Post your ITB Setup

[Hcarraro]

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[gearheadgreg]

Originally Posted by Jim2

From several years ago. Home built 49mm throttles on a cammed 3.6.

That's awesome. Any more pics and info on the TBs or the engine build?

[betterair]

97 varioram conversion>3.6 L with RS cams,Ceramic = length Headers,MK 2/2, and Koenengsberg (KMS) ECU.
(Pic is w dansk2/2 )
Build is by Specialty Cars -Nick Burkit /Allentown ,Pa.

[Tremelune]

How does the ram vario without that crazy stock intake?

[1968SWTs]

72 911T TWM Tec3r Cam Position Sensor

[betterair]

Tremalune , the vario is no longer, hence ,3.6 vario conversion.

1986SWT , Nice !!
Questions:
What Injector size/vol?
What was the motivation to go with Tec3r Cam Position Sensors?
How long have you been running the Tec3r?
Are the air filters std PMO bases w K&N's or modified filter bases?

Are the internals stock,or is it massaged a bit ?

[gwag]

Do the Rennsport and Rothsport plenum setups truly have an operational valve between plenums?

I understand the purpose and existence of these valves, just wondering if they are present in these specific setups?

If there have valve just hard to see from the pics I've seen.

Also if they have a valve, what triggers it, the ECU?

[1968SWTs]

Originally Posted by betterair

Tremalune , the vario is no longer, hence ,3.6 vario conversion.

1986SWT , Nice !!
Questions:
What Injector size/vol?
What was the motivation to go with Tec3r Cam Position Sensors?
How long have you been running the Tec3r?
Are the air filters std PMO bases w K&N's or modified filter bases?

Are the internals stock,or is it massaged a bit ?

Had it for a while but only over the last month have I started to tune. It was an inherited frankenstein project with megasquirt and butt connectors everywhere and the engine was a complete mess with valve timing way off and things torqued wrong everywhere and missing gaskets so I got frustrated and went shrink wrapped in order to get Clewett's help if needed. I went with the cam sensor to get rid of the hideous crank wheel but also to go sequential. The air filters are Weber (also PMO) based that needed to be drilled slightly to fit the TWMs. Injectors are 944, so I need to replace those if I ever find the money. I posted the data and flight data (and video) on the technical thread so you can take a look at the particulars. Internals are stock. But don't ever buy an engine that has been taken down!

[sp_cs]

Originally Posted by gwag

Do the Rennsport and Rothsport plenum setups truly have an operational valve between plenums?



I understand the purpose and existence of these valves, just wondering if they are present in these specific setups?



If there have valve just hard to see from the pics I've seen.



Also if they have a valve, what triggers it, the ECU?

Yes they do. I received a quote from Rothsport which detailed the resonance tube, solenoids etc

[sp_cs]

Originally Posted by sp_cs

Has anyone used shaftless ITBs - my engine builder had the below made up and is recommending them due to being able to run narrower bores compared to say Jenveys to maximise midrange - with William Knights input I'm thinking of running them with a 993 intake and t-piece filter as shown by Steve Weiner above.

Now on the market via Reno Rennsports in the US:
https://renorennsport.com/wp-content/uploads/2016/11/AT-Power-Porsche-Throttle-body.pdf

[Tremelune]

Shaftless, drive-by-wire throttle bodies?

[David Borden]

Originally Posted by Raceboy

Most ECU's suck at getting ITB's to run perfectly on the street. Because a) they have only speed density tuning strategy available (which is useless with ITB's), b) they have only Alpha-N mode available (also useless on anything but a race car).

Key to getting ITB engine running perfectly is to have at least MAP compensation table+MAT compensation table on top of Alpha-N or the best method is to have MAP/Alpha-N hybrid load.

Check out the AEM Infinity ECU. You can set it up to use throttle for load, MAP for fueling and Baro/altitude and it works REALLY WELL on the street.

A buddy of mine just finished his install and the car runs just as good with ITBs with throttle based load as it did using MAP only and a regular intake on a Ford Coyote.

My car is currently running throttle based load and MAP based fueling and it runs great on the street.

David

[sp_cs]

Originally Posted by Tremelune

Shaftless, drive-by-wire throttle bodies?

Just shaftless, not drive by wire, at least not the ITBs.

[al lkosmal]

Those are very cool and I admire the design ingenuity. However, I would be very interested in seeing some back-to-back, 3rd party, test results between ITBs with shafted butterflies (doesn't sound good or perhaps they're just the male of the species)) vs shaftless butterflies. Does this invention and the associated flow improvements translate into price/performance gains that will be meaningful and significant to the end user(s).

I'm always very interested in new design improvements...... and then gaining and understanding of how the improvement translates to improvements in the real world.

regards,
al

[Ferrino]

Those ITBs look great. I'm less interested in the shaftless design than the direct-to-head config - looks really sharp!

[gearheadgreg]

I haven't used or built any shaftless style throttle bodies, but I've been around them and talked with people that have built and used them - so for what that's worth: The slide throttle setup seems to be hard to make easily progressive at lighter openings, because the vacuum is pulling the slide against it's runner/guide etc. Barrel throttles don't seem to have that issue, but more of a seal/leak issue due to the machining involved.

These shaftless ones - I'd be interested to hear about as well. From old flowbench work, of course reducing or removing the shaft increases max flow, but if the throttle bodies flow more air than the engine can use at redline, it's no benefit...

[al lkosmal]

Yes....regardless of shafts or no shafts...i really like the design of these ITBs.

regards,
al

[billewizz]

Take a look at ATpower in the U.K. They have just started manufacture of these straight to head tbs I don't think they actually have them on there web site currently, I have one set of the first manufacturing run for my ss3.2 anodised black breathing through mfi air box, I'll update on quality once delivered.

[Lowrance10]

Hi,
Brian from Reno Rennsport. A customer of ours informed me that there were some posts on here regarding the Shaftless throttle design from AT that we adapted for 911 engines. Happy to answer any questions.

We originally developed these for our Spec 911 cars as competition is very high in the class and small gains are of high value. But now we have been using them on street cars as well because the performance was a bit more than expected.

In short we have seen improved port velocity leading to power gains starting as low as 3500 and of course top end power was much improved also.
Throttle response is also greatly improved as the butterfly can be placed closer to the head and still have clean air.

We are currently working with AT on a drive by wire single throttle which should be ready sometime this summer.

thanks.

[fanaudical]

I love seeing this stuff - it's always fun to see what others are playing with.

Regarding the setup shown in the picture of post #150 - Are the push-connect fittings and poly tubing used to gather a vacuum reference? (Most push-connect fittings are not rated for vacuum applications and tend to leak under light vacuum.)