Turbo manifold horsepower differences.
10-19-01, 02:30 PM
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Turbo manifold horsepower differences.
I am wondering if there is a considerable difference from using a cast manifold (HKS type) opposed to using a custom tubular header/manifold? If so what type of numbers are we talking about?
10-19-01, 02:33 PM
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That would be a hard thing to get hard numbers for since tuning is different for each manifold. Think of it like headers on a piston motor. Cast manifold doesn't make as much power as a long tube header.
Spoolup time is faster with a tubular manifold that is divided along with more availible power.
Edit: Boy this is one of the worst posts I have made. Very little info there. I tried, sorry.
Spoolup time is faster with a tubular manifold that is divided along with more availible power.
Edit: Boy this is one of the worst posts I have made. Very little info there. I tried, sorry.
10-20-01, 05:15 AM
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Boy do you have a job ahead of you........there is a science to it actually. You need to decide the diameter of piping you will use as this could be one of the most important factors. Then you need to find out how long to make the initial pipes before they turndown as this can build torque or not. The overall length will determine if you have bottom end power or more top-end.
We have built many manifolds for different cars and dynoed them to find out what did what. What a difference the smallest changes can make.
What would you be using for a collector? Making your own? You must have quite a bit of experience with metal working to even consider this huh? Well......good luck
We have built many manifolds for different cars and dynoed them to find out what did what. What a difference the smallest changes can make.
What would you be using for a collector? Making your own? You must have quite a bit of experience with metal working to even consider this huh? Well......good luck
10-20-01, 07:50 AM
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I am in the middle of this project right, and to be honest, I am using the HKS as a template for my own manifold..
2" short radius weld els from an industrial plumbing store are almost exactly the same I.d. as the HKS runners..
The mounting flanges only took me about 1.5 hours to make with a bandsaw and drill press out of 1/2 plate steel, not to hard at all, as for the collector, use a 2" sched 40 tee with the backside of it cut off and angle cut on the run side of it for rotor 1 and to tie in rotor 2 port on the branch the wrap 1/4 plate aroung the front side to close it in..
The upside of using weld els is that the runners arent going to have all the funky indentations and bumps in them that the HKS has for the bolt holes on the turbo mounting flange, also it allows you to use any wastegate you want, not just the ones the hks is drilled for..Total materials cost is about 30 bucks...
I would agree its a not a job for everyone though, the right tools are a must, and some skill has to be there, I biult a stainless header for my n/a so I have had some practise that is helping me, plus I have done lots of industrial pipefitting , which gave me the knowledge of where to buy the materials and how to work with them, if you own a propane torch and multibit screwdriver, this job isn't for you, access to a bandsaw, a compound drill press, sawzall, die grinder, oxyacetalyne torches and minimum 150 amp stickwelder is needed...
Check out the tech pages at SDSEFI.COM for info on biulding stuff at home...Max
2" short radius weld els from an industrial plumbing store are almost exactly the same I.d. as the HKS runners..
The mounting flanges only took me about 1.5 hours to make with a bandsaw and drill press out of 1/2 plate steel, not to hard at all, as for the collector, use a 2" sched 40 tee with the backside of it cut off and angle cut on the run side of it for rotor 1 and to tie in rotor 2 port on the branch the wrap 1/4 plate aroung the front side to close it in..
The upside of using weld els is that the runners arent going to have all the funky indentations and bumps in them that the HKS has for the bolt holes on the turbo mounting flange, also it allows you to use any wastegate you want, not just the ones the hks is drilled for..Total materials cost is about 30 bucks...
I would agree its a not a job for everyone though, the right tools are a must, and some skill has to be there, I biult a stainless header for my n/a so I have had some practise that is helping me, plus I have done lots of industrial pipefitting , which gave me the knowledge of where to buy the materials and how to work with them, if you own a propane torch and multibit screwdriver, this job isn't for you, access to a bandsaw, a compound drill press, sawzall, die grinder, oxyacetalyne torches and minimum 150 amp stickwelder is needed...
Check out the tech pages at SDSEFI.COM for info on biulding stuff at home...Max
10-20-01, 05:09 PM
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Good info.....very detailed
The HKS is a short runner cast isn't it? Yours should be the best of both.....bottom end and some nice top end.
I'll have pics of mine up within a couple days. I'll post the different ones that we've done......civic,prelude,supra,7,240sx,etc......
The HKS is a short runner cast isn't it? Yours should be the best of both.....bottom end and some nice top end.
I'll have pics of mine up within a couple days. I'll post the different ones that we've done......civic,prelude,supra,7,240sx,etc......
10-21-01, 09:29 AM
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Yeah Silvr, the HKS is extremely compact, a little larger than the stocker, but the port for rotor 1 is maybe 4" long..
I was thinking of lengthening the runners to move the turbo up and forward, however the heat loss through the tubes does start to become and issue, some manifolds are really long, but according to all the books I have this should be avoided as it creates thermal losses in the piping, and increase the expansion amount which leads to cracking, might be ok for racing, but for street driving, I am gonna stick with something that is somewhat proven...
Another good thing about using mild steel, is if I chose to go divided, its simply a matter of welding a divider in the manifold plenum chamber..
Another tip to anyone making their own manifold, drill the exhaust stud holes one size larger, and slot them towards the outer edge, otherwise the exhaust studs will shear off with the expansion...Max
I was thinking of lengthening the runners to move the turbo up and forward, however the heat loss through the tubes does start to become and issue, some manifolds are really long, but according to all the books I have this should be avoided as it creates thermal losses in the piping, and increase the expansion amount which leads to cracking, might be ok for racing, but for street driving, I am gonna stick with something that is somewhat proven...
Another good thing about using mild steel, is if I chose to go divided, its simply a matter of welding a divider in the manifold plenum chamber..
Another tip to anyone making their own manifold, drill the exhaust stud holes one size larger, and slot them towards the outer edge, otherwise the exhaust studs will shear off with the expansion...Max
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10-21-01, 04:36 PM
#8
Old [Sch|F]ool
You're going to use a stickwelder? Cool... I have a MIG that I've used to weld thick plating (~1/4-3/8" thick) with excellent results. I was all worried when I saw that the SDS site said you have to use a TIG... but if I don't overheat the metal I should probably be OK. (I only have 20% duty cycle at max power anyway... lil' 110v pocket mig 
)
Racing Beat sells header flanges that are 1/2" thick, I paid $25 I think for a 12A flange, last year, and it fits perfectly. I was thinking of bolting it to a spare 12A exhaust manifold to keep it from warping while welding.
The only problem is, I don't particularly want a turbo'd 12A anymore... oh well. Maybe I'll change my mind again in the future.
)Racing Beat sells header flanges that are 1/2" thick, I paid $25 I think for a 12A flange, last year, and it fits perfectly. I was thinking of bolting it to a spare 12A exhaust manifold to keep it from warping while welding.
The only problem is, I don't particularly want a turbo'd 12A anymore... oh well. Maybe I'll change my mind again in the future.
