Staring down the EFI rabbit hole again, /6 intake design, Which way around for the 964 plenums in a 914? |
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Staring down the EFI rabbit hole again, /6 intake design, Which way around for the 964 plenums in a 914? |
Mark Henry |
Feb 17 2021, 10:34 AM
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#1
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
One of the locals fell on some hard times, his plans changed and his 930 was sold, so he offered me a smoking deal on an EFI system.
SDS EM5-F /6 system with twin plug coil packs, Siemens 55lb injectors, cold start valve, crank trigger and /6 trigger mount, extra relay outputs (had meth injection), Beru plug wires X2, manuals, base maps, dizzy hole block off, Bosch one wire (Djet) head temp sender plus all the cabling, fuses, etc that are not included with an SDS system. I already have a Wabro 300hp FI pump, a Djet fuel pressure regulator, 14point7 wideband O2 meter and an O2 bung in both headers. This is not a discussion on which Aftermarket EFI system is better, etc but rather on plenum based intake design. I'm not new. I've been playing with a SDS EM4-F /4 system since 2003-2004 that's now on my '67 bug T4 2600cc conversion, I know that ITB's are better for peak HP, but I'm after overall improvement, usable vacuum signal for MAP, drivability, fuel economy and etc. FYI I have also asked this on the bird board here for some more info on the build. This thread shows my /6 conversion a few years back and has all the engine specs here. Plus I've built my own motorcycle ITB's before here. Please I only want to discuss a single TB plenum based intake for performance EFI. |
Mark Henry |
Feb 26 2021, 02:35 PM
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#2
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
This is not a discussion on which Aftermarket EFI system is better, etc but rather on plenum based intake design. Gee....that's right in the very first post. But I guess there's always that guy. You can get around this by running TPS only, also known as AlphaN, to bypass the MAP but you lose things like altitude correction and the system is more sensitive to pedal inputs, which can be a pain on long trips. But EFI of course wins on fuel mileage. Between having to run in AlphaN or carbs, I think carbs wins on drivability as they're not as touchy to pedal inputs as the EFI in AlphaN. Look into the feature set of Megasquirts hybrid alpha-N mode, should take care of most if not all of these issues depending on the motor. Ive run it on an ITBd 2270 and while it is a good deal more complex to initially tune the results are pretty amazing. I already have the SDS EM5-F6 system, not interested in anything else. I'm not saying SDS is the best, but then MS is isn't as well, honestly I don't give a **** *** what is the best system, that's not the topic. (IMG:style_emoticons/default/rolleyes.gif) |
JamesM |
Mar 1 2021, 02:13 PM
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#3
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Senior Member Group: Members Posts: 1,900 Joined: 6-April 06 From: Kearns, UT Member No.: 5,834 Region Association: Intermountain Region |
This is not a discussion on which Aftermarket EFI system is better, etc but rather on plenum based intake design. Gee....that's right in the very first post. But I guess there's always that guy. You can get around this by running TPS only, also known as AlphaN, to bypass the MAP but you lose things like altitude correction and the system is more sensitive to pedal inputs, which can be a pain on long trips. But EFI of course wins on fuel mileage. Between having to run in AlphaN or carbs, I think carbs wins on drivability as they're not as touchy to pedal inputs as the EFI in AlphaN. Look into the feature set of Megasquirts hybrid alpha-N mode, should take care of most if not all of these issues depending on the motor. Ive run it on an ITBd 2270 and while it is a good deal more complex to initially tune the results are pretty amazing. I already have the SDS EM5-F6 system, not interested in anything else. I'm not saying SDS is the best, but then MS is isn't as well, honestly I don't give a **** *** what is the best system, that's not the topic. (IMG:style_emoticons/default/rolleyes.gif) Just throwing it out there as an interesting thing to read up on from a solution standpoint (and possibly a backup plan for anyone with unsolvable drivability issues.) I have zero opinion as to any system being the "best" they are all just different in their feature sets. As long as they get the fuel into the engine in the way you want it... who cares. I cant offer anything more than theoretical on 6 plenum design as all my first hand experience with that is on the 4s, but that 964 setup looks like the hot ticket. The SDS intake setup looks really nice though i suspect the plenum volume of the one pictured might be less than ideal on a larger engine. |
Mark Henry |
Mar 1 2021, 02:40 PM
Post
#4
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
This is not a discussion on which Aftermarket EFI system is better, etc but rather on plenum based intake design. Gee....that's right in the very first post. But I guess there's always that guy. You can get around this by running TPS only, also known as AlphaN, to bypass the MAP but you lose things like altitude correction and the system is more sensitive to pedal inputs, which can be a pain on long trips. But EFI of course wins on fuel mileage. Between having to run in AlphaN or carbs, I think carbs wins on drivability as they're not as touchy to pedal inputs as the EFI in AlphaN. Look into the feature set of Megasquirts hybrid alpha-N mode, should take care of most if not all of these issues depending on the motor. Ive run it on an ITBd 2270 and while it is a good deal more complex to initially tune the results are pretty amazing. I already have the SDS EM5-F6 system, not interested in anything else. I'm not saying SDS is the best, but then MS is isn't as well, honestly I don't give a **** *** what is the best system, that's not the topic. (IMG:style_emoticons/default/rolleyes.gif) Just throwing it out there as an interesting thing to read up on from a solution standpoint (and possibly a backup plan for anyone with unsolvable drivability issues.) I have zero opinion as to any system being the "best" they are all just different in their feature sets. As long as they get the fuel into the engine in the way you want it... who cares. I cant offer anything more than theoretical on 6 plenum design as all my first hand experience with that is on the 4s, but that 964 setup looks like the hot ticket. The SDS intake setup looks really nice though i suspect the plenum volume of the one pictured might be less than ideal on a larger engine. I believe the plenum formula is used within limitations, a fudge factor, reason #1 is going to be "will it fit" in the engine bay. In this case I imagine the center tubes are counted as part of the plenum volume. Also I know the EFI system, I have about 18 years experience with an SDS EM4-F4 that I've had on 4 engines. I sold the previous 3 engines, a stock 1.8, 2.0 and a 2.0 with a C25 mild carb cam. This system is currently on my 2600cc Nickies engine, in my '67 bug, that I daily drove till I got my /6 on the road. I've chipped the EM4 twice so far, I'm debating whether I should chip it again (just over $100) or up grade it to EM5 which is IIRC $500. The EM5 ECU I'm using for this project I sent in for an data cable upgrade ($125), no more chip, I can download the upgrades. |
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