914 ITB's, Pro's and Cons, option opinions and show us your setup!! Options

[Steve]

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?

[Mark Henry]

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.

[john77]

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 (IMG:style_emoticons/default/biggrin.gif)

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.

[Mark Henry]

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 (IMG:style_emoticons/default/biggrin.gif)

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.

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".