '80s and early '90s. Could all the above indicate why Porsche started using
knock sensors with the 964 in '89? That's the only and most effective way to
optimize ignition timing and thereby avoid engine damage the result of pinging.

special tool

Guys - it looks like you are being sucked in by a person with a social/mental problem. They are not listening to evidence - why would you continue to argue with a monkey?

Lorenfb

Isn't interesting how very few people have contributed with intelligent posts.
The typical post is either name calling or posts about how the chip "feels".
You'd think you might expect more from a Rennlist forum.

rzepko6194

Loren, do you care about the actual decible range of your car stereo or just how it sounds? Are more concerned with the actual G-Forces your tires can generate or just how the car handles? A "normal" person would be concerned with the latter in both cases.

My Carerra idles better, is much quicker off the line and has better drivability. What does the dyno show? I have no idea nor do I give a crap.

What more could you ask for a lousy $280?

JP

1987 Carrera Targa

993chaz

Lorenfb,

Who cares about intelligence as long as we are happy with our cars and what we do to them. You need to chill!!

James Achard

Loren, How would you suggest I go about adjusting my A/F ratio without changing the chip( this is a Club Racing car so I would like a ratio of 12.6). I also want to increase my rev limiter.

James

Steve W

LOLs! Why don't I just post the code on the internet and let you copy it?



Anyone who knows anything about programmable EFI systems knows that the ignition and fuel maps are 3 dimensional and load vs rpm dependent. Are you really that ignorant, or are these just your continued tactics to instill fear amongst those not in the know? Maybe you should go to my website and learn more about the fuel and ignition maps, or just stick to rebuilding alternators and old Bosch CD boxes.

Except of course when it is your ingenious idea of a wideband with a performance chip done by you, then it's a brilliant product. What hypocrisy.

Lorenfb

As usual, missed the key point, as has been the case many times.

Performance chips advance the timing since additional fuel yields little.
With the additional timing advance comes pinging which becomes
worse with additional temperature and load. So when the designed
worst case load (predetermined on a dyno by Porsche) occurs and
the performance chip provides an additional advance offset over the
stock chip at each RPM, pinging occurs.

Without having knock sensors to deal with the additional advance offset
for the worst case load, pinging occurs. The performance chip can't be
programmed for max performance because it doesn't know in real time
where/when pinging will occur. The DME uses the air flow meter and
RPM to determine load to set the timing but can't determine the pinging
condition and as a result must always assume a advance timing safety
margin (stock Porsche chip) to avoid pinging. To get a performance increase,
the chip eliminates the margin or reduces it to a point where pinging
occurs, i.e. the DME never really knows what the real load is, it only
has a proxy for it (air flow meter & RPM).

Thus, if it were possible to compensate for additional temp pinging,
additional unknown engine load conditions still will cause pinging which
requires a knock sensor to avoid the pinging, e.g. the 964 and later
Porsches, as the timing is "pushed" for increased performance.

As I said, there's always a tradeoff, i.e. more performance, less/no
margin of safety from pinging.

James Achard

Actually, I think you always miss the point. I find it intersting that you always ignore my questions and data when I post them. My car is a track car, therfore I have different needs than most folks on this board yet you feel compelled to beat into everyone that all chips are bad, regardless of the application. This issue is not black and white, as you portray it but instead has many grey areas which is something I feel you have a hard time understanding.



Cheers, James

Lorenfb

The points I've made apply to the average stock street Porsche, not a race
car where if the engine gets destroyed it's just a bad weekend.

Learn how to drive better by spending your money on a DE versus wasting
it on a chip. You'll probably turn better lap times. Good drivers don't need
to rely on chips which do little to improve the lap times.

James Achard

Ummm, I do drive my car(20 DE days+/- plus seven races a year). I have a chip too. Does this make me a bad driver? According to your logic, it does. But, as you said, it does improve laptimes. Please tell me how this is bad in a racing environment. Once again, you have not addressed my question in my previous post. Why is this so difficult?

James