 914 ITB's, Pro's and Cons, option opinions and show us your setup!! |
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| Steve |
  Mar 23 2021, 02:15 PM
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#1
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914 Guru  Group: Members Posts: 5,606 Joined: 14-June 03 From: Orange County, CA Member No.: 822 Region Association: Southern California 
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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? |
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| roblav1 |
Mar 23 2021, 03:01 PM
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#2
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Senior Member Group: Members Posts: 528 Joined: 18-September 12 From: KY Member No.: 14,943 Region Association: MidAtlantic Region |
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.
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| michelko |
Mar 23 2021, 03:04 PM
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#3
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Senior Member Group: Members Posts: 867 Joined: 30-November 03 From: Germany, Lambsheim Member No.: 1,404 Region Association: None |
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 |
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| mepstein |
Mar 23 2021, 03:22 PM
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#4
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914-6 GT in waiting Group: Members Posts: 19,307 Joined: 19-September 09 From: Landenberg, PA/Wilmington, DE Member No.: 10,825 Region Association: MidAtlantic Region
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Slippery slope (IMG:style_emoticons/default/biggrin.gif)
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| worn |
Mar 23 2021, 03:31 PM
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#5
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can't remember Group: Members Posts: 3,156 Joined: 3-June 11 From: Madison, WI Member No.: 13,152 Region Association: Upper MidWest
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QUOTE(Steve @ Mar 23 2021, 12:15 PM)  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, 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. |
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| Steve |
Mar 23 2021, 03:36 PM
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#6
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914 Guru Group: Members Posts: 5,606 Joined: 14-June 03 From: Orange County, CA Member No.: 822 Region Association: Southern California
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QUOTE(mepstein @ Mar 23 2021, 02:22 PM) (IMG:style_emoticons/default/agree.gif) 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. |
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| Steve |
Mar 23 2021, 03:43 PM
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#7
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914 Guru Group: Members Posts: 5,606 Joined: 14-June 03 From: Orange County, CA Member No.: 822 Region Association: Southern California
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QUOTE(worn @ Mar 23 2021, 02:31 PM) QUOTE(Steve @ Mar 23 2021, 12:15 PM) 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, 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. 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!! |
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| mepstein |
Mar 23 2021, 04:37 PM
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#8
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914-6 GT in waiting Group: Members Posts: 19,307 Joined: 19-September 09 From: Landenberg, PA/Wilmington, DE Member No.: 10,825 Region Association: MidAtlantic Region
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QUOTE(Steve @ Mar 23 2021, 05:36 PM) QUOTE(mepstein @ Mar 23 2021, 02:22 PM) (IMG:style_emoticons/default/agree.gif) 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 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. |
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| Luke M |
Mar 23 2021, 04:59 PM
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#9
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Senior Member Group: Members Posts: 1,374 Joined: 8-February 05 From: WNY Member No.: 3,574 Region Association: North East States
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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. (IMG:style_emoticons/default/beerchug.gif) |
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| Steve |
Mar 23 2021, 05:16 PM
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#10
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914 Guru Group: Members Posts: 5,606 Joined: 14-June 03 From: Orange County, CA Member No.: 822 Region Association: Southern California
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QUOTE(Luke M @ Mar 23 2021, 03:59 PM) 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. (IMG:style_emoticons/default/beerchug.gif) 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. |
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| Luke M |
Mar 23 2021, 06:00 PM
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#11
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Senior Member Group: Members Posts: 1,374 Joined: 8-February 05 From: WNY Member No.: 3,574 Region Association: North East States
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QUOTE(Steve @ Mar 23 2021, 04:16 PM) QUOTE(Luke M @ Mar 23 2021, 03:59 PM) 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. (IMG:style_emoticons/default/beerchug.gif) 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. |
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| Coondog |
Mar 23 2021, 06:25 PM
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#12
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Advanced Member Group: Members Posts: 2,089 Joined: 24-September 15 From: Apple Valley Calif Member No.: 19,195 Region Association: Southern California
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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.
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| pete000 |
Mar 23 2021, 07:19 PM
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#13
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Senior Member Group: Members Posts: 1,885 Joined: 23-August 10 From: Bradenton Florida Member No.: 12,094 Region Association: South East States |
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| horizontally-opposed |
Mar 23 2021, 10:28 PM
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#14
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Advanced Member Group: Members Posts: 3,432 Joined: 12-May 04 From: San Francisco Member No.: 2,058 Region Association: None
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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. |
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| Maltese Falcon |
Mar 23 2021, 10:52 PM
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#15
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Advanced Member Group: Members Posts: 4,686 Joined: 14-September 04 From: Mulholland SoCal Member No.: 2,755 Region Association: None  |
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 !
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| Mark Henry |
Mar 24 2021, 06:18 AM
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#16
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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 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. |
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| horizontally-opposed |
Mar 24 2021, 06:24 AM
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#17
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Advanced Member Group: Members Posts: 3,432 Joined: 12-May 04 From: San Francisco Member No.: 2,058 Region Association: None
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QUOTE(Mark Henry @ Mar 24 2021, 05:18 AM) 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. (IMG:style_emoticons/default/idea.gif) |
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| Steve |
Mar 24 2021, 08:27 AM
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#18
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914 Guru Group: Members Posts: 5,606 Joined: 14-June 03 From: Orange County, CA Member No.: 822 Region Association: Southern California
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QUOTE(Coondog @ Mar 23 2021, 05:25 PM) 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. 6k installed? I doubt it. |
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| ConeDodger |
Mar 24 2021, 09:36 AM
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#19
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Apex killer! Group: Members Posts: 23,606 Joined: 31-December 04 From: Tahoe Area Member No.: 3,380 Region Association: Northern California
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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.
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| Mark Henry |
Mar 24 2021, 09:42 AM
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#20
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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 |
QUOTE(Steve @ Mar 24 2021, 10:27 AM) QUOTE(Coondog @ Mar 23 2021, 05:25 PM) 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. 6k installed? I doubt it. 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. (IMG:style_emoticons/default/biggrin.gif) 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 |
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