fast951

springer3, in an earlier post you stated that your car is "freshly tuned"? What did you mean by it? Are you running the stock engine and engine management?
I don't think the test you guys performed is accurate at all. For a starter, there is weight difference, how much it's hard to tell (weight of car, weight of driver, how much fuel did each have at the time).. What tire diameter are you running? Any difference in tire size will yield a different RPM at the same speed. A smaller tire works same as gearing affecting acceleration.
All of this is water under the bridge.. However there is a simple and safe way to get accurate results (sorry I'm not into street racing). Would you be willing to put your car on the dyno? You can test with the factory chip/DME/AFM, then we can swap to the MAF & measure the performance gain. This will give us a good idea of what your car is making before and after. I'm sure Derek can be talked into putting his car on the same dyno with the factory chip/DME/AFM. This tells us how the 2 cars compare in stock form, as well as with the MAF. Are you willing to do this test? I will supply the MAF for the test, you don't need to purchase it. Of course the results are to be shared with the rest!

Heirsh

There was another MAF replacement advertised several months back. There was a promise of dyno's before and after, but I never saw anything about it. I asked once and got no response.

To me Springer's test was pretty good. Of course a dyno would be more appropriate, but there never seems to be the appropriate dyno readings. Without one of those, what Springer did means more to me than what someone feels in their pants.

The thing is people are somewhat skeptical about things like this and are going to react as such.

I personally have a suspect AFM and I am extremely interested in replacing it with a MAF. Jason A. mentioned he was working on a straight up replacement, but I havent heard anything recently.

Regarding your product...

If you can document with controlled before and after dyno runs of a product that shows equal or improved performance over stock you will get even more interest.

watching with anticipation

springer3

John: Please! If you read the description of the test, we answer most of your questions. I was expecting to lose. I wanted to lose, and learn that a simple MAF conversion would add reliable power. The test was very fair. Running side-by-side is far more accurate for detecting small power differences than back-to-back dyno runs . We knew we were sucking in the same air, and you can never say that about dyno runs at different times of the day. Temperature, pressure, and humidity change, especially in room where powerful engines are running.

I ran a similar test against a car that had 50 extra HP. I saw his tail lights after a few short seconds, and I was behind by 10 car lengths at the end of a similar 3 rd gear test.

Freshly tuned means a year ago during the Christmas break I changed the oil, the spark plugs, and adjusted the valves. I fitted a primary bypass, and that is the first modification to an otherwise unmolested 964 C2. The engine controls are original. I have 16 inch wheels. I think Derek's were 17s, but the tire OD and road speed at our 2000 RPM starting point is the same.

Weight and acceleration are the only factors needed to define power. I said Derek's car was around 60 lb heavier. At 13 lb/HP, that is 5 HP, but I forgot about Derek's LWF which is an advantage on acceleration.

I am not interested in taking off factory parts for aftermarket. It would be fun to run my stock set-up on a dynomometer, and I am fine if you want to verify I am running a stock chip and no other mods. I have the primary muffler to reinstall if we want to see if the bypass provides any advantage other than weight reduction.

fast951

springer3, I'm not questioning your intentions. Again, there are way too many variables to make any conclusion, we both know it. The ONLY way to make a claim, such as you did, that the MAF kit yields no power is to do a before and after test. The only way to claim that Derek is not making the power as measured on the dyno is to compare his results to a well known configuration. The race you both did is not a accurate measure of the engine's performance; too many important variables are involved.


There is no way to tell (without a dyno) what kind of power your car is making. Maybe you are making stock hp or 50hp over stock, we have no idea. We know what Derek's car made power wise, we have no idea what your car is making.

Based on your test and your conclusions, your car should be making about the same HP as Derek's car (5hp difference). This may or may not be the case, nobody knows. Easy to verify, you run your car on the same dyno with a stock DME/chip, you should yield the same results as Derek did. This leaves the variable of the dyno reading differently between the time Derek dynoed and the day you dyno. This variable can be eliminated as well.
To go further, if Derek agrees, both of you will run the same dyno test with the factory setup. To be more accurate, the same dyno, the same factory DME/chip, the same 93oct fuel is to be used on both cars. Since both cars are stock, the performance across the board should not be more than a few hp difference. Same day, same dyno, same configuration!

By testing both cars in stock form, under the same conditions, we know for sure what is the base line for each car. Then, we can measure and determine which modification increased or decreased the performance.

Once we have accurate data, then we can draw conclusions. Of course, the dyno will only tell us the performance under WOT. Crisp response, smoothness,... cannot be measured on the dyno.

Let's try to keep this thread alive and add some fun to it.

Now, I got to do some Xmas shopping.

TR6

+1. The rolling drag race test is meaningless. Two different cars. Too many variables. You can try to list the specs/stats on each car all day long and it doesn't matter. They are two different cars.

The only meaningful way to measure a mod on a car is a controlled dyno comparison. Same day, same weather conditions. Change only the one variable that you are testing for. Do three runs with each configuration to normalize for error. If you do that, the delta in power output is real and indisputable. Not the absolute power output, mind you. Different dynos can come up with different numbers. Only the relative difference in power output is meaningful using a given dyno.

eg. If you are measuring the effect of a cat bypass, dyno the car with the oem cat, do three pulls, and then swap for a cat bypass and do three more pulls in the same hour or as close in time as feasible.

Lorenfb

"By testing both cars in stock form, under the same conditions, we know for sure what is the base line for each car."

As mentioned in a prior post, the "acid test" has been performed.
That test replicates the conditions most/all drive their cars under
and where they would expect a mod increase to be verified.
More comparative efforts are a waste of time and money for all involved.

All previous MAF mods (by themselves) have yielded little to no gains.
From a theoretical standpoint one should realize that the MAF by itself
does not increase the volume of charge entering the cylinder, given
the basic same intake area as the original AFM. Thus, without more
charge, there's no increase in energy to yield more torque.

Granted, a MAF can result a little more throttle response, but basically
a tweaked AFM can also improve throttle response. The MAIN reason
for OEMs using a MAF versus the AFM was improved load measurements
for fuel economy and emissions control.

Bottom line: Time to discuss more about suspension improvements for
a better return on dollars spent.

mjshira

Loren

So based on what you're saying here, how much benefit can one derive from Motec?

kos11-12

biger injectors ??
sorry to jump in
Konstantin

jeff522

It would seem that the hot wire of the MAF would allow for better less turbulent flow. The old "barn door" of the AFM should induce a lot of turbulence to the flow, and resistance. Less restriction to flow and less turbulence makes a big difference with heads, and intakes. Anything which improves flow will allow the engine to get more air/fuel mix in the cylinder during the open valve portion of the engine cycle. The same seems also true on the exhaust side as well.

The statement was made that auto companies went to the MAF to improve MPG/L and to reduce pollution. "Pollution" is the result of incomplete combustion of a fuel. If the MAF causes the engine to burn cleaner( less pollution) then the fuel is being more completely Burned/combusted. The more fuel you burn the more power you make. The improvement in MPG/L points to a engine which is operating in a more efficient manor. Making more power per unit of fuel used.

How much power is the ?. Since I don't have a dyno nearby, I have always used 1/4 mile trap speed to follow changes in performance with mods. The Autothority MAF did show an improvement over stock of about 25 to 30 hp showing about a 2 MPH improvement in trap speed. I am in the middle of nailing down some grounding issues with my 964. As soon as this is completed and the weather is agreeable, I will be doing some road testing of the Vitisse MAF.

fast951

Yes we can handle bigger injectors!

Lorenfb

"It would seem that the hot wire of the MAF would allow for better less turbulent flow. The old "barn door" of the AFM should induce a lot of turbulence to the flow, and resistance."

Very minor, but a good sales pitch to many.

"Less restriction to flow and less turbulence makes a big difference with heads, and intakes."

True, but hardly a good analogy to apply to an AFM vs MAF.

"If the MAF causes the engine to burn cleaner( less pollution) then the fuel is being more completely Burned/combusted."

That's true. But to further state:

"The more fuel you burn the more power you make."

Is not totally correct. The MAF allows for more precise fuel metering for a
given fuel quantity.

"The improvement in MPG/L points to a engine which is operating in a more efficient manor. Making more power per unit of fuel used."

No, not totally correct. Yes, more efficient but not necesarily more power.
There's more available TOTAL power output, e.g. driving distance, per fuel
quantity (because less is being used per time), but not necesarily more HP.

"How much power is the ?."

Please do a Rennlist search. It's not as if this is a new type of mod.
It's been presented many times over the years with basically zero results.

"The Autothority MAF did show an improvement over stock of about 25 to 30 hp showing about a 2 MPH improvement in trap speed."

25 to 30 hp? HARDLY! If any resulted, it was because of the "pushed timing"
advance.

N51

You're all such great sports. Springer, you and Derek are to be complimented for your evaluation.

The results are real. You've both eliminated many variables. It's an easy read.

HoBoJoe

How about we all stop discussing whether a MAF is a power gaining mod and just wait for the final dyno results? The way I view this modification (coming from owning a 951) is that it should give smoother power, some extra HP/TQ, more out of your current mods, and over all better drivability. John is not the type of retailer just to take your money and run; he supports and stands behind all his products. I have never once heard of someone with an ill remark of his company.

Lorenfb

"Springer, you and Derek are to be complimented for your evaluation.
"The results are real. You've both eliminatated many variables. It's an easy read."

Right! It's that simple. But we have many that have their own BELIEVES
and fail to accept the facts and realities. Could this be the result of previous
purchase decisions which now indicate the lack of any real factual basis?

Christer

Let me put it this way (to support the real-life test above) that anyone who drives my car now will not even need any comparison to a standard car to know that the performance has been increased considerably. The proof is always in the pudding, so thank you for dessert guys! I would not be 'investing' in a MAF for performance reasons on the info above if my car was standard....although if new data surfaces then I promise to keep an open mind...