Who has advanced their timing for more power?

[burgermeister]

Hmmm... can't keep from throwing 2 more cents in.

I looked and looked, and I can't find anywhere on Loren's website any reference to him selling chips or advocating using them. It does say someplace that modification of the DME maps is not done at his shop. Not sure why he just doesn't say so in a calm manner.

I actually agree with much of Loren's writings, though they could be presented in a more pleasant and clear manner for sure. Not walking in his shoes, I can't judge him (or anyone else posting), but this is a good post topic, and more calm and factual discussion of timing advance strategies is useful IMHO.

Loren says 3.2's need 95 octane. I believe that's research octane. US fuel is quoted as (Research Octane + Motor Octane) / 2 (says on the pump R+M/2), and I believe 95 RON is pretty close to 90 or 91 octane as labeled on the pump. Steve W claims 3.2's were tuned for 87 octane. I can't remember where, but someplace on my 88 (or its documentation) Porsche stated 91 octane is the required fuel.

Assuming the content of Steve W's website is factual, it looks like Porsche made some tuning changes on US spec 3.2 engines as well, which does indicate that at least SOME ignition map changes can be made safely. Of course, I didn't see any fuel maps - maybe the ignition map changes were accompanied by other changes as well? I'm no expert - just asking questions.

As far as vacuum advance goes, I can only speak to my old Firebird. It was a 12 or 14 degree advance unit, and it came on when engine load was light. Its sole purpose is to improve emissions and fuel economy. It did not affect performance in any negative way, and I would not suggest anyone remove a vacuum advance unit from the distributor for street use. All the hot rod tuning books I read stated the same thing.

That said, I recurved my F-car distributor for better throttle response (and it did make a noticeable difference below 3500 RPM). And I also had to run 93 octane gas on my stock 8.2 compression Pontiac 350 afterwards to keep it from pinging on occasion. And I adjusted the carb to run a bit rich. I would think GM left greater margins for error than Porsche, so I would be very nervous changing much on a Porsche without taking care to gain some margin elsewhere. Not sure how that is done easily except with fuel octane, and 87 to 93 is a much bigger jump than 91 to 93. I guess one could refrain from using WOT when the engine is running hot also (Steve W says his chips leave the part throttle maps unaltered I believe).

We were at a wedding in Iowa recently, and my father in law had issues because the best gas he could find was 90 octane (his Lexus IS250 said 91 or 93 required). I assured him the knock sensors would take care of things... BUT, 93 octane fuel is NOT available everywhere except California.

There has never been any harm in listening to both sides of an argument, as long as everyone retains the freedom of personal choice afterwards....

[88-diamondblue]

Burgermeister,
Do a search on the "performance chips". There are hours of reading on the subject. Loren has tried to bash everything and anything to do with performance chips and especially from SteveW. Porsche themselves made changes in 88 to a more aggressive mapping,(part # ending in 58) but of course Porsche wouldn't have left anything on the table according to Loren. If you haven't been the target of Loren (I have) then you don't know how nasty he can be. He has been temporarily banned here and at Rennlist for doing this. You are watching usual behavior for him on this subject. After you have been here a while and been subjected to his ranting on this you will understand.

Steve Weiner is one of the top engine builders in the country and Loren rebuilds Motronic equipment Hmm which would you trust to get advice on what to do with your engine? I know who I would trust and it isn't Loren. I have had a chip in my car since 1992 (Autothority) and most likely has been there before that (only have records back to 1992) and it was in the car at that time. I switched to a SteveW chip 4 years ago and now have a custom program chip due to going to 3.4 upgrade. I rebuilt the engine due to two broken head studs. The engine was is great shape including P&C's. I am one of those according to Loren that does not know anything even though I did the entire rebuild of my engine except for machine work myself. I have not seen any CHIPPED Motronic equipped cars that have had damage to the engines. And everything that goes wrong will get put on this board. I have run my car at the track on very hot days with no problem and I don't hesitate to take advantage of red line anytime I can. So consider the source of information and the experience that goes along with that information then make any decisions from that point.

[mca]

I don't mean to re-open this painful thread .... but ....

... I checked my timing today (haven't done so since it was tuned up a year ago by a local shop). It looked to be around 10-12 degrees BTDC at 950 rpms.

I set it back to TDC and took her for a drive. I couldn't believe the difference.

IT WAS SOOOO LETHARGIC!!!!!!!!!!

I know that I need to do a rebuild in the next year or so ... therefore, woud it be so terrible if I set it back to 10-12 degrees BTDC ?

[RoninLB]

Originally Posted by burgermeister

We were at a wedding in Iowa recently, and my father in law had issues because the best gas he could find was 90 octane....

I've been in some desolate towns where 87 & 85 was only offered at the pump.

next time i'm taking a pic

[SP2]

mca,
I don't think you timed it correctly. I thought I read in the past that it doesn't really matter what the timing is at idle. You want to set the timing at 5000 RPM. For my 3.0SC I was told to try 32degrees.

[beepbeep]

Originally Posted by Lorenfb

A thread that went nowhere!


No, it takes knowledge and resources, e.g. Porsche/Bosch. That's why Porsche/Bosch used
knock sensors to max the timing under ALL conditions starting with the 964 engine.

Hmm...I fiddled a bit with Bosch Motoronic equipped with knock sensors and found out that timing isn't maxed at all.

Bosch used knock sensors as extra safety-net and not as a way of finding optimum ignition timing at all loads, most beacuse knock sensors go deaf at higher revs and ignition timing is tapered into "safe area" to avoid knock where sensors cannot hear it, if car was fueled with low-octane brew.

Only 100%-sure way to detect knock is to fit in-cylinder pressure senders (musho $$ and only used in factory test-cells) or use ion-detection circuitry by applying control-voltage across the spark-plug gap and checking for formation of ions (as burned mixture will start conducting in a certain manner a short moment after pre-detonation occured).

Bosch didn't use ion-detection in their early Motoronic (and as far as I know, still isn't?) so there are definite "hard-stops" in software where ECU stops increasing timing even if detonation didn't occure. So there is certainly an untapped margin of ignition advance that can be explored by moving these hard-stops a bit further, depending to owners will to gamble and usage of hi-octane fuel.

I believe I read a piece on this where Car & Driver measured the effect by fueling three cars with 89 and 93 octane and doing the dyno-runs. Cars were fitted with no knock-sensor, a knock sensor and ion-detection ECU respectivly.

That being said, there is another side of the coin. I'll take my car as an example:

I have a turbocharged 2L 4-valve pentroof engine with 9.1:1 C/R. I converted it to run on ethanol-based fuel called E85, made from 85% ethanol and 15% gasoline. It's very knock-resistent and it's higher evaporating temperature makes it cool the mixture much better (and make cold-starts much worse, but that's another story). It's very hard to make this car ping. As long as I limit thee boost, it will not ping at all, even when passing the ignition-optimum sweet spot. But such aggressive ignition mapping will also raise in-cylinder pressure (and crank/piston/rod loads accordingly) to alarming levels wich might be harmful to engine.

So essentially we have many parameters to play with here, depending on engine design:

1. Compression ratio (the higher it is the greater the chances are of running into knock before hitting max BMEP)
2. Combustion chamber design (Porsche 2-valve aircooled heads are big and have quite long flame-front propagation. They also run hot, as water-coolant cannot stabilize the temperatures in same manner as in water-cooled units)
3. Fuel octane number
4. Intake air temperature and presence of forced induction.

So depending on engine design, you might or might not run into one of limiting factors.

I venture to say that aircooled Porsche engines, even being somewhat special and more knock-prone than later designs, can be tuned further by careful ignition re-mapping. But it will take substantially more effort, knowledge and precaution to do so compared to modern watercooled engines.

[burgermeister]

I do not know the standard SC timing specs (I have a Carrera), but I can't imagine a car that runs well with timing set to TDC at idle, unless there is a silly amount of mechanical advance in the distributor. Most anything needs a wee bit of advance! Most distributor-timed cars I've worked on were in the 8 to 12 deg BTDC at idle range. As SP2 noted, also gotta check timing at high RPM's. Considering the Porsche hemi-head design, 32 to 36 degrees sounds reasonable to me. On the Detroit cars, you have to unplug the vacuum advance before checking, otherwise you get another 12 or 14 degrees of advance when checking the timing at off-idle RPM ... which of course goes away when you are actually driving and you mash the throttle. Not sure if this applies to the Porsche's.

[mca]

Originally Posted by SP2

mca,
I don't think you timed it correctly. I thought I read in the past that it doesn't really matter what the timing is at idle. You want to set the timing at 5000 RPM. For my 3.0SC I was told to try 32degrees.

From what I can gather ... timing needs to be set at 5 degrees (+ or - 2 degrees) BTDC at 950 rpms. I can't remember right now what it is supposed to be at 6000 rmps but I know it varies a little.

Just going from the Bentley manual ... even within the SC years, there are different specs for timing.

[Deschodt]

You *must *verify the timing is correct at higher RPM so as to avoid damage to the engine. Whether you do it hoses disconnected or connected or both is up to you, but you MUST check the timing at higher RPM. You don't know that your distributor works correctly by timing at idle. Idle timing is a base point assuming that your distributor operates perfectly (it's supposed to give you x amount of advance so if you time it 3 deg at idle you get 3+x at speed)...

Except that any gumming up of the mechanism or degradation after 25+ years might give you less advance or too much advance... you cannot be sure until you check.

I advanced my timing on my car to help a hot running condition, I thought that was brilliant until I heard pinging under load anywhere above 4000 rpm. I backed it down to factory specs quickly...

The one thing I found hard to find is the advance values with the car buttoned up. I think the manual gives you an idle and 5000 rpm w/ vacuum hoses disconnected, but what I wanted to find was the same numbers with the hoses connected normally so I could tell all at once if my vacuum advance was working as advertised...

Say, how many degrees at idle and 3,4, 5000 with the hoses on the distro....

[mca]

Thanks Greg ... I am going to check values at throughout rev range.

I only set mine back 5-7 degrees from where it was.

[dweymer]

So what does overly retarded timing cause?

[Lorenfb]

"Bosch used knock sensors as extra safety-net and not as a way of finding optimum ignition timing at all loads, most beacuse knock sensors go deaf at higher revs and ignition timing is tapered into "safe area" to avoid knock where sensors cannot hear it, if car was fueled with low-octane brew."

Conflicting statement (like - a nonsequitur)!

1. "Bosch used knock sensors as extra safety-net and not as a way of finding optimum ignition timing at all loads"

To max timing (safety net) - Call it what you want.

2. "knock sensors go deaf at higher revs"

Hardly! Tell that to ALL the OEM auto manufacturers who use them.

3. "ignition timing is tapered into "safe area" to avoid knock where sensors cannot hear it."

That's your "guess" at what happens! Do some tech reading at the library beyond what gets posted on the internet.

And it's Motronic and not Motoronic.

[tobluforu]

Originally Posted by dshepp806

A reread for me, as well,..reveals the same conclusion as Mo_Gearhead...again, for me.

Being an engineer (although not a mechanical one), I seem to see both sides' points, but modding should be approached with higher degrees of caution. I bought my 89, 3.2L in November, last year. She's bone stock and is adequate for me (not racing). If it were, I would certainly look to ALL 'squeezes' of increased HP/response (naturally)....... this part being a personal decision.

Having been on this board under a year, I've had some exposure to the dialogues between several users here when it comes to both chipping and "personalities". I really hate to see things come to that,....in engineering, there's a thing called "designing for worst case condition" (whatever that "condition" may be). For me (and my car) it's the things that can go bad if NOT done carefully, and within the right environments. Knowing little about all of the (possible) negatives,..and spending the entire frikin' weekend reading about predetonation, ignition (pre?) , combustion, the cylinder materials.....on and on,...GEEEEZ,..scared the SH*&^*^%&^t out of me,..the thought of "something going bad". Some readings (provided by gracious Pelanites) rendered MY answers to the phenoms...this resonance bandwidth of mistimed sparking or (mis) advanced timing conditions and super-related to what Loren (and some others in the industry) have stated about not knowing that a condition is, in fact, existing..............HOWEVER (and as have MANY Pelicanites have certainly noted), where are the masses of 3.2L 911 owners using present (market) chips that have experienced engine deaths? Certainly this speaks to something,..or am I frikin' crazy? This board alone would reveal some malresults,..yes? Where the hey are they?

Knowing a bit more now ( lightly,..NOT claiming to be, now, an expert [[[[[[[pleeze...]]]] ),..I would think that chipper would possibly display more data (maybe it's already there?) that demonstrates that these terrible resonances, in fact, are NOT happening,...? Not sure,.... Being a relative newbee to this, compared to other long term owners, TRUE P-wrenches and automotive consultants who hang here in this great group,..it's hard to generate highly technical questions (renderings?) until more education comes in to play (and, obviously: doing)... all of you guys' patience is appreciated. Surely I've missed many things, as there is much to learn.

Ya' know,..I eagerly look to reading the major players' posts here (characterizations aside).... To watch Grady Clay dart in with his precision of words on so many diverse areas,..or Steve (BOTH),....or Pete,...and MANY MANY others.... I really hate to see the name calling and wish that it could just disappear,..at least for a while ,..while I try to digest all information, ..........looking at the analytics of the matters at hand,..pros/cons...Thank you all for your technical statements and observations.....ALL parties should intelligently step up to the plate and LET"S """DISCUSS""""" these issues...inquiring minds (with frikin budgets) wanna' know (without the name-calling, ...I must say that Mr. Wong (for the most part) asks very poignant questions to Loren,...and these should be answered, respectfully...lot's of knowledge between these two fellows........I NEED BOTH!!!!!!!!!!!!!!!

Some of the threads have been SO heated in the past..please,..leave it be.

dammit: TEACH ME ABOUT WHAT YOU , MINUS THE Bullsh&t KNOWS!!!!!!!!!........say it in a frikin professional manner...let this crap go.....and get back to business here.

I draw no sides here...just absorbing.

How could a RUSH freak NOT paste the lyrics to a related song (by RUSH): (apply, as needed)


HALF THE WORLD (RUSH)

Half the world hates
What half the world does every day
Half the world waits
While half gets on with it anyway

Half the world lives
Half the world makes
Half the world gives
While the other half takes

Half the world is
Half the world was
Half the world thinks
While the other half does

Half the world talks
With half a mind on what they say
Half the world walks
With half a mind to run away

Half the world lies
Half the world learns
Half the world flies
As half the world turns

Half the world cries
Half the world laughs
Half the world tries
To be the other half

Half of us divided
Like a torn-up photograph
Half of us are trying
To reach the other half

Half the world cares
While half the world is wasting the day
Half the world shares
While half the world is stealing away

(ahem............................................. .....)

(truly) Best to ALL of you...

...back to "technical"....................

Finally something in this thread that I can relate too, and that is another "Rush" freak. Hail to all that loves "Xanadu". The best Rush song ever IMHO.
Now back to the thread I say, but one comment from the peanut gallery.
Lorenfb-Tuning a car on the street is one of the best ways "a tuner" can tune a “modified street car." Your comment about using a laptop to do this? What the hell else would you use for “certain cars”?
Sorry to stray.

[911pcars]

Originally Posted by dweymer

So what does overly retarded timing cause?

At idle, engine runs slightly hotter; perhaps reduced exhaust emissions depending on mixture setting.

At higher rpm, you could be leaving some power on the table as well as fuel mileage.

The trick is to identify the ideal timing for all engine speeds under all operating conditions. It ends up to be a compromise with older engine management systems.

Sherwood

[Eagledriver]

Apparently Loren doesn't know the difference between RON and MON octane numbers. Quite the expert on these matters.

-Andy

[dweymer]

Originally Posted by 911pcars

At idle, engine runs slightly hotter; perhaps reduced exhaust emissions depending on mixture setting.

At higher rpm, you could be leaving some power on the table as well as fuel mileage.

The trick is to identify the ideal timing for all engine speeds under all operating conditions. It ends up to be a compromise with older engine management systems.

Sherwood

Cool, I was wondering if also could cause damage likt detonation would.

D

[PPilot]

Oh, the horror! I plugged a SteveW chip (84 Euro 3.2 93 oct.) into my Carrera and ran the living crap out of it on 93 oct. My engine, being illiterate with no access to the ongoing controversy, was definitely more responsive, with a noticable increase in power. I bought the chip with the usual curiosity and reservations, but have been totally pleased with it for the last 4 months...This is in very hot, humid conditions with no indications of any problems.. Not meant to be a plug for Steve, necessarily, but this the experience I have had....I have raced and messed with various engines for many years, and there is always room for improvement over stock, not a big revelation to anyone who has been around very long...duh. Alas, the flip side also applies, more power= more stress=less margin=shorter life=less reliability. As has been pointed out, ...thanks, Gordon.

[Wavey]

Geez Gordon, don't you know you can't trust your own experience? All you have to do is look at the evidence Loren has posted. You know, pics of broken rings, broken ring lands, holed pistons, stuff like that. Oh, wait....

[dshepp806]

tobluforu: funny,.....we know who we are,...and better yet, "why" we are.......thanks..I didn't know what else to do with the thread....so frictional, at times....inanycase,..thanks!

How does a knock sensor "go deaf" at high RPMS? I don't quite understand....... what are the circumstances....I ask this quite earnestly,..so as to learn more about it.....being a recording/audio engineer, I'm, quite interested to learn more of these resonances and what creates them. Thanks to this great group, I've uncovered great reads as to these resonances...cool stuff, me thinks..

As always,..many thanks to all for opening your minds and sharing the "fuel"...

Best to all,

[dshepp806]

Better yet,..do the sensors' sensitivities differ at different frequencies (the device itself)? Why would one design a sensor that isn't somewhat more broader-banded, if you will?

If someone has some nice trace displays (scope-based) of this phenomena, I would love to see it........even better if on a specral analysis plot..(just simply transforms would do...)

Thanks again!!!