Airflow/Horsepower limit for stock 2.0L intake system? |
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Airflow/Horsepower limit for stock 2.0L intake system? |
greggearhead |
Dec 12 2019, 11:32 AM
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#1
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Newbie Group: Members Posts: 35 Joined: 19-March 11 From: Colorado Springs, CO Member No.: 12,836 Region Association: None |
OK, I did search, and couldn't really find anything.
My basic question - when does the 914 2.0L intake become a restriction to power? I have a built VW 412 - 2056 cc Type 4 * 9550 RAT cam * LE-180 heads (914 2L combustion chamber, 42mm intake, 36mm exhaust) * Mallory Unilite vacuum advance distributor, Mallory Promaster coil, Mallory Hyfire CDI * Stock 412 heater boxes & Thunderbird exhaust * 2L Bus plenum and throttle body * 2L 914 runners * Ford "Design II" F1TE-D9A (Bosch 0280150947) 24# injectors (modified) * SDS programmable EFI * Oil bath air cleaner housing modified to use large circular filter element I have a pair of IDF manifolds, and some VFR throttle bodies. Roughly equivalent to Weber 40IDFs (maybe a bit better in terms of flow). Engine made 115hp at the wheels. I'm just wondering if the (improved) stock intake is a cork or not? (IMG:http://www.914world.com/bbs2/uploads_offsite/i61.photobucket.com-12836-1576171976.1.jpg) |
Mark Henry |
Dec 12 2019, 03:47 PM
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#2
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
For the OP it's a tradeoff, the big limits for him is he doesn't have space for a much bigger plenum. Personally just smile and drive because that is what it is.
Everything is a tradeoff in building an engine... and intake and exhaust are part of that package. I run 46mm gxsr bike TB's so a good machinist could cut the top off of existing T4 alunimum weber manifold and weld up a shorty base to adapt a bike TB or the CB performance TBs.It still won't be perfect, but it would work. Nothing will beat ITB's for WOT, but plenum based systems pull better vacuum and are less likely to need to run in SDS's "TPS only" or MS "alphaN", both of which are basically the same thing. AlphaN (TPS only) is great for the track and "shits and giggles" street roding, but gets old fast in stop and go traffic. With ITB's it has incredible pick up and engine braking, but you have hold the peddle real steady in slower traffic. Higher RPM's it has less of this effect but who wants to do stop and go at 4K+rpms. A plenum system with a usable vacuum signal for the MAP sensor would dampen this effect. |
Mark Henry |
Dec 13 2019, 11:41 AM
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#3
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
Are you reading my posts?
I run 46mm gxsr bike TB's so a good machinist could cut the top off of existing T4 alunimum weber manifold and weld up a shorty base to adapt a bike TB or the CB performance TBs. It still won't be perfect, but it would work. edit I'm talking about ITB's here, I think most here would know that. No one makes a 411/412 shorty intake manifold, so either you do a hack job to your engine hatch and stick ITB's out of the holes or you do the above. |
greggearhead |
Dec 13 2019, 12:01 PM
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#4
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Newbie Group: Members Posts: 35 Joined: 19-March 11 From: Colorado Springs, CO Member No.: 12,836 Region Association: None |
Are you reading my posts? I run 46mm gxsr bike TB's so a good machinist could cut the top off of existing T4 alunimum weber manifold and weld up a shorty base to adapt a bike TB or the CB performance TBs. It still won't be perfect, but it would work. edit I'm talking about ITB's here, I think most here would know that. No one makes a 411/412 shorty intake manifold, so either you do a hack job to your engine hatch and stick ITB's out of the holes or you do the above. Again - did I ask anywhere about fitting ITBs? No. Did I ask about what ITBs to use? No. Did you see my post where I talked about having used ITBs (in fuel injection and carburetor form) many times over the years? Apparently not. Moderators - I'm fine with locking or deleting this thread. There is no good info coming out of it and no good discussion about the topic. |
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