Hey guys, I have a pretty simple question but I haven't really seen much discussion on this in other areas of the forum so I thought I'd ask here.

I know that "log" style manifolds have issues providing enough exhaust flow past ~400WHP, and also don't allow lowering the VTEC engagement point by much.

Mid/high level boost guys on this forum seem to have unanimously decided on the front-facing, "scroll" style manifolds, which flow much better than logs and allow for lower VTEC.

I'm curious where ram-horn style manifolds sit on this comparison. I know they perform better than logs, but I doubt they're as good as reputable scroll manifolds like Full-Blown, Full Race, AFI, etc.

I have a TrackForged ram horn manifold. I don't know if it's true, but after calling Forged a few months ago when I bought this manifold I was told by one of their guys that they only produced 3 of the ram horn manifolds before producing exclusively scroll manifolds for the S2000.


Edit: Here's the only picture of the ram horn that I have on hand.

 

The only Ram horn style is the Full-Race pro street (Trackforged limited production ramhorn but I don't count it since no longer/never made it to full production) and as for limits, there really isn't one. As long as the turbo fits, you can boost until your hearts content. The only downside to the pro street is that it generates a crap ton of heat but to this day seems to produce the best torque numbers of any s2000 manifold.

 

First of all there is no such thing as scroll type. And what you mean is twin scroll which uses a divided t3 or t4 flange with cylinders 1&4 and 2&3 match together with a divided /twin scroll turbine housing for better spool and response

Rame horn style manifolds can make just as much power as a front facing manifold. It will even spool better due to shorter exhaust runners. In terms of power production the full race ram horn style manifolds are limited to a gt35r style turbos because of space. You simply can't fit a bigger turbo between the frame and motor. So if your looking for more power than the 700whp a gtx3582r can make than you will need a bigger turbo with a ram horn style cannot support.

 

Thanks buddy, good to hear I'll look forward to running this thing then!

And yeah, I know that ram-horns also have a habit of trapping more heat than scrolls, due to how their tubes have an "overhead" type design. It's also a much bigger PITA to install ram horns; I have VERY little working room to install the turbo bolts, and I think some people end up having to shave away parts of their engine bay if they get a large turbo. My little S256 should probably be fine though

So if anyone is reading this in the future, definitely aim for a scroll if it's available!

 

Thanks for the info man. And yeah, I don't really know much abut the twin-scroll manifolds outside of really basic performance traits.

 

I acutally wanted the full race pro street manifold. The heat issue can be address with some proper "heating precautions" ...turbo blanket, heat wrap, that expensive shiny heat foil/shield thing. But i got a killer deal on a pfab top mount. Which is basically the same thing but reversed.

 

Please correct your vocabulary. There is No such thing as a "scroll" manifold. I'm pretty sure you just referring to sidewinder/ front mount turbo manifolds.
These type of front facing turbo manifolds will always have more heat/engine bay heat issues that a side mount/ram horn style manifold due to the manifolds being much bigger and it being not tucked away between the engine and the frame.

 

A properly built 'Ram Horn' style manifold will have no problem reaching 4 digit whp numbers (assuming the complimentary components are up to the task).

 

It's not the manifold itself that is the limit but where it places the turbo that creates the problem. You would be hard pressed to fit a 1kwhp turbo there. Also can you fit a 4 inch Downpipe with a ram horn?

 

While this might not apply fully to the S2000, due to space constraints and other factors. Our testing many years ago, with turbo headers, log manifolds, full length headers and so on was informative.

Log manifolds, while compact and effective, do tend to limit HP and spool up/response.

Equal length shorty turbo headers, such as the rams horn type, generally provide a nice HP increase at the same boost levels.

Full length headers make only slightly more HP than properly designed shorty headers.

More than any other factor, a smooth flowing collector is important. Even if tube lengths/volumes are different. This is where log manifolds fail, and properly designed "shorty" headers can do very well.

Back in the late 1970's and early 80's, we used full length headers on Ford prototype cars to achieve 700-800HP from 1.7L engines. Interestingly, the guys in the paddock next to us, with F1 cars, used shorty headers on 1.5L engines to achieve 1500HP.

My car has the "Inline Pro" log manifold, and there is no question it feels exactly like a car with a log manifold and too large turbo. A bit difficult to drive smoothly, and very laggy.