Sumtoc

Have a 95 C2, I am the 3rd owner. I shopped pretty hard and actually drove 5-6 other 993s before I drove and bought this one. It pulled much better and seemed stronger to me.

Was looking forward to putting in one of Steve's chips, pulled the ECU to get the (partially rubbed off) PN to give to him and noticed that the alum prongs on the cover had been bent, cover removed. So in I went, and presto, there is an Autothority chip. Doh... no wonder this car drove differently than the others. I had asked the last owner if he had done any mods, he did not, so it had to be one of the other POs. No record of this chip change and of course no stock chip to be found. So, kinda disappointed since now it seems that one of the easy (instantly gratifying) mods has already been done.

Question is, has anyone had both chips, and if so have they seen any difference? Would you think that the difference would be worth the $500?

BTW, spoke with Steve about this at length. What a pro. Very helpful and patient. Been fiddling with cars for 30+ years, have not met better.

Lorenfb

A performance chip is a performance chip. They're all basically the same, i.e. they
all "push" the timing maps to further ignition advance. Check out this web site
( www.andial.com ) on the FAQ page for Question #2. This info is most applicable
to 964/993 engines with knock sensors.

Check out this info ( www.systemsc.com/tests.htm ) to get an idea of how much
the timing is typically "pushed" by tuners to get the performance "feel", even
though the data is for a 911 3.2.

Steve Weiner-Rennsport Systems

With all due respect to Loren, I'd disagree that chips are "all basically the same",...

Thats akin to saying that "all people are the same". Wide sweeping generalizations are simply not accurate: we all have eyes, noses, ears, etc, but certainly people (like chips) have different personalities and some are nicer than others.

As with most things; the "Devil is in the Details" and chips (people) are really no different in this respect.

Thats what separates one product or person, from another,.... Lumping everyone (and all products of ANY type) is summarily unfair, inaccurate and denigrates the good folks as well as all the properly designed & engineered products that are offered.

To Loren's credit, there are some poorly made chips out there that can potentially damage an engine from using the wrong fuel or from excessive RPM and I'm thankful that he points that out.

akolodesh

not sure how the other chips perform but I can attest to Steve's chip. It creates a noticeable increase in midrange power. More imoportantly (for me at least) it has never triggered a CEL.

jusafan

FWIW, I have a '95 C2 and I bought Steve's chip and have found it to be very good. The chip adds useful power across the rev band, but the difference is particularly noticeable between 3,000 and 5,000 rpm, where it pulls much more strongly in 2nd, 3rd or 4th gear than before. By far the nicest thing, though, is the power is delivered much more smoothly. With the stock chip, there are peaks and valleys, and after you get used to the car, you can feel them in the various rpm ranges. Now, with Steve's chip, there's much more smooth power delivery across the rev band. Of course, whether it is actually faster or not, I don't know. But I can say the driving experience is much better. I did a lot of research, checked with other chip manuafacturers, including Autothority, and liked what I heard from Steve most. He really knows his stuff, and I didn't want to do anything that might jeopardize the car. So I went with Steve. Best $500 I ever spent on the car.

That's my $0.02. LWFW is next. Steve's you'll hear from me soon :-)

Chris

Mankster

I have always felt its best to get you car custom mapped on a rolling road. We all know that there car to car variation when the cars were new, and as much as 10% on our used examples. So a standard off the shelf chip for a new car may not really be the best one for a car with some miles on it and other mods like air box/ exhaust.

PedroNole

DITTO!

Ruf-Dan-Ruf

Sorry this is long, hope it's useful.

Slightly off topic but Loren (or anyone), you say the chips advance timing, how do they do this with an engine that fires using a mechanical distributor?

This may be a dumb mechanical question! but I am trying to learn . I understand computers very well and have reprogrammed many car computers but they all used computer controlled ignitors for firing.

I have asked similar questions on different post about timing, ignitors, distributors etc and no one responds to my questions/statements. I am wondering if I am being ignored because I am so dumb or knowledge on the subject is scarce?

On topic now.

My opinions on chips go like this.

Note this is overly simplified!!
The chip programmers use a car and write their maps for fuel, (maybe timing), boost etc and test it. This is done at a certain altitude(their location), with certain fuel, and with the modifications that that particular car has. The more they push the limits the greater the margin for error because the ability for the car to alter the master maps is limited.

The reason the ability for the car to alter the master maps is limited is because the car relies on mechanical devices, O2, MAF, MAP sensors etc to get readings about what is going on with the car. If one of these devices starts going faulty and sends wrong data it would be very bad for the computer to be able to alter master settings on the fly by more than 5ish or so %. i.e the O2 sensor starts reading rich in error and the computer drops the master fuel setting to compensate. The car now is actually running to lean but the computer thinks things are fine.

So back to chips. They are a pot luck install for each car because of the differences in fuel, altitude, car setup of the chip manufacturers car/location and yours.

I have seen MANY examples of chipping cars and getting worse dyno results than the standard chip. It's not that the new chip is bad but more that the new chip was bad for that car.

Wire-in computers are the way to go. You can get them altered/programmed for your car. If you make a mechanical change, new exhaust etc, you can then reprogram.

Just my opinion / flame away

JasonAndreas

Sumtoc,
Don't buy an off-the-shelf ECU upgrade that doesn't come without a money-back guarantee and then have your car dyno tested with and without the new chip. When people here on Rennlist actually try to measure the improvements versus relying on seat-of-the-pants BS the chips usually end up being removed (Tom W, what chip did you use?). Where are you located, there are a places that can dyno-tune your car which can get you 10+ measurable HP (the off-the-shelf chips rarely seem to have that luck). I still think it would be real fun to videotape a stock 993 accelerating against a chipped, regeared and new R&P'd 993 so that people could see what $10k worth of mods doesn't necessarily buy you.

Lorenfb

So, Porsche/Bosch lacked the "know-how" to maximize their engines via fuel
and ignition mapping? Please!

"A performance chip is a performance chip. They're all basically the same, i.e. they
all "push" the timing maps to further ignition advance."

As I stated above, most/all performance chips basically just advance the timing
for a stock engine. If no real intake or exhaust mods are made, NO benefit
can be achieved by fuel map changes. Therefore, they're all basically the same, with
some just "pushing" the timing more than others.

Bottomline: It's all a matter of how close you push your engine to pinging and/or
detonation. Check out the 911 forum to see pictures of an early 911 piston
where the rings/ring lands were broken the result of detonation. As Steve
puts so well about this problematic situation, "detonation maybe sub-audible".
Pinging/detonation is a function of; engine load, engine temperature, fuel octane,
and ignition timing. The results of all these input variables, determined how
Porsche/Bosch set the ignition maps and the safety margins for pinging/detonation.

Broken Pistons - 911 Forum

"One must remember that using one's ears as defacto "knock-sensors" will result in the kinds of damage shown above. You simply cannot hear everything that these engines are doing due to ambient noise levels. Sub-audible detonation breaks rings & ring lands over time if not resolved."

- Steve Weiner -

What was done 25 years ago on the 911SC by turning the distributor for more
advance with a 13MM wrench in 2 minutes had the same results. There's nothing
new here with performance chips now or 20+ years ago, or with any old 911 which
had a conventional distributor ignition with a modified advance curve.

chris walrod

So, why do so many people that have aftermarket 'chips' change to other brands of aftermarket chips and clearly note behavoir differences? Some worse than others.

I think what Steve is saying is that, yes, -all- aftermarket chips do advance timing and/or enrichen fuel delivery, but some more radically than others.

Ruf-Dan-Ruf

Emporers new clothes syndrome. they go faster as there is now less weight in their wallet

If done on a dyno and the chip is custom produced for your car then benifits can be made with a chip.

Still no one piping up how you can have a computer advance timing maps on a distributor fired car? Being this is the 993 forum and I believe all factory 993's use distributors???

Once again please correct me if i'm wrong, just trying to learn about these Porsches.

Scanners

I think what you most need to be concerned about, is how the DME interprets your day to day driving and somehow detunes you over the mnths till you next get a service and they blow all that info off the DME and you start with a new DME chart and it feels much perkier again..... for a while :-)....
Im looking for a switch somewhere to hit clear whenever i feel like it.
in the meantime disconnecting the DME cable under the seat for 3 hours gets to the same point.

Lorenfb

"Still no one piping up how you can have a computer advance timing maps on a distributor fired car? Being this is the 993 forum and I believe all factory 993's use distributors???" - Ruf-Dan-Ruf -

On the 964/993, the distributors only "point" to WHERE the spark should go and
not WHEN. The DME unit determines how soon before TDC (timing advance) that
the spark should occur. The rotor can be +/- a few degrees from perfect alignment
of the distributor cap plug element and not affect the timing. Only when the timing
advances too much does the spark jump to the wrong cylinder. Also, there's a
centrifugal mechanical advance on the rotors to maintain some alignment with
the caps with RPM.

Caveman

Sorry to be another ignorant driver but I thought the point of the chips being remapped was that they could be adjusted to reign in some of the tolerances that the car doesn not need like (for the UK) running at high altitude, running below -10 degrees celcius and stuff like that? Presumably, custom mapped chips can also be "tuned" to suit the particular car (a bit like fine tuning the carbs on a car where the supplier has given them jetted to suit the engine you described)?

Thanks and regards,

David