FVD MAF Kit on the 964
08-12-2020, 12:34 PM
#31
I suspected my barn door AFM was worn out a few years back and I came across a lightly used Vitesse MAF kit:
http://www.vitesseracing.com/html/91..._air_flow.html
While I love almost everything "vintage" about air cooled 911s, I liked the idea of better, newer MAF technology when it came to idle, throttle response, and fuel delivery. I didn't really feel like cracking open the AFM and messing with the contacts as opposed to trying the used Vitesse MAF kit out. I figured I could always resell it if I didn't like it. I can report that I have been very pleased with it and would never consider going back to the stock AFM. I noticed a stabilized idle and what I perceive to be better, smoother throttle response. I assume the FVD and Vitesse kits produce similar results, so I would suggest trying one out for those who feel the same way I did.
http://www.vitesseracing.com/html/91..._air_flow.html
While I love almost everything "vintage" about air cooled 911s, I liked the idea of better, newer MAF technology when it came to idle, throttle response, and fuel delivery. I didn't really feel like cracking open the AFM and messing with the contacts as opposed to trying the used Vitesse MAF kit out. I figured I could always resell it if I didn't like it. I can report that I have been very pleased with it and would never consider going back to the stock AFM. I noticed a stabilized idle and what I perceive to be better, smoother throttle response. I assume the FVD and Vitesse kits produce similar results, so I would suggest trying one out for those who feel the same way I did.
08-12-2020, 01:22 PM
#32
But does the design of the original AFM limit the amount of air that can pass through it at it's fully open position at 4k rpm's and above? If the MAF can flow more air at WOT than the AFM, along with the chip tuned to compensate for it, then it should give more hp. Add some higher flow injectors, also tuned to match, and the increase is even higher. HOWEVER - if the AFM at its fully open position can flow more air than the engine can use/need, then the MAF would not give any additional hp at full throttle or higher rpm's.
Rhonda - have you guys tested this? The max volume of air than can pass through the afm vs the maf and if the engine starves for air at WOT with it's original afm?
I agree also that the main benefit of the maf is driveability and throttloe response by getting rid of the lazy barn door.
Just as an experiment, while I have my engine out, i opened my afm, cleaned the contacts (I've already repositioned the arm), and released the tension on the barn door spring by one tooth. Just to see if response improves at all. That one tooth does not seem to make much of a difference to my hand, but possibly to the engine. I'll see when I put it back together. Otherwise it's easy enough to put it back the way it was.
Rhonda - have you guys tested this? The max volume of air than can pass through the afm vs the maf and if the engine starves for air at WOT with it's original afm?
I agree also that the main benefit of the maf is driveability and throttloe response by getting rid of the lazy barn door.
Just as an experiment, while I have my engine out, i opened my afm, cleaned the contacts (I've already repositioned the arm), and released the tension on the barn door spring by one tooth. Just to see if response improves at all. That one tooth does not seem to make much of a difference to my hand, but possibly to the engine. I'll see when I put it back together. Otherwise it's easy enough to put it back the way it was.
was achieved once the included chip was replaced with a stock 964 chip. Do a Rennlist search, there're many discussions on this topic.
Last edited by Lorenfb; 08-12-2020 at 01:37 PM.
08-12-2020, 02:01 PM
#33
Rennlist Member
Loren--I read that thread and I gathered from it that a MAF won't operate at all with the stock chip. Apparently the voltage values are different between the stock barn door and MAF. I don't remember seeing that anybody attempted the test you describe. Correct me if I'm wrong and provide a link.
My primary interest is in drivability and responsiveness. If it gives a couple more horses, that's cake.
My primary interest is in drivability and responsiveness. If it gives a couple more horses, that's cake.
08-12-2020, 10:40 PM
#34
Loren--I read that thread and I gathered from it that a MAF won't operate at all with the stock chip. Apparently the voltage values are different between the stock barn door and MAF. I don't remember seeing that anybody attempted the test you describe. Correct me if I'm wrong and provide a link.
My primary interest is in drivability and responsiveness. If it gives a couple more horses, that's cake.
My primary interest is in drivability and responsiveness. If it gives a couple more horses, that's cake.
08-12-2020, 10:43 PM
#35
Loren--I read that thread and I gathered from it that a MAF won't operate at all with the stock chip. Apparently the voltage values are different between the stock barn door and MAF. I don't remember seeing that anybody attempted the test you describe. Correct me if I'm wrong and provide a link.
My primary interest is in drivability and responsiveness. If it gives a couple more horses, that's cake.
My primary interest is in drivability and responsiveness. If it gives a couple more horses, that's cake.
08-12-2020, 11:54 PM
#36
Rennlist Member
The thread you referred to, that's which thread. I read a couple different MAF threads to help make my decision. If, as I stated, MAF won't work with a stock chip your claim is disingenuous at best. Link the thread.
What's your view on throttle response, idle, and drivability of MAF compared to AMF?
What's your view on throttle response, idle, and drivability of MAF compared to AMF?
08-13-2020, 04:08 AM
#37
With regard to the chip that's included with the typical MAF kit, a Rennlist test of a MAF kit was posted on this forum which indicated that no performance gain
was achieved once the included chip was replaced with a stock 964 chip. Do a Rennlist search, there're many discussions on this topic.
was achieved once the included chip was replaced with a stock 964 chip. Do a Rennlist search, there're many discussions on this topic.
Unless there is a source for new or rebuilt AFMs that I am not aware of.
08-13-2020, 08:57 AM
#38
The issue we are all facing here is not whether we can get extra HP or torque from our engines, but whether we can use them at all. I am on my 2nd AFM , and I can only hope it lasts for a while more before the reference tracks get too worn for reliable use. After that, we need a valid alternative.
Unless there is a source for new or rebuilt AFMs that I am not aware of.
Unless there is a source for new or rebuilt AFMs that I am not aware of.
08-13-2020, 09:03 AM
#39
The thread you referred to, that's which thread. I read a couple different MAF threads to help make my decision. If, as I stated, MAF won't work with a stock chip your claim is disingenuous at best. Link the thread.
What's your view on throttle response, idle, and drivability of MAF compared to AMF?
What's your view on throttle response, idle, and drivability of MAF compared to AMF?
08-13-2020, 09:11 AM
#40
Rennlist Member
I can't attest to FVD's product only speculate but I am not sure how much of a difference it is to the Autothority unit I had. As I stated the Autothority unit did change the characteristics but no power increases were observed.
08-13-2020, 09:16 AM
#41
Well, installed and tested a well known brand 964 MAF kit yesterday. Took me 30 min to install.
What is my experience after a one hour (evening) drive (it's hot over here).
1. Looks like throttle response is a little bit more response, but limited;
2. No noticeable power gain;
3, the typical 1500-4500 'lag' is less noticeable.
That's it. I decided not to buy the kit.
A lot of money for a hotfilm and pretty simple translation of table values (MAF - AFM - Motronic)
I have VEMS kit, this will be my winter project.
Cheers
What is my experience after a one hour (evening) drive (it's hot over here).
1. Looks like throttle response is a little bit more response, but limited;
2. No noticeable power gain;
3, the typical 1500-4500 'lag' is less noticeable.
That's it. I decided not to buy the kit.
A lot of money for a hotfilm and pretty simple translation of table values (MAF - AFM - Motronic)
I have VEMS kit, this will be my winter project.
Cheers
08-13-2020, 12:10 PM
#43
Originally Posted by Sire
Did you do before and after dyno. If not, it's nice wright up but it says nothing no facts.
I'm sure the gain you will see on the dyno will not be the 50hp as advertised. This is simply not possible looking at the limitations a stock 964 has. My setup is cup pipe+sport car.
A MAF kit is a good solution if you are looking for a more responsive engine, but looking at the cost I would spend the money on a VEMS setup with some injectors not limiting the tuning you can achieve with the VEMS.
Anyway, lot's of 964 friends I have are very pleased with their MAF kit.
Cheers
08-13-2020, 03:54 PM
#44
Racer
I understand that you say you know your darling, but no facts is just saying what you think you feel. From mine own experience when installed a MAF the HP game arround 293 indeed not the 50HP.
08-13-2020, 03:57 PM
#45
Originally Posted by Sire
I understand that you say you know your darling, but no facts is just saying what you think you feel. From mine own experience when installed a MAF the HP game arround 293 indeed not the 50HP.
If we are both happy with the performance of our cars it's all good.
Cheers