exhaust manifolds question

[iXNAY]

I ndont think you understood my point, you cant make one to mount the stock turbo in the same position, including the same exhaust housing clockiing.

why would u want to mount the stock turbo in same position on a custom manifold?

[WidebodyWoody]

I agree that you wouldn't really want to, but it can easily be done. End of story.

[Adriano]

I had reason to, as when the previous owner of my current starion went to twin cam, he wanted to retain the highflow turbo and custom dump pipe, it ended up not being possible, and we had to rotate the exhaust housing to allow more room, end of story. Unless you consider easily done to make a crappy log manifold.

[OLD FART]

I had reason to, as when the previous owner of my current starion went to twin cam, he wanted to retain the highflow turbo and custom dump pipe, it ended up not being possible, and we had to rotate the exhaust housing to allow more room, end of story. Unless you consider easily done to make a crappy log manifold.

I know you're a mechanic BUT I have discussed this with my fabricator and all that is needed to make a custom steampipe manifold to mount a stock turbo in the stock position to the mm is the stock manifold to make a jig and it won't be "a crappy log manifold "
Not wanting to start a verbal stoush just stating a simple fact

[Adriano]

I understand making a jig to replicate the stock position, its just that there isnt physically enough room for a merge collector and th ebends coming out of cylinder 2 and 3, did he try making one?

[OLD FART]

I understand making a jig to replicate the stock position, its just that there isnt physically enough room for a merge collector and th ebends coming out of cylinder 2 and 3, did he try making one?

W ith a bit of ingenuity it can be done by taking no 2&3 port runners to the outside
If you really want one then I can ask my fabricator to make you one
PS imho the most important thing is to have all of the runners having as straight as possible entry into the turbine inlet
Quite a few years ago my fabricator had a daily driver 1800 cc sohc Gemini doing an 11.4 quarter (his wife drove it to work !!!!!!!) and that manifold was quite short and the runners were not equal length

[docile]

It is a quite well known fact that having the shortest runners possible is more important then equal length.

Why couldn't you have Cyl 2 & 3 merging into the RHD side of collectors and 1 & 4 into the LHD collectors ? Surely that would fit. Also the collectors don't have to be the same length which would help space and routing wise.

Btw, collectors are only beneficial if you are running mild+ (272deg) overlap cams, anything less and the results are minimal at best as you can see in OEM trends.

[Adriano]

I really couldnt be bothered arguing, but until you have a jig on a block in front of you it is purely speculative, there is simply not enough room with the balance shaft preventing the collector, let alone pipes.

This is why my car has had the exhaust housing rotated, as remaking the dump pipe, was a far easier and better solution than trying to make a manifold that wouldnt fit.

[redzone]

It is a quite well known fact that having the shortest runners possible is more important then equal length.

from my personal experience, and obviously that of the 80's F1 teams, thats a well known old wives tale

number 1 consideration is getting the angle going into the exh housing right, to stop turbulence taking the inertia out of the exhaust gas which happens when they slam into each other or into the manifold port walls..

[OLD FART]

I really couldnt be bothered arguing, but until you have a jig on a block in front of you it is purely speculative, there is simply not enough room with the balance shaft preventing the collector, let alone pipes.

This is why my car has had the exhaust housing rotated, as remaking the dump pipe, was a far easier and better solution than trying to make a manifold that wouldnt fit.

I'd like to think that we were all discussing things and expressing our point of view
I guess we will have to agree to disagree

[4gpwr]

http://www.gurneyflap.com/Resources/DSCN4175b.jpg

[docile]

It is a quite well known fact that having the shortest runners possible is more important then equal length.

from my personal experience, and obviously that of the 80's F1 teams, thats a well known old wives tale

Lol, have you actually seen an old F1 Turbo Engine dyno plot ? It only starts to make some reasonable numbers at 7000rpm so of course its going to run a set of inertia tuned length exhaust manifold to help reduce lag (by increasing VE) and reversion due to the high-boost levels plus using inconel 625 helps offset the heat lost through the use of longer runners also, but I assume you knew that ?

[TomVR4]

how does high boost cause reversion? I thought boost reduced reversion

[JD_Stazza_Brendan]

As long as your manifold doesnt look like this, you should be fine.

[smodgee]

Thats what happens when you let the wife out of the kitchen ;)