Fitting the Specialist Components Engine Managment Kit - DIY
06-13-2016, 04:00 PM
#106
Rennlist Member
Thread Starter
The goals with the kit were better throttle response through the MAP sensor replacing the AFM and unlocking more power through the free air intake and more modern fueling/spark. Maybe up to 25bp more than standard. Although I have to be fair and say the kit promotion doesn't promise extra power.
Post the install I modified the idle settings (still rock solid) found that I had a coil out plus had omitted to connect the resonance flap. With those fixed I thought I was finally on the way.
It's the overrun that's the final nail in this case. Without after sales support the DIY mechanic is left relying on people's goodwill and Robt has been great, but I think I have hit a wall here. Unlike the idle I can't see a setting that will stop the car eventually blowing my muffler out and burning my bumper.
I have been through the wars with this car, most recently a problematic box rebuild. I just want to enjoy it. In any case I can still hold out hope that Anthony or others will come back with a Eureka moment and share a map for a standard engine that behaves as well as the Motronic but unleashes a few extra HP. There is always hope. Who knows I may come back to it at some later date and develop it myself, just not now.
Post the install I modified the idle settings (still rock solid) found that I had a coil out plus had omitted to connect the resonance flap. With those fixed I thought I was finally on the way.
It's the overrun that's the final nail in this case. Without after sales support the DIY mechanic is left relying on people's goodwill and Robt has been great, but I think I have hit a wall here. Unlike the idle I can't see a setting that will stop the car eventually blowing my muffler out and burning my bumper.
I have been through the wars with this car, most recently a problematic box rebuild. I just want to enjoy it. In any case I can still hold out hope that Anthony or others will come back with a Eureka moment and share a map for a standard engine that behaves as well as the Motronic but unleashes a few extra HP. There is always hope. Who knows I may come back to it at some later date and develop it myself, just not now.
06-13-2016, 07:00 PM
#107
Racer
John, sorry to hear about your troubles. It is a misconception that the factory Bosch air flow meter is a restriction to the intakes of the 964, and the 3.2 that uses the exact same meter. Repeated dyno tests performed between the stock air meter and very well designed and profiled MAFs have shown no HP or torque differences between the two, not even 2 hp at full throttle at 7000 rpm. On a 964, the intake restriction is not the air flow meter, but the airbox cover. With the cover is cut open, you would typically see a 4 hp gain at the wheels after 4500 rpm.
Best really is to restore back the original Motronic system and run a good chip. It will also restore the anti-knock protection system and give you a factory diagnostic port to pinpoint problems. You won't be giving up any power to what you have, and get rid of all the running problems you are experiencing. The rich running condition you have now will wear out your motor rapidly, washing the oil off your cylinders and dilute the motor oil, carbon up your pistons and valves, and accelerate wear on your valve guides.
Best really is to restore back the original Motronic system and run a good chip. It will also restore the anti-knock protection system and give you a factory diagnostic port to pinpoint problems. You won't be giving up any power to what you have, and get rid of all the running problems you are experiencing. The rich running condition you have now will wear out your motor rapidly, washing the oil off your cylinders and dilute the motor oil, carbon up your pistons and valves, and accelerate wear on your valve guides.
06-13-2016, 07:41 PM
#108
Rennlist Member
Thread Starter
Thanks Steve. I have your chip in the original ECU. As soon as I get my old injectors checked (might as well given they are out of the car now) I will put it back in the car. I feel like I'm admitting defeat but the risk / reward isn't there and I had forgotten about the loss of knock protection.
In SC's defense I think this is a case of a buyer (me) with insufficient knowledge and commitment (dyno and $) to make it what it could be.
In SC's defense I think this is a case of a buyer (me) with insufficient knowledge and commitment (dyno and $) to make it what it could be.
06-13-2016, 08:07 PM
#109
Racer
RC Engineering in Torrance, California is a good place to send your injectors for testing and cleaning. The stock injectors are sufficient, even for many 3.8s. They may reach a limit on some 3.8s that have aggressive cams and a very open exhaust. In which case I usually recommend raising the fuel pressure by about 0.5 bar which scales the injectors back to what stock duty cycles are. Stock 964 injectors measure about 191-195cc at 3.0 bar. Your replacement 440cc injectors were just way overkill and could make for less resolution control at lower duty cycles and could contribute to rich running issues.
06-14-2016, 11:13 AM
#110
Steve, thanks for your comments. Some remarks (not all directed at you but the community in general)
I agree 440CC injectors as used in the SpecialistComponents kit are on the large side, using RC engineering's advise on calculating size 350CC shows up for a 320HP 6 cilinder engine with 80% duty cycle threshold. Recalculating this for 3.8 Bar fuel pressure (instead of 3.0 Bar test pressure) we arrive at 310CC.....still a long way from the 964's 192CC injectors.
On the subject of performance; both Colin and Geoffrey have posted multiple dyno sheets on here showing 300-305HP being the max on their dyno using standard injectors, with barn door vs. Maf indeed not showing any difference in output....although throttle response is more instant with Maf.
Their dyno's also show 325HP being possible when running larger injectors on standard engine internals with an optimised non cat exhaust and length tuned ram pipe / air filter tube running without metering device (MAP controlled).
That's a 7% increase over standard injectors measured on the same dyno. Of course this only shows with proper mapping of either the Motronic or standalone ecu. A standalone ecu giving easier access to programming not having to rely on emulation, the Motronic providing knock sensing and on board diagnostics.
Whilst knock sensing is very nice, the 3.2 911 did without this feature so it's not a total game changer, and can be added as an extra if so required. The flexibility of standalone is nice when planning future upgrades such as cams, ITB's, injector type....otherwise Motronic is just fine as long as you have access to someone knowledgeable and able to program it.
With the SC kit approaching the price of well known Maf conversions or performance chips, at least price is no longer the leading factor in coming to a decision. None of the chips/Mafs I know of offering ready made solutions that involve suitable larger injectors, therefore requiring additional development to seize the utmost potential if so requested.
My 2C.
I agree 440CC injectors as used in the SpecialistComponents kit are on the large side, using RC engineering's advise on calculating size 350CC shows up for a 320HP 6 cilinder engine with 80% duty cycle threshold. Recalculating this for 3.8 Bar fuel pressure (instead of 3.0 Bar test pressure) we arrive at 310CC.....still a long way from the 964's 192CC injectors.
On the subject of performance; both Colin and Geoffrey have posted multiple dyno sheets on here showing 300-305HP being the max on their dyno using standard injectors, with barn door vs. Maf indeed not showing any difference in output....although throttle response is more instant with Maf.
Their dyno's also show 325HP being possible when running larger injectors on standard engine internals with an optimised non cat exhaust and length tuned ram pipe / air filter tube running without metering device (MAP controlled).
That's a 7% increase over standard injectors measured on the same dyno. Of course this only shows with proper mapping of either the Motronic or standalone ecu. A standalone ecu giving easier access to programming not having to rely on emulation, the Motronic providing knock sensing and on board diagnostics.
Whilst knock sensing is very nice, the 3.2 911 did without this feature so it's not a total game changer, and can be added as an extra if so required. The flexibility of standalone is nice when planning future upgrades such as cams, ITB's, injector type....otherwise Motronic is just fine as long as you have access to someone knowledgeable and able to program it.
With the SC kit approaching the price of well known Maf conversions or performance chips, at least price is no longer the leading factor in coming to a decision. None of the chips/Mafs I know of offering ready made solutions that involve suitable larger injectors, therefore requiring additional development to seize the utmost potential if so requested.
My 2C.
06-14-2016, 12:50 PM
#111
Three Wheelin'
A couple notes-
"Whilst knock sensing is very nice, the 3.2 911 did without this feature"
The 3.2 also uses a pretty conservative timing curve. That's the first thing you push when tuning. Knock control only becomes more important when you push the timing.
I'm pretty sure that Steve can accommodate larger injectors into his chips if asked for. That isn't a motronic limitation.
The only inherent problem with motronic is the one-size-fits-all fuel and timing at higher load. On a stock motor, at about >4500rpm and >75%, the afm door is pushed completely open. When the afm is 100% open, the motronic moves to the wot maps which are simple rpm vs advance, and rpm vs fuel 1-D maps. Motronic can jump to the wot maps at as little as ~75% throttle. For a motor with more hp/breathing, the threshold will only decrease- maybe 65% throttle will max out the afm door on a built motor. Using the same amount of fuel and timing for 65-75% throttle and 100% throttle is obviously pretty inefficient.
That is the one and only area where a stand-alone will make a difference.
I'm sure Steve knows his injectors well too. From what I can figure, our engines are hitting only 0.4 or so BSFC. Using that, and our 55.1psi fuel pressure, a 250cc injector will get you to 320hp with an 80% duty cycle.
"Whilst knock sensing is very nice, the 3.2 911 did without this feature"
The 3.2 also uses a pretty conservative timing curve. That's the first thing you push when tuning. Knock control only becomes more important when you push the timing.
I'm pretty sure that Steve can accommodate larger injectors into his chips if asked for. That isn't a motronic limitation.
The only inherent problem with motronic is the one-size-fits-all fuel and timing at higher load. On a stock motor, at about >4500rpm and >75%, the afm door is pushed completely open. When the afm is 100% open, the motronic moves to the wot maps which are simple rpm vs advance, and rpm vs fuel 1-D maps. Motronic can jump to the wot maps at as little as ~75% throttle. For a motor with more hp/breathing, the threshold will only decrease- maybe 65% throttle will max out the afm door on a built motor. Using the same amount of fuel and timing for 65-75% throttle and 100% throttle is obviously pretty inefficient.
That is the one and only area where a stand-alone will make a difference.
I'm sure Steve knows his injectors well too. From what I can figure, our engines are hitting only 0.4 or so BSFC. Using that, and our 55.1psi fuel pressure, a 250cc injector will get you to 320hp with an 80% duty cycle.
06-14-2016, 01:15 PM
#112
Good input! Congrats on your 928th post;-)
As you know I didn't imply Motronic can't be adjusted for larger injectors (although you're stuck with impendance)....it just makes it less accessable driving around with a wideband and laptop in place making adjustments on the fly, or using closed loop auto tune.
Thanks for your input on barn door location vs. WOT maps. I knew the system was rather crude, but this in actuality seems almost medieval:-) How does the 993 motronic compare as the Maf signal when properly processed should offer much higher density in adjustability?
As you know I didn't imply Motronic can't be adjusted for larger injectors (although you're stuck with impendance)....it just makes it less accessable driving around with a wideband and laptop in place making adjustments on the fly, or using closed loop auto tune.
Thanks for your input on barn door location vs. WOT maps. I knew the system was rather crude, but this in actuality seems almost medieval:-) How does the 993 motronic compare as the Maf signal when properly processed should offer much higher density in adjustability?
06-14-2016, 02:05 PM
#113
Three Wheelin'
Oops, didn't mean to imply anything regarding injectors! I see that the tone didn't come out right.
The high-load part-throttle thing is definitely crude- in theory. In practice, it's hard to know what the effect is. I don't have any files in front of me, but lower load timing should be more advanced than wot timing. The motronic logic would then be limiting the advance that you could be running at 75% throttle. That would very likely make a difference in upper-rpm throttle response that you could feel.
My stock motor had some very rich dips when plotting afr vs rpm. I can only imagine how much worse those dips were when the wot maps were triggered and the throttle was less than wot. I've since tweaked the wot fuel map a lot closer 13.1:1, and my tailpipe doesn't get black anymore. The wot map rpm bins are pretty coarse too and there are still some chunky rich dips in my afr curve.
993 should give much better throttle response at high-load part-throttle. Hard to compare with the other 993 motor differences. If anyone wants to volunteer to disassemble the motronic code... a chip could be written to correctly use a maf signal from 0-100% throttle, same as 993. A fellow on pelican has done exactly that for the 3.2 ecu.
In the meantime, we have to wait for Steve Wong to retire and the spill the beans
The high-load part-throttle thing is definitely crude- in theory. In practice, it's hard to know what the effect is. I don't have any files in front of me, but lower load timing should be more advanced than wot timing. The motronic logic would then be limiting the advance that you could be running at 75% throttle. That would very likely make a difference in upper-rpm throttle response that you could feel.
My stock motor had some very rich dips when plotting afr vs rpm. I can only imagine how much worse those dips were when the wot maps were triggered and the throttle was less than wot. I've since tweaked the wot fuel map a lot closer 13.1:1, and my tailpipe doesn't get black anymore. The wot map rpm bins are pretty coarse too and there are still some chunky rich dips in my afr curve.
993 should give much better throttle response at high-load part-throttle. Hard to compare with the other 993 motor differences. If anyone wants to volunteer to disassemble the motronic code... a chip could be written to correctly use a maf signal from 0-100% throttle, same as 993. A fellow on pelican has done exactly that for the 3.2 ecu.
In the meantime, we have to wait for Steve Wong to retire and the spill the beans
11-29-2016, 11:58 PM
#114
Rennlist Member
Thread Starter
An update. After a road trip and track day where my exhaust regularly backfired with flames continuing to singe my bumper I decided to revert to my OE Motronics ECU with Steve Wong chip.
It wasn’t supposed to be a permanent reversion but I had offers for the kit within a day or so of removing it from the car, one of which I accepted. On balance I decided that if I was going to dyno and sort the car mapping I would have done so by now so it made sense to sell. It made me feel good likely helping out the new owner with his idling problem. He understands that there will be dyno time required.
On reflection, as I’ve written before, I believe this kit has most value to those with altered engines e.g. 3.8 and/or aggressive cams. The apparent requirement to dyno map the engine management system wasn’t evident at the outset, especially as I only have minor exhaust mods. While I’ll miss the rock solid idle and fatter power curve, I won’t miss the secondary muffler explosions or yellowed bumper. I accept that those were likely resolvable with dyno time, but I didn’t have the time or inclination to spend more on the system.
It wasn’t supposed to be a permanent reversion but I had offers for the kit within a day or so of removing it from the car, one of which I accepted. On balance I decided that if I was going to dyno and sort the car mapping I would have done so by now so it made sense to sell. It made me feel good likely helping out the new owner with his idling problem. He understands that there will be dyno time required.
On reflection, as I’ve written before, I believe this kit has most value to those with altered engines e.g. 3.8 and/or aggressive cams. The apparent requirement to dyno map the engine management system wasn’t evident at the outset, especially as I only have minor exhaust mods. While I’ll miss the rock solid idle and fatter power curve, I won’t miss the secondary muffler explosions or yellowed bumper. I accept that those were likely resolvable with dyno time, but I didn’t have the time or inclination to spend more on the system.
11-30-2016, 04:07 AM
#115
Three Wheelin'
Hi John, sorry to hear you didn't get it sorted. It's very odd, there must be something at play here as like me, your engine is 99.9% mechanically stock yet with the exception of tweaks to the idling controls both the fuel and ignition maps have proved bang-on. More recently I have made further changes to the acceleration enrichment that were way to rich between the 800 - 2500 range but this effects only transient conditions so wouldn't be the cause in your case. shame you didn't get to the bottom of it.
11-30-2016, 04:00 PM
#116
Rennlist Member
Thread Starter
Rob, thanks for your help over the period of ownership. I felt it was an overrun issue as the AFR seemed to be ok on acceleration and it was only backfiring as I came off the throttle. No doubt the new owner will sort it quickly. I'm happy as I now have a second C4 I'm refreshing and it keeps me busy at my skill level.