i know this a noob question but can someone give me a rundown on the pros - cons of all the different types of exhaust manifolds???

 

Evans Tuning ran some comparisons. You might try their web. Most postings I've seen seem to advise against using log manifolds.

 

It really depends on what you want out of the setup. Each of them have their own pro's and cons.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EK k kay &raquo;</TD></TR><TR><TD CLASS="quote">It really depends on what you want out of the setup. Each of them have their own pro's and cons. </TD></TR></TABLE>

please elaborate. that was the whole point of this thread, i wanted to know the pros and cons of each so I can decide what I want

 

If i recall, it's all about peak HP. The ramhorn, makes more peak power than the log, but the topmount makes more power at the top end than the ramhorn, but spool up characteristics change. The log spools the fastest by as much as 350-450rpm faster than the ramhorn, and the ramhorn spools faster than the topmount.

So again, it depends on if you want a street step-up, or a full drag set-up, or somewhere in between, and if you want PS/AC. If you want a good street set-up with PS/AC, the a log manifold would work just fine, if you want a little more HP, then a ramhorn would be right for you.(There are small ramhorns that are PS/AC compatible). If you want a full drag set-up, then topmount is the way to go.

I'm sure you can pick this apart and argue certain things, but these are the basics, and it comes down to what type of driving/racing you will be doing, and what rpm range you are working with/needed for that type of racing(drag, circuit...etc)

 

bumop for more info

 

Mugencrx summed it up really well.

Log - fast spool limited power

Ramhorn - moderate spool moderate power

Top mount - slow spool big power

Also, log and ramhorn have limited space for large turbos. Log are limited due to the rad and may require Civic 1/2 rad conversion. Ramhorn is dangerous because the turbo might not clear the block. Top mount and custom provide the most room for large turbos.

 

I don't know where you guys are getting that the Top mounts are spooling later then the ramhorns But the top mounts is spooling the 42R probably around 800rpm faster on the topmount then the ramhorn and making around 80 hp more, +/- some depending on the setup.

 

Can anyone explain scientifically why a topmount makes more power?

 

A ramhorn is an inferior design. The runners do not go into the collector in the right order. They do have nice flowing radii though. A properly designed topmount will have the runners go into the collector in a round about way that matches the firing order of the engine.

Any good manifold will not have a symetrical design to it. Just by the nature of the firing order.

&gt;&gt;&gt;&lt;&lt;&lt;

 

A nice other little thing about a topmount manifold is the fact that you can have good oil drain on your turbos as they position the turbo so high above the block.

 

What exactly is the round about way according to the firing order that the runners should flow into the collector?

 

i dont see how top mounts and ramhorns are much different. basically the same/similar design, just reversed

 

The firing order on a honda is 1 3 4 2. So that would make a circle like this:

_1_3_
_2_4_

A ramhorn or any other symetrical design will have a criss cross flow pattern:

_1_2_
_4_3_

&gt;&gt;&gt;&lt;&lt;&lt;

 

^^ pics of a manifold like this?

 

Just get a topmount and call it a day!!

 

 

doesnt this only matter if u are using a divded housing turbo with a divded housing manifold.


not just nessessairily a peroperly designed top mount?

 

How do you guys feel about the pro race mani's that the guy with the one piece front end uses.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nickromeo &raquo;</TD></TR><TR><TD CLASS="quote">doesnt this only matter if u are using a divded housing turbo with a divded housing manifold.
not just nessessairily a peroperly designed top mount?</TD></TR></TABLE>

while it is much more benificial to seperate the collection pulses for a div. turbine setup. it is also very benificial to "organize" the entry position and timing of the pulses in a 4-1.

4-1 ex:
O1 O2
x
O4 O3
(see: any ramhorn mani )

HTH

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ken Peak &raquo;</TD></TR><TR><TD CLASS="quote">

while it is much more benificial to seperate the collection pulses for a div. turbine setup. it is also very benificial to "organize" the entry position and timing of the pulses in a 4-1.

4-1 ex:
O1 O2
x
O4 O3
(see: any ramhorn mani )
</TD></TR></TABLE>

This shows a ramhorn or any symetrical manifold. The firing order is 1 3 4 2 so #1 fires and then #3 which is across the manifold. Then #4 followed by #2 which is again across. This doesn't promote good flow.

&gt;&gt;&gt;&lt;&lt;&lt;




Modified by F20Cteg at 3:06 PM 8/24/2006

 

Basically its catergorized like this

Log type such as greedys and edlebrock are built for best results for low end spool.

long runner such as your " top mount " are built custom and it supplys a new location for the turbine only.

Any " ramhorns and modusa " are basically made for new location.

Good luck on your quest for info.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ken Peak &raquo;</TD></TR><TR><TD CLASS="quote">

while it is much more benificial to seperate the collection pulses for a div. turbine setup. it is also very benificial to "organize" the entry position and timing of the pulses in a 4-1.

4-1 ex:
O1 O2
x
O4 O3
(see: any ramhorn mani )

HTH</TD></TR></TABLE>

so having organized pulses is more important than having pipes of relatively similar length and amount of bends such as a ramhorn?

are there any manifolds out there that are like this but are not topmounts?

 

I believe TurboJesse has come out with one now, that has paired firing order and is a ramhorn style.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by F20Cteg &raquo;</TD></TR><TR><TD CLASS="quote">The firing order on a honda is 1 3 4 2. So that would make a circle like this:

_1_3_
_2_4_

A ramhorn or any other symetrical design will have a criss cross flow pattern:

_1_2_
_4_3_

&gt;&gt;&gt;&lt;&lt;&lt;</TD></TR></TABLE>

your dead wrong on this one.