Lorenfb

To many, there appears to be some mystical property associated with
performance chips. To some, Porsche/Bosch lacked the knowledge in
the early '80s to fully maximize the potential of the 911 Carrera engine.
Others believe that "savvy" computer programmers have "discovered"
special programming techniques for achieving additional performance.

To demystify these performance chips and determine what they actually
do, three performance chips as used by some on Rennlist were "opened"
and analyzed. This included analyzing all the fuel & ignition maps. As a
comparative base, a stock '88/'89 Porsche Carrera chip was also analyzed.

The results indicate that all the performance chips have kept the fuel
maps essentially unchanged from the stock '88/'89 911 Carrera.
The other similarity between all the performance chips, though, is the
"pushed" ignition timing maps. The timing maps of these chips have
advanced the timing as much as 10 degrees over the stock maps to
a value of 50 degrees advance BTDC. This 50 degree advance value
exceeds by more than 10 degrees what Porsche techs consider the
maximum advance for octane levels and fuels available today.

In many cases, the "pushed" timing maps have advanced values which
may result in inaudible pinging/detonation under certain loads, even
though the timing has been advanced only a few degrees beyond stock.
Obviously, for those using the performance chip which "pushed" the
timing to 50 degrees, the pinging/detonation will be very noticeable.

Since the '84-'89 911 Porsche Carrera lacks the knock sensors of the
964/993, this can be very problematic for a 911 engine. Actually, the
964/993 may also be confronted with pinging/detonation when their
ignition maps are "pushed" beyond knock sensor control. The 964/993
can only retard the ignition by a maximum of 9 degrees.

To minimize the data presented, selective ignition map values are shown
for the stock '88/'89 chip and three commonly used performance chips
as mentioned by Rennlist members for the '84-'89 911 Carreras.

Based on the data, it now becomes obvious why performance
chips "feel" the way they do. The same results were achieved with the
911SC by just turning the distributor to advance the timing, although
without as much control over the advance curve. The same problematic
issues arose then as now with the later Carreras, i.e. pinging/detonation
as a result of engine loads, temperature, & fuels.

There was nothing new then as there's nothing new now, except some
become mystified and pay more for the same effect from a performance
chip versus using a socket wrench on the 911SC! Furthermore, the performance
chips available now are basically the same as those supplied 15+ years ago,
i.e. "pushed" timing maps.

Hopefully, the results of the analysis will provide an insight into what
a performance chip really does and the excessive timing values used
to achieve a noticeable effect, e.g. timing advances > 40 degrees.
As many have indicated, Porsche may have been conservative in the timing
values used, but exceeding 40 degrees can't be considered good tuning,
it's ridiculous & damaging to the engine.

Note: The data set for each chip is a 12 X 12 matrix plus a WOT
vector. The selective data below indicate where variations exist in
in the matrices and vectors from the stock chip. The data points
not shown were basically the same as the stock values. The data
were determined by using an EPROM editor on a PC which provides
actual timing advances & fuel enrichments.

82Targa

Interesting, but could someone expand on the significants of 'pinging' and 'detonation'. I understand that they are the results of pushing the timeing to far, but what are the negative effects from them?

J. Brinkley

regardless of what anyone says of Loren I always learn something, and have always solved my idle/mix/O2 etc, problems using his advice, and or checklists. I always come away smarter, or maybe less ignorant because of his knowledge.
He just comes across as a dick sometimes. But then lots of people do
My sincere thanks Loren

NOH20

I have a Wong chip in my car tuned for an '86 with SSI's, dual in single out muffler, and 94 octane gas (Sunoco). My car has never pinged in hot or cold temepratures and never hunts for idle as it did previously. With that said, the PO had an Authority chip in the the DME before I replaced it with Steve's chip.

I'm not an opponent or proponent of performance chips, but from my experience Steve's chip was a big improvement over the Authority chip. I'm sure the stock chip is as good but I don't have one to compare with my Wong chip.

Dan Cobb

Loren,
Could you please elaborate a bit on your test results:
Specifically;
1- What brand and octane rating was the fuel used?
2-What spark plugs and wires?
3-What was the inital timing set to at the distributor?
4-Which version of DME was used (2K or 4K)?
5-Were the test runs dynoed as well?

Thanks,
Dan
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fixnprsh

performance chips set timing curves for higher octane gas which is required for use.

To protect themselves Porsche went conservitive on their mapping to error on the side of saftey for someone who is traveling and decent gas is not availible, or the cheap skate who wants a Porsche and puts the lowest, cheapest gas availible. That way the motor wont suffer from detonation in extreme heat on low gas. So thats why with a chip you use 91 octane, or higher if availible.

Chips are like tuning a set of carbs in the old days, just figure out what it needs and write a map accordingly. Just as you would fatten up the mixture and adjust your timing curve by putting a bigger cam in a 67 427 Vette.

So by the same rules when you get a 3.2 Carrera with 964 cams, extrude honed intake and exhaust, you do the same, except it is done by the DME with a chip and you dont have to get out the timing light. I've seen more damaged cylinder walls from improperly cleaned K&N filters than I've ever seen a chip do. They wont hurt your engine unless you have a whammy dammy hybrid turbo motor with MFI and you cook it on the dyno before you get it mapped right. I can get a GT2 to around 600 fwhp with nothing more than a chip and some 93 octane, 570 here in Cali. better living through technology.

Lorenfb

1- What brand and octane rating was the fuel used?
2-What spark plugs and wires?
3-What was the inital timing set to at the distributor?
4-Which version of DME was used (2K or 4K)?
5-Were the test runs dynoed as well?

None of the above were relevant/considered, as the analysis was just to show what
was modified in a performance chip to affect the performance enhancement "feel".
So, anytime you "push" the timing over stock, ANY engine always "feels" better.
There's nothing unique/special about "hacking" the ignition maps as shown by the analysis.

r911

the significance of 'pinging' and 'detonation' (two words for the same thing, except that pinging can be heard) is that they will, if prolonged, destroy the engine

fixnprsh

I would like to see the A/F ratios, pulse width in m/s, and fuel maps for these four chips and the dyno charts so we can draw our own opinions. Every chip I've ever installed in a Volkswagen, Audi or Porsche comes with a 30 day money back guarantee, I've never had anyone call saying they dont like it and want a refund, or dont feel a differance. I've also had customers tell me their mileage has inproved in later cars. I've also never seen any ill fated side effects either and have had customers running chips with greater timing, boost, and fuel in daily driver turbo cars for 70K+ with NO ill side effects (unless you count tickets). My own GTI has 130K on it and it runs as strong as the day the chip was put in with NO ill effects.

All these performance chips are doing is taking into account the known good fuel that will be used and thats where the "feel" is. Dyno numbers dont lie so post them up along with the other stuff I mentioned since you have access to it all, or drop your preaching.

webini

Loren:

1. Have you ever driven a Carrera with a performance exhaust and one of Steve Wong's chips?

2. Are you currently or have you ever attempted to market your own chip?

r911

'drop your preaching'

- It's valid to say he presented selective information and to challenge him for full information, but not to say he can't present his point of view - even if biased.

Ed Hughes

And the point of this thread is what?

Dave Thomas

IF Loren's claims were true, then surely at least one of the hundreds of Steve Wong chip users would have experienced some engine damage by now. Hasn't happened. If you can prove it has, please provide such proof or stop making these ridiculous claims.

Ocane rating IS totally relevant. Higher octane and a performance chip go hand-in-hand. No point in using higher octane with a stock chip - there's no benefit. But using higher octane allows one to enjoy the benefit of more advance, safely.

Edward

I've seen (with some amusement for some time) many "chip" threads and the hammering that Loren gets. I don't know Loren, but I find that from my outside perspective judging from what I've read in this thread and others in the past, there are many who disagree with him, then go on to berate him for it. Forgive me, but I don't get it. In this thread, for example, he has simply shared his findings and you may take them for what they are. But why the animosity? If you don't believe it, then don't. But I have not yet witnessed him trying to gain anything (e.g. hawking his own chips) from his disagreements with "chipping."

In my humble experience of backyard tuning & modding motorcycles/cars for 20+ years (I know it's pure amature stuff but you learn things along the way if you pay attention), I understand how timing alone (in the absence of fuel delivery alterations) affect performance. So if his findings are accurate (and why would one doubt them, is my contention), then take them for what they are ...his findings and his conclusions based on those findings.

Personally, what he says makes here makes sense. We all know that Porsche set up the maps pretty conservatively for the DME cars, so we know that the "lowest common denominator" to run the cars safely isn't the fastest setup ...no surprise there. Compound that with the fact that Porsche's octane requirements had to account for the possibility of poor fuel. So if one drops in a chip which advances timing and you pop in some premium fuel, you'll get more power. Guess what, no surprise there, either. Loren's statement here, if I'm reading him correctly, simply states that you can do this on your own without that magic chip ...again, no surprise there as we backyard monkeys have been doing this for years. Further, he alludes to detonation that is inaudible. This is very important since detonation easily escapes our hearing. Beyond the obvious point that many replace their mufflers with louder ones or that some are not attune to knowing what detonation even sounds like, the very nature of our aircooled engines would mask at least a portion the tell-tale sounds of destruction. C'mon, you can hear "all" detonation at 5K RPMs with the wind rushing by and as you focus on the tach and the road? ...I guess you're better than I am, or just more trusting. Also probably why Porsche went with knock sensors on the 964+ cars: to tune more aggressively WITH greater safety to the engine.

Frankly, I know nothing of the performance chip tuners or what they do specifically. But can we at least allow the possibility that Loren et.al. are simply sharing their experience, and then we can draw our own conclusions w/o getting personal? And this is in no way an attack on the chip makers that market their wares honestly (though many don't). A responsible tuner will be candid AND specific as to what his chip does and does not accomplish. All just in my humble opinion of course, so please feel free to disregard me and the (limited) experience I've gained over the years.

And as a final note, my personal thanks to Loren for providing his findings on this subject. Though I am interested, too, in the info that he omitted (by his own admission, and for the sake of brevity). I have no horse in this race since I choose to keep my 993 stock, and my SC, well, is an SC and not a DME-er. But as a gearhead myself, I want to know, even if it is purely academic.

Perhaps, Loren, you can let us know what you left out of your summary.

Edward

Dan Cobb

I'm certainly no expert when it comes to performance chips, HOWEVER...
I cannot understand why you would suggest that none of these are relevant without having recorded the data and PROVING them to be irrelevant.
I would be willing to bet that changing any/some of the above 'control factors' might yeild different results for ANY chip tested.
This is why I asked for the information, because I would be willing to bet (yep, once again!) that at least 1 of the aftermarket chips tested was designed to capitalize on at least 1 of the above 'control factors' NOT being left to a irrelevant/not considered condition (i.e. designed to run on higher octane fuel, for example).
I've also noticed a significnat difference in the way my completley stock 3.2 runs depending on which brand of fuel I have used. This is CERTAINLY going to impact the data derived from a real test.
If nothing else, I can't see why you bothered with such a 'test' if you didn't at least record what type of fuel was used and what the inital timing settings were.
It seems like the timing advance created by a chip will COMBINE with the settings at the distributor to achieve the values provided in your test.
So the question is this: Is it better to use advance created by the chip, or advance created by rotating the distributor, or a combination of both to achieve higher performance without sacrificing engine integrity, longevity, and overall capability?
I also thought running with too much advance would likely cause the engine to run hotter. Does this have any impact on performace in the long run? Likely, but who knows for sure WITHOUT DATA?
Did you even bother to record any engine temps during your test or is that also insignificant? Were the chips tested sequentially in a progressively hotter engine or were they tested on a stone cold motor?
I'm beginning to think that your test matrix is short a few reference points, not to mention it appears to be a prime example of how not to run a controlled expirement. Perhaps a quick review of "Design of Expirements" is in order on your part.
Installing a chip cannot be done (in my opiniion at least) without setting the engine up to accomodate/work WITH the chip.
(Perhaps this is why one very popular vendor provides different chips based upon the configuration of the engine, exhaust, etc.!!!???)
Although.... those factors might just be irrelevant as well.
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