It seems like ITB's are all the rage with our air cooled sixes.
The throttle bodies are either PMO or direct to head either with butterflies or AT-Power with no butterflies.
Mark dug up some of the pricing!! Thanks Mark!!

X-Faktory uses Megasquirt, Link or Motec M84
https://www.x-faktory.com/uploads/6/3/9/3/6...efi_systems.pdf
Starting at $4754

Clewett uses TEC
https://www.clewett.com/index.php?main_page...dex&cPath=2
Starting at $8400

Rasant uses exclusively Motec, which is the most expensive
https://rasantproducts.com/collections/mote...84-ecu-packages
Starting at $5700 for the ITB's and $6200 for the EFI

AT-Power offers throttle bodies without butterflies, but use special cams to optimize
https://www.atpower.com/
Starting at $13K

Lots of options which can raise or lower the price.

I have a stock Euro 3.2 with DME that does run fine, but I miss the sound of the webers, but I don't miss the hassle of webers, cold start, poor gas mileage, etc.

I know ITB's are expensive, but option 2 at X-Faktory is not that bad and pretty popular over on the Pelican 911 technical forum.

Anybody on this forum have any experience with any of these toys?

I had an 84 911 with a 3.2 and altered and installed Suzuki GSX-R 750 throttle bodies with Megasquirt. It ran but never did get it right. I then installed Weber 40 IDAs and was immensely disappointed. IMO, it needed bigger camshafts and a "real" exhaust to get the feel of early S and E engines. I sold the car just before doing my 1st 914 993 conversion.

I did my setup with triumph speed triple throtzle bodies.
The ecu is an megasquirt 2.
Works nice after fidling out some issiues.
Much better thsn the zenith carb i previous had on the 2.4 engine.

Michael

Slippery slope

Have to say that I really like the part where the 3.2 runs fine. I really like driving that car...but I am also an old fart, mostly in the way of things.

If your going for horsepower than your better off upgrading to a 3.6 from a 3.2. Probably around the same price. The hp gains from ITB’s on a stock motor are around 20 hp for a 3.0 or 3.2 motor. Best gains seem to be on a CIS motor.

I feel the same way. If it ain't broke don't fix it. It's also a lot of work to swap it out for ITB's and probably very expensive to let someone else do it, but they do sound awesome!!

I think you usually go for itb’s so you can use more aggressive cams, compression, etc. Peter Dawe said the stock manifold is good for up to 300hp. We have an engine at the shop with 290 rear wheel hp that he helped to build. It has itb’s, but is a 3.5 built on a 3.2 case.

There is a good market for used 3.2 parts but from just a HP perspective, the conversion doesn’t make $ sense. If it makes you happy, then it’s worth it.

On my 3.4 build I went with the Rasant Products/PMO ITB's just to keep it kinda factory looking. Not sure how it's gonna work out as I have other things to do before I get there.

Oh yeah it's not a cheap setup either. Hopefully it all works well.

Why did you choose Rasant over the other vendors? Most of the other vendors offer PMO ITB's with there lower cost Engine Management Solutions.

I asked over on the bird site which was the better product. Rasant came in on top for a quality product and customer service. I also got the COP, better ecu, just a complete bolt on kit. I wanted the Org look of carbs but not the headaches of tuning them.

James Patrick pitched this to me last month with a price around 6k. While it sounded nice I just didn’t want to mess with a system that’s not broke.

Also

Honestly, I'd love a way to run 3.2 Motronic—complete—on my 2.2.

Suspect the runners would be too big, and the chip would need "minor" revisions, and that there would be other issues—but one of the things I don't like about aftermarket setups is long-term parts/support. I'd hate to be in a 2020-2040 version of maintaining a 386 or 486 to run an old race car. No thanks…

But I'd also love to move on from carbs.

This is a 3L SC engine with upgraded cams, Borla itb's and MoTec management. Also runs our headers + a custom fit gt3rs muffler. Sounds delish !
Click to view attachment

One thing about all these ITB systems is if your engine itself isn't up to snuff then it just expensive lipstick on a pig.
EFI itself doesn't add HP, the ITB open things up, but an engine is the sum of all its parts not just the bolt ons.

We'll see if there's much HP loss going from my 40mm webers with a Patrick twin plug dizzy to a single honda TB modified 964 intake with SDS EFI with crankfire. My engine is still fresh perfomance twin plug with healthy WEB 120/104 cams. My bet is there won't be a huge difference, especially for a street car. My prime objectives is a bit better gas milage,a bit less intake noise and less matanance than the carbs. Also I have another 914 project that will need the carbs and dizzy for.

If there's a big downgrade in HP I can always add ITB's, but I'd do another motorcycle TB mod like I did on my 2.6 nickies T4.

Sounds like you're on the right track with reasonable goals. Jerry Woods used to say that you don't gain much peak hp with EFI vs carbs, but you gain a lot of performance. More torque, more of the time. More drivability. More consistent throttle response, which leads to more confidence, which leads to more speed.

Marty, that Borla setup looks delish. Didn't know they were in the ITB game, and have had Borla products in the past…and they were superb. Also like that it's a name that's been around a long time.

6k installed? I doubt it.

ITB's can pretty much force you to tune by throttle position. All of that area opening up at the same time is confounding to MAP tuning.

I have to agree, $6K is the price for the entry level PMS ITB's alone, not including the EFI system.
To me the prices of the 911 ITB's are crazy money. I'd be buying a pair Triumph triples.

https://patrickmotorsports.com/collections/...njection-system

I'm building a 964 plenum based EFI system, I'm aiming to do it for under $1500....Canadian.

Below is my T4 motorcycle TB build, not counting build time I have no more than $200 into them.
http://www.914world.com/bbs2/index.php?sho...p;#entry1862152

I put the entry level prices in the post, but I did it on the quick so check my figures.
wowzers

I'm such a cheap ass.

I purchased VEMS for my 3.2 but haven't installed it yet. It doesn't change the look of the induction, just modernizes the electronics and programing and is plug and play to the existing wire harness.

i was lurking on this thread wondering if this was the case.

I've never built an engine (although I've paid for a couple, one of which will have ITBs) and it was my understanding that ITBs only really make sense if the engine is built from scratch with them in mind.

I was toying with getting them for my 2.7 but a friend who builds engines told me not to waste my money as the performance upgrade would be negligible, if at all.... Or as you so eloquently put it, lipstick on a pig

There's nothing wrong with lipstick but unfortunately our cars don't do much to show off the engine well.

What does it include? There website is horrible and I don't see any installation manuals. I also have a mustang MAF with adapter that works with stock DME. I noticed a small uptick with wide open throttle. Otherwise at low RPM's it didn't do much. In Bruce Anderson's book he said a MAF is good for around 10hp, chip for another 10hp and better exhaust for around another 10hp. I already have a Steve Wong chip and ben's heat exchangers. The chip and ben's heat exchangers have been the best improvement so far.

For the most part you're correct.
These systems will have little HP gain on a stock engine, it could even make things worse.

The FI system itself makes ZERO extra HP. This info/fact is often buried in the fine print.
But the ITB's do increase flow, so with the right cam, head, piston, etc. and header combo this does equal more HP.

Often this upgrade is WAY more than just slapping a set of ITB's on...it will also involve cams, pistons, etc. upgrades.... the very definition of "Slippery Slope".

I purchased it through Peep, Raceboy on Pelican. He builds a wire harness for it so it can plug into the stock 3.2 harness. I mostly purchased for a custom 3.2 I'm building with hot cams, 3.4 cylinders, max moritz pistons, higher compression, etc. It uses the stock 3.2 reference sensors and modern injectors.
I don't think the FI adds power but will be very tunable to let the engine achieve it's best results. It was ~ $1,200

It sounds like you've already attended to the low hanging fruit with the chip and exhaust. While you might see your engine as a bit boring, I would be really hesitant to touch it. One of the best things about a 3.2 is it's "boring" ability to start and run smooth and dependably when you turn the key.

Sum of the parts, the mechanical stuff...the cams, pistons, CR, intake, exhaust, etc, this is what will bump the HP.
The FI is just what runs all this new kit.

It should be a healthy engine Mark.

Thanks everyone for the responses and feedback. I am in no hurry to throw money away.
My DME was a mess until i replaced all the sensors. So now it's seems to be really reliable and always starts. I drove to and from the last WCR event in Petaluma and the car ran great with no issues. I won an award for driving the furthest.
Pelican has a "Show your ITB" thread.
http://forums.pelicanparts.com/porsche-911...-itb-setup.html

I would love to see the same thing here. Post your 914 ITB/EFI solutions and educate us, with what is possible.

When I built the 4.0 monster motor, I debated on ITBs. Because I started with a burned engine, I didn't have an intake. But I chose the stock 3.6 intake and Motronic. It may be restricting the HP some, but I like the fact that it just works.

Frankly, I loved the sound produced by the MFI on the 2.4 I pulled out of the car. But it was a PITA to live with for a car that I wanted to drive on a regular basis. With Motronic, you just turn the key and it idles, hot or cold.

ITBs are going to require much more adjustment than a basically stock Motronic.

Maybe I am getting older, and don't want to fool with it as much.



Clay