Equal length turbo header/manifold
Discussion
Smooth flowing, non-restrictive manifolds that achieve good gas speeds, will always perform better than crap ones that dont. Even with a turbocharged system.
BUT
You do have to consider at what point this is worth the cost ? Crappy cast manifolds can and do achieve good results also, they are less prone to cracking and flanges warping too. So will generally be more reliable.
So if its for show, or you are seeking a lot of power, then tubular is a good option.
If not, it could be seen as a waste of money.
BUT
You do have to consider at what point this is worth the cost ? Crappy cast manifolds can and do achieve good results also, they are less prone to cracking and flanges warping too. So will generally be more reliable.
So if its for show, or you are seeking a lot of power, then tubular is a good option.
If not, it could be seen as a waste of money.
I've got to make one for my engine, so it will have to be tubular. It'll be stainless and appearance is important, but I'm going for the low mount arrangement for packaging reasons. Of debate too is what material to make it from. General consensus from the yanks I talk to is to use schedule 10 tube, but that's about 3mm wall and seems like overkill to me.
i used 316 stainless tube for the tubular 'top mount' setup i made, but if i was doing it again i would definitely use mild steel not stainless. mines on a racer, so dont care about the finish. many other have used 'steam pipe' which is popular with the yanks, but christ its as heavy as the head iteslf! as steve said, crappy 'log-style' cast manifolds give good results, or certainly better than theory suggests, but their greatest advantage is the strength and resistance to cracking. most tubular setups do suffer from flex and eventually cracking, made worse by the properties of stainless. i braced mine back to the head and also hung the whole assembly from a rosejointed 'gallows' style framework from the rocker cover/head casting. its not designed to take the weight when cold, the rosejoints 'rattle' in fact, but when the manifold is glowing at full chat the weight of the turbo tends to sag the manifold which the 'gallows' resists. i used rosejoints to allow for some sideways expansion as if not this is likely to have caused as many issues as it stops. to get an idea look at a Bailey motorsport cossie head to turbo brace, which is what inspired mine or email me for some pics of my DIY setup.
HTH
CNH
HTH
CNH
Steam pipe may be an option, but like you say is very heavy. The other option is to make it from mild steel and then have it coated (appearance will be important on this car), but then If i get a crack the manifold becomes scrap. Easier to chuck some stainless wire in the welder and weld up a crack every now and then, I think.
Got a feeling that with the 16v head I'm using my primaries will have to be at least 1 3/4" just to fit over the ports.
Got a feeling that with the 16v head I'm using my primaries will have to be at least 1 3/4" just to fit over the ports.
my worry about using too large a diameter for the primaries, is that whilst it will ultimately flow better at high rpm with a big turbo, the gas velocity will be lower at lower rpms if that makes sense (does in my head lol) which could affect your spool up and lower rpm on-boost performance (say 4.5k to 5.5k rpm for instance). maybe not a problem if the tubby is sensibly sized for the engine/application i guess. short tapered SS tubes or cones are avaialble to step down off the ports to the main primaries if that helps. generally the ports are square/rectangular/oval/any bloody shape bar what you need lol, so a bit of 'percussive persuasion' is needed anyway at the port flange end.
oh and steam pipes crap imho. i bought a steam pipe manifold from canada for a friend as i was having some inlet manifolds shipped over, and i weighs as much as my manifold and T28 turbo on its own!!
oh and steam pipes crap imho. i bought a steam pipe manifold from canada for a friend as i was having some inlet manifolds shipped over, and i weighs as much as my manifold and T28 turbo on its own!!
Edited by CNHSS1 on Thursday 1st November 20:57
yes it can be very important even on a turbo charged set up. the reason is the turbo runs off of 2 things the exhoust gas pressure and temp being 1 and the 2nd being exhoust pulse because of thoes 2 varables the better the exhoust desine the better the turbo will work. theres also what size turbo the size of all piping and a lot of other things to consider.
Scott
Scott
On a 2.0 4cyl for example, i cant see any real reason to use tubes larger than 38mm unless seeking over 500bhp.
Even then, perhaps 40-42mm would be ample.
321 is the best stainless to use, then 316, 304 etc. But it also depends on its useage. A normal road car, that doesnt see huge EGT's all the time, might last a very long time before it cracks, or gives problems.
On the other hand, a severe duty racer might last no time at all.
heavier wall may or may not help. Thicker means more rigid, and possibly more prone to cracking, as it isnt free to expand. Long tubes, that might allow a little flex, may be less prone, as they can flex.
DIY Log manifolds do crack, they do warp, and can be a PITA. Ive been there so many times.
Steam pipe is strong, and heavy, but it too will crack eventually. Or maybe my welding is just shite lol
One thing that can often be overlooked....if you can find a standard cast manifold, and perhaps adapt it....they will often last a very long time. And be cheap.
Even then, perhaps 40-42mm would be ample.
321 is the best stainless to use, then 316, 304 etc. But it also depends on its useage. A normal road car, that doesnt see huge EGT's all the time, might last a very long time before it cracks, or gives problems.
On the other hand, a severe duty racer might last no time at all.
heavier wall may or may not help. Thicker means more rigid, and possibly more prone to cracking, as it isnt free to expand. Long tubes, that might allow a little flex, may be less prone, as they can flex.
DIY Log manifolds do crack, they do warp, and can be a PITA. Ive been there so many times.
Steam pipe is strong, and heavy, but it too will crack eventually. Or maybe my welding is just shite lol
One thing that can often be overlooked....if you can find a standard cast manifold, and perhaps adapt it....they will often last a very long time. And be cheap.
Whilst I originally put this forward as a general question for discussion, I do have this issue to address. There is a cast manifold available, but it is rare and not particularly good. It is also designed for LHD cars only. It is also the ugliest manifold you ever saw!
I'm going to initially attempt to make one from tube rather than steam pipe due to the weight issue.
With regard to primary volume, the sheer size of the ports requires a large diameter.
A guy on one of the other forums I frequent just made 519 RWHP @ 2opsi on basically a stock motor (+300cc's) using this homemade manifold. For reference to size that's a 3" downpipe:
I'm going to initially attempt to make one from tube rather than steam pipe due to the weight issue.
With regard to primary volume, the sheer size of the ports requires a large diameter.
A guy on one of the other forums I frequent just made 519 RWHP @ 2opsi on basically a stock motor (+300cc's) using this homemade manifold. For reference to size that's a 3" downpipe:
Edited by BB-Q on Friday 2nd November 11:42
That book by Corky Bell is a good read wrt to making a decent manifold, Maximum Boost (£10 so no excuse)
If in doubt, do what other people who are doing well/running big power do
Agree the above wastegate is in a precarious place. Surely flexi-jointing the wastegate > exhaust downpipe is the best idea? (Corky talks about this specifically in his book Maximum Boost)
Dave
If in doubt, do what other people who are doing well/running big power do
Agree the above wastegate is in a precarious place. Surely flexi-jointing the wastegate > exhaust downpipe is the best idea? (Corky talks about this specifically in his book Maximum Boost)
Dave
4cyl volvo ?
http://www.proturbo.fi/index_en.htm
These guys stuff are not expensive. Although I found them difficult to contact via email when I was looking a Cossie manifold recently. Ended up going PeterG instead.
16v
or for some real works of art, check Peter G's stuff
http://www.petergproduction.com/3cf5bc12-ec7f-4478...
http://www.proturbo.fi/index_en.htm
These guys stuff are not expensive. Although I found them difficult to contact via email when I was looking a Cossie manifold recently. Ended up going PeterG instead.
16v
or for some real works of art, check Peter G's stuff
http://www.petergproduction.com/3cf5bc12-ec7f-4478...
Edited by stevieturbo on Friday 2nd November 17:22
stevieturbo said:
or for some real works of art, check Peter G's stuff http://www.petergproduction.com/3cf5bc12-ec7f-4478...
my goodness he stuff looks amazing! the divided cossy manifold looks amazing and will help spool aswell Edited by stevieturbo on Friday 2nd November 17:22
what are the prices in though???thanks Chris.
chuntington101 said:
stevieturbo said:
or for some real works of art, check Peter G's stuff http://www.petergproduction.com/3cf5bc12-ec7f-4478...
my goodness he stuff looks amazing! the divided cossy manifold looks amazing and will help spool aswell Edited by stevieturbo on Friday 2nd November 17:22
what are the prices in though???thanks Chris.
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff