Originally posted by Crankshaft
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H23 Intake Manifold on F22a
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Your engine is a giant air pump. It can only flow as well as the greatest bottleneck allows. Unless you get a wild camshaft and do some head work, there is a definite limit to the benefits of increasing airflow into and out of the engine. An aftermarket throttle body won't hurt anything, but you may not see gains enough to justify the cost.
As for using a gutted stock plate, it essentially serves the same function as a spacer. You'd have to plug up the holes and smooth things out, but it'd work the same. The only difference perhaps is that the spacers are usually better at insulating the plenum from heat soak. Whether or not that's an actual problem on anything comparable to your current setup is the question. My guess is that it probably wouldn't really matter one way or the other.
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Originally posted by deevergote View PostYour engine is a giant air pump. It can only flow as well as the greatest bottleneck allows. Unless you get a wild camshaft and do some head work, there is a definite limit to the benefits of increasing airflow into and out of the engine. An aftermarket throttle body won't hurt anything, but you may not see gains enough to justify the cost.
As for using a gutted stock plate, it essentially serves the same function as a spacer. You'd have to plug up the holes and smooth things out, but it'd work the same. The only difference perhaps is that the spacers are usually better at insulating the plenum from heat soak. Whether or not that's an actual problem on anything comparable to your current setup is the question. My guess is that it probably wouldn't really matter one way or the other.
That's what I was thinking with the spacer, plus the plastic is lighter!
I'm seeing a couple different designs of spacers, ones that have holds matching the runners, and ones that are just completely open.
The open spacer would allow for more air volume in the plenum, but I don't really know which one is best. I do wanna go turbo in the future if that would change anything.I'm faster then a prius
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The open spacer acts like a plenum extension, whereas the spacer with the holes acts as a runner extension. Generally, longer runners produce greater low-end power, and shorter runners produce greater high end power. A larger plenum helps mainly in high-end power.
Since you're currently running a fairly low horsepower engine with a powerband close to the stock range, I'd say stick with the spacer with the holes (or a properly prepped gutted stock plate.)
Another intake option that may produce decent benefits would be a velocity stack. I've heard 3-5hp gains are standard. I have no personal experience with them, nor have I done enough research to say I can truly believe those gains, but many big-dollar builds do seem to use them. Based on that, I assume they do something at least!
There are a ton on ebay for cheap, but most would replace your air filter (a bad idea, running without a filter.)
I did find this Blox one with a filter. Not sure on the quality of the filter, but it's made to fit over the velocity stack, so that's good.
I'm actually considering one for the Miata now.
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Originally posted by deevergote View PostThe open spacer acts like a plenum extension, whereas the spacer with the holes acts as a runner extension. Generally, longer runners produce greater low-end power, and shorter runners produce greater high end power. A larger plenum helps mainly in high-end power.
Since you're currently running a fairly low horsepower engine with a powerband close to the stock range, I'd say stick with the spacer with the holes (or a properly prepped gutted stock plate.)
Another intake option that may produce decent benefits would be a velocity stack. I've heard 3-5hp gains are standard. I have no personal experience with them, nor have I done enough research to say I can truly believe those gains, but many big-dollar builds do seem to use them. Based on that, I assume they do something at least!
There are a ton on ebay for cheap, but most would replace your air filter (a bad idea, running without a filter.)
I did find this Blox one with a filter. Not sure on the quality of the filter, but it's made to fit over the velocity stack, so that's good.
I'm actually considering one for the Miata now.
That velocity stack looks almost interesting.I'm faster then a prius
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I don't know off hand. Take one of your existing bolts out, measure the length. Add the thickness of the spacer to it.
Edit: Did find this thread: http://www.cb7tuner.com/vbb/showthread.php?t=103171Last edited by Fleetw00d; 05-14-2017, 04:37 PM.90 LX 4dr 5 spd 396,014 (sold 1/1/2022) - MRT: http://www.cb7tuner.com/vbb/showthread.php?t=201450
08 Element LX FWD AT 229,000 - MRT: fleetw00d : 2008 Honda Element LX - CB7Tuner Forums
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Pretty sure there was a good DIY about this, but I seem to remember the pictures disappearing some time ago. Probably one of those that we had talked about redoing, but never got around to.
A couple notes:
1) The function of all of the black vacuum boxes is the same. It is essentially a reservoir of vacuum so that the butterflies on the intake manifold only open when they are supposed to. At a specified RPM, the computer tells a valve to open on the tank, which releases the vacuum and causes the butterflies to open. (Vacuum, such as at idle, is what keeps them closed) At low vacuum (large throttle openings) they will open without that tank, regardless of RPM. This will kill low end torque because the air will no longer flow through the longer runners and the volume will increase substantially. Short runners and more flow aid top end power.
2) The IAB extensions or "plates" work OK, but aren't really that noticable IMO. They tend to choke the top end slightly.
3) With the H series plenum and H series throttle body, I don't think there is going to be a huge benefit to putting a larger throttle body on. That intake plenum and throttle body are designed to support a similar sized engine with 20-65 more HP. Just switching to the plenum and stock throttle body makes a pretty noticeable difference.
4) I would agree with the comment above that the cam seems to make the biggest difference from the A6. It was a pretty noticeable improvement in power output and really works well with the H series runners and plenum. Also my opinion, but considering you can probably find a good condition one for next to nothing, it is worth it. It also gives you an excuse to pull the rocker assembly off and change a bunch of seals that probably need changed anyway.
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Originally posted by owequitit View PostPretty sure there was a good DIY about this, but I seem to remember the pictures disappearing some time ago. Probably one of those that we had talked about redoing, but never got around to.
A couple notes:
1) The function of all of the black vacuum boxes is the same. It is essentially a reservoir of vacuum so that the butterflies on the intake manifold only open when they are supposed to. At a specified RPM, the computer tells a valve to open on the tank, which releases the vacuum and causes the butterflies to open. (Vacuum, such as at idle, is what keeps them closed) At low vacuum (large throttle openings) they will open without that tank, regardless of RPM. This will kill low end torque because the air will no longer flow through the longer runners and the volume will increase substantially. Short runners and more flow aid top end power.
2) The IAB extensions or "plates" work OK, but aren't really that noticable IMO. They tend to choke the top end slightly.
3) With the H series plenum and H series throttle body, I don't think there is going to be a huge benefit to putting a larger throttle body on. That intake plenum and throttle body are designed to support a similar sized engine with 20-65 more HP. Just switching to the plenum and stock throttle body makes a pretty noticeable difference.
4) I would agree with the comment above that the cam seems to make the biggest difference from the A6. It was a pretty noticeable improvement in power output and really works well with the H series runners and plenum. Also my opinion, but considering you can probably find a good condition one for next to nothing, it is worth it. It also gives you an excuse to pull the rocker assembly off and change a bunch of seals that probably need changed anyway.
Do you think an aftermarket throttle body would benefit me if I was doing a turbo?
I saw an A6 cam at a yard yesterday, but it had some slight scoring on it, so I ditched on that one.. As soon as I find a good one I'd like to do a timing belt job at the same time, replace some seals while it's all apart.
All that info is super helpful btw, thanks for sharing that!I'm faster then a prius
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Originally posted by GTRON View PostThat really helps me understand how that vacuum box works, so I how I get the ECU to tell that valve to open (to open the butterflies at the right rpm)?
Do you think an aftermarket throttle body would benefit me if I was doing a turbo?
I saw an A6 cam at a yard yesterday, but it had some slight scoring on it, so I ditched on that one.. As soon as I find a good one I'd like to do a timing belt job at the same time, replace some seals while it's all apart.
All that info is super helpful btw, thanks for sharing that!
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Originally posted by dj_ender View PostYes, it's worth it, even with the PT6.
Yes you'll need another IAB gasket and 3 A/C compressor bolts from a CB7, and 2 A/C compressor bolts from a early 90's (pre 92) Prelude.......father in law has it back again. Time to shine
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