Promax Motorsports SciVision MAF kit Installation and Impressions part 2
04-26-2006, 08:33 AM
#61
Race Car
Originally Posted by Transaxle
Since the MAF kit was developed as a compatible replacement for the AFM it should run with the stabdard DME software. So we designed it for the 11.36 ms reading intervall.
The Bosch HFM5 sensor is very fast and precise. That means that it measures also the pulsation in the intake system. You could actually use it as a rpm-meter. Here is a picture that shows the differences (Yellow=MAF, Blue=AFM, Magenta=FT Signal):
The resolution on the timescale is 1 ms.
We read the MAF value every 0.6 ms and calculate the REAL massflow based on a 5 ms time window (= kg/5ms). That means the signal to the DME is updated every 5 ms based on ~8 measured MAF values.
The Bosch HFM5 sensor is very fast and precise. That means that it measures also the pulsation in the intake system. You could actually use it as a rpm-meter. Here is a picture that shows the differences (Yellow=MAF, Blue=AFM, Magenta=FT Signal):
The resolution on the timescale is 1 ms.
We read the MAF value every 0.6 ms and calculate the REAL massflow based on a 5 ms time window (= kg/5ms). That means the signal to the DME is updated every 5 ms based on ~8 measured MAF values.
Thanks for the explanation.
TS
04-26-2006, 03:54 PM
#63
Legend Killer
Rennlist Member
Rennlist Member
Join Date: Jul 2005
Location: Nor-Cal
Posts: 4,296
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by promax_motorsport
Hi All,
The SciVision MAF works equally well with the factory set-up or a Manual Boost Control set-up using Guru/Vitesse or any other DME chip.
The important thing to understand is that most chip solutions do not have overboost protect and knock retard. As Thomas explains, this is very critical on the 951. With the SciVision chips, all these controls are in place and you can run increased boost (1.0 or 1.2 bar) in complete safety. If you have no knock control and you take the car on the circuit or drive at sustained high speed at almost maximum revs - there is a good chance that things will get hot and knock will take place. The SciVision chips allow the knock sensors to feed information to the ECU and induce ignition retard until the knock stops. If it's too severe - overboost protect will be triggered.
So, what does all this mean? It means you can achieve 300bhp with almost total safety knowing that you can push your engine to the max without worries of popping a head gasket or holing a piston.
The factory design using the cyling valve and Knock and Air Pressure Control computer (KLR is a german abbreviation for Knock Luft Regulator - Thomas will be able to confirm) is a very good one and ensures that everything is kept in check.
Hope that makes sense to everybody - please feel free to ask further questions.
Regards,
Andrew
www.promaxmotorsport.com
The SciVision MAF works equally well with the factory set-up or a Manual Boost Control set-up using Guru/Vitesse or any other DME chip.
The important thing to understand is that most chip solutions do not have overboost protect and knock retard. As Thomas explains, this is very critical on the 951. With the SciVision chips, all these controls are in place and you can run increased boost (1.0 or 1.2 bar) in complete safety. If you have no knock control and you take the car on the circuit or drive at sustained high speed at almost maximum revs - there is a good chance that things will get hot and knock will take place. The SciVision chips allow the knock sensors to feed information to the ECU and induce ignition retard until the knock stops. If it's too severe - overboost protect will be triggered.
So, what does all this mean? It means you can achieve 300bhp with almost total safety knowing that you can push your engine to the max without worries of popping a head gasket or holing a piston.
The factory design using the cyling valve and Knock and Air Pressure Control computer (KLR is a german abbreviation for Knock Luft Regulator - Thomas will be able to confirm) is a very good one and ensures that everything is kept in check.
Hope that makes sense to everybody - please feel free to ask further questions.
Regards,
Andrew
www.promaxmotorsport.com
Thanks for the explanation.
I was not aware that everyone (including myself) that is running a MBC has actually eliminated the KLR's ability to provide overboost protection. Is this really such a bad thing?.....I mean for a street car...since I could definately understand that for a track car it could be bad.
My understanding now is that the DME even with the CV disabled can retard the timing and so this is some protection (according to Vittesse).....is it enough?
Andrew,
You didnt answer the follwing questions I asked previously.
Is it safe to use pump gas when running 17.4psi with the ProMax chips?
Does it matter what type of turbo, injectors and such you have on your engine like it does with other vendor's chips or do the ProMax chips work regardless of what you have on your car?
04-26-2006, 06:35 PM
#65
Racer
Originally Posted by Andial951
Andrew,
Thanks for the explanation.
Is it safe to use pump gas when running 17.4psi with the ProMax chips?
Does it matter what type of turbo, injectors and such you have on your engine like it does with other vendor's chips or do the ProMax chips work regardless of what you have on your car?
Thanks for the explanation.
Is it safe to use pump gas when running 17.4psi with the ProMax chips?
Does it matter what type of turbo, injectors and such you have on your engine like it does with other vendor's chips or do the ProMax chips work regardless of what you have on your car?
ProMAX chips are similar to Vitesse / Guru etc. and rely on setting the boost level to match the DME. The SciVision chips can use lower octane fuel as they have the full knock retard and overboost protect capability.
SciVision chips are designed for standard injectors. We can modify them for use with any injector type by changing the FQS scaling values.
Regards,
Andrew
www.promaxmotorsport.com
04-26-2006, 06:42 PM
#66
Instructor
Join Date: Feb 2002
Location: Germany
Posts: 201
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by danny951
What is the "FT Signal" in that graph?
04-26-2006, 07:18 PM
#67
Addict
Rennlist Member
Rennlist
Site Sponsor
Rennlist Member
Rennlist
Site Sponsor
Originally Posted by promax_motorsport
Hi Roger,
ProMAX chips are similar to Vitesse / Guru etc. and rely on setting the boost level to match the DME. The SciVision chips can use lower octane fuel as they have the full knock retard and overboost protect capability.
ProMAX chips are similar to Vitesse / Guru etc. and rely on setting the boost level to match the DME. The SciVision chips can use lower octane fuel as they have the full knock retard and overboost protect capability.
We do keep knock control (timing), however we recommend using high octane once you go over a specified boost level.
Last edited by fast951; 04-26-2006 at 07:44 PM.
04-28-2006, 09:19 AM
#69
Racer
Originally Posted by danny951
I think he was talking about your AFM chips, john
That's right - I was talking about AFM chips (just a generic reference to chips used with MBC set-ups).
Regards,
Andrew
www.promaxmotorsport.com
04-29-2006, 12:37 AM
#71
Pro
Join Date: Apr 2002
Location: N. Virginia
Posts: 549
Likes: 0
Received 0 Likes
on
0 Posts
Two questions about Promax:
How does one increase boost in the Promax maf while maintaining the CV in the loop so that significant HP gains can be attained?
Also, I thought that the stock injectors were limited to about 300HP in output. Doesnt the 1.2 bar boost and MAF exceed this HP limitation? (at least for 26/8 turbos)
How does one increase boost in the Promax maf while maintaining the CV in the loop so that significant HP gains can be attained?
Also, I thought that the stock injectors were limited to about 300HP in output. Doesnt the 1.2 bar boost and MAF exceed this HP limitation? (at least for 26/8 turbos)
04-29-2006, 09:32 PM
#72
Wow. I'm surprised at the lack of basic technical understanding in some of the above posts!
Basically the KLR is a faily blunt instrument which on detecting knock takes out a chunk of ignition, then if the knock continues effectively dumps all the boost to save the engine. Very safe, but not much finesse.
There is no reason that an engine with all components working and running fuel of consistent and correct quality with a good map in the DME should ever get to the stage of dumping boost. On that basis you don't "need" the KLR to have control of boost to make sure the engine won't grenade.
Where you will get problems is if the DME map is not as good as it might be for your particular engine (something that is always a risk with off the shelf chips of any flavour) or if the boost is beyond that the DME map expects. How many of us have used something like an LBE or AccuBoost and turned it up too high on a standard car? That triggers the boost dump through knock.
There is no facility for the DME / KLR combination to measure boost and account for extra by adding fuel in the standard car and I am pretty sure nobody has been able to add that facility subsequently. In fact I am pretty sure the boost is only measured at all so the KLR knows when to open the cycling valve and to run the gauge in the dash, it's only knock and not boost pressure that trips the safety system.
There is no way a set of chips can be used regardless of injector size; it just isn't possible. The chips effectively tell the injectors how long to stay open to deliver the correct quantity of fuel and without being told the flow rate of the injector they can't calculate the duration correctly. It is possible to put maps for several injector sizes on one set of chips and choose them using jumpers, but you still have to do that manually.
Because all engines are slightly different any off the shelf chips can't go too close to the edge. That means they are a compromise and they err slightly on the side of safety. They all (to my knowledge) retain the KLR to modify timing on detection of knock and that should be plenty if the chips are even close to safe. If you fitted chips that triggered the KLR to dump boost you'd take them out again pretty quick. In other words none of the aftermarket chips depend on the KLR being able to control boost.
If you want to get a little extra from a basically stock 951 then you can do so by replacing the AFM with something less restrictive and adding mild extra boost. That seems to me to be what Transaxle has designed the SciVision MAF to do.
To get significantly more power you need to get rid of the standard wastegate. It's a poor design and it bleeds boost even when the CV is closed. To replace it you have to lose the CV and with it the KLR's ability to control the boost.
I can't see how the stock wastegate would ever get anywhere near holding 1.2 bar never mind 1.5 bar, and if it did you would most definitely need bigger injectors to keep up with the fuelling. You'd also need a bigger turbo to provide that level of boost in the first place, even if you have a K26/8 car.
Can you get 300bhp from just an AFM replacement and set of chips on the standard wastegate and CV? I seriously doubt it. Maybe 270's, and that's flywheel not rear wheel, and with a K26/8 on the Turbo S. K26/6 cars probably could make 250 to 260 fwhp in that configuration.
I've seen a lot of people here in the UK start out with things like the Guru chips and wastegate shims, then move onto a TiAL or Lindsey DPWG and get 10% to 15% improvement. When they go on to bigger turbos and bigger injectors then the off the shelf chips start to fall down, regardless of what the vendor says and what jumpers they might have on them that supposedly match the parts on the car. That isn't a pop at any one vendor, I've seen it with several: AFRs into the 10's on boost, or AFR's that bounce around like a seismograph trace during an earthquake. None of them seem to run lean, but that's the safety margin they have to add with generic chips - throw in extra fuel and the engine will not make the most power, but at least it won't detonate to destruction and have someone suing.
The bottom line is that you can get an extra 15% out of a 951 really cheaply with off the shelf chips. If you want a bit more you might get close to 20% with a better wastegate and decent electronic boost control. With decent chips and sensible boost you'll be safe like that without the KLR controlling boost.
To go beyond that you need to start replacing turbos and injectors and at that point you need to know what you are doing in terms of the map. The best will always be a custom map on your car for your mods, and if you have that done and you stick to the fuel grade you used during mapping (or better) you shouldn't see any knock problems.
If you want to go right to the edge and have the engine management pull you back from knock to get absolutely the maximum power then you have to go standalone because the DME/KLR are close to 30 year old technology that was never designed to do that. For that reason I personally don't believe anyone making generic chips should be depending on the DME/KLR to prevent detonation at all. Porsche desgined them as a safeguard against poor grade fuel and/or a component failure, not as a dynamic engine tuning system.
Basically the KLR is a faily blunt instrument which on detecting knock takes out a chunk of ignition, then if the knock continues effectively dumps all the boost to save the engine. Very safe, but not much finesse.
There is no reason that an engine with all components working and running fuel of consistent and correct quality with a good map in the DME should ever get to the stage of dumping boost. On that basis you don't "need" the KLR to have control of boost to make sure the engine won't grenade.
Where you will get problems is if the DME map is not as good as it might be for your particular engine (something that is always a risk with off the shelf chips of any flavour) or if the boost is beyond that the DME map expects. How many of us have used something like an LBE or AccuBoost and turned it up too high on a standard car? That triggers the boost dump through knock.
There is no facility for the DME / KLR combination to measure boost and account for extra by adding fuel in the standard car and I am pretty sure nobody has been able to add that facility subsequently. In fact I am pretty sure the boost is only measured at all so the KLR knows when to open the cycling valve and to run the gauge in the dash, it's only knock and not boost pressure that trips the safety system.
There is no way a set of chips can be used regardless of injector size; it just isn't possible. The chips effectively tell the injectors how long to stay open to deliver the correct quantity of fuel and without being told the flow rate of the injector they can't calculate the duration correctly. It is possible to put maps for several injector sizes on one set of chips and choose them using jumpers, but you still have to do that manually.
Because all engines are slightly different any off the shelf chips can't go too close to the edge. That means they are a compromise and they err slightly on the side of safety. They all (to my knowledge) retain the KLR to modify timing on detection of knock and that should be plenty if the chips are even close to safe. If you fitted chips that triggered the KLR to dump boost you'd take them out again pretty quick. In other words none of the aftermarket chips depend on the KLR being able to control boost.
If you want to get a little extra from a basically stock 951 then you can do so by replacing the AFM with something less restrictive and adding mild extra boost. That seems to me to be what Transaxle has designed the SciVision MAF to do.
To get significantly more power you need to get rid of the standard wastegate. It's a poor design and it bleeds boost even when the CV is closed. To replace it you have to lose the CV and with it the KLR's ability to control the boost.
I can't see how the stock wastegate would ever get anywhere near holding 1.2 bar never mind 1.5 bar, and if it did you would most definitely need bigger injectors to keep up with the fuelling. You'd also need a bigger turbo to provide that level of boost in the first place, even if you have a K26/8 car.
Can you get 300bhp from just an AFM replacement and set of chips on the standard wastegate and CV? I seriously doubt it. Maybe 270's, and that's flywheel not rear wheel, and with a K26/8 on the Turbo S. K26/6 cars probably could make 250 to 260 fwhp in that configuration.
I've seen a lot of people here in the UK start out with things like the Guru chips and wastegate shims, then move onto a TiAL or Lindsey DPWG and get 10% to 15% improvement. When they go on to bigger turbos and bigger injectors then the off the shelf chips start to fall down, regardless of what the vendor says and what jumpers they might have on them that supposedly match the parts on the car. That isn't a pop at any one vendor, I've seen it with several: AFRs into the 10's on boost, or AFR's that bounce around like a seismograph trace during an earthquake. None of them seem to run lean, but that's the safety margin they have to add with generic chips - throw in extra fuel and the engine will not make the most power, but at least it won't detonate to destruction and have someone suing.
The bottom line is that you can get an extra 15% out of a 951 really cheaply with off the shelf chips. If you want a bit more you might get close to 20% with a better wastegate and decent electronic boost control. With decent chips and sensible boost you'll be safe like that without the KLR controlling boost.
To go beyond that you need to start replacing turbos and injectors and at that point you need to know what you are doing in terms of the map. The best will always be a custom map on your car for your mods, and if you have that done and you stick to the fuel grade you used during mapping (or better) you shouldn't see any knock problems.
If you want to go right to the edge and have the engine management pull you back from knock to get absolutely the maximum power then you have to go standalone because the DME/KLR are close to 30 year old technology that was never designed to do that. For that reason I personally don't believe anyone making generic chips should be depending on the DME/KLR to prevent detonation at all. Porsche desgined them as a safeguard against poor grade fuel and/or a component failure, not as a dynamic engine tuning system.
Last edited by Fen; 04-29-2006 at 09:59 PM.
04-30-2006, 12:29 AM
#74
Addict
Rennlist Member
Rennlist
Site Sponsor
Rennlist Member
Rennlist
Site Sponsor
FEN, I agree with most of your points, however... The AFM sensor and the AFM software are very limiting. The DME does not know boost, however with a proper MAF sensor and software it will always know the flow (more boost = more air) and will calculate the fueling.. Injector size must be know up front for any chip to work properly.. I wouldn't call the DME/KLR too old and no longer good. Soon, you will see a system that uses the KLR data to trigger many user defined events such as (reduce additional timing than the KLR, add fuel, activate water injection, or even reduce or diump boost)..
I strongly agree that a well mapped chip, and using the proper octane the maps were designed for are key ingredients for no knock.
I disagree about "all" chips having AFR all over the board. Perhaps you haven't seen the Vitesse latest software in action..
Very good observations.
I strongly agree that a well mapped chip, and using the proper octane the maps were designed for are key ingredients for no knock.
I disagree about "all" chips having AFR all over the board. Perhaps you haven't seen the Vitesse latest software in action..
Very good observations.
04-30-2006, 05:24 AM
#75
Burning Brakes
One other point (I may have raised before, sorry Fen), custom chips (or standalone managment) is only as good as the person programing it. We have seen on the dyno custom maps be beaten by off the shelf chips. I feel you need a lot of dyno time invested before you find all the tricks for big power on the 944 engine. I think Guru chips had the knowledge (did I read somewhere someone else (not Danno) did the development work on them). I believe Vittesse know how to get the best from it.
Over here I think Rick has discovered a trick or three in his many dyno hours, I dont doubt Andrew has had a good look at the guru code (and others).
I dont doubt that getting a custom chip on your own car is the way forward to getting the best from it but I think to get the very best you need someone who has spent a lot of dyno time experimenting with various combinations of ignition/spark and fuel on the 944 engine.
That is why some off the shelf chips can still beat some custom chips on the dyno.
Tony
Over here I think Rick has discovered a trick or three in his many dyno hours, I dont doubt Andrew has had a good look at the guru code (and others).
I dont doubt that getting a custom chip on your own car is the way forward to getting the best from it but I think to get the very best you need someone who has spent a lot of dyno time experimenting with various combinations of ignition/spark and fuel on the 944 engine.
That is why some off the shelf chips can still beat some custom chips on the dyno.
Tony