Promax MAF 3.2

[david.avery]

Hey guys

Saw a thread over on Rennlist, about the promax MAF kit for the 3.2

http://www.promax.uku.co.uk/maf_kit911.htm

I know Steve Wong also is offering one of these... anyone have any thoughts on the real gains with this system? I wonder what it would be like on a turbo 3.2 ?

[PorscheGuy79]

I dont even have a 3.2 and im interested in this one. Correct me if im wrong, MAF sensors detects what the air is like on the way in to adjust fuel and ignition to create more power? Right?







...peanut butter jelly with a baseball bat.

[cgarr]

I have seen this also, Just waiting for the exchane rate in our favor!!

[silverc4s]

I think the difference is that our normal "barn door" air sensor is measuring an analog of the VOLUME of air that passes by - the mass air flow sensor, OTOH actually can determine the MASS of the air going in , which can vary quite a bit with climatic conditions and altitude.
The computer that is using this info must also be calibrated accordingly to do any real good. There are a LOT of dissastisfied users of MAF conversions on Motronic systems, for that reason...

[PorscheGuy79]

Bill, could you explain more about what the calibrating does?

[JeremyD]

Hmmm

Live mid-market rates as of 2006.02.11 16:41:29 UTC.
749.95 GBP United Kingdom Pounds = 1,308.14 USD United States Dollars
1 GBP = 1.74430 USD 1 USD = 0.573295 GBP

and a reported 15% increase in HP (from 217 = ~ 32.55 hp) = $40.19 per HP - that's cheap!

[Jeff Alton]

I think 15% is stretching the ummm errrrrrrr truth a little bit. But, you never know!

Cheers

[silverc4s]

Originally posted by PorscheGuy79
Bill, could you explain more about what the calibrating does?

Well, in very simple terms, the computer is there to adjust the injector duty cycle, pulse width, or whatever, to provide the proper fuel mixture (~14:1 under power, for example) for proper combustion.

This really determined by the MASS of the air mixture combined with the fuel, NOT the VOLUME, although the volume is a decent approximation, MASS is really what the computer needs to know.

SO, a MAF is better only if:
1. The Computer is remapped for the new, more useful info. (That's that little thingy in a metal box they are selling along with the MAF sensor assembly.
2. The Computer is capable of using the improved information.

[silverc4s]

Another consideration that I have been made aware of is that the mechanical characteristics of the barn door have been taken into account in the programming of the Motronic and other things like flywheel weight, etc.

The response of the barn door is sluggish when compared to a MAF, and has some hysterisis associated with it as well, which the MAF does not.

The end result can be an engine with more power and more throttle response that is also more prone to stalling, and has a less smooth low end response, which is where you are most of the time in normal street driving...

[raceman]

lf Steve Wong has one,go with his which is a Bell-M unit and like the Autothority. On a boosted car this will make no difference at all.l did a lot of research on this before l gave up my mass flow and went turbo.lf you`re determined to try it on a turbo car you won`t be able to run a "blow through" system.The charge heat messes things up so you`d need to place the mass flow sensor BEFORE the turbo(suck through) like a lot of factory turbo cars...Saab,Volvo,VW,etc. Ultimate horsepower will be the same though and you`ll need a piggy-back unit to optimize things.So you`ll need a wideband system,fuel pressure guage,etc,etc to keep it in tune.So basically.....not economical for a turbo car and at that price no better for a NA car.

[PorscheGuy79]

So Bill you would say its much more suited as a Track toy upgrade rather than a street machine? Sounds like this would create driving problems similar to a racing flywheel on a street car stuck in traffic.

Jeff's got it right here, marketing on products with horsepower claims are often skewed in their favor. I usually low ball my expectations that way when there is more, im even happier.

Its kinda like driving around in a 911, girls think you are compensating, so I play off that and then when the time comes they are pleasantly surprised. LOL!

[david.avery]

Thanks Raceman, that's what I was wondering about.

[Carrera3.5L]

Jeff's got it right, you guys are getting all worked up over wild horsepower claims.

Look into other methods for significant power gains on a 3.2L, this does not appear to be one of them.

The stock AFM works just fine and will not restrict peak power in most instances, even on modified larger displacement offerings.

If you do decide to throw your money away, at least ask them for a money back guarantee to substantiate their power claims on your engine.

Ralph

[silverc4s]

Originally posted by PorscheGuy79
So Bill you would say its much more suited as a Track toy upgrade rather than a street machine? Sounds like this would create driving problems similar to a racing flywheel on a street car stuck in traffic.

Jeff's got it right here, marketing on products with horsepower claims are often skewed in their favor. I usually low ball my expectations that way when there is more, im even happier.

Its kinda like driving around in a 911, girls think you are compensating, so I play off that and then when the time comes they are pleasantly surprised. LOL!

PG79,

A more accurate statement might be: that the MAF conversion's improvements would be more suited to track use, just like folks go to Webers/PMOs on later engines for track use, but not many throw away their Motronic systems for a PMO conversion on the street. SMOG requirements aside, the drivability would be much worse.

There are two ways that MAF could give more HP:
1. Less restricted airflow
2. Improved fuel/air ratios in places across the band

I doubt the 15HP claim, but do think that the curve could be flattened somewhat by the improvements.

I have looked into this a number of times in the past, and always decided to leave the Motronic alone, except for a chip of course.. until other mods are made I will stay with the barn door, personally.

EDIT: MAF type air systems are virtually universal now, so clearly they are an improvement.
My point is that in these newer apps the entire engine SYSTEM was designed that way from the get go...

[don911]

How would this gain any more the any other MAF system? I have a Autothority MAF on my stock 3.2L motor with a cat bypass. I had Steve Wong do a custom chip and have roughly 250fwhp,(assuming 15% loss)
I think the driveability is actually better than with the stock airmeter.

[JeremyD]

In all fairness, I received a reply from them... Seems they are willing to put their money where their mouth is...


Hi Jeremy,

Thanks for your message. You should expect to see gains of +25bhp and 30lbft torque - it will vary from car to car.

The MAF kit has been dyno tested on a number of 964 and 911 3.2 models. Power gains were typically 18bhp (some were more, some were less). Once the DME chip was re-worked to take into account of the increased airflow, the power increased more and torque spread increased too. On both the 964 and 911 3.2, I would expect the gain to be about 25bhp peak and over 30lbft torque. However, the main benefit will be improved smoother running, more torque and better drivability.

I have two installs scheduled for this coming week - I'll get those customers to provide a testimonial once they have had a chance to drive their cars with the kit fitted.

The kit is being supplied to US customers with a 30 day money back warranty. If it doesn't do for you what I describe above - you can remove it from the car and return it. I'll even pay your return shipping.

Have a great weekend!

Regards,
Andrew

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Andrew Sweetenham
ProMAX Motorsport
Porsche Performance Specialists
Tel: +44 (0)1908 524468
Mbl: +44 (0)7831 393633
email: andrew@promaxmotorsport.com
web: www.promaxmotorsport.com

[Carrera3.5L]

Can't beat that Jeremy! I wonder if the bloke knows how much shipping is going to cost from Florida back to the UK.

My peak horsepower/torque gains with a similar HFM5 set-up were marginal over the stock AFM doing repeated back-to-back dyno tests, although I do admit the the around town drivability was smoother.

This is also on a larger displacement motor with all of the normal 3.2L based enhancements (intake, exhaust, cams, etc) which leads me to believe that the stock AFM is not a power restriction on a warmed over street engine.

Based on my experience, I would be HIGHLY surprised to see a gain of even a 1/3 what they're quoting, because I didn't see it with my engine.

Ralph

[Jeff Alton]

It seems from reading 911 and Porsche World and seeing some posts from shops in the UK (about chips etc ) that the UK folks seem to over estimate their power gains by a fair margin.

Don has a nice dyno plot but I am not sure how much more he is making with the MAF than if he had Steve do a custom chip for him using the stock AFM.

25hp is a fair whack to gain. I am just a little skeptical after having another chap from the UK tell me North Americans can't tune properly and he can get up to 55hp from a chip swap on a 964!!!! All the adds in the magazine claim power outputs that the North American consumer would have a hard time with.

Having said that, if he will give you your money back, try it. But it is interesting that they went from claiming 15 % (32hp) to a probably much more realistic 18 hp "some more, some less".

My guess is you will get 18hp if you are lucky and probably "some less"

Cheers

[Bill in OKC]

I am a *relatively* new Porsche owner, my car had a MAF sensor already installed when I bought it. I didn't know enough to know this wasn't stock. The car starts in all situations, warm, cold freezing and runs great in city driving - though I've no way of comparing it to stock. The bad thing is that the company that made this system went out of business so replacement parts could be difficult to find

[don911]

Originally posted by catca
Don has a nice dyno plot but I am not sure how much more he is making with the MAF than if he had Steve do a custom chip for him using the stock AFM.

I had a Steve W chip with the stock AFM but never did a dyno with it. I can tell you the MAF with custom chip "feels" like more hp and torque. I have no proof of that however. Here's a dyno sheet for a stock 3.2L for comparison.

can't upload a photo. Here's a thread with the dyno sheet from stock.
More kudos for Steve W and dyno sheets