Lorenfb

Sorry for no reply. I assumed your question was rhetorical.

A chip alone won't allow you to optimize the AFR at 12.6 and hold it
there. It your chip supplier is telling you that, he's got a credibilty
problem. You need a feedback element like a wide band O2 sensor
with its' electronics to control the AFR. A narrow band O2 will only
set the AFR to 14.7 without modifying the fuel injection system with
some front-end electronics.

What provides the simplest approach for racing is to tweak the air
flow meter. This will get you great throttle response without having
to worry about pinging. If you really want performance, the best
approach for optimum AFR for racing is to change the fuel system
to an aftermarket one.

Yes, you do need to have the stock chip modified for an increased
redline. This can be done without affecting the fuel & ignition maps,
though. Autohority (www.autothority.com) and others can
provide you with this capability.

Addtional Note:

Once the throttle reaches about 2/3 to 3/4 full throttle, the air flow
meter maxs out. Since the DME uses the air flow meter & RPM to
determine engine load, the DME can't really deterimne the load
accurately after this point which further compounds the pinging
problem.

Steve W

Wrong again. Pay attention, EFI 101, wide open throttle mapping ignores any AFM or O2 sensor inputs, therefore the WOT injector timing if programmed to say 12.6:1 afr to match the engine configuration or modifications of the street or track car, stays there, all day, all night, period. Take a look at some of the dyno charts. Second, you can set the Motronic part throttle AFRs to what ever particular value, without using some hokey complex wideband setup. Reread what I already stated in this thread. This is what is called open loop. By disconnecting the O2 sensor, or programming the eprom to ignore the it, you can program in whatever part throttle AFR you want at each particular rpm and load point, and it will stay there, all day, all night. The elegance of this approach is that you can set a more fuel efficient AFR at lower loads, a richer AFR at progressively higher part throttle loads. Simple, reliable, and inexpensive without additional complex unreliable add on circuitry. How did you think the European cars work without their O2 sensors?

So you conceed that the stock Porsche system is not optimal, and can be improved upon to a level of what you consider 'great throttle response'. You have just contradicted all your past statements claiming that the improvements in throttle response chip customers have been reporting were in their head. Tweaking the AFM basically increases the fuel quantity on acceleration, part of what a performance chip does, and why they produce 'great throttle response' as you state. Unfortunately though changing the AFM tension and settings throws off the load points that part throttle igntion maps need to determine the corrrect igntion timing. As a looser spring tension will indicate higher engine load, the ignition timing will retard to a lower value, decreasing power and fuel efficiency. Tinkering with the AFM also does not change the WOT air fuel ratio as it is ignored at WOT. This does absolutely nothing for full throttle power, and with modified or track cars, such as Mr. Achard's case where additional fuel is needed, it can lead to pinging and engine damage, unless additional fuel is provided, which can only be provided by reprogramming the chip.

All conjecture and theoritical. I'll let you in on a little secret. The AFM does not bottom out at 2/3 to 3/4 throttle. It in fact does not bottom out until it hits approximately 5000 rpm, at near WOT, at which point if you still haven't engaged the WOT switch, the DME defaults to a superrich AFR, which does not cause pinging. In every other region, the AFM is still provided an accurate load signal and as the part throttle ignition maps have a multitude of load and rpm points of reference, it does not compound any pinging problems.

All this from someone who claims using synthetic oil in a 911 engine is bad and will accelerate valve guide wear as you stated in the following thread. Great going Einstein.

https://rennlist.com/forums/showthre...c&pagenumber=2

Lorenfb

"By disconnecting the O2 sensor, or programming the eprom to ignore the it, you can program in whatever part throttle AFR you want at each particular rpm and load point, and it will stay there, all day, all night."

Based on the above quote, I guess engines don't really need an O2 sensor
after all, e.g. 14.7 for optimum emissions. Furthermore, I guess mass air flow
sensors are of no value either, since it's not necessary to worry about the air
density at high altitudes affecting the AFR, since the AFR can be controlled
fully within an EPROM. Too bad the automotive industry hasn't discovered
this yet.

FACT - You can program in any fuel value/quantity, but the air quantity/mass
is a variable somewhat inaccurately measured by an air flow meter (mass air
flow sensor)! Hence the need for a feedback element - an O2 sensor to maintain
an AFR of 14.7 for optimum emissions. THAT'S WHY THEY'RE USED!

Also, remember that the position of the air flow meter is a function of load,
and as a result there are load conditions where 2/3 to 3/4 throttle will yield
a max on the air flow meter. Maybe that's another benefit of mass air flow
sensors.

It can't ping? Tell it to those that have broken piston rings!
Bottomline: Pinging can occur in any engine under certain conditions
without the use of knock sensors. THAT'S WHY THEY ARE USED!

Speaking of EFI 101, someone may have been asleep for that lecture
or doesn't USC ofter that course (They do lack a lot of REAL courses.),
or maybe someone's spent too much time watching scrolling 1s & 0s
or Matrix movies.

So as I said, listen closely on those hot days and check those plugs for that
white metal stuff. Porsche had a reason for not pushing the ignition timing
for max performance, i.e. engine life.

If you really think that you must have a performance chip, then
visit these web sites; www.autothority.com, www.weltmeister.com -
a Dinan chip). Those chips were developed on dynos and not by playing
on a laptop with trial/error chips, e.g. "If your car runs a little rich, we'll
try again and send you another chip. Hey, life's not perfect and you can
help test the chips until we get it right." Remember, as the saying goes;
"You get what you pay for.".

Most Porsche people don't recommend switching to a synthetic oil when
the engine has been run for many years with petroleum based oils,
especially for high mileage engines.

Diamond Blue

Loren, Until you can show the tests that YOU have done to backup what you are saying, your credibility on chips and synthetic oils are zero. Seems that Porsche remapped their own chip in G cars to be more aggressive and recommends synthetic oils. According to what you have been saying about these subjects Porsche must be wrong. If Porsche had any issues with these they would not have done the more aggressive chip or recommended the use of synthetic oils. Evidently you must be right and Porsche wrong or maybe the other way around. What is it?

Lorenfb

For those really interested in race/track car performance fuel injection,
check out this web site (www.electromotive-inc.com). The fuel injection
system provided utilizes O2 feedback to control the AFR for max performance.
This should help explain why you really can't fully control the AFR without
some form of exhaust gas feedback.

Steve W

Really?? From the Electromotive Tec3 manual:



Great work for helping restate what I already repeated twice in this thread: that for performance such as at WOT or high load situation, you run 'open loop' which means you DO NOT utilize the O2 sensor feedback.

John in Norcal

Good job, Steve!

I don't understand half of what is being discussed and argued here but I'm happy with your chip in my car.

Lorenfb

It's kinda like not understanding what you've put in your car.
But like most, sure feels good, even though it now makes funny noises!

John in Norcal

Your analogy is flawed. Have you ever been to a restaurant and loved the food yet don't know the exact recipe. Does that invalidate your claim that the food tastes great?!

I'm a humble enough person to admit that I'm not an expert in automotive engineering like some others on this board. But I've owned many Porsches have been driving them for years. I'm merely stating that my cars with Steve's chip runs great ...nothing more and nothing less.

One more thing ....my car does not make funny noises.

Lorenfb

Really now, you don't care what you put in your car only how it "feels" in the end.
That's hardly the view of a typical Porsche owner.

John in Norcal

I do care. That's the great thing about these internet boards. You can check the feedback from other owners before you decide what to put in your car. I think there are enough people here and on the Pelican board that feels the same about Steve's product. I'm not the only one.

I did extensive research on the Upsolute chip before I put it in my 996TT. Alot people said a $500 chip for a twin turbo must not be as good as the $3500 GIAC chip. Well, after enough owners reported excellent results with the Upsolute product, I went ahead and pulled the trigger. My 415hp car now puts out over 500+ hp. I would say it's the best $500 I've ever spent on a car mod, even better bang for the buck than Steve's chip.

I don't try to figure out how Steve or Upsolute programmed their products. I'm just happy with the results. If that makes me different than the 'typical Porsche owner' as you say, so be it.

Have fun,

Lorenfb

So, what are the long term effects? Don't know, do you.

And for that 996, just wait until it's emissions test time.
Those cars have enough problems as is without mods to
the engine, the DME, and/or the emissions control system.

To use your quote, "even better bang for the buck", beware of those
pistons rings and connecting rods as they get stressed beyond Porsche's
design limits with your performance chips.

Your statements exemplify your naivete. In attemptiing to "squeeze" an
additional 85 HP without knowing the effects to the engine, you do exactly
what I stated in my post, i.e. add-on mods you know little about other than
marketing hype. Furthermore, you and others use testimonials from new
Porsche owners or ones who have little to no technical background when
it comes engine knowledge, only that it "feels" good.

qbvu911

Guys, life is to short to worry about engine life. By the way, what is the life expectancy of 88 3.2? My doctor told me that I can have maximum of 10000 ejac! I do not want to save 9800 when I hit 60 years old. Do now

g-50cab

I'll pull a Loren here and ask for proof. I want to see all the Steve Wong chipped engines that have been ruined with pinging and detonation. Post em up!

In the same context, I want to see all the engines ruined by synthetic oil - come on - post em.

In the mean time - I'll just be a satisfied wong chipped customer.