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Itb tech question


Steve (sdh2903)

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Steve (sdh2903)

Have a couple of questions for you knowledgeable folk. 

 

Am planning on running itbs on the v6. Does it matter if the itbs contra-rotate or not? 

 

Keeping them stock would mean they both rotate in the same direction but I think I can adapt them to contra rotate aswell. 

 

Jenvey seem to contra rotate

 

https://www.facebook.com/rocketeerltd/videos/1575338732485245/

 

Also that leads on to my second question.

 

In the vid above. The throttle plates 'tip in' on the opposite side to the injector. Again is this the usual orientation and does it matter? My injectors are on the inner side of the bodies vs the outer side of the jenvey

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Ian Kinder (Bagpuss) - Joint Peak District AO
13 minutes ago, Steve (sdh2903) said:

Have a couple of questions for you knowledgeable folk. 

 

Am planning on running itbs on the v6. Does it matter if the itbs contra-rotate or not? 

 

Keeping them stock would mean they both rotate in the same direction but I think I can adapt them to contra rotate aswell. 

 

Jenvey seem to contra rotate

 

https://www.facebook.com/rocketeerltd/videos/1575338732485245/

 

Also that leads on to my second question.

 

In the vid above. The throttle plates 'tip in' on the opposite side to the injector. Again is this the usual orientation and does it matter? My injectors are on the inner side of the bodies vs the outer side of the jenvey

 

There could be some impact, however I guess they contra rotate for packaging ease. As with all things in engineers, compromises have to be made and this could be one of them! Have you looked at other V6, V8, V10, V12 throttle bodies? 

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Consider the whole inlet arrangement from induction trumpets or plenum through throttle body, throttle flaps and to inlet valves

 

Now consider if the throttle plates help or hinder that flow of air or if opening one way or another helps direct the air down the intake. Try not to ask the air to backup or change direction more than necessary. 

 

Alignment of throttle flap can make a percentage  improvement .

 

Sketch it out as a section and see how flap opening may impact or direct flow especially at part throttle.

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Steve (sdh2903)
2 hours ago, Ian Kinder (Bagpuss) - Joint Peak District AO said:

 

There could be some impact, however I guess they contra rotate for packaging ease. As with all things in engineers, compromises have to be made and this could be one of them! Have you looked at other V6, V8, V10, V12 throttle bodies? 

 

I've only really found the bmw e9x m3 v8 on itbs from a production car perspective. 

 

These don't contra rotate and the injectors are all on the outboard side. So one bank tips in on the injector side and one doesn't. Which would suggest it's not critical? Although that engine will have a far more sophisticated control system and individual throttle actuators on each bank. 

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Ian Kinder (Bagpuss) - Joint Peak District AO
2 minutes ago, Steve (sdh2903) said:

 

I've only really found the bmw e9x m3 v8 on itbs from a production car perspective. 

 

These don't contra rotate and the injectors are all on the outboard side. So one bank tips in on the injector side and one doesn't. Which would suggest it's not critical? Although that engine will have a far more sophisticated control system and individual throttle actuators on each bank. 

I was thinking more exotic- such as these-

 

https://www.ebay.co.uk/i/402277781692?chn=ps&norover=1&mkevt=1&mkrid=710-153316-527457-8&mkcid=2&itemid=402277781692&targetid=4585307089523139&device=c&mktype=&googleloc=&poi=&campaignid=398226941&mkgroupid=1307319560325275&rlsatarget=pla-4585307089523139&abcId=2145997&merchantid=87779&msclkid=5786b083ba8f1f40db2def39394f1e0c

 

Though I assume your injectors are already in the head? Is blanking them off and having them in the bodies an option

 

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Steve (sdh2903)
2 hours ago, Arm said:

Consider the whole inlet arrangement from induction trumpets or plenum through throttle body, throttle flaps and to inlet valves

 

Now consider if the throttle plates help or hinder that flow of air or if opening one way or another helps direct the air down the intake. Try not to ask the air to backup or change direction more than necessary. 

 

Alignment of throttle flap can make a percentage  improvement .

 

Sketch it out as a section and see how flap opening may impact or direct flow especially at part throttle.

 

Thats a great idea thanks @Arm the only problem is I can make arguments for both directions!

 

This is the inlet looking straight down

 

20201122_151211.thumb.jpg.b735fede0ab7004ae92d9f88c0f18d02.jpg

 

So then sketched out (badly) with the throttle tipping in opposite to the injector I would say would give a better mix accross the injector however the air would then have to make a sharper turn to the valve? 

 

20201122_151918.thumb.jpg.2b00cbf11f188fdb178e6cb87ebd719d.jpg

 

But then the other way would have a smoother curve. 

 

20201122_151904.thumb.jpg.0054dec08ead5c52c539b9f15e39a001.jpg

 

I know this is an incredibly simplistic way of illustrating and that air will be passing both sides of the butterfly. But i assume there will be a slight bias to the tipped in side of the butterfly? 

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Steve (sdh2903)
12 minutes ago, Ian Kinder (Bagpuss) - Joint Peak District AO said:

 

Though I assume your injectors are already in the head? Is blanking them off and having them in the bodies an option

 

 

Injectors are in the lower manifold as seen in the pic above. I'm leaving them there as I'm doing this little project on the cheap incase it ruins the driveability or has a drastic loss of power and I can easily refit my existing inlet manifold. 

 

Key factor is space aswell. The bodies I'm using are effectively just throttle plates on a common spindle and are very compact. 

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Yes it may be you consider the throttle flap a turning vane. Some engine inlet arrangements it makes no difference and some it helps. But as you are doing its well worth thinking about.

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Gary Taylor - Scotland AO

Imo the first picture will provide smoother airflow and the fuel will be injected into the  airflow keeping the atomisation as intended.

the second picture you are bouncing the airflow off the sides of the inlet tract, the downward airflow will suppress the injector spray pattern thus resulting in a slower intake airflow and poor fuel atomisation.

just my thoughts....

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Steve (sdh2903)

How did you orientate yours on the v6 gary? 

 

Any pics of your linkage setup? 

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Gary Taylor - Scotland AO

Here’s a top picture, sorry no pic of the linkage but it was made with 2 rose joints 1x lh and 1 x rh and some Rod that was threaded to match ( I believe Weber’s have various linkages like that as well) this way you can balance both banks of itb’s for equal throttle opening

I had to make up an actuating arm as obviously one linkage drove from the bottom of the spindle and the other from the top

will see if I can get any extra pics of it

322D37E3-CD57-4566-9152-95427059B043.jpeg

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Depending on the actual dimensions id think for helping the air around the corner the first version of your drawing as in that instance throttle is acting as a turning vane. 

It may be an extreme (poor) interpretation for the 2nd option which sends air towards the injector but is making it go one way and then the other at the lower radius. Unfortunately I don't have access to cfd anymore.

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CosKev

If you were forcing charged air in I think this would need more thinking about?🤷🏾‍♂️

But as the engine is only sucking it in I can't see it's such a big issue?🤔

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Steve (sdh2903)

I got a response from jenvey today as I sent In an another email fishing for more details on their kit. They said they didn't have any gain results but would estimate 20-30bhp. But then said the 90mm trumpets gave the best gains? 

 

They also said they have their throttle butterflies tipping in on the opposite side to the injector to minimise injector spray pattern disruption. So you were right @Gary Taylor - Scotland AO.

 

I will therefore copy the people who know a thing or 2 about throttle bodies. 

 

Thanks all

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