ITB EFI DIY guide

[Cheshire Cat]

Since ITBs are the new black (Pork Chops?) and we have quite a few projects done\going on the forum I`ve realized that there are people who don`t really understand the concept of ITB on aircooled 911s. I`m not going to dig into the physics and aero\thermodynamics but will try to explain what is it, what the typical kit should be like and how hard will it be to setup. With the brands and rough prices.

Well, let`s start with the terms. ITB - individual (independent)  throttle bodies. In our case there are 6. Intake manifolds (runners) - the peace of metal that attaches the ITBs to the intake channels on engine heads. There are roughly two, one per each side. EFI - Electronic fuel injection. ECU - electronic control unit (a brain) the thing which tells the injectors when and how much fuel do give and igniters to spark.

Basically what you need in the kit for a complete install:

ITBs

Big Brands are

PMO - http://www.pmocarb.com/products.htm

Hargett Precision - http://hargettprecision.com/index.php/porsche-products/porsche-throttle-bodies/porsche-itb-s.html

Jenvey - http://www.jenvey.co.uk/products2/throttle-body-kits/porsche-2-bolt-large-port-sf-taper-throttle-body-kit-ckpeo2

AT Power - https://www.atpower.com/products/porsche-911-45mm

Borla Induction https://www.borlainduction.com/3003-series.html

Rothsport Racing http://www.rothsport.com/Products/Engine/Fuel-Injection-Systems/FI-Systems.htm

Smaller brands are

X-Factory - http://www.x-faktory.com/store/p3/EFI_Kit_S3-EFI-001_.html

ClosedCourseMotorsport - http://closedcoursemotorsport.com/triumph-itb-setup-for-911-aircooled-engines/

Racehead - http://racehead.com.au/products-page/throttle-body-kits/porsche-bolt-on-itb-kit/

And complete DIY setup is based on Triumph Motorcycles ITBs (we are lucky they have 3 cylinders). I`ve seen so far setups based on Triumph Daytona 955 and 675R bikes. They are not that expensive, from 100 to 200AUD for a set (we need two sets). Last two companies mentioned in the list utilize 955s TBs in their kits. 

Pretty much all above don`t have EVERYTHING to complete the kit but it is due to many variations of the execution of the setup. Most of them include ITBs, intake runners\adapters\manifolds, Linkage, fuel rails and airhorns. The rest like X-Factory and CCM have a bit more than that but again, you should add some to their kits as well. 

Intake manifolds...

and adaptors. As I mentioned before most of the setups have them which makes everything easier. But if you are going hardcore and want to build a kit yourself I`d recommend to use Triumph 955 TBs since you can order a set of adapters\manifolds for them. Look at X-Factory and ClosedCourseMotorsport products. 
But if you are familiar with TIG welding then you have no limits. Say I had to send my 675R TBs with manifolds to Eastern Europe to  Soara Performance company so they could weld the TB`s right to the aluminium adapters made by themselves. They will do it again if you are interested for about 200USD for the whole lot + shipping.
The PMO style manifolds sold here http://youroil.net/weber_carb_parts.html or Ebay or PP forum

Airhorns

With the big brands you have them in the kit. With Triumph stuff you can use the original ones bought on Ebay for quite cheap. And EFI Hardware can make some custom ones.

Air filters

Same as with the Intake manifolds. Most of the big brands use either ITG or K&N. But you can use sock type filters. In my kit I use UNI Filter Australia (yep, they are aussie) sock filters. 

Insulators and gaskets

Usually you have them in the kit. But you can obtain ones here http://youroil.net/weber_carb_parts.html

Fuel Rails

Included in a kit. But for DIY - EFI Hardware in Melbourne can make whatever you want for a about 200AUD for a pair. 

Fuel pressure regulator

Lots of options. Easy to get and to very expensive.

Injectors

Andrew at Rasant (http://rasantproducts.com) sells Bosch 300+ cc but it`s up to you. Just keep in mind that some ECUs have limitations on resistance. So, be careful and find out are they hi or low impedance and what your future (or present) ECU can work with.

Ignition

1 coil, 3 coils, 6 coils or 6 coils on plug. Clewitt Engineering (http://www.clewett.com/index.php?main_page=index&cPath=1&zenid=delgghjkbe0963krilcnptqd17) has a few options, but there are cheaper things on the market. Again Rasant has some VAG coil on plugs option which is quite alright (http://rasantproducts.com/bosch-coil-on-plug-ignition-coils/).

UPDATE - One must consider a few things when he`s going to 6 COPs setup - 6 Coils on plug + 6 connectors (could easily cost another 100+ bucks) + wiring - not too bad, but if you going twin plug set up - everything is doubled. Additional - aesthetical look is pretty rough. Seems like I have just found a neat solution - 6 cyl VW ignition pack with built-in igniter (smart coils, something like this https://www.amazon.com/URO-Parts-021-905-106/dp/B01AWXXIIA ) - 2 packs for twin plug, just to add another set of leads, easy to hook them up rather then 12 COPs

Fuel lines and fittings

Well here are the art part comes in. You can spend hundreds of bucks for a aussie made stuff or make it reasonable cheap buying stuff on Ebay or in the U.S.  

In addition. There are two (feed line and return line) tricky (convex) angled adapters needed to use original Porsche metal fuel lines in the engine bay with any aftermarket solution. Common M14 to AN6,8,10 (or whatever) adapters don`t work. But it seems like we have at least 1,5 (yep, one and a half) solutions for that. The first one proposed by the guy named Boxter GT (in this thread http://forums.pelicanparts.com/porsche-911-technical-forum/389363-looking-fuel-line-fitting-size-2.html) the adapters might cost you anything from 30 to 50 per part. Another solution (I`m still testing it and can`t see why it shouldn`t work) is mine. You take a common adapter and put an O-ring at the bottom of the nut which has M14 thread and tighten the adapter up. The O-ring works as a spacer\rubber seal.

Crankshaft sensor and\or camshaft sensor

The most reasonable and easy to install is AEM EPM thing but you have to get an adapter which is sold on http://rasantproducts.com/engine-management-components/engine-position-sensors/

Other options are here http://www.clewett.com/ . There are lots of options really. 

Vacuum lines and fittings and\or vacuum distributor

Ebay, ClosedCourseMotorsport, X-factory etc

Intake air temperature sensor

Same as above

Oil temp sensor

Same as above

Throttle position sensor

Same as above but most of Triumph TBs sold on Ebay have them. 

ECU and loom

And pretty much none of those kits I`ve mentioned have any. Except the X-Factory one. 

Anyway, I`ll explain. Since Australia and New Zealand are full of this stuff it`s quite logical to buy one made here. Easy to get, warranty, tuner shops etc but. Rasant sells really nice kit based on AEM ECU and as far as I know provides you with the knowledge, experience and maps. http://rasantproducts.com/engine-management/porsche-engine-management-kits/

Same with X-Factory, Al has ton`s of power of knowledge and experience as well as maps and online tuning. And his weapon of choice is MegaSquirt - DIY ECU. 

Anyway, the brands are:

EMS

Wolf

Link

Adaptronic

Haltech

MoTec

etc. depends on your budget. But be careful some of the brands sell their ECU with no loom so add another 300 or so bucks on a top. 

Air fuel ratio meter

It is quite vital to get one, but most of the pro tuners have them, however if you`re in DIY tuning you can`t go far without one.

The players here are: AEM, Innovate, PLX, Zeitronix, 14point7 and others. For the tuning purposes you need a wideband sensor and controller but for monitoring you will def need a gauge. Recent researches show that plx, zeitronix and spartan by 14point7 are more reliable and faster\more accurate than AEM and Innovate devices. But it`s a matter of argument if course.

I really hope all of it makes any sense guys, trying my best to cover this so, if you have anything to add or to correct - feel free to do so

 

 

[Coastr]

Can you add anything about sizing the TB size to different engine displacements and/or desired HP?  Do ITBs allow for more aggressive cams?

[Peter John]

Thanks for sharing! Lots of knowledge and contact details!

[Cheshire Cat]

Can you add anything about sizing the TB size to different engine displacements and/or desired HP?  Do ITBs allow for more aggressive cams?

I will try for sure :))

Thanks for sharing! Lots of knowledge and contact details!

You are welcome!

[Pork Chops]

Can you add anything about sizing the TB size to different engine displacements and/or desired HP?  Do ITBs allow for more aggressive cams?

For sure.  As long as you've got a programable ECU (and you do) you can do anything with them.  The trick is to match everything.

From @x-faktory (Al Kosmal).  Can I say Al is a top bloke and if you really want the challenges / headaches (depends on your point of view) taken out of things I can recommend a kit from him.  Not taking anything away from other options but I'm talking to my experiences.

Since ITBs are the new black (Pork Chops?)

 

Yes .  In my house anyhow.  Its about time Porsche hotrods got into the next century...Who knows maybe someone will come up with something like this for Porsche Motronic systems one day.  Well done George you got skillz waaaaay past my own.  

[MFX]

Great work putting that all together. A great resource for those looking into doing it in the future.

[Zelrik911]

Great summary.

How is your fine-tuning going? Proof is in the pudding!

[wilburforce]

Thanks @Cheshire - great summary!

[Cheshire Cat]

Who knows maybe someone will come up with something like this for Porsche Motronic systems one day. 

I know that some guys can do the same with BMW Motronic systems and I believe it should be quite close to Porsche ones in a technical way. But since BMW have really lots of models using it and Porsche just a few - I assume there no reasons to mess with it. I can ask to double check if you want. 

I'm pro standalone ecu myself so... 

 

No worries guys, I'll add some more to make it complete as much as it possibly could be with time.

How is your fine-tuning going? Proof is in the pudding!

Well... It's going a bit slow I have not much time to do it in one try. And again - with on the road tuning you always need someone to help you out. Got the idle on lower rpm. 

Hopefully before Xmas I'll make it to a dyno to get some numbers

[Troubleshooter]

CCat,

Whilst I'm maybe, most definately probably never, going to mess about with DIY ITB's on an aircooled (detailed mechanics not my forte) Many thanks to you for putting together such detailed info and links for all those that way inclined. One of the reasons this site is such a tremendous resource and infotainment and meeting place is because of guys like you that take the time to share the knowledge and spend much time compiling and typing it all in

MUCH RESPECT

[88-ben-88]

Great post. 

I am wondering what solution you came up with for the injectors? Finding flow rate specs on the standard Triumph 675 injectors seems impossible, so am wondering if any other commonly available injectors will fit or if any mods need to be made to fit alternative injectors to the throttle bodies?

Any help greatly appreciated!

Cheers

Ben

PS: Another fabricator of manifolds is DanSt Engineering in the Uk, they have a ebay store as well.

[neill]

Bosch injectors fit the Triumph ITB's. Just need to use different o-rings.

I will get together some pictures and add my experience too. A thread similar to this with all the info in one place would have been amazing when I first started.
 

 

[88-ben-88]

Thanks Neil, i have been keenly awaiting news on the progress of your installation. 

My planned set up is close to yours, although looks substantially rougher.

I would also be keen to understand how you got the inlet port diameter down from the throttle bodies 44mm ID to the port ID of 38mm...assume the 'manifold' port was turned up on a lathe before welding?

My manifolds are a basic 44mm ID pipe welded to a flange, so i need to find a way of stepping down to the port diameter to ensure a smooth and fast airflow.

I look forward to your post.

cheers

Ben

[Philbee]

Thanks @Cheshire Cat and other contributors... ... Plenty of great info and bedtime reading for us (me) uninitiated mugs...!

[neill]

Thanks Neil, i have been keenly awaiting news on the progress of your installation. 

My planned set up is close to yours, although looks substantially rougher.

I would also be keen to understand how you got the inlet port diameter down from the throttle bodies 44mm ID to the port ID of 38mm...assume the 'manifold' port was turned up on a lathe before welding?

My manifolds are a basic 44mm ID pipe welded to a flange, so i need to find a way of stepping down to the port diameter to ensure a smooth and fast airflow.

I look forward to your post.

cheers

Ben

I had a cone made on a lathe and used it to flare my 38mm pipe out at the top to be 44mm. Making each runner on a lathe would have cost me a bunch more.

the cone slipped into the tube I had and I used a workshop press to push it down into the tub and it flared it out. I used a ring of thinner walled 44ID tube around the outside and welded at the top to give a flat surface to clamp to.

Pictures will probably explain it better.

[neill]

As for sensors, injectors and all the other little bits I am running the following -

Link G4 ECU
Head temp sensor - This is basically some flat bar aluminium with another bit of tub welded to it that I have threaded to screw a Bosch sensor into. The flat bar slides between the fins on the head for cylinder number 3.
Oil temp sensor - This runs in the lower pipe to the oil tank.
Oil pressure sensor - Screwed into the top of the block to the right of the breather cover.
Air temp sensor - Left hand side of the engine bay (above the ecu in the engine bay picture above).
TPS - The standard Triumph Daytona TPS is being used in its stock location.
Igniter - I am using a Nissan SR20 igniter pack, using three of the 4 channels (I'm running wasted spark).
Coil packs - Ford BF XR6 Turbo coils, made by VDO, look to be good quality and work reasonably well in a 4.0L Turbo 6. Also are not internal ignited which worked for my loom setup. They also have a kink in the stem that goes to the plug which suits the diagonal down hole in the Porsche heads.
Injectors - Again, Ford BF XR6 Turbo. Easy to source, plenty big enough for what I need. The rail is a pair of stock 964 rails with an fittings welded on each end.
Fuel pump - Bosch 044
Crank trigger - Sourced from Clewett Engineering in the states, good quality part, easy to install and removes the dizzy.
Cam trigger/sync - Also sourced from Clewett Engineering, again good quality part, a little more involved fitment wise.
Idle control - I have a mac valve connected to a vac chamber which all the throttles also link to. This may or may not work, time will tell.

Some other misc info - 

The trumpets I am using are from JNT Performance in NSW, the mouth at the top 90mm OD. Also because I have spaced my throttles out to the same as the heads the traditional filters you see wont work (not long enough). I have done a whole heap of searching and the best option was from Pipercross in the UK, they make a sock style filter that is 90mm ID. Not the prettiest, but better than being open to the atmosphere.

In the engine bay pic above you can see a coil block with 6 outlets. Originally I had wanted to run plug leads (mainly for the look, to try and retain some form of the original looks), The issue I had was the coil block was overpowering the leads I had (Magnecore off the shelf Porsche leads) and was basically firing all the plugs when sending a signal on any of the channels. I conceded and moved to individual coils to solve the issue. Now that its done I prefer the cleaner look of the individual coils, so a win I suppose.

My dash guages, for the most part, are still run by the stock sensors in the stock locations (you can see most of them in the pic above). The tach is run from the ECU now and my Speedo is GPS (mostly because my speedo was shot and a GPS speedo was easier to source at the time). I am using the speed signal from the gearbox as an input into the ecu still however.

Throttle pedal uses all stock linkages up until the lever block ontop of the engine, from there I have made cables to operate each bank of throttles.

Link do not have a base map for use on a Porsche, you will need to make it yourself from scratch.

My whole setup has been done to a reasonable budget, mainly because I have made most of it myself. I could have gone another whole level on the electronics side of things but for what I intend to do with the car its more than suffice in my opinion. It will bring you more headaches than buying an off the shelf kit, sure, but I enjoy a challenge and making things (and saving money).
 

[Redracn]

Igniter - I am using a Nissan SR20 igniter pack, using three of the 4 channels (I'm running wasted spark).
Coil packs - Ford BF XR6 Turbo coils, made by VDO, look to be good quality and work reasonably well in a 4.0L Turbo 6. Also are not internal ignited which worked for my loom setup. They also have a kink in the stem that goes to the plug which suits the diagonal down hole in the Porsche heads.

 

How do you propose to wire the ignitor to the coils? You should not drive two coils from the one ignitor and expect them to work very well for a lot of technical reasons.

[neill]

I currently have ecu signal to one channel of the igniter than the output from the igniter splits in two.

 

How do you suggest doing it? And as it currently is what will be the issues it will have?

 

Entirely open to criticism, it's how we learn.

[Redracn]

I currently have ecu signal to one channel of the igniter than the output from the igniter splits in two.

 

How do you suggest doing it? And as it currently is what will be the issues it will have?

 

Entirely open to criticism, it's how we learn.

Im not critising just helping you get a better (actually works) result?. The first issue is that the current will be shared between the two coils resulting in half as much energy for the spark. From memory the SR20 ignitor is current limited at about 7.5Amps. So rather than the designed 7.5Amps each coil will only get about 3.75Amps of primary current (They don't share equally either). No current limited ignitor I know of has a high enough limit for two coils. Some ignitors have no active current limiting but they do have a maximum which is also likely to be two low for two coils but you would need the specs to sort that. But all that is besides the point due to the second main issue and that is most of the energy stored in both coils will be absorbed by the spark-plug with the lowest arc voltage which is the wasted one. The coils primary's are connected together so do not operate independently. You could diode isolate the coils but that is another issue. The next issue is that you are firing the coils at twice the spark rate they were designed for so they will get a lot hotter. This becomes an issue if you intend to operate a prolonged high RPM as the coils can be overheated. There is more but now we are getting technical.?

Don't forget you will also need to set/tune the dwell for the coils and/or ignitor.

Ignitors and coils need to be matched in relation to current and primary voltage clamp plus more. Fortunately approx 7.5Amp coils and 7.5 Amp ignitors are relatively common along with turns ratios from 70 to 100 and ignitor protective voltage limits of 350 to 400V so you get lucky more often than not. 

Best option is to use two by SR20 ignitors and full sequential ignition. 

Hopefully this should save a lot of heartache and get you a good reliable result.

 

[Pork Chops]

^ I was going to say that.

[neill]

So say I had a rb25 igniter pack (my friends are mostly jap cars guys). They are a 6 cylinder igniter.

 

I split the ecu signal to 2 separate channels on the igniter then an individual channel to each coil.

 

That would solve the issue?

 

I only have an ecu with enough outputs to run them wasted spark, so I am confined to doing that.

[88-ben-88]

Great post Neil, thanks for the info.

The ignition side if things is well beyond me so i am using a Ford EDIS system. Uses the same trigger system you already have. It is perhaps not using the ecu to its potential but it should (hopefully) be easier to set up.

My intention is to get the ECU running ignition only initially, just to get it all functioning. Once that is proven, I then hope to ditch the CIS in favor of the ITB's.

Keep posting on your progress, i am sure there are plenty here who are contemplating this, an the experience is invaluable.

 

[Redracn]

So say I had a rb25 igniter pack (my friends are mostly jap cars guys). They are a 6 cylinder igniter.

 

I split the ecu signal to 2 separate channels on the igniter then an individual channel to each coil.

 

That would solve the issue?

 

I only have an ecu with enough outputs to run them wasted spark, so I am confined to doing that.

You should be ok as far as spark energy is concerned. Other issues are can one ECU output drive two ignitor inputs. From memory they require a current source of around 20mA per ignitor input. The other is that both the coils and the ignitor will be operating at twice the design spark rate so if running at 6000rpm the coils and ignitor will be efectively at 12,000 rpm. You will also have twice the amps draw from your power suply so twice as big a fuse and wiring are required compared to running it full sequential. 

[neill]

So today I redid the wiring and now have two of the sr igniters wired in (I had a spare already, so was the easiest option). So one channel per coil now. We spoke to Link about driving two igniters per channel and they seem to think it will be ok.

The double rpm thing I knew about from the beginning, the car is primarily going to be used on the road and if it see the track more than once a year I'd be surprised. So it shouldnt be to big a problem for my use.

Thanks for your input Redracn, hopefully end up with a better overall result.

[88-ben-88]

Hi Neill,

you mentioned the Bosch injectors fit into the 675 throttle bodies with a different o ring. What’s the difference? Do you have specs, part number or any other details?

cheers

ben