3.6 Conversion and Octane Levels

[drums]

My 3.6 conversion was completed in July of this year. Shop that did it did an excellent job.
The engine/brain are '97, so the brain was sent to Germany for a reprogram to 'Euro specs'.
The engine 'pings' lightly at low RPMs using 'Supreme' [91 octane in Ca.]. When I mix 91 octane with 100 octane [race gas], it goes good with no 'pinging'. Using 100 octane turns the thing into a growling beast that is difficult to hold back.
My question is: What are 'Euro specs' on a '97 engine? I have not seen any h.p. difference between the Euro cars and the U.S. cars.
I bought the engine from a respected 3.6 engine guy that is fairly well known on this board. I have asked him but I think he assumes that I know the specs.
Help!
Drums

[2.7RACER]

From Bruce Andersons book, the ROW 3.6 has more cam, bigger valves and is rated at 300HP. The US version is rated at 285HP. Both are shown as 11.3:1 compression. No question it will come alive with higher than 91 octane fuel.
Some folks think the 11.3:1 is actually closer to 10.5:1. I don't have any facts to support that assertion.
When you get tired of putting the race gas in, bring it to New Mexico or Colorado. It will run fine at our high, 5,000+ ft. altitude.

[drums]

In GT magazine [U.K.] it shows the '97 as 285 H.P., that is why I assumed the H.P. was the same[?], here.
It runs like it has 300+ H.P. with race gas in it [100 octane]. Is 115 MPH in 3rd gear [6800 RPM] to be expected with this combination? 120 MPH in 5th gear @ 4,000 RPM ['89 stock G-50].
Drums

[Bill Verburg]

Originally posted by drums
My 3.6 conversion was completed in July of this year. Shop that did it did an excellent job.
The engine/brain are '97, so the brain was sent to Germany for a reprogram to 'Euro specs'.
The engine 'pings' lightly at low RPMs using 'Supreme' [91 octane in Ca.]. When I mix 91 octane with 100 octane [race gas], it goes good with no 'pinging'. Using 100 octane turns the thing into a growling beast that is difficult to hold back.
My question is: What are 'Euro specs' on a '97 engine? I have not seen any h.p. difference between the Euro cars and the U.S. cars.
I bought the engine from a respected 3.6 engine guy that is fairly well known on this board. I have asked him but I think he assumes that I know the specs.
Help!
Drums

Someones yankin yer chain
The difference between a '97 US M64//23 and a ROW M64/21 is 88pin OBD2 vs 55pin OBD1, all mechanical specs(including octane requirements) are identical. The chips are not interchangeable, the primary maps are pretty much the same but the US have additional maps for SAI and emission related cold and part throttle regimes.

[Bill Verburg]

Originally posted by 2.7RACER
From Bruce Andersons book, the ROW 3.6 has more cam, bigger valves and is rated at 300HP. The US version is rated at 285HP. Both are shown as 11.3:1 compression. No question it will come alive with higher than 91 octane fuel.
Some folks think the 11.3:1 is actually closer to 10.5:1. I don't have any facts to support that assertion.
When you get tired of putting the race gas in, bring it to New Mexico or Colorado. It will run fine at our high, 5,000+ ft. altitude.

Not hardly

There are numerous n/a 3.6 versions
GEN 1, 964
M64/01 all 964 US and ROW manual trans from '89 - '94 250hp
M64/02 all 964 US and ROW tip trans from '89 - '94 250hp
M63/03 '92 ROW 964RS 260hp from chip tuning and component selection

GEN 2, 993 the mechanical specs i.e. cr, bottom end etc of all 993s(both gen1 and gen2) are pretty much the same and a big improvement over gen 1 964s, differences abound in the heads and intakes.
M64/05 all 993 ROW manual trans from '94 -'95 272hp bigger exhaust valves, bigger ports than 964, exhaust improvements
M64/06 all 993 ROW tip trans from '94 -'95 272hp
M64/07 all 993 US/CDN manual trans from '94 -'95 272hp
M64/08 all 993 US/CDN tip trans from '94 -'95 272hp

GEN 3 993 w/vram
M64/20 all '95-'96 ROW 993RS 300hp, 3.8, vari-ram, biggest valves/ports, mg intake components,cam
M64/21 all 993 ROW manual trans from '96 -'98 285hp, valves bigger than /05 but smaller than /20
M64/22 all 993 ROW tip trans from '96 -'98 285hp
M64/23 all 993 US/CDN manual trans from '96 -'98 285hp
M64/24 all 993 US/CDN tip trans from '96 -'98 285hp

[drums]

So I can gather from what you are saying is that the brain was changed only to operate in my early '89. Do you think it was possible that the brain could have been reprogrammed for better performance? I know that the '97 doesn't have a replaceable chip like most cars, but can it be reprogrammed as he is saying it was [performance]?
Drums

[Bill Verburg]

The DME itself does need to be changed to work in an '89 just the external connections.

The problem you are experiencing w/ 91 octane is common to all 964 up, they need good gas even w/ knock sensors.

Most folks that live where 91 is the max normally available are doing what you are.

You could also get a less aggressive gas map for the DME from Steve Weiner at Rennsport

[drums]

Thanks, Bill!
Drums

[2.7RACER]

Bill Verburg,
My response referred to drums 3.6, '97 engine and brain. That was the subject.

[Steve@Rennsport]

Drums:

Bill offered some great information.

Euro ECU programming is based on 95-98 RON (93-94 R+M/2) fuels; something you don't have in California unless you buy 100 octane unleaded race gas.

With 91 R+M/2 pump premium, it sounds like your ECU programming is too aggressive for what you're using. If it pings at this time of year, just imagine what will happen next Spring & Summer,....

Perhaps the folks who did your ECU can program the thing for California's 91 fuels and can fix that for you. If not, I'd kindly suggest that you think about having the ECU re-programmed by someone in the US who is equipped to deal with the wide disparities in octane availabilities, nationwide.

[drums]

Thanks so much [I think].
Will the reprogram for rotten fuel hinder the performance when using 100 octane?
Drums

[Steve@Rennsport]

Originally posted by drums
Thanks so much [I think].
Will the reprogram for rotten fuel hinder the performance when using 100 octane?
Drums

My pleasure.

Not really,...

I will tell you that pump gas programming & race gas programming does differ and one optimizes this for the fuel(s) that will be used.

If this is not a dedicated race car that will exclusively use 100 octane or better, I'd advise you to have the ECU programmed for the lowest common denominator (local pump gas) so you do not put your pistons & cylinders at risk.

[Bill Verburg]

My response referred to drums 3.6, '97 engine and brain. That was the subject.

And this part is dead wrong

From Bruce Andersons book, the ROW 3.6 has more cam, bigger valves and is rated at 300HP

*all 993 use the same cam except the RS
*all 964 use the same cam including the RS
*for a given year there is no difference between ROW and US valves or ports
*no 3.6 is rated at 300hp, the 993 3.8RS is

it is true that the nominal 11.3 cr appears to be optimistic, but that can also be because of different methods of obtaining the data

[drums]

Steve,
What happens to the pistons and cylinders? Will damage occur if it 'pings' only at low RPMs [taking off from a dead start, slowly, etc.] and only for a very short duration and very light and quiet?
I sure would hate to lose the performance this engine has by changing the fuel maps to a 91 [California Panther Piss] octane.
What to do?

[2.7RACER]

Bill Verburg,
First to preface this, I have no desire to get into a pissing contest.
I have no direct experience with 3.6's or 3.8's. I used Bruce Andersons "911 Performance Handbook" as the source of my info.
I have included part of page 112 from his book.
As you can see for Motor type M64/22 '96-- he shows:
Carrera Rest of World (993), Increased output for manual transmission. For valve sizes he shows intake 50mm, exhaust 43.5mm. As compared to 49mm and 42.5 respectively for motors rated at 285HP.
He also shows the cams for this engine as the same as the cams used in the M64/20, 3.8 liter. About 4 degrees more intake as compared to the M64/21 motor.
He shows "this motor" at 300HP@6500RPM, Torque at 261.6@5400RPM. All this at 11.3:1 compression.
Bill, this was my source. I apologize if Bruce Anderson got it wrong or if perhaps this is a simple mis-print.
According the Frere's book the only difference between the ROW for 1996 and the US models is a electric secondary air pump and OBDII in which the O2 sensors (He calls it a Lambda Sond), are placed before and after the catalytic converter. The "after" O2 sensor turns on a indicator if the "before" O2 sensor isn't doing it's job.
So ultimately perhaps I made a mistake by using Mr. Andersons data. In this case since I do not have any personal experience I find myself only as good as my data.
I think it was Chris Bennet that commented on the compression ratio as quoted by Porsche to be "perhaps" a little optomistic.
Bottom line, we ask questions, looking for answers. You have supplied us with plenty of answers, Thanks,

[Bill Verburg]

Don't believe everything you read, even Bruce, or his proofreaders anyway, can be wrong. There are numerous errors in that book. Never the less it is a tremenous piece of work.

M64/22 is a '96 -'98 ROW tip engine, no difference from M64/21 manual trans except in the harness and flywheel.

There was a power kit for manual trans ROW vram 993s which included 102mm p/c and RS cams but not the valves/ports/raised injector blocks or mg. intake pieces, this was a dealer or special wishes installed package.

[Bill Verburg]

Originally posted by drums
Steve,
What happens to the pistons and cylinders? Will damage occur if it 'pings' only at low RPMs [taking off from a dead start, slowly, etc.] and only for a very short duration and very light and quiet?
I sure would hate to lose the performance this engine has by changing the fuel maps to a 91 [California Panther Piss] octane.
What to do?

I'm not Steve but it's usually the rings that will go first.

This is probably not something you will want to do either but an old hotrod trick that will ease low rpm ping is to use cams w/ lots of overlap.

[drums]

Thanks, Bill
Will remapping the ECU for a lower octane fuel hurt performance if using 95-100 octane gas, once in a while?
Drums

[Steve@Rennsport]

Drums:

I will unequivocbly tell you that if you let it ping, over time you will replace a set of broken rings and perhaps pistons due to heavy upper ring land wear. BTDT, far too many times. Detonation (light) is detonation (heavy), and you really want to prevent this from happening.

IMHO, its FAR cheaper to prevent this proactively rather than suffering the consequences. Fact is, 91 octane fuel is somewhat marginal in these cars (look in a 993 owner's manual for Porsche's octane recommendations) and you need to prevent any detonation when using 91 premium fuels.

An ECU mapped for lower octane fuels certainly does run better when using 95-100 gas,....

[drums]

Thanks, Steve.
Too bad the dummies writing the laws here in California aren't car enthusiasts. Oh well.....