YB intake port length

**Simjim** · 20-09-2023, 11:11

Anyone know the distance to the inlet valve from the inlet face on the head?

Looking at total runner length for bodies.

**katana** · 20-09-2023, 16:35

Is it really that important? And what can you adjust to get a 'theoretical ideal' figure? Most builders fret about long or short ram pipes LOL!

**Simjim** · 20-09-2023, 20:09

I'm currently offshore with not much to do at night.

So of course, I can just wait till I get home, but I don't get much time off.

My millington runs 50dco carbs. And I want to change to bodies. Millington won't answer my emails, or Smith and Jones, I suppose serious people trying to buy will phone, but that's not really an option where I am in the world.

I notice the latest designs have injectors placed furthest away with very short trumpets.

The 52-54 xe bodies millington sell uses a 170mm manifold and it's 225mm overall, so would be interested to know what figure they came up with when added to the port length. I know the SF body is 66mm so I can get a good idea.

I spoke to jenvey and they just quoted me a set from there standard parts catalogue despite me telling him they were for a millington and virtually every millington engine I look at runs spacers. I don't understand why jenvey didn't mention them.

So I'm just looking at a starting point, whilst im offshore with a bit of time on my hands and I can play about on CAD before getting home and finding out a bit more.

Maybe just a bit of fun looking into these things.

https://www.millingtonengines.co.uk/...e-kit-complete

https://www.millingtonengines.co.uk/...hrottle-bodies

Look at the latest SBD design, same thing.

https://sbdmotorsport.co.uk/product/...ttle-body-kit/

I don't want to fit bodies and make less power than my carbs. They atomise right near the ram pipe in the middle of the air stream, which seems a lot better than the jenvey equivalent.

I'm assuming jenvey can't sell me their customer designs and I have asked if millington will sell me some, but no answer at all. It's a bit frustrating, also tried Smith and Jones, nothing.

So if anyone knows the port length. It's better than not knowing. And im sure millington placed the injector there for a good reason. Can't be the butterfly, their series 2 uses barrels built into the head.

**Simjim** · 20-09-2023, 20:15

C20XE port length would be interesting to know.

The YB manifold is 73mm, a 50mm spacer takes it up to 223mm. That sounds better than none at all. Max size on the mani is 50mm. A 50-52mm spacer plus an SF body 52-54 will give a fairly consistent taper I think.

**stevieturbo** · 20-09-2023, 21:15

A single peak power number is not as important as a wide range of power/torque

What is your engine and what are your goals ? what application ?

Short runner will tend to make more power higher up, longer the opposite. Although given space limitations in most cars, I doubt many would ever really be able to use "long" runners anyway.

Fit what you can that has room for good air filter setup

**Forest_rallying** · 21-09-2023, 20:24

Originally Posted by Simjim

I'm currently offshore with not much to do at night.

So of course, I can just wait till I get home, but I don't get much time off.

My millington runs 50dco carbs. And I want to change to bodies. Millington won't answer my emails, or Smith and Jones, I suppose serious people trying to buy will phone, but that's not really an option where I am in the world.

I notice the latest designs have injectors placed furthest away with very short trumpets.

The 52-54 xe bodies millington sell uses a 170mm manifold and it's 225mm overall, so would be interested to know what figure they came up with when added to the port length. I know the SF body is 66mm so I can get a good idea.

I spoke to jenvey and they just quoted me a set from there standard parts catalogue despite me telling him they were for a millington and virtually every millington engine I look at runs spacers. I don't understand why jenvey didn't mention them.

So I'm just looking at a starting point, whilst im offshore with a bit of time on my hands and I can play about on CAD before getting home and finding out a bit more.

Maybe just a bit of fun looking into these things.

https://www.millingtonengines.co.uk/...e-kit-complete

https://www.millingtonengines.co.uk/...hrottle-bodies

Look at the latest SBD design, same thing.

https://sbdmotorsport.co.uk/product/...ttle-body-kit/

I don't want to fit bodies and make less power than my carbs. They atomise right near the ram pipe in the middle of the air stream, which seems a lot better than the jenvey equivalent.

I'm assuming jenvey can't sell me their customer designs and I have asked if millington will sell me some, but no answer at all. It's a bit frustrating, also tried Smith and Jones, nothing.

So if anyone knows the port length. It's better than not knowing. And im sure millington placed the injector there for a good reason. Can't be the butterfly, their series 2 uses barrels built into the head.

Have you tried to phone Roy Millington and ask him those questions, he’s a very approachable Man. I know he’s on Face Book if that’s any help.

**Simjim** · 22-09-2023, 04:02

Yes, I called when I was in the UK, is it Margaret or something? Said she would ask him. I also sent him two emails. Nothing.

Bought the engine from their website, it's still on their. He sent me an email when I bought it, so I've got the email correct.

To be honest, 54mm is as big as they go. The manifold can only be bored to 50mm so if I use a 50mm spacer and taper it, I'll have a decent starting length with a very gradual taper, velocity stacks will be down to available space.