Top mount manifold?
09-23-2010, 01:21 PM
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Top mount manifold?
I'm sorry if this is covered somewhere, but I couldnt find it, the question I wanted to ask is - what is the point of top mount manifold? is there some performance gain vs standart type turbo manifold like "ram horn", or is it only turbocharger placement?
I'm just working my skill up with TIG and I want to try to weld my own manifold for my CA18DET S13, and as I was Honda guy some time back, didnt know any Nissan forum to post this question up, so
I'm here :D
Thanks for answers
I'm just working my skill up with TIG and I want to try to weld my own manifold for my CA18DET S13, and as I was Honda guy some time back, didnt know any Nissan forum to post this question up, so
I'm here :DThanks for answers
09-23-2010, 02:54 PM
#2
Man U FTW
Re: Top mount manifold?
A topmount manifold, with fewer curves than shorter-runner manifolds, has a more efficient, high-rpm flow on an efficient, high-revving engine like a B series. The topmount style allows for a few benefits as well. Since the runners sit as they do (in the down and back up style with plenty of room for manueverability), it is easier to make divided T3 and T4 setups. Furthermore, it is easier to fit larger turbos into the engine bay. This isn't necessarily true with all engine/chassis setups, but for most Hondas (D, B, and H series), it is. The placement also allows for easy access to 3" or even 4" downpipes.
One more thing to realise is that your engine may not be overly efficient at higher RPMs which would completely negate the benefits of a long runner topmount. This is why topmount use is mainly restricted to Hondas. That's not to say that other engine combinations wouldnt work well with a topmount, but many setups are able to use shorter runner manifolds with the same performance as what would have been seen in a topmount.
The downside of the topmount is that the longer runner length increases lag time. As with any style, longer runners will increase lag time as will excessive curves. If this is your first time building a manifold, you may want to check out the Welding/Fabrication forum for more insight.
One more thing to realise is that your engine may not be overly efficient at higher RPMs which would completely negate the benefits of a long runner topmount. This is why topmount use is mainly restricted to Hondas. That's not to say that other engine combinations wouldnt work well with a topmount, but many setups are able to use shorter runner manifolds with the same performance as what would have been seen in a topmount.
The downside of the topmount is that the longer runner length increases lag time. As with any style, longer runners will increase lag time as will excessive curves. If this is your first time building a manifold, you may want to check out the Welding/Fabrication forum for more insight.
09-23-2010, 10:41 PM
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Re: Top mount manifold?
A topmount manifold, with fewer curves than shorter-runner manifolds, has a more efficient, high-rpm flow on an efficient, high-revving engine like a B series. The topmount style allows for a few benefits as well. Since the runners sit as they do (in the down and back up style with plenty of room for manueverability), it is easier to make divided T3 and T4 setups. Furthermore, it is easier to fit larger turbos into the engine bay. This isn't necessarily true with all engine/chassis setups, but for most Hondas (D, B, and H series), it is. The placement also allows for easy access to 3" or even 4" downpipes.
One more thing to realise is that your engine may not be overly efficient at higher RPMs which would completely negate the benefits of a long runner topmount. This is why topmount use is mainly restricted to Hondas. That's not to say that other engine combinations wouldnt work well with a topmount, but many setups are able to use shorter runner manifolds with the same performance as what would have been seen in a topmount.
The downside of the topmount is that the longer runner length increases lag time. As with any style, longer runners will increase lag time as will excessive curves. If this is your first time building a manifold, you may want to check out the Welding/Fabrication forum for more insight.
One more thing to realise is that your engine may not be overly efficient at higher RPMs which would completely negate the benefits of a long runner topmount. This is why topmount use is mainly restricted to Hondas. That's not to say that other engine combinations wouldnt work well with a topmount, but many setups are able to use shorter runner manifolds with the same performance as what would have been seen in a topmount.
The downside of the topmount is that the longer runner length increases lag time. As with any style, longer runners will increase lag time as will excessive curves. If this is your first time building a manifold, you may want to check out the Welding/Fabrication forum for more insight.
I'v checked already that forum Hmm, but if I'm intrested in top mount location, and I'm able to make top mount with not so long runners, but bends like standart ram horn? can I do that?
P.S. really greatful for this response
you made it really clear
09-24-2010, 09:56 AM
#4
Man U FTW
Re: Top mount manifold?
If you're basically making an inverted ramhorn solely for clearance issues, that would have results similar to a ramhorn obviously. Manifolds like that are commonly used on S2000 turbo setups actually...There is no room for a bottom mount ramhorn so why not invert..? Be sure to upload pictures when you're done 
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