Electronic Boost Controllers
- Thread starter John Sims
- Start date
AndrewS
Member
Hi John,
Greddy Profec B-Spec 11 works well, is very discrete and has an overboost protect feature. It has switchable high and low boost, adjustable gain and you can choose to hold a firm figure to maximu RPM or have the boost taper off.
Graham Francis has one for sale. Personally I think they are excellent and do a good job. Worth 15-20 bhp if used correctly and the car is mapped to use the boost.
Regards,
Andrew
Greddy Profec B-Spec 11 works well, is very discrete and has an overboost protect feature. It has switchable high and low boost, adjustable gain and you can choose to hold a firm figure to maximu RPM or have the boost taper off.
Graham Francis has one for sale. Personally I think they are excellent and do a good job. Worth 15-20 bhp if used correctly and the car is mapped to use the boost.
Regards,
Andrew
I am using a Greddy Profec 2, it was interesting from the dyno results as one of the cars has exactly the same mods as mine apart from the boost controller and mine making an extra 14Bhp. Interesting?
It is fitted in the glove compartment out of the way of (my) temptation.
I am still experimenting with it, seems a little complex in setting up so I am adjusting gradually, I get the impression an EBC can hold the pressure better and offer improved spike protetion of an MBC.
It is fitted in the glove compartment out of the way of (my) temptation.
I am still experimenting with it, seems a little complex in setting up so I am adjusting gradually, I get the impression an EBC can hold the pressure better and offer improved spike protetion of an MBC.
AndrewS
Member
Hi Scott,
I can confirm that an EBC controls the boost better than a Manual Boost Regulator. The standard control mechanism deployed by Porsche is also a very good electronic boost control system. As this is integrated into the cars Motronic knock control system - it functions as an effective safety net too.
With an MBC (Manual Boost Controller or Regulator), you have no overboost protect. Most EBC units have a degree of overboost protect and you can tailor the speed at which boost builds and tails off.
The unit used in Jason's car was also used on the 402bhp car on Saturday. As you correctly point out - AFR needs to match the boost characteristics laid down by the controller, wastegate and turbo charger. As 1.2 bar is the realistic maximum that can be achieved on the 944 Turbo (unless making other modifications) - it makes sense to make the most of the available boost and an EBC helps achieve this.
Regards,
Andrew
I can confirm that an EBC controls the boost better than a Manual Boost Regulator. The standard control mechanism deployed by Porsche is also a very good electronic boost control system. As this is integrated into the cars Motronic knock control system - it functions as an effective safety net too.
With an MBC (Manual Boost Controller or Regulator), you have no overboost protect. Most EBC units have a degree of overboost protect and you can tailor the speed at which boost builds and tails off.
The unit used in Jason's car was also used on the 402bhp car on Saturday. As you correctly point out - AFR needs to match the boost characteristics laid down by the controller, wastegate and turbo charger. As 1.2 bar is the realistic maximum that can be achieved on the 944 Turbo (unless making other modifications) - it makes sense to make the most of the available boost and an EBC helps achieve this.
Regards,
Andrew
From what I have learnt of the Greddy so far.
It is programmable for two settings, Hi and LO, so you may decide to have a safe mode for everyday driving and a setting for track use. You can buy an addon which enables switching between the two to be done remotly, Knight Rider style.
Programming the Greddy involves setting a maximum boost pressure as a percentage 0% is stock and 100% is the wastegate limit.
You then have to set the GAIN, this is the consistancy, I think this is something to do with the sensitivity of the EBC control valve. (not sure) I know if I play with this the power delivery is very 'wibbly' or better described as 'flutters'
The next setting is to provide the maximum level of desire boost and enable an alarm to sound.
The final setting is to tell the EBC %age to decrease the boost pressure by when you get to the maximum. If you do get to the maximum and overboost, the origonal engine managment cuts power still.
When not in setup mode, the display shows boost, there is also a facility to store maximum boost reached too.
I guess the Greddy is very safe entry level model and gives a basic control of the wastegate.
Jason
It is programmable for two settings, Hi and LO, so you may decide to have a safe mode for everyday driving and a setting for track use. You can buy an addon which enables switching between the two to be done remotly, Knight Rider style.
Programming the Greddy involves setting a maximum boost pressure as a percentage 0% is stock and 100% is the wastegate limit.
You then have to set the GAIN, this is the consistancy, I think this is something to do with the sensitivity of the EBC control valve. (not sure) I know if I play with this the power delivery is very 'wibbly' or better described as 'flutters'
The next setting is to provide the maximum level of desire boost and enable an alarm to sound.
The final setting is to tell the EBC %age to decrease the boost pressure by when you get to the maximum. If you do get to the maximum and overboost, the origonal engine managment cuts power still.
When not in setup mode, the display shows boost, there is also a facility to store maximum boost reached too.
I guess the Greddy is very safe entry level model and gives a basic control of the wastegate.
Jason
eastendr
New member
I was using the Blitz-SBC-iD, but it just did not do the job properly. The Profec seems the best from dyno plots. I'm now using a complete custom designed system on WUF that is mappable in 125RPM increments.
Switchable boost is a waste of time - god gave you a right foot to control the car [
]
If you were to use a switchable boost control, you would probably want to run slightly lower boost on the track where boost is sustained for much longer than in typical road driving where brief high boost may be more acceptable ( and indeed is part of the strategy of more enhanced engine management systems than found on the 944).
MBC's also vary a lot. Some give a very flat top, while others give a sloping boost curve - look at Simon Peckham's one for example
Rick.
Switchable boost is a waste of time - god gave you a right foot to control the car [
]If you were to use a switchable boost control, you would probably want to run slightly lower boost on the track where boost is sustained for much longer than in typical road driving where brief high boost may be more acceptable ( and indeed is part of the strategy of more enhanced engine management systems than found on the 944).
MBC's also vary a lot. Some give a very flat top, while others give a sloping boost curve - look at Simon Peckham's one for example
Rick.
Diver944
Active member
I have the Greddy Profec B-Spec 11 and it definitely does what it says on the tin. Last year I was trying to hold 18psi boost to the red line to counteract my extremely rich AFR after 5000rpm. Previously I was using an MBC and it would hit 18psi with no problem on my tiny K26/6 but the boost would drop off after 5000rpm (as you would expect)
I plumbed in the Greddy and after a few hours of pushing the buttons (it is a pain to setup[]) I did get it to hold 18psi right to the redline (even on the K26/6). The unit is very small and I had temporarily fitted it to the underside of the radio cubby, the overboost warning is very useful as is the peak boost display. I was planning to set the low boost to 12psi for wet trackdays. Unfortunately the turbocharger ate a nut from the airbox before I could get back to the dyno and check out the AFR [&:]
I plumbed in the Greddy and after a few hours of pushing the buttons (it is a pain to setup[
]) I did get it to hold 18psi right to the redline (even on the K26/6). The unit is very small and I had temporarily fitted it to the underside of the radio cubby, the overboost warning is very useful as is the peak boost display. I was planning to set the low boost to 12psi for wet trackdays. Unfortunately the turbocharger ate a nut from the airbox before I could get back to the dyno and check out the AFR [&:]I'm kind of with Rick on the Hi/Lo setting, because if the DME can't dynamically adjust fuel for boost it has to run a fixed fuel map tailored to a specific boost level and if you run anything but that boost curve your fuelling will not be correct. The only safe thing to do is map the fuel for high boost setting and that means that on low you will be running rich, wasting fuel and washing oil from your bores so accelerating engine wear.
This is another instance where standalone shines. With mine you can select a different boost map for different gears, loads, rpms, coolant or oil temps etc. and the fuelling will be recalculated to suit the actual boost (and intake temps etc.) based on the parameters that were in use when it was mapped. You can also vary other parameters such as ignition with boost should you have a need to, and you can allow a short period of overboost to aid bursts of acceleration as Rick mentions above (plus anti-lag, traction control, launch control, full throttle upshifting, water injection, nitrous etc. etc.)
In some ways the 944 EMS was very advanced for its day, but it's a computer and it's day was when it was designed in the late 70's. Think how other computers have progressed since then. As I understand it it is crippled by the KLR being unable to pass boost data back to the DME to allow fuelling and ignition to be altered with boost, in other words aside from when knock is detected the DME is flying blind of boost pressure. Remember that Rck has also pointed out that the DME only measures temperature once (at startup) so it is also blind of intake temperature and only knows about abmient when the ignition was first turned on. Imagine how accurate that isn't. Now imagine how accurate that even more isn't if you start the car at 10am in your shaded garage on a spring morning after a frosty night and drive it for 3 hours straight in the sunshine so at 1pm it still thinks ambient is 7degrees when it's actually 17degrees.
I'm not saying the DME/KLR is bad, but it's not great. Look at Mark K's AFR plot if you don't believe me; 402bhp but a fuel plot like the Himalayas and relatively extremely poor torque. By comparison Rick's car has the same turbo and some other components but with a standard head and intake yet his still posted slightly higher peak power and much higher peak torque (like 10% higher) because it has an EMS that is capable of controlling the engine so much better. Mark's car must have a lot more to come when it's been mapped properly (and it can be better than it is now on the DME/KLR I imagine); a standalone properly set up would unleash a lot more from it.
Sorry that went a bit off from just EBCs; they are a good idea and much better than manual, but forget the Hi/Lo setting unless you have an EMS that can compensate the fuelling to match the boost.
This is another instance where standalone shines. With mine you can select a different boost map for different gears, loads, rpms, coolant or oil temps etc. and the fuelling will be recalculated to suit the actual boost (and intake temps etc.) based on the parameters that were in use when it was mapped. You can also vary other parameters such as ignition with boost should you have a need to, and you can allow a short period of overboost to aid bursts of acceleration as Rick mentions above (plus anti-lag, traction control, launch control, full throttle upshifting, water injection, nitrous etc. etc.)
In some ways the 944 EMS was very advanced for its day, but it's a computer and it's day was when it was designed in the late 70's. Think how other computers have progressed since then. As I understand it it is crippled by the KLR being unable to pass boost data back to the DME to allow fuelling and ignition to be altered with boost, in other words aside from when knock is detected the DME is flying blind of boost pressure. Remember that Rck has also pointed out that the DME only measures temperature once (at startup) so it is also blind of intake temperature and only knows about abmient when the ignition was first turned on. Imagine how accurate that isn't. Now imagine how accurate that even more isn't if you start the car at 10am in your shaded garage on a spring morning after a frosty night and drive it for 3 hours straight in the sunshine so at 1pm it still thinks ambient is 7degrees when it's actually 17degrees.
I'm not saying the DME/KLR is bad, but it's not great. Look at Mark K's AFR plot if you don't believe me; 402bhp but a fuel plot like the Himalayas and relatively extremely poor torque. By comparison Rick's car has the same turbo and some other components but with a standard head and intake yet his still posted slightly higher peak power and much higher peak torque (like 10% higher) because it has an EMS that is capable of controlling the engine so much better. Mark's car must have a lot more to come when it's been mapped properly (and it can be better than it is now on the DME/KLR I imagine); a standalone properly set up would unleash a lot more from it.
Sorry that went a bit off from just EBCs; they are a good idea and much better than manual, but forget the Hi/Lo setting unless you have an EMS that can compensate the fuelling to match the boost.
Fen - fair comments there. The dyno readings are invaluable, mine show a rich mixture, not sure if it is classed as very rich, at idle and when boost starts it leans out too just over 11 then richens up to 10 mid boost then leans back out again.
I think there is room for improvement in my boost settings. Am I correct I can lean out up to around 12. (sorrt going off topic a little here)
(Plot courtesy of Rick)
From my boost chart you can see the PSI tails off to quite a low level, I think this is due to my safety net. If I can get this to flatten out would my torque improve?
I think there is room for improvement in my boost settings. Am I correct I can lean out up to around 12. (sorrt going off topic a little here)
(Plot courtesy of Rick)
From my boost chart you can see the PSI tails off to quite a low level, I think this is due to my safety net. If I can get this to flatten out would my torque improve?
AndrewS
Member
Hi Fen,
The Motronic 3.1 DME actually supports 3 different Fuel and Ignition maps. These are selectable via the Region Coding and Impedence Adapter plugs. Hence, the Greddy Hi/Lo setting can select these maps as it has a switched output making this possible. This means (for example) you can select a 1.2 bar map via the Greddy and a 1.5 bar map just by switching from Lo to Hi on the Profec B Spec 11.
On the road, the AFR is much more level. Most of the plots from WRC do show the AFR going very rich as the boost builds. On the road, if you log the AFR to an LM1 - this is not the case (probably becuase of the effects of the intercooler with the considerable air coming over the car at speed). What's important with Mark's car is that the fuel matches the advance throught the RPM/load range. In this respect it is totally detonation free and safe (both on the dyno and the road).
As for standalone management. I agree - there are much more sophisticated systems around than the original Motronic 3.1 which is now over 20 years old. However, it's still a reasonable EMS and the engine still turns at the same speed and requires the same spark (although it is a little weak compared to direct coil ignition). We are currently looking at a new type of standalone which hopefully will be a little easier on the pocket than the Wolf 3D (an excellent system - but very expensive). Experience with the LS1 re-mapping has taught us a great deal about what can be achieved.
Regards,
Andrew
The Motronic 3.1 DME actually supports 3 different Fuel and Ignition maps. These are selectable via the Region Coding and Impedence Adapter plugs. Hence, the Greddy Hi/Lo setting can select these maps as it has a switched output making this possible. This means (for example) you can select a 1.2 bar map via the Greddy and a 1.5 bar map just by switching from Lo to Hi on the Profec B Spec 11.
On the road, the AFR is much more level. Most of the plots from WRC do show the AFR going very rich as the boost builds. On the road, if you log the AFR to an LM1 - this is not the case (probably becuase of the effects of the intercooler with the considerable air coming over the car at speed). What's important with Mark's car is that the fuel matches the advance throught the RPM/load range. In this respect it is totally detonation free and safe (both on the dyno and the road).
As for standalone management. I agree - there are much more sophisticated systems around than the original Motronic 3.1 which is now over 20 years old. However, it's still a reasonable EMS and the engine still turns at the same speed and requires the same spark (although it is a little weak compared to direct coil ignition). We are currently looking at a new type of standalone which hopefully will be a little easier on the pocket than the Wolf 3D (an excellent system - but very expensive). Experience with the LS1 re-mapping has taught us a great deal about what can be achieved.
Regards,
Andrew
Diver944
Active member
Excellent news![
] I hadn't realised that it could do that.In my earlier post I also hadn't thought through the ramifications of having a lower boost setting which would of course lead to a richer AFR on the lower setting [
] I agree the Motronic is nowhere near as advanced as the standalones, but this is good news if the EBC can help out a little.Get one John [
] it's only moneyGood point on getting the EBC to switch the maps available in the DME - I didn't consider that (or know if it had an output to do it). I guess you need to reset the ignition to do it and it needs a bit of intermediate hardware, but it's still an option. Paul's wet setting is the only time I can see myself ever wanting to use a Lo setting, though []
I don't doubt that Mark's car has no detonation and certainly didn't intend to suggest it did, but I think you'll agree one of the places you'll get more out of it is with better EMS and mapping time? The CDI is a good point and something I forgot to mention. I had my car running with it for long enough to know that it makes a phenomenal difference to driveability, specifically idle and throttle response. It's less easy to see the benefit of fatter spark at the top end for me as I only got about 6 miles out of the car to play with it after it was mapped, but I'm sure it's there and contributed to finding an extra 53bhp from the last time it ran on the WRC rollers. Of course the DME can only run one coil, so CDI is not an option without standalone.
]I don't doubt that Mark's car has no detonation and certainly didn't intend to suggest it did, but I think you'll agree one of the places you'll get more out of it is with better EMS and mapping time? The CDI is a good point and something I forgot to mention. I had my car running with it for long enough to know that it makes a phenomenal difference to driveability, specifically idle and throttle response. It's less easy to see the benefit of fatter spark at the top end for me as I only got about 6 miles out of the car to play with it after it was mapped, but I'm sure it's there and contributed to finding an extra 53bhp from the last time it ran on the WRC rollers. Of course the DME can only run one coil, so CDI is not an option without standalone.
AndrewS
Member
Hi Fen,
Totally agree. I think we have taken the Motronic 3.1 to the limit there - stand alone EMS is the way to go.
I am very keen to try and adapt a modern EMS to the 944 Turbo for a relatively low cost (less than £1500 would be nice) - hopefully on the track car to start with (which is now scheduled to hit the paint shop on June 6th).
This is probably part of the reason why Roger's 600bhp LS1 conversion makes such massive torque at low RPM. All the cylinders have individual coil packs and the shock you can get grabbing a plug lead is a little more intensive than on a standard 944 Turbo - ouch! I've been walked through all the mappable aspects of the Bosch PMS system used on the GM LS engined cars and the flexibility you have is enormous (compared to Motronic) - this is why I think we could put a 600bhp LS1 into a 944 Turbo without stripping the transmission when you boot it (or crushing the engine mounts) - modern mapping can make this a possibility.
Regards,
Andrew
Totally agree. I think we have taken the Motronic 3.1 to the limit there - stand alone EMS is the way to go.
I am very keen to try and adapt a modern EMS to the 944 Turbo for a relatively low cost (less than £1500 would be nice) - hopefully on the track car to start with (which is now scheduled to hit the paint shop on June 6th).
This is probably part of the reason why Roger's 600bhp LS1 conversion makes such massive torque at low RPM. All the cylinders have individual coil packs and the shock you can get grabbing a plug lead is a little more intensive than on a standard 944 Turbo - ouch! I've been walked through all the mappable aspects of the Bosch PMS system used on the GM LS engined cars and the flexibility you have is enormous (compared to Motronic) - this is why I think we could put a 600bhp LS1 into a 944 Turbo without stripping the transmission when you boot it (or crushing the engine mounts) - modern mapping can make this a possibility.
Regards,
Andrew
sawood12
New member
The fundamental flaw in this whole thing as I see it is fuel mapping full stop. Fuel mapping is not closed loop and doesn't attempt to maintain a set AFR in real time. I suppose this is where the more modern EMS systems come in. So how does the lambda probe affect things and link into the DME on a cat equipped car? My understanding is that the lambda probe monitors the AFR and modifies it in realtime to protect the cat and make sure the AFR is maintained at a level that allows optimal operation of the cat.
Unfortunately an EBC does seem like a worhwhile mod if not just for the overboost protection it offers. Are there more simple EBC's on the market that do not offer all the bells and whistles like switchable boost settings as I would just want a set and forget solution as i'm not looking to run particularly high boost levels - 1 bar is plenty for me!!
Unfortunately an EBC does seem like a worhwhile mod if not just for the overboost protection it offers. Are there more simple EBC's on the market that do not offer all the bells and whistles like switchable boost settings as I would just want a set and forget solution as i'm not looking to run particularly high boost levels - 1 bar is plenty for me!!
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