Staring down the EFI rabbit hole again, /6 intake design, Which way around for the 964 plenums in a 914? Options

[Mark Henry]

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.

[ClayPerrine]

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.

Just buy a 964 intake and throttle body assembly. You will have to make some adapters to hook it to early heads, but it is a very good EFI plenum design. You can even use the SDS to control the resonance flap.

Hope that helps.

Clay

[Mark Henry]

I could just buy an intake but holy carp have you seen the prices peeps want for 3.6-up Porsche /6 intake? Evil bay I see $600 to 1200 which will be $1000 to $2000 Canadian and I'd still have to fab the injector/head flanges, the TB, clamps, hoses, crossover, etc...so fuchs that.
So unless someone wants to donate a plastic 993 intake or GT3 intake to my cause I think I'm on my own.

Porsche plastic 3.6, is it from a 993 or is this 964?
(IMG:http://www.914world.com/bbs2/uploads_offsite/i.ebayimg.com-26-1613580571.1.jpg)

What I'll likely do is a mild steel manifold similar in construction to some of the aircraft intakes that SDS has made.

(IMG:http://www.914world.com/bbs2/uploads_offsite/www.sdsefi.com-26-1613580572.2.jpg)
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.sdsefi.com-26-1613580572.3.jpg)
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.sdsefi.com-26-1613580573.4.jpg)

But I think I'll keep the two separate intake halves like Porsche does.
Maybe a mustang 75mm TB?

Any one wish to add their 2 cents on a intake design?

[mepstein]

3.2 Carrera intake. About $500 and good to about 300hp.

[GregAmy]

Depending on your airflow requirements (total displacement, cams, RPM, etc) I don't think it will be nearly as important on plenum design as it will be for efficient fuel delivery.

For example, we, at our level, don't have the flow bench and aerodynamics knowledge to properly work on resonance, dynamics, blah blah blah. And honestly, for a street engine, it really won't be a significant or noticeable advantage either way, sincer w'ere not playing at the edges.

It can make a difference on how we mount the injectors and deliver the fuel. You won't, for example, want a plenum or TB injection system. But I do like what SDS does on their plenums for that reason.

I'd suggest finding a bolt-on Porsche induction system that has good injector placement, and size a single TB for the WAG'd amount of airflow you'll need for 85% of the time. It'll be a good driveable engine.

[Mark Henry]

Just looking on the SDS site I can send in my ECU to have the case drilled for a PC input and the cable kit for $135. This will give me full data-logging plus allow me to update the chip via download...so in effect updating to brand new spec.

I'll also need a 1 bar MAP sensor as this has a 2 bar right now.

[horizontally-opposed]

3.2 Carrera intake. About $500 and good to about 300hp.

(IMG:style_emoticons/default/agree.gif)

Porsche, looking for total performance as well as peak performance, moved to a common plenum and never looked back. 3.2 setup is good, 964 and 993 setups better, and latest stuff is better still. Only recently, with the 4.0-liter Speedster and GT3s, has Porsche Motorsport returned to ITBs in a road car. And while they are magical, with what I can only describe as "high-resolution throttle response," there is a lot of tech (and calibration) at work in that magic.

One road that could be of interest is other normally aspirated production flat sixes with plenums of little to no interest to the air-cooled hot-rodders. Fortunately, there are a lot of them, and I suspect there isn't much demand for these parts from salvaged cars. Think Subaru 3.0 flat sixes as well as flat sixes from 986/996, 987/997, and 981/991.1.

Porsche's water-cooled flat sixes had plenums for 2.5, 2.7, 2.9, 3.2, 3.4, 3.6, and 3.8 liters—with and without direct injection depending on displacements—and the plenum doesn't care if an engine is air- or water-cooled. These are light, very nice pieces that were engineered for tight spaces (particularly in Boxsters and Caymans). And if an adapter has to be made to use a later air-cooled plenum, why not make adapters for something even better? And if you can control a resonance flap with SDS…

[ClayPerrine]

Mark,
there is a 964 complete intake system with throttle body and Idle air controller for US $549.00

https://www.ebay.com/itm/Porsche-911-964-C2...2QAAOSwgMFe9STu


When I got the 964 motor, it had the aluminum intake on it, and it was fried from the engine fire. So I bough this setup and was very happy with it.

Just make 6 injector plates with the correct bolt pattern for your heads.

Clay

[ClayPerrine]

If you want the aluminum plenum setup I got with my 964 motor, you can have them for the cost of shipping. You will have to clean them up and come up with a throttle body. But it might save you some fab time.


You can see pictures of the intake if you go to my build thread. They are at the beginning.

http://www.914world.com/bbs2/index.php?showtopic=279084

Clay

[Mark Henry]

If you want the aluminum plenum setup I got with my 964 motor, you can have them for the cost of shipping. You will have to clean them up and come up with a throttle body. But it might save you some fab time.


You can see pictures of the intake if you go to my build thread. They are at the beginning.

http://www.914world.com/bbs2/index.php?showtopic=279084

Clay

Thanks Clay I think I'll take you up on that! Worth it even if I'm just looking at what Porsche did.

I love this community (IMG:style_emoticons/default/first.gif)

[Mark Henry]

3.2 Carrera intake. About $500 and good to about 300hp.

One road that could be of interest is other normally aspirated production flat sixes with plenums of little to no interest to the air-cooled hot-rodders. Fortunately, there are a lot of them, and I suspect there isn't much demand for these parts from salvaged cars. Think Subaru 3.0 flat sixes as well as flat sixes from 986/996, 987/997, and 981/991.1.

Porsche's water-cooled flat sixes had plenums for 2.5, 2.7, 2.9, 3.2, 3.4, 3.6, and 3.8 liters—with and without direct injection depending on displacements—and the plenum doesn't care if an engine is air- or water-cooled. These are light, very nice pieces that were engineered for tight spaces (particularly in Boxsters and Caymans). And if an adapter has to be made to use a later air-cooled plenum, why not make adapters for something even better? And if you can control a resonance flap with SDS…

I have a 3.4 996 and a 3.8 997.1 manifold here, OK for the basics, center sections, the flap, 1999 has a cable TB, but the runners themselves are spaced too wide.

[Mark Henry]

Couple of pics of the system.
(IMG:http://www.914world.com/bbs2/uploads_offsite/forums.pelicanparts.com-26-1613586904.1.JPG)
(IMG:http://www.914world.com/bbs2/uploads_offsite/forums.pelicanparts.com-26-1613586904.2.JPG)
(IMG:http://www.914world.com/bbs2/uploads_offsite/forums.pelicanparts.com-26-1613586905.3.JPG)

[ClayPerrine]

If you want the aluminum plenum setup I got with my 964 motor, you can have them for the cost of shipping. You will have to clean them up and come up with a throttle body. But it might save you some fab time.


You can see pictures of the intake if you go to my build thread. They are at the beginning.

http://www.914world.com/bbs2/index.php?showtopic=279084

Clay

Thanks Clay I think I'll take you up on that! Worth it even if I'm just looking at what Porsche did.

I love this community (IMG:style_emoticons/default/first.gif)

It will take some time for it to warm up outside, and for me to get out in the garage and gather the parts up to send to you.

I will include a set of the 964 injector mount tubes. You may be able to use them to make ones to fit your heads.

Clay

[jd74914]

Just looking on the SDS site I can send in my ECU to have the case drilled for a PC input and the cable kit for $135. This will give me full data-logging plus allow me to update the chip via download...so in effect updating to brand new spec.

Can't beat that!

[targa72e]

HI Mark,

I also thought of using the later watercooled Porsche intakes on earlier car as a inexpensive intake. I went as far as to mock it up and it looks doable. You are correct that the later intake is too wide. However it looked like the center tubed could be cut down easily to make the intake narrower. They are connected to each side by rubber tube and clamps so should be easy. you would need to make a adapter to connect the oval tubes of the manifolds to the the round inlet on air cooled head. The intake I have (2.7 boxster I think) has a resonance tube and injector mounts so only would need adapter. I have not taken this any further as I had my friends 2.7RS spec motor with Mod S cams and webers in my 914 for a while and now I am hooked on top end rush of hotter cam. I decided the milder cams for single throttle intake would not cut it and will go ITB. Still might try and use intake over ITB's we will see.

john

[Steve]

[quote name='Mark Henry'

But I think I'll keep the two separate intake halves like Porsche does.
Maybe a mustang 75mm TB?

Any one wish to add their 2 cents on a intake design?
[/quote]
PRO-M had a 80mm? Mustang MAF kit with MAFTuner for my 3.2. I had it on my car and it did breathe better. At the time I didn’t have a air/fuel gauge and was paranoid, so I took it off. I now have a gauge. The plan is to wire it up and put the MAF back on.
http://www.promracing.com/pro-m-racing-mass-air-meters.html
http://www.mustangandfords.com/how-to/inte...pro-m-maf-tuner

[Mark Henry]

Cool Steve, do you have any more pics of your intake?
All I need is a TB with a TPS on it, that why I thought of the mustang TB, I'll start looking at sizes.

I'll have to wait a bit on the manifolds, Clay's area is getting hammered with the cold and power problems, obviously I told Clay I'm not in a rush.
Plus I think he has to remember where he put them. (IMG:style_emoticons/default/biggrin.gif)

In the meantime I'm going to clean the system up and start planning on where I'm going to mount the ECU, wiring, programmer, etc.
It has the crank trigger on a plate that bolts to the pulley, but it's a two groove pulley and I think my mount only fits a one groove.
So I have lots of little jobs to do.

[ClayPerrine]

Cool Steve, do you have any more pics of your intake?
All I need is a TB with a TPS on it, that why I thought of the mustang TB, I'll start looking at sizes.

I'll have to wait a bit on the manifolds, Clay's area is getting hammered with the cold and power problems, obviously I told Clay I'm not in a rush.
Plus I think he has to remember where he put them. (IMG:style_emoticons/default/biggrin.gif)

In the meantime I'm going to clean the system up and start planning on where I'm going to mount the ECU, wiring, programmer, etc.
It has the crank trigger on a plate that bolts to the pulley, but it's a two groove pulley and I think my mount only fits a one groove.
So I have lots of little jobs to do.

I am going to send the complete intake system, including the injector mounts, and the center section with the throttle body. But the throttle body is fried from the fire.

You will need the rubber boots and the hose clamps, and the fuel rails for the injectors.

[rick 918-S]

Probably don't have to tell an experienced engine guy like you about this but for others that may not be aware, cam shaft lift and duration are key with EFI. At least with CIS as too much pulse in the intake makes for wacky reactions to drivability. Maybe you can expand on how it effects more modern EFI stuff.

[Steve]

Cool Steve, do you have any more pics of your intake?
All I need is a TB with a TPS on it, that why I thought of the mustang TB, I'll start looking at sizes.

I'll have to wait a bit on the manifolds, Clay's area is getting hammered with the cold and power problems, obviously I told Clay I'm not in a rush.
Plus I think he has to remember where he put them. (IMG:style_emoticons/default/biggrin.gif)

In the meantime I'm going to clean the system up and start planning on where I'm going to mount the ECU, wiring, programmer, etc.
It has the crank trigger on a plate that bolts to the pulley, but it's a two groove pulley and I think my mount only fits a one groove.
So I have lots of little jobs to do.

That’s the only picture I have of the intake. Nothing special all stock 3.2 intake with a mustang MAF to Home Depot sewer pipe to stock boot. Only the stock air flow meter is gone. The under dash MAFTuner adapts the mustang MAF to stock DME computer.