TR6

On the street accelerating up to, say, 5K rpms? That was my only point. As I said, on the track, dragging another car along a straight to pass him before the next corner, I don't doubt that 19 extra hp makes a difference. But I had the Steve Wong chip in it yesterday and had driven it with that SW chip for some time, and then swapped the stock chip back into it yesterday afternoon. I could not tell a noticeable difference in 0-5K rpms in take offs from stoplights and spirited highway driving. You guys may be more attuned to the subtle differences in the feel of these cars than I am. Or the difference is perhaps more noticeable above 5K (which I didn't run up past yesterday as I still breaking in a new engine). Or maybe there are other variables at play in my car that I don't know about. Dunno. It was just a personal observation.

N51

Perfectly expressed.

Lorenfb

"What John has done is effectively the difference between a 964 engine running older Motronics and and AFM for metering fuel, and a 95 993 using MAF for metering fuel."

You don't know this as fact, or did you fully reverse engineer the mod,
e.g. analyze the ignition maps?

The KEY POINT which some fail to understand and which has been mentioned MANY
times is that TWO variales exist:

1. the MAF vs the AFM, and
2. the chip with pushed timing vs stock timing.

Without knowing the INDEPENDENT effect of each, one CANNOT arrive at a valid conclusion!
From the dyno graphs, it's apparent that pushed timing has provided the greatest effect.

Bottom line: So without knowing the above, how can one make a rational decision (non-naive)
as to whether to just buy a "pushed timing" (so-called perfromance chip) or do a MAF mod?

fast951

It amazes me how people that have no fricking clue of what was done in the code, yet claim to know best.

It amazes me how people make a claim of no performance gain from the MAF kit, when proven wrong, twist things around and continue to debate the issue.

It amazes me how people claim to want performance out of their 964, yet the moment something new is offered with proof, most tend to think it's not real.

Now I understand why not many vendors are developing new products for the 964. It has been an interesting experience to say the least.

warmfuzzies

John,

I wouldn't worry if I were you, Loren has added much to the debate, but unfortunately.....he perpetually continues to go on a one man crusade and only ends up making himelf look a nunce. Pity really he seems like an intelligent bloke who can't seem to clear the red mist.

Still each to thier own.

Kevin.

porktastic

I for one would like to congratulate John on developing this MAF unit for our cars - I see EVO MS seem to have dropped their supercharger, leaving Ninemeister and TPC as the main purveyors of 964 performance kit.

There will always be people who believe things cannot/should not be changed. Just look up discussions on MOTEC However I believe there are far more people watching this with interest than those spouting off from their respective soapboxes.

Personally I decided to buy the MAF unit for the simple reason that it can handle larger injectors (does this make the unit similar in effect to the Motec system supplied by Ninemeister - optimally managed increased air/fuel input )

Geoffrey

Loren, let me be a little more specific on what I was trying to say because I did not say that he reverse engineered the 95 993 engine nor did imply it to be fact. Obviously that would be impossible since the engine is mechanically different, with larger intake ports, smaller stem valves, different exhaust, lighter crankshaft and conecting rods. I was drawing an analogy between a 95 993 and a 964 with MAF used as the load sensing device.

That is not apparent to me. How can one tell what is the contributing factor, increased airflow, better metering of fuel, optimized air fuel ratio, or ignition timing. I don't think that you can conclusively say that it is any one of those things without testing each one.

And whose responsibility is that?

After this thread it would be a waste of time to post anything on the MoTeC cars we're doing over the winter.

Lorenfb

"That is not apparent to me. How can one tell what is the contributing factor, increased airflow, better metering of fuel, optimized air fuel ratio, or ignition timing. I don't think that you can conclusively say that it is any one of those things without testing each one."

That's the point being made, i.e. "I don't think that you can conclusively say that it is any one of those things without testing each one."

So why has it been concluded that a MAF device in itself is the main contributor????

"apparent" - bad choice of words
appears - better choice

fast951

Is anyone here offering a MAF sensor by itself? Does the MAF sensor by itself, without any change to the code work on the 964 (excluding signal massagers)? NO and NO!

So why is the discussion becoming a MAF vs. XYZ? This is a MAF kit hardware & software. Hell, if you can extract the same power by mixing sand with the fuel or by using a fuzzy dice, go for it!

There is an old saying "You can lead a horse (or ??) to the water, but you can't make it drink!".

Fast4525

Loren,

Your focus seems to be on "pushed timing" as if it is an evil change. Are you suggesting that the original Porsche timing map is perfect with no room for improvement?

Porsche no doubt wrote a very conservative timing map that caters to the lowest common denominator of driver/owner, i.e. one who might fill the tank with 87 or 89 octane and drive the car at WOT for extended periods. I would be happy to remove such a conservative timing map from my car in exchange for more engine output even if it means nothing but 91+ octane.

What changes, modifications or upgrades would you suggest in the sub-$5000 range to get more power/perfomance from an internally-stock 964 engine? Can we please leave weight-reduction, DE training, etc out of the picture and focus on mechanical changes?

Fast4525

John aka fast951,

Let me start by saying that I want to buy one of your 964 MAF kits and as a modaholic I am always looking for ways to improve my cars, however incremental the change might be. I do however have two primary concerns.

1 - The hardware (MAF, wiring, etc) isn't anything super special but the software is vital to the overall performance and life of the engine. The other chip tuner (Wong) has spent a long time spread out over dozens, if not more, of 964s getting the mapping "right". Your software (chip) was done in a relatively short time on a single vehicle. IMO, this isn't ideal and leaves room for more testing before it should be released to the market.

2 - The filter needs to be as large as possible and it would be great to see some type of shield to keep the hot engine air away from the inlet. Also, the filter should be sourced only from K&N, ITG or BMC and not from one of the knock-off companies!

Anxious to hear your thoughts.

fast951

First, I do look forward to working with you on getting the performance package you require for your car.

1 - I cannot comment on anyone else's work, so I will just fill you in on my own. We are not new to the tuning world! There are 2.5L 951s with over 400-500rwhp running our MAF conversion. We have plenty of 911 3.2L, 944... race cars using our MAF kits for years. The 964 Motronic is not that new to us, there is another Porsche that uses similar Motronic DME, which we converted a while back to MAF. So converting the 964 to a true Air Mass to support the MAF was not a huge deal for us. Tuning the 964 was done on the dyno. Since we know the Motronic code, not just the fuel and ignition maps, we can get things done efficiently and correctly without any guess work. I admit we have an edge here. Air Mass has many advantages, we use every bit of it to allow us to tune the car quickly and to account for some variation between cars.
Once we had a solid running & safe car, we went to the dyno to tune it and get the power out of it safely... Of course, unique cars require unique tuning. The customer is made aware of this! Then he has the choice to either let us tune it for him on the dyno. If due to geographical it is not possible, we offer the PiggyBack so customers can fine tune the setup to match their car 100%.

This leaves us the difference in octane rating. Here in GA we have 93oct, which we tune for. Customers out West, must use 91oct. We are already working with someone to get us the data based on 91oct. The bottom line, our experience goes a long way, we are not new.

At this time we have multiple 964 MAF kits out there, we work closely with the customers and if we find there is a need to make alterations we will adapt. We stand behind our products, our products deliver, a Rennlist search will give you a better idea.


2 - We tried 2 filters, both K&N. Performance wise, they are comparable. However, we opted to use the larger one as it sounded awesome. (Customers seem to agree).
A shield or a cold air intake is a good idea. The MAF & air filter size will allow different configurations. We have no plans to introduce this. I can see it now, people wanting to know what is the HP difference between various shield designs. Then when the information is provided, we get accused of something...

Ritter v4.0

On the heat shield; from what I gleaned here after much reading (factory box vs. holes vs. cone etc.), it appears at any kind of speed the air in the engine compartment is replenished so rapidly, the air being drawn in would not really benefit from the shield- or did I get that wrong?

springer3

Dereks "before" dyno run is on a modified engine - cat bypass is the particular concern. Was the O2 sensor operating, and did the change in back pressure from the cat and primary bypass invalidate the factory settings on the stock chip?

What is still missing from this discussion is power of factory stock system vs power from the MAF modification. Our road-dyno suggests the difference between stock engine and the Vittesse MAF system is +/-5 HP. The best estimate is they are dead even.

I offered to run my car as the test reference, and offered to pay for dyno runs on my car. I also offered to be the independent observer and objectively document the results for this forum. The offer was not taken. I am disappointed as I hoped there was a an economical way to extract more reliable horsepower. So far, this is not proven.

mjshira

John I am sorry you've been raked over the coals.