M18 still around?
- Thread starter Brule
- Start date
4inch from the RHD footwell is easy enough. Difficulty with the M18 will be with the length of an EFR so an early turndown past the steering knuckle and steering shaft will drastically limit your dump size. Obviously a much easier prospect with LHD.
You can see the lack of room in this old motiv kit shot.
You can see the lack of room in this old motiv kit shot.
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Great products . The manifold is getting the RHD community pretty excited but, the worry is trying to confrim we can fit a dump pipe in, hopefully a 4inch. Hoping you can share any examples EFR or even external gate versions
@Brule basically said in this very thread that he doesn't have an M18 manifold and reckons a 3" dump won't even fit with it on a RHD N54. From what I understood, @TedIsBoosted was asking the broader question of whether a 4" downpipe can fit on a RHD N54. The answer to that is yes.
I certainly didn't think it would be necessary to point this out. But here we are.
Cant see a way this manifold has the room for 4 inch down pipe on RHD, if it does I'd be interested in one as the current crop of RHD top mount manifolds are less than average.
This does look interesting if it works.
This does look interesting if it works.
We are all in agreement that there likely isn't enough room to even fit a 3" dump on a RHD car with the M18 manifold. 4" is certainly out of the question in this use scenario.
Again, on the broader question of "can you fit a 4" dump on a RHD ST N54", there certainly is room to do so, as Brule has already done it.
Marty how much power are we talking from going from a 3in dump like doc race comes standard with to a 4in?
There is lots of variance, like inlet size and design, filter flow, manifold design.
then it depends on how much boost your going to run.
Picked up 50rwk going from a 3.5 inch to 4 inch on 28 psi as the pipe was chocking our turbo.
It would have made more we just ran out of fuel as the pi injectors where not big enough.
then it depends on how much boost your going to run.
Picked up 50rwk going from a 3.5 inch to 4 inch on 28 psi as the pipe was chocking our turbo.
It would have made more we just ran out of fuel as the pi injectors where not big enough.
Just go through the hood or out the side 
My top mount LHD ACF kit has a 3.5'' DP and it is a VERY tight fit.
Going from a 3 to 4 inch pipe is going to be marginal for gains at the HP most people are at. People have made ~1000hp on this platform with a 3'' DP. Unless you are going to build your engine and shoot for high HP a larger DP is really not needed. Lots of other things to contemplate about and spend money on before considering paying to fab up a larger DP. If it was easy to fit then of course we would all run 4'' DPs, there is a reason there are only a handful of 4'' DPs on this platform.
Diameter - Surface Area
3" - 7.06"
4" - 12.56" (178% of 3")
5" - 19.63" (278% of 3")
6" - 28.28" (400% of 3")
My top mount LHD ACF kit has a 3.5'' DP and it is a VERY tight fit.
Going from a 3 to 4 inch pipe is going to be marginal for gains at the HP most people are at. People have made ~1000hp on this platform with a 3'' DP. Unless you are going to build your engine and shoot for high HP a larger DP is really not needed. Lots of other things to contemplate about and spend money on before considering paying to fab up a larger DP. If it was easy to fit then of course we would all run 4'' DPs, there is a reason there are only a handful of 4'' DPs on this platform.
Diameter - Surface Area
3" - 7.06"
4" - 12.56" (178% of 3")
5" - 19.63" (278% of 3")
6" - 28.28" (400% of 3")
I am personally not fussed with a 3 inch dump. The extra top end power of 4inch is nice (even a 3.5inch gives a bump) but, you will get enough to make you very happy out of 3 inch dump as mentioned if you had to compromise.
Here is an actual 'engine dyno' for a good comparison. This channel is also good for a variety of engine building, power accessories and tuning dyno driven tests.
Turbo dump comparsions;
Here is an actual 'engine dyno' for a good comparison. This channel is also good for a variety of engine building, power accessories and tuning dyno driven tests.
Turbo dump comparsions;
Nice video. But goes to all that trouble for a solid comparison and then makes the lengths and mufflers different to exaggerate the differences...
When you have a head like ours worrying about a 4" dump does not feel productive. Although all respect to the efforts of Brule.
The m18 manifold looks good bang for buck, I'd like to see how those rear runners look internally. The external WG certainly added a headache to my manifold for space but at the same time having an IWG limits the turbo options. Still I reckon I'd give it a go if I were starting from scratch. I might even consider it in the future if I want to try an efr.
The problem with this setup on RHD is going to be the very sharp bends that are needed to run this manifold so the bigger the pipe the better.
If your going to limit the power or not using a large turbo a 3 inch dump is more than enough but if aiming for a high output or trying to break records you might want to look at a proper bottom mount.
I think this manifold design is great to replace twins with a efr, looking forward to results.
If your going to limit the power or not using a large turbo a 3 inch dump is more than enough but if aiming for a high output or trying to break records you might want to look at a proper bottom mount.
I think this manifold design is great to replace twins with a efr, looking forward to results.
Why do you say look at a proper bottom mount ? Most of the higher hp n54s are running long runner manifolds
Because a proper bottom mount will have a good flowing manifold and will be able to use a 4 inch dump pipe with good flowing bends when looking for big top end.
I like the manifold which we adapted for RHD, now that manifold is a work of art and because it's bottom mounted you can basically run any size dump you want on LHD or limited to 4 inch on RHD.
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I released it to the new buyer.
3 and 3.5 inch downpipes are all thats needed the different from 3-4inch was minimal at the track. Just a bit more duty cycle to get to the same boost pressure. So not really worth the effort making a 4 inch dump unless you cracked 1000hp and are going for 8 second 1/4.
