Performance Tuning - The Myth -
 

Most are under the impression that the so-called 'performance' tuning of a stock
engine is an effort that is specialized requiring knowledge beyond simple
automotive engine basics, and that the effort maximizes performance
beyond what Porsche was capable of achieving when they developed their
engines without any compromises or trade-offs. So what is 'performance'
tuning for a stock unmodified engine really?

Well, the reality is that performance tuning is neither an effort requiring any
knowledge and capabilities beyond what most back yard mechanics knew
when the internal combustion engine was first developed nor yields any
additional performance without engine compromises and trade-offs. The simple
fact is that performance tuning is nothing more than increasing the timing
advance beyond what was specified for reliability by Porsche. Furthermore,
the hyperbole of tweaking the AFRs for added performance yields basically
no performance improvement once the AFRs are within one to two points
of the ideal AFR of 12.6, which is the case for a factory stock engine.
Thus, it's mis-leading to most to indicate that tweaking the AFRs will improve
performance for a stock engine.

Dyno tests (see below) have demonstrated on a 911 3.2 engine, whether
stock or non-stock, that for every one degree change in the advance timing,
a three to four horsepower change occurs from about 4500 to 5500 RPMs.
Many 911SC engine builders were aware of this effect and achieved a simple
performance effect by just loosening the distributor and slightly readjusting
the timing a few more degrees advanced, as has been the case for many
years with all early non-ECM (engine control module) controlled Porsche engines.
Obviously, this effect is limited to small changes in the timing.

So based on this simple and basic effect, it can appear to a Porsche owner that
so-called performance tuning has really accomplished something significant when
in reality it has just compromised the margin of engine safety that Porsche included,
to just achieve a marginal performance change. This 'tuning' is nothing more than
a minor engine tweak requiring no real testing and evaluation, as would be the
case for a major engine development effort. Additionally, this effort hardly requires
any real knowledge other than being able to buy a laptop, a 'tuning' app, and
programming a memory chip, i.e. An effort now days learned in high school auto shop.

Like many of the automotive performance products, 'performance' tuning is just
another marketing game of convincing the car owner that the owner needs
the product and relies heavy on word-of-mouth evangelists to promote the product
image. As is usually the case with hyped products, few purchasers really understand
what the product really is, what it really does, and what real effects it has.
So included in this thread are graphical data from dyno runs which demonstrate
what the so-called performance tuning really is all about and the myth that exists.

For more testing data on this topic, read here: Tests

Bottom line: Therefore in summary, the dyno tests demonstrated that small changes in ignition
timing result in significant torque changes versus small changes in the AFRs which produce very
little effect on torque once the AFR is near the idea. Besides, the AFRs are changed continuously
based on the intake air temp, irrespective of what the 'tuning' setting was. Based on this,
'performance' tuning of a stock engine in reality is basically just 'pushing' the ignition timing,
given the marginal effect of an AFR change, beyond the stock values and nothing more for the
claimed performance improvement. These were the actual results obtained for a 911 3.2 engine
during a 'live' dyno session. If one disagrees with the results, then one can always buy dyno
time and demonstrate a different outcome.

Here's the dyno graph where small changes (3-4 degrees) in the timing resulted
in significant torque changes:

http://forums.pelicanparts.com/uploa...1339649594.jpg

Here's the dyno graph where changes in the AFR had basically no effect on torque
once the AFR was close to the ideal of 12.6:

http://forums.pelicanparts.com/uploa...1339649650.jpg

Here's the well known standard graph of how ineffective AFR changes are on
torque once the AFR is near the ideal of 12.6 (AFR = Lambda X 14.7):

Graphs

Additional Supporting Data:

The actual torque changes are only about 3% over the AFR range of about 11.8 to 14.7.
Reference:
"Automotive Handbook - Second Addition", Bosch, 1986, pg 439, ISBN 0-89883-518-C

"In the areas of interest - near the maximum power point and the minimum fuel
consumption point - those curves are relatively flat. Even if the system can be
adjusted to deliver the perfect mixture (just at the point of maximum power),
the gain promises to be pretty small. There are no huge amounts of horsepower
to be unlocked there."

"Bosch Fuel Injection & Engine Management", Charles O. Probst, Chapter 7, pg 7,
ISBN D-8376-0300-5

getting out the popcorn.....

So I guess Loren is now calling out Steve Wong and saying he is selling snake oil.

This Loren person loses more and more credibility with every post.....

Scott

I'd like to see the guys who sell Performances chips response to this... A lot of what Loren is saying isn't wrong, performance chips do advance the timing of the motor, beyond what Porsche thought was a safe limit for the octane gas available

I think beyond switching cam duration/ lift profiles, and needing to readjust injector pulse duration, "chipping" a stock motor really wasn't worth the time and money

Me too!!!!!!:eek:

With the number of engines of various kinds that I have built over the years (too many to remember)...there is one thing that is consistant in the whole bunch....no two are completely alike!
I was once asked to build several 350 cu in Chevy engines...all with the same compression, cam, valves, etc....and the dyno run differences were amazing.
Even with all the same equipment...there was alost a 25 HP difference between the top and bottom of the bunch.
All that this proves to me is...there will be hidden HP in every engine...subject to altitude....temperature...humidity...and every other change in earth position and variance. (maybe even hemisphere?).
I think Loren is both correct and wrong because of this...given the narrowness of his statements.
Sorry man...you are on the right track...but keep an open mind.
Steve Wong chips probably address the advance curves and mixture control...as do others of the after market type...but that's not all they do (depending on the before mentioned variances).
After market chips will almost always pull out better numbers than the factory ones...simply because of the date...the factory ones were designed a long time ago...Wong's chips and the others are designed with time on their side (newer gas...better plugs...etc.).
My $.02 for what it's worth.
Bob

And me :D

Well stated Bob!!! In the late '60s and early '70s when I was building racing engines for modifieds (round track).. We found the same thing.. Even with all the technology available today, all principles still remain true!!

in the test you did, did you just adjust one parameter at the time? Eg just changing ignition timing and the other test just change AFR?

This post by Loren is really an oversimplification almost on the edge of "malicious intent".

First, reprogramming an ECU is not that simple if done properly. Even old systems like the Motronic used in 3.2 rely on 3D maps tying several variables simultaneously. So, you dont change a value here and there, you have to change many at the least, then you have to verify on the dyno (and road) and repeat...

Second, it should come as no surprise that sometimes the gains are significant. Porsche, like any manufacturer, tunes the engine to accept a broad range of gas quality, and always with emissions control in mind. When you're tuning, usually you can afford to forget about that, so with much less constraints, it's no wonder you get better results.

Third, dyno tests (for power and torque) are not everything. Something that can be improved (and usually is) over the factory spec is engine response / "revability". Specially in the older days, quick throttle response meant more emissions. If you care less about emissions, this too can be improved.

This post by Loren is really an oversimplification almost on the edge of "malicious intent".

First, reprogramming an ECU is not that simple if done properly. Even old systems like the Motronic used in 3.2 rely on 3D maps tying several variables simultaneously. So, you dont change a value here and there, you have to change many at the least, then you have to verify on the dyno (and road) and repeat...

Second, it should come as no surprise that sometimes the gains are significant. Porsche, like any manufacturer, tunes the engine to accept a broad range of gas quality, and always with emissions control in mind. When you're tuning, usually you can afford to forget about that, so with much less constraints, it's no wonder you get better results.

Third, dyno tests (for power and torque) are not everything. Something that can be improved (and usually is) over the factory spec is engine response / "revability". Specially in the older days, quick throttle response meant more emissions. If you care less about emissions, this too can be improved.

True enough! Tuning any engine is 3D...old geezers that would jump the timing up and enrichen the mixture in hopes of finding more power rarely were successful. Well made DME performance chips are more sophisticated than that.

Dynos can be misleading too. We campaigned a Laverda 1000 3c back in the day. Out of tune it would make about 70hp on the dyno (factory claimed 90hp). A well tuned Kawasaki 1000 (factory claimed 90hp) would make about 78hp on the same Dyno.

On the drag strip..the same out of tune Laverda was near on a second faster vs the Kawasaki with the Laverda's taller gearing and a slipping clutch.

A Charlotte Motor Speedway the Laverda (once tuned, we backed the ignition timing down from factory specs and went with some slightly leaner jets, and the clutch repaired) was 10mph+ faster and clocked 10 seconds faster on an average lap. (better brakes and handling)

My point is that it is not just dyno results as the dyno is only a base to start your tuning. It is thoughtless to advancing the timing and throwing extra fuel in an engine to try and find increased performance. I doubt SW uses this tuning technique.

Some track time comparing the before and after would be interesting.

The maps in DME chips are a wonderful place to refine the tuning of a 911 engine.

https://lh5.googleusercontent.com/-m...576/racer1.jpg

Hmm...can't disagree with Loren on this statement, but it seems to contradict what he was claiming just 8-10 years ago both on Rennlist and then here. I'm parapharsing, but in a nutshell, Loren's take was essentially that there was no REAL difference between chips (Porsche 84-86 stock, vs Porsche 87-89, vs Steve Wong, etc.) and we were all "feeling" things. So here it is in a nutshell...if you have access to "better gas", then a chip that advances the timing just a bit will indeed yield better performance. Caveat...it was NOT a "night & day" difference in my case, but incremental....just like most of the mods I've made. Oh yeah...Loren also warned us plenty about the DANGER of aftermarket chips...10 years now and my motor is still going strong.

"Chips suck, case closed" - Lorenfb (circa 2004 as I recall).

To think that Loren has a "hidden agenda" is a mild understatement imho :)

Not this again ???:(
I just hope this time round Loren provokes the right people into explaining exactly what is done to acheive the results we all feel as real and beneficial, its not i fear as simple as he would have you believe...
A...

So then, don't run low octane gas on a hot day at the track if chipped? --sounds like good advice.

Sounds to me like Loren is trying to educate people who blindly believe in a black box of magic. I know guys like that. It is a bit annoying that they have no understanding of what changes happen w/ a chip. ...or what changes happen "mechanic in a can" ... "Stop leak" or whatever mystery marvel.

Well, he's doing that, and having his subversive influence on the sales of . . .popcorn. Ask Toby.

You otoh, loses more and more credibility with every whiny post.....


. . .Mmmmm . .. Popcorn ...

Oh, and disclaimer time. I have no dog in this fight --have an SC where I get to advance the time as I like.-- no dog, other than to say that Loran has annoyed me at about the same level as those people who blind buy "mechanic in a can"

You may now return to your regularly scheduled ..... http://forums.pelicanparts.com/uploa...1339684561.gif

My experience is telling me that Loren is not too far off the mark. Where he is correct is in saying that a modified chip does tend to push reliability further out than was initially intended by the factory. I realize that emotions run high on this subject, but in engine tuning, just like life, "there is no free lunch".

And I see mentioned above, the need for longer duration/higher lift cams being introduced into the mix. Very true, for an engine is essentially an "air pump". So when a chip is used, just where is that extra horsepowere coming from?

I have donned my Flame suit.

exactly.

Good point. ..and one that I've made before. Factory 911's, from '84 on really lost throttle response. (for emission concerns)

I guess that means that Loren is trying to say that Steve Wong is set to destroy the earth. MUHAhahahaha. .. ... :D


Where's that popcorn....

I'm thinking that this might get Loren banned.

I mean, everyone has seen this...

http://forums.pelicanparts.com/uploa...1339685589.jpg


Right? :cool:

I have no dog in this fight either, but I am failing to see where there is even a thread of "Malicious Intent" in the initial post. An "opinion" is just that, an "opinion".

Is there a history here of which us newer folks may not be aware?

Yeah, I think that Loren works (worked?) in a similar industry as Steve Wong. ...but I wouldn't call it malicious intent. I mean, the "hey, do you like your chip too?" fawning threads are a bit ghey. ...right? ...you don't see threads on SC owners jumping up and down with glee about disconnecting the O2 sensor and tweaking the timing and mixture. ...maybe because that mod doesn't cost as much. -dunno...

"Well made DME performance chips are more sophisticated than that."

- dbcooper -

Really? And tell us how.

"The maps in DME chips are a wonderful place to refine the tuning of a 911 engine."

- dbcooper -

And varying the maps is how the dyno results were produced, i.e. from varying both
the ignition and fuel maps independently, i.e. only one variable is changed between
dyno runs. That's not like what one is presented with when one views a 'before' and
'after' of a stock chip versus a 'performance' chip, i.e. It appears that so-called
overall 'tuning' produces significant results. Re-read the main issue of the initial
post.

More back slapping and a$$ patting going on in those chip threads than is seen in professional sports. And yes, it is totally ghey.

Thanks for the refreshing dose of honesty in your reply.

The one thing I find funny..or perhaps amusing..is that the "chips" themselves are less than $5.00 each to buy in bulk.
They are just programmed memory circuits.
The real secret is in what has been put into that memory...some have had a lot of time and effort... and the programmer is looking to receive payment for his/her work.
I would like to see a truly "programmable" chip come into the industry...one that had multiple settings...grocery getter/Dad's street/mild race/all out race .... sort of thing.
Or perhaps one that lets you choose your MPG (and you live with the performance it gives).
Ah the possibilities.
Bob

It's been / being done elsewhere... For the motronic in the 3.2 shouldn't be too hard if you don't mind shutting off the engine between map switches...

This has been on the market for years. A buddy of mine had one for an older Audi S4, and it had like five or six settings that were changed by using a transmitter that looked like a key-chain sized Garage door opener. It even had a "Valet" setting, so the young punks couldn't take the car for a beating.

to extrapolate further, I look (with amazement) at the sensing information and programability of of the systems on my Cayenne thru the Durametrics port. ..Hooked up to a PC you pull up ..EGTs (multiple), timing, intke temps and pressure...etc (huge list of variables) all mapping in real time. If I wanted, I could put up a command center in the car that looked like a NASA operation.

So, IMO, the future is already here. ..this new stuff makes chip mapping look like quaint old rug weaving. ...or some such.

...not that there's anything Wong with old rug weaving.

What did T.O. used to say, "Getcha popcorn ready!"
 

Popping the popcorn as I type this. This is going to be very interesting! http://forums.pelicanparts.com/support/smileys/wat.gif

Do the 3.2 Motronic in the 911s have knock control or something to pull timing back if the engine knock when a performance chip is installed?

"I look (with amazement) at the sensing information and programability of of the systems on my Cayenne thru the Durametrics port. ."

There's no programming available thru the use of the Durametrics diagnostic software.
It's just basically an expanded OBDII capability for reading module data and resetting
fault codes. Even the factory PIWIS tester has no direct programming capability for
modifying maps.

"Do the 3.2 Motronic in the 911s have knock control or something to pull timing back if the engine knock when a performance chip is installed?"

No, and that's the BIG problem when tweaking the timing, i.e. No safety control!

The original statement is grossly oversimplified.
Engine performance tuning is the act of optimizing the parameters of combustion as controlled by the OEM fuel, valve timing and ignition systems.
For some applications, specifically more modern cars with engine management systems, there may not be much performance tuning left on the table. For others, such as old CIS engines with mechanical ignition distributors there are very significant gains to be made without pushing the limits of reliability.
If the original statement is an attack on the performance chip industry then that verbiage needs to be added for clarification.

Then there's the discussion that Loren completely avoids. And for good reason.

What about the 3.2 RoW motors? Where did all that extra HP come from? From upgraded (stronger) internals? More agressive timing maps? And why, in Porsche's obviously perfect wisdom, would they "compromise" reliability for the RoW models, but leave the U.S. models as paragons of engine longevity? Maybe PAG just hates everyone but Americans? I mean, if we're going to throw out completely unfound speculation, let's go ALL the way, right?

Then there's the small matter of demonstrated failures. Another area where Loren seems to practice a little bit of avoidance.

I will now predict some personal attacks by Loren, along with some cagey avoidance, subject change and re-iteration of hazy "logic".

That extra horsepower came from different pistons and cams as far as I have read. It was definitely not just a "chip tweek". :)

pistons for sure creating high compression. i think the cams were the same.

I thought performance tuning meant getting the jets right on your Webers

"Engine performance tuning is the act of optimizing the parameters of combustion as controlled by the OEM fuel, valve timing and ignition systems."

And that's called engine performance modification (engine mods). Performance
tuning is typically tweaking of the engine management system, i.e. the ECM
which controls the fuel and ignition or in the pre-ECM days re-'curving' the
distributor timing or re-jetting the carbs.

I pretty much agree with the "thesis" of his statement, having personally tuned my Supra. However, in that case there were quite a few products readily available to do the tuning with no requirement to burn a chip. In addition, I had the ability to do logs while driving to assess driveability after the initial tunes were (done on a dyno) to get it close.

In the case of my 1986 911, what equipment would be required to do it myself? Are they readily available? And cost effective? I'm guessing not.

So in this case, a chip is they way to go simply because the equipment required is a bit out of reach for most owners (I would guess) despite the owner likely being able to tune it themselves. Whether you chose a Wong chip (more expensive option) or a an FR Wilk PowerProm chip (more reasonable option) it's just more cost effective than getting the equipment and doing it yourself. This might exclude racers who frequently mod and /or tune their car based on track conditions. But for the average enthusiast a chip is easier and cheaper.

OK, you're half-way there. The RoW cars have higher compression. Higher compression motors have draw-backs - ones in common with lower-compression motors that have more advance dialed in.

Hmmm, same motors (except the HC pistons), except one is dangerously (???) compromised by running more advance than what it ran coming from the factory.

That's a head-scratcher, for sure.

No. More like a head-shaker.

I think you have summed things up pretty well here,:)
I would like to think that even the least mechanical or technicaly minded here understand that you cannot get something for nothing, The reprogramed chips on offer from for eg'; Steve Wong just take advantage of the extra potential that is already there by fine tuning and carefully optomising the parameters within the MAP program' in conjunction with the fuel available.
Its not magic, yes, sure, the basic eprom chip costs a few dollars, thats not what your paying for, its the use of someones gained knowledge and expertise, i am sure even Loren cant argue with that.
A...