"I believe in keeping my 86 as stock as possible which includes leaving the stock chip alone and have been able to fine tune my air flow meter to give me all the low end torque and throttle response I need with great gas mileage at the same time.

I would suggest getting familiar with your air flow meter and learn how to optimize it to give all the performance you need before making any changes with a well proven DME." - Joe -

Joe has done exactly what I've done to my car and many others at many of my customers.
Once the AFM is tweaked on Porsches/BMWs, these cars are much more responsive
and provide better overall performance. With proper PMs, most AFMs never require
replacement.

Chips are great if you don't mind ping.
Mine's out. I can run 87 and no ping. Running 92, I still had plenty of it with the chip. Makes a difference in power until the PING kicks in at high RPMS, but in general, if the chips were better per se, Porsche woulda put em in there at the factory.

The dyno data speaks for itself.

Also, my owners manuel says to run 92 oct. , so putting in a SW chip didn't change anything I did. Gas is about 30 cents a gallon more in LA than here, so I suppose that may be more important out there than here.

Steve no longer writes on this board because of all the controversy drummed up a few months ago, But i will say I am happy with it and I bet 98-99% of his customers are too.

Loern:
How is the AFM tweaked? Is the spring tension adjusted, or the CO setting?
Thanks,
J.P.

Loern:
How is the AFM tweaked? Is the spring tension adjusted, or the CO setting?
Thanks,
J.P."

Both -

"The dyno data speaks for itself." ???

Not really, as there are mixed results

Loren:
Do you decrease the spring tension?
Regards,
J.P.

You'd be surprised what a little more tension could do. And if you should over do it, it's just as easy to back it off. Let the seat of your pants be the judge.

Try that with a chip!

Joe

Loren:
Do you decrease the spring tension?
Regards,
J.P.

Yes -

On my 88 the factory sticker on the fuel lid has 91 octane minimum which is and has been used in the car. I guess the factory must have increased that from your 84 Curt, Evidently yours must have been the early factory chip for the 3.2 since Porsche upgraded their chips to the "58" designation later on with the 3.2's which required 91 octane. Also I am curious as to other than severe detonation which we can hear, how you could detect what Loren keeps telling us we can't hear? Why would you want to run 87 octane? And Porsche did change the chip from the "57" to "58" to be more agressive. My engine should have grenaded long ago (84,000 miles) due to what I hear you telling us, since it has been chipped since 1991. Currently have the SteveW and Autothority when I got the car. Have not had any problems with pinging at any temperature. The price difference here is about $4.00 more for a fillup with 87 octane. By the way Loren, I get 27 mpg cruising at 85 and have no pinging.

http://forums.pelicanparts.com/showthread.php?s=&threadid=178204&highlight=Steve+ Wong+Chip+Dyno

Mixed Results?

Loren,

I think you just intimidated anyone who wanted to make adjustments to their air flow meters by the mention of 1.5 percent CO @ 2000 rpm. which, of coures, means access to a CO meter.

I have been adjusting airflow meters without the need to measure the CO on VW type IV's, 914 1.8's, my fathers 280ZX Turbo, 944 and Carreras for years without any problems.

Let's not turn this into rocket science but more like adjusting your carburator to make it run better like the good ol' days.

How many of us had CO meters then?

Cheers,

Joe

Loren:
Does 1.5% CO equate to a reading of 0.4-0.5V taken from the O2 sensor voltage (assuming the O2 sensor is working properly)?
Thanks,
J.P.

BMW uses the same system:

http://www.autospeed.com/cms/article.html?&A=2055

http://www.drivewerks.com/catalog/shopcart/MISC/POR_MISC_INNOVT_pg1.htm

"Several companies tried and the result was a slew of inexpensive lean-rich indicators that were only really accurate around 14.7:1. The rest of the time, the best these gauges could do was tell you that you were "richer" than 14.7 at wide-open throttle (WOT), which wasn't very useful."

http://carcraft.com/techarticles/116_0402_tune/

Joe

Another 1988 CE Cab here in New England
 

Check out this web site ( www.perfectpower.com/Technical_info/afr.asp ) for some
info on AFRs. The relationship to O2 voltage to AFRs is not as exact, i.e. nominal AFR
of 14.7 is about .55 volts at the O2 sensor. So for a good CO setting at
2000 RPMs, the O2 reading should probably be between .60 & .70 volts.
Obviously, this is not nearly as accurate as using a gas analyzer.

Randomly screwing with the AFM spring tension is like doing brain surgery with a rusty butter knife. Loren, for a guy who demands precise scientific data from everyone else, you're pretty lax with your own methods.

Again, you ignore the most current data which disputes your outdated point of view, and you focus on old information that doesn't have anything to do with Steve Wong's chips. Give it up.

Why so much controversy here. Is it possible to modify the spring tension on the AFM to increase response, yes or no? Bosch Performance Hanbook has a chapter regarding the K Jetronic AFM spring tension, the only warning is not to make it to slack and it may affect emissions. If one is not concerned about emissions, it shouln't be an issue.
Couldn't a combination of AFM and perf. chip work?(This should keep both camps happy).
j.p.

What is "ping" and how would I notice it? (only at high rpm?) I ask because I just installed Dansk pre-muffler and am about to install Steve W chip. Can ping be avoided by adding octane booster to the gas?

"Randomly screwing with the AFM spring tension is like doing brain surgery with a rusty butter knife."

Wavey,

This is not brain surgery any more than it is rocket science.

I do not consider it random when every notch of added or subtracted spring tension is noted, tested on the car, repeated, adjusted, and tested again until satisfied. And because every starting point is indexed, there is never any problem setting things back to stock.

Of course if you've never done this before, I can see how you might think of it as brain surgery just as I did when I ran my first natural gas line branch to my kitchen electric cooktop to convert over to gas.

It all looked like brain surgery and rocket science until I got started and got my hands dirty.

So try to think of it more like getting your hands dirty or getting your feet wet.

Cheers,

Joe

Hello Joe:
How many teeth did you reduce the tension on your AFM?Did you also re-index your wiper arm? Do you have a stock chip?
Thanks,
J.P.