TeamCapri
Tech, Repairs, Upgrades => Capri XR-2 89-94 => Topic started by: Gaz on February 23, 2017, 08:21:22 PM
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Has anyone used one?
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Not that I know of on the Capri.
From what I remember - their purpose is to help keep the throttlebody a bit cooler
Our entire intake tract cooks on top of the engine :/
Additionally, there is a coolant circuit that heats the throttle body to prevent ice buildup on the throttle blade. I usually bypass this
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Additionally, there is a coolant circuit that heats the throttle body to prevent ice buildup on the throttle blade. I usually bypass this
Interesting idea. I think I may try that.
I was wondering about the spacers that supposedly create a turbulent flow in the intake. Do you think that would actually make any difference?
Jack Byrd
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I seem to make a difference on turbo Subaru is, but I think most of that is just for the way that their engines are designed. Where the intake sits, anyway.
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The flow of these manifolds isn't really ideal. When I was experimenting with a 5th injector system way back in the day, it seemed to favor the two center cylinders.
A spacer might add a marginal amount of plenum volume, which may be beneficial, the plenums are not well matched to our engine displacement based on some intake manifold research I've done.
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The flow of these manifolds isn't really ideal. When I was experimenting with a 5th injector system way back in the day, it seemed to favor the two center cylinders.
A spacer might add a marginal amount of plenum volume, which may be beneficial, the plenums are not well matched to our engine displacement based on some intake manifold research I've done.
What would you use for an intake? Custom log?
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I had considered an Extrudehone to improve the flow, but you're saying the manifold isn't properly designed to begin with? Is the plenum not large enough and how much larger does it need to be? Is there not a manifold that will work? Am I full of questions or what?
Jack Byrd
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If I had to design one, it would have to eliminate the hump it has just before the inlet ports, for starters. Then, I would create a larger volume throttle chamber, while using a larger throttle body. Maybe a Honda with built in map sensor.
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Does the XR2 use the same manifold as a N/A?
Jack Byrd
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Does the XR2 use the same manifold as a N/A?
Jack Byrd
Nope the intake mani on the xr2 has a much larger plenum, and throttlebody. The XR2 manifold I believe also sits slighty higher due to longer runners but I could be wrong its been awhile since ive been face to face with one.
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B6T and B6D use the exact same intake manifold. The easiest fix is the JDM/EDM intake manifold with the way larger plenum.
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Does the XR2 use the same manifold as a N/A?
Jack Byrd
Nope the intake mani on the xr2 has a much larger plenum, and throttlebody. The XR2 manifold I believe also sits slighty higher due to longer runners but I could be wrong its been awhile since ive been face to face with one.
Incorrect. They used identical manifolds, the only difference being a sticker :)
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If I had to design one, it would have to eliminate the hump it has just before the inlet ports, for starters. Then, I would create a larger volume throttle chamber, while using a larger throttle body. Maybe a Honda with built in map sensor.
I'd maybe use a Miata or JDM base with a custom plenum.
I would switch to a larger TB - but not too big, the larger the TB the less linear response you get. It becomes more of an on/off switch.
Stock TB size is 50mm. Maybe an aftermarket Honduh unit (cheap) that's 60 or so mm in dia
The OE throttle body on my 91 Isuzu Impulse (also a 1.6L turbo dohc) is 62mm if I remember right. It made ~160hp, factory, with a slightly larger turbo than the Capri (i believe it's equivalent to the VJ11)
I believe I've read optimal plenum size is 1.5x engine displacement. But I would recommend further research on this before diving down that rabbit hole. There are a LOT of dynamics at play in intake manifold design.
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To those who have TB spacer, did you notice any increase in torque?
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Didn't I see on here or FB where a member listed different sizes of throttle bodies for Mazda based vehicles from 55mm to 60 mm?
Jack Byrd