MAF Kit for 84-89 Carreras - 25 real HP - any interest?

ZCAT3 · 02-26-2003, 03:30 PM

Hello All - I recently went on a MAF frenzy after reading in Bruce Anderson's book that this was a good way to get power and then speaking with several Porsche tuners about it. I was put off by the only readily available kit, though, as the price for that one is $2000. So I started doing some research and found the source for the MAF units and bought one (at far less than $2000). The downside of course was that it was not exactly setup for my 87 Carrera. But after a lot of time and research (and treating my car like a poor test mule), I was able to get the MAF installed and tuned properly (I have since cleaned up the wiring in the picture with some Silicone Fusion Tape - very cool stuff).

I went to a local Dyno shop on Monday to do the final tuning and to see what power I was making. Before the MAF was installed I was making 185 HP at the wheels. The dyno testing allowed me to monitor the A/F ratio under various conditions, such as heavy load and during cruising conditions. This made all the difference in getting it set up correctly.

Now for the good part - I got 210 HP and 190 ft/lbs torque at the wheels. Using 15% drive train loss, this is 247 HP and 224 ft/lbs at the crank (vs. what is listed as stock on my car 214/195). From a power/weight ratio that puts me almost on par with the 993s. Not too bad from an 87 Carrera with 111,000 miles on it. That means the MAF gave me over 25 HP. The car feels much more responsive through the power band and is better under virtually all conditions (for example you can cruise at 2,000 RPMs without any surging). I will be testing it out on the track at Willow Springs next month.

The MAF itself is totally tunable with a tuner box and a PC, so if changes are made to the car in the future it can be adjusted. The car also seems to run a tad cooler with the added airflow. In addition, the maf tuner box (which is locate in the passenger compartment) can be easily unplugged which serves as a fuel cut off switch (a nice anti-theft device).

I put a lot of work into this and want to make this available to the Porsche community without the normal "Porche Price Penalty." Depending on interest, I think I can put this kit together for $900. There are some things that need to be done, such as installing the MAF curve, creating some brackets, writing some real instructions, etc., but if interest is there I will move forward. I have already spoken with 2 reputable Porsche shops / tuners about this and they are interested in selling the kit as I have tuned it. In any event, I am trying to gauge interest in this to see if it is worth continuing with. Thanks.

Bill

fig911 · 02-26-2003, 03:38 PM

I would like to learn more but $900 for 25hp sounds good to me...At the risk of sounding like a dumb a$s, what does MAF stand for? It looks like an air filter?

ZCAT3 · 02-26-2003, 03:42 PM

Sorry about that - it is a Mass Air Flow system. It actually replaces the airbox and the mass flow meter in your car (that gray plastic box with criss-cross ribbing on top). The filter is not a big deal, it is the new airflow metter that makes a difference. Authothority sells a similar setup with a chip for $2000. This uses the same airflow system, but the chip is not necessary as the MAF tuner box makes this completely adjustable to your car.

Colby · 02-26-2003, 03:49 PM

Huntley Racing has a kit out for $1195 that includes the MAF, filter, and a programming computer that can stay in the car or be removed. What are you offering with your kit? How do you program the MAF?

Colby

ZCAT3 · 02-26-2003, 03:55 PM

Hi Colby - first it will not be my kit. I will turn it over to a few Porsche shops to sell (but can get a lower intitial price if we have some orders up front). I looked hard at the Huntley Racing kit and had a few problems - one is that they have no dyno numbers for a U.S. spec stock car, and I also wanted to pay less (I almost ordered from them - they are nice folks).

The MAF has a tuner box attached that allows you to adjust the air/fuel ratio via 4 knobs that correspond to throttle position or by hooking it up to your PC via a USB cable and using provided software (this allows you to adjust 64 data points on the throttle range). I have tuned the MAF for use with the 87-89 Carrera, and would expect the 84-86 cars to be pretty much the same. I cna drop this tuned curve into each MAF tuner before it is sold. A little fine tuning via the knobs may be necessary after install. The kit also comes with a complete wiring harness.

Fast951 · 02-26-2003, 03:56 PM

Bill,

Nice work, I guess you are using the Pro Flow system with the new "Power Flow" MAF tuning box. Pro Flow can provide you with an existing calibration file to match the stock AFM. I have done this a while back, however you still have the issue of handling the Air Temp sensor which is inside the AFM. The MAF compensates for temp, but the algorithm in the DME takes into account the temp sensor input.

The performance gain that you obtained is due to running the correct fuel mixture, which could be attained by a good set of chips.
Not to undermine your effort, but at the HP levels of a 3.2L the AFM is not restrictive and you are just emulating the AFM signal (MAF + Tuning Box = similar output to AFM).
I have been tuning 944T and going with MAF vs AFM. Unless you go over the 300hp mark, there is a no drawback to AFM. On a NA car, there is very little gain, and most of it due to changes in timing.

ZCAT3 · 02-26-2003, 04:02 PM

Thanks Fast951 - you are correct - the MAF is from Pro-M. I have tried several of the chips out there and never really saw much of a gain. When I research the MAF idea (and saw that Bruce Anderson found it to be one of the best bolt-on upgrades) I wondered why these were not used more on the 3.2s - I guessed it must be the high price. I am not technical enough to know why the HP gain was so strong - other than to say that the new air flow metering system must just work a lot better than the stock system used from 84-89. It did take a fair amount of dyno time and effort to get it tuned in. I figure if there is interest I can pass it on.

marcesq · marcesq's Garage

Bill:

What exhaust system are you running. Any other engine mods. The 25 hp is impressive if the engine is totally stock and the exhaust system and cat are in place. I would be interested with a little person to person discussion of the process.

I am familiar with the Authourity MAF system and was quickly disuaded by the price tag.

I'll send you a pm with contact stuff

Edit: Sorry I type slow and there are now 3 other posts, so it is appearent that the car is stock.

Fast951 · 02-26-2003, 04:12 PM

Bill,

What shape was your air filter at the time of test?
I believe you should be able to save the calibration file and reuse it on other units. Some of the things to monitor is cold start problems, if you do pm me and I'll assist you.
I personally know the guy that designed the tuning box, it's a very nice unit.

ZCAT3 · 02-26-2003, 04:15 PM

I actually did a pre-Dyno run before I did anything and got 180 at the wheels (212 crank). I then switched my cat out to a Euro pre-muffler from Huntley Racing while doing a valve adjustment and got 185. The rest is from the MAF. I doubt the cat would effect it - but I am not sure as I did not dyno it with the MAF and cat in place. Dyno time is pricey and I already have many hours into this (my wife thinks I have lost my marbles).

ZCAT3 · 02-26-2003, 04:19 PM

FAST951 - I am not having any issues at all - it runs much better than before and is smooth throughout the range. If you look at the blue curves on the syno sheet you can get a feel for how well it dialed in. The MAF air filter was brand new (maybe a few hundred test miles). The pre-test air filter was a newly cleaned and oiled K&N cone filter. I had just cleaned that thing and made it perfect when the MAF idea struck.

Fast951 · 02-26-2003, 04:44 PM

Bill,

I couldn't clearly view the dyno chart. But your A/F ratio is very linear, which is good. If the Blue line was with the MAF, then it appears that you leaned out your mixture.
Great that you are enjoying the unit. This same setup was tested (part of the development process) on a 3.6 engine..

enjoy

ZCAT3 · 04:54 PM

We did lean it out a bit for the last run (the red line) as it was running a bit rich at the higher positions. You can see that this smoothed out the HP and Torque lines. I am trying to get some of the guys I know with 964s to give this a try as well. I think those cars could see a similar benefit.

widebody911 · widebody911's Garage

Stu @ http://www.schatzandkrum.com/ has been working on a Carrera MAF setup in conjunction with a UniChip, you might try him. I drove a '88 Carrera that he did and it was pretty peppy, all things considered 8p He's supposed to be doing a 3.6L version some day.

ZCAT3 · 02-26-2003, 04:57 PM

Well this one is ready to go if there is interest. Both Imagine Auto in Kansas and CT Automotive in the SF Bay Area would like to carry it. I figure it is better for people to have real tech support and a Porsche mechanic behind the product. I figure I will try to get an initial group to try it out and then step away.

89911 · 02-26-2003, 05:06 PM

Nice work. I have had a Huntely MAF on my car for the past 2 years. Its nice to see some investigation work and to verify to HP gains. And 25 HP on an engine that is already designed to be about as efficient from the factory is a great gain. I have stated before that with a MAF, bored throttle body, high pressure fuel regulator, SSI's and performance exhaust, a 50 hp gain is not out of the question. Mine comes with the Huntley Racing Split Second Air/fuel Ratio Calibrator ARC2-HR. This is the unit you were talking about I believe. I have noticed that they have done away with this and are using a different unit. Any thoughts why? Also, when you dynoed your MAF, any hints on the protocol? I will be dynoeing mine as soon as the weather breaks. As far as Huntley, they are OK but their support can be difficulty due to the size of their company. Derrick does know his stuff though. I would attest to the benefits of MAF. So would alot of C2's and 993's I run with!

ZCAT3 · 02-26-2003, 07:14 PM

The most important part of dynoing the MAF for tuning purposes is to ensure that the car stays within the appropriate air fuel parameters. I had the dyno tech kneel by the passenger door and he would tell me the ratio as we went through the power band. If it got too lean, he would signal to stop and we would recalibrate the MAF. Through trial and error we were able to dial in a very powerful and stable curve. It was actually pretty cool

With the setup I am using I can easily download the curve to another tuner or even send it via e-mail.

masraum · 02-26-2003, 07:45 PM

Don't forget there is a company in France that does an upgrade on Euro non-cat 3.2 L cars that gains 30hp. They take a Euro car with no cat, stock 10.3 comp ratio. They ADD a catalytic converter (metal high flow), change the car to a Genuine Porsche "hot wire" maf, put in bigger injectors (they say the stock injectors aren't up to the job), and then retune the DME. all of this bumps the hp to 257 or something like that, about 30 over stock. And that's with adding a cat. The place we lose is the lower comp ratio. Shoot, if you go to a cat bypass you should be able to make up some of the difference.

Steve W · Steve W's Garage

The Pro-M MAF meter is good for about 10 hp over just a chip installed in the car with the stock AFM. Bill dynoed 25 hp because he was comparing a car with a stock chip to a retuned MAF system running more fuel to his premuffler system. Normally with chips averaging a 14-15 hp gain with a revisied fuel and ignition curve, the MAF system freed up an extra 10 hp netting him the 25. This correlates to what almost everyone gains (myself included) that installs one. I know what FAST951 is saying about the stock AFM, and how little restriction it really is by theory, but for some reason, replacing it always nets that 10 horse gain. If you look down that large 3 1/2" diameter tube of a Pro-M meter, you will know what I mean. It's like looking down the throat of a shark and staring directly at its stomach.

Bernd Andritzky · 02-26-2003, 11:44 PM

Hi Bill,

i´m also working on an MAF-Kit for the Euro-3.2 and so i want to share my experiences with you:
1) Your statement that a chip is not necessary because the a/f-ratio is controlled by the MAF tuner box is not correct, because at WOT the AFM/MAF-signal gets irrelevant for the DME and the fuel injection is only controlled by the WOT-fuel-map of the DME-Chip. So if You get more air into Your combustion chamber You also have to tune the fuel-mapping. I´m sure SteveW and Marc could help You with that.
2) 25hp from the AFM is not possible with a stock engine, normally You can get 10 to max. 15hp from that. The other 10-15 hp are the removed cat and measuring tolerances (on a dyno You can be glad to have less than +-5 hp difference when measuring the same car several times).

Best regards,

Bernd Andritzky