NA-T Manifolds

[Noz]

Just wondering what peoples general opinions are on log style manifolds, and particually this one. I know DaveH runs a log style and sells them, am looking into different options. Anyone find a viable requirement for dual wastegate?

 

http://www.exoticspeed.ca/product_info.php?currency=CAD&cPath=73_338_476&products_id=3938&osCsid=383eabd32c2ed16dc7f9bededb7d9645

 

http://www.exoticspeed.ca/product_thumb.php?img=images/IMG_3803-S.JPG&w=593&h=480

 

Found some information regarding this manifold on Supra Forums: http://www.supraforums.com/forum/showthread.php?456494-SPA-Cast-Turbo-Manifold

Edited April 28, 2012 by Noz (see edit history)

[V8KILR]

Log manifolds are good for getting quick spool-up of the turbo, but will limit max power a bit compared to a nice long runner manifold. Great on a street car but really depends on your hp goals and whether you want to drag race or not.

[Noz]

In what way do they limit the max power mate?

[Colin-mkiv]

Its down to flow rates and pulse rates mate

[Noz]

Ah I see. Never really looked into it. I work with pressure, but its typically static when I work with it, so it's trying to understand the flow dynamics. At a first glance, it would be easy to assume with the same volume capacity as a tubular manifold, the smaller distance to the turbo housing is to blame for the quick spool and didn't expect any other issues, would be interesting to look into the flow and pulse rates, I spose this is to do with the fact all chambers are firing at a different phase to each other.

[Nic]

The wastegate opening on that cast manifold is very narrow and probably would need machining out bigger.

 

See Dan's project thread here, he's using a cast manifold on his 2JZ-GTE http://www.mkivsupra.net/vbb/showthread.php?194439-Dan-s-Supra-Project&highlight=cast

 

I think Wez is also using a cast manifold on his, see here http://www.mkivsupra.net/vbb/showthread.php?179831-Wez-Track-Supra&highlight=cast

[Colin-mkiv]

Ah I see. Never really looked into it. I work with pressure, but its typically static when I work with it, so it's trying to understand the flow dynamics. At a first glance, it would be easy to assume with the same volume capacity as a tubular manifold, the smaller distance to the turbo housing is to blame for the quick spool and didn't expect any other issues, would be interesting to look into the flow and pulse rates, I spose this is to do with the fact all chambers are firing at a different phase to each other.

 

I'm no officionado, but as I understand it..... longer, equal length manifold pipes allow more accurate tuning for higher BHP applications, this is in order to get the timing between pulses spot on. It's less important in turbo cars than in NA cars tho as in a non-turbo engine each pulse will help 'drag' the pulse from the next cylinder and also push the pulse from the previous one. Turbos tend to just cut everything up no matter what so its only when you get up to wanting more power that every little bit makes a difference. The cast one should be fine unless you want to go huge I reckon.