aside from the 213432432$ custom pieces that have been around in the forum since before the VH and VK section, what is everyone doing for N/A headers?
There is a metal shop a few miles from my house that will make flanges for super cheap (about 12-14$ per flange for a 3/4" header flange. (their ad on ebay). After some late nite browsing, I found that the 4.6 DOHC exhaust flange is VERY similar to the VH flange, only the exhaust bolts are offset on the opposite side of the exhaust ports.
What I'm looking at doing is finding a set of cheap flowtech 4.6 dohc headers, cutting the flange off and welding on the VH flange that I made similar to the way this guy makes LS1 longtubes from 5.0 headers.
Headers
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elwesso
- Posts: 30810
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2007 BMW M Coupe
2007 Infiniti G35 S 6MT - Location: Indiana
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Re: Headers (defrag010)
Defrag, one of the Q guys thought about trying this.. He even got a set of mustang long tube headers cheap... Maybe hed hook you up, his name is Mike (blackbirdVQ on NICO).. he also hooked us up with the lightweight crank pullies, which are currently being tested...
At any rate, i think its a reasonable idea, certainly easier than making your own.... Personally, i was going to try and modify the stock manifolds to make a good header.. If you look at the stock manifolds youll notice all 4 of the turn downs from the flange are identical in length... With this start, we know the headers are equal length to this point and they bolt to the motor... From there I was just going to bend some steel into place, because on the Q the steering column gets in the way a little bit...... Passenger side is a little tight as well...
Its just hard to say how much modification will be needed... Its possible they may fit in nicely, its also possible that they mayneed to be almost redone in order to clear the steering colum in the Q.... i know your probably not concerned about their fitment... Oddly enough, i am definitely in a minority trying to tune a VH45DE in the car it came in!!!!!!
Is the only reason you dont want to use the stock flanges is because theyre oval instead of round?
At any rate, i think its a reasonable idea, certainly easier than making your own.... Personally, i was going to try and modify the stock manifolds to make a good header.. If you look at the stock manifolds youll notice all 4 of the turn downs from the flange are identical in length... With this start, we know the headers are equal length to this point and they bolt to the motor... From there I was just going to bend some steel into place, because on the Q the steering column gets in the way a little bit...... Passenger side is a little tight as well...
Its just hard to say how much modification will be needed... Its possible they may fit in nicely, its also possible that they mayneed to be almost redone in order to clear the steering colum in the Q.... i know your probably not concerned about their fitment... Oddly enough, i am definitely in a minority trying to tune a VH45DE in the car it came in!!!!!!
Is the only reason you dont want to use the stock flanges is because theyre oval instead of round?
I thought the stock manifolds were cast? I haven't even looked under the heat shields on mine yet.
I didn't even think of using the stock flanges... out of all the late nights I spend awake thinking about this stuff, I totally overlooked that. The 4.6 dohc header primaries are the same oval shape as the VH's primaries, which is why I chose them in the first place.
If the stock VH headers are tube steel instead of cast iron, then they can be easily modified because the whole reason I want new headers is because of the super tiny collector diameter on the stock VH headers. Possibly the stock primaries with a 2.5" collector?
I didn't even think of using the stock flanges... out of all the late nights I spend awake thinking about this stuff, I totally overlooked that. The 4.6 dohc header primaries are the same oval shape as the VH's primaries, which is why I chose them in the first place.
If the stock VH headers are tube steel instead of cast iron, then they can be easily modified because the whole reason I want new headers is because of the super tiny collector diameter on the stock VH headers. Possibly the stock primaries with a 2.5" collector?
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elwesso
- Posts: 30810
- Joined: Sun Feb 23, 2003 4:52 pm
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2007 BMW M Coupe
2007 Infiniti G35 S 6MT - Location: Indiana
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Re: (defrag010)
No the stock manifolds are tube steel, you can tell.....
zerothread?id=170884
There is a picture of the stock manifolds there.. All of the turn downs are equal length, it doesnt look like it in the picture, but the extra 94 manifolds i have in my attic are.....
You could probably almost use the precat holder, gut the precat, and run all 4 pipes right into that... After the precat, it goes to about a 2.5 flange i think, maybe 2.25. would probably be easier to use a premade deal though....
zerothread?id=170884
There is a picture of the stock manifolds there.. All of the turn downs are equal length, it doesnt look like it in the picture, but the extra 94 manifolds i have in my attic are.....
You could probably almost use the precat holder, gut the precat, and run all 4 pipes right into that... After the precat, it goes to about a 2.5 flange i think, maybe 2.25. would probably be easier to use a premade deal though....
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Mettler
- Posts: 1283
- Joined: Sun Jan 15, 2006 4:05 pm
- Car: HR31 GTS-8 coupe, VH41/45 Hybrid Transplant
My mate's custom making my extractors for me...
I purchased one length of 1.3/4" tube, and 5 x 1.3/4" donuts with 2mm wall thickness.
In round form, the surface area of this size tube is greater than the surface area of the oval exhaust port, but only marginally, and when shaped to be the same profile oval as the port, the surface area decreases and becomes identical.
In short, 1.3/4" tube with 2mm wall is the ideal runner material, and put them into a 4 into 1 collector :p
I purchased one length of 1.3/4" tube, and 5 x 1.3/4" donuts with 2mm wall thickness.
In round form, the surface area of this size tube is greater than the surface area of the oval exhaust port, but only marginally, and when shaped to be the same profile oval as the port, the surface area decreases and becomes identical.
In short, 1.3/4" tube with 2mm wall is the ideal runner material, and put them into a 4 into 1 collector :p
Re: (Mettler)
So what is the best size and layout for exhuasts? I have a single 3" already in place (for the old motor) but was thinking a twin setup will be easier to install but how will this effect the power / torque of the engine. I'm going to look at modifying the factory manifolds to fit between the chassis rails.
Re: Headers (defrag010)
This is what I was trying to get at in my thread I just didn't exactly come out and say it.defrag010 wrote:aside from the 213432432$ custom pieces that have been around in the forum since before the VH and VK section, what is everyone doing for N/A headers?
There is a metal shop a few miles from my house that will make flanges for super cheap (about 12-14$ per flange for a 3/4" header flange. (their ad on ebay). After some late nite browsing, I found that the 4.6 DOHC exhaust flange is VERY similar to the VH flange, only the exhaust bolts are offset on the opposite side of the exhaust ports.
What I'm looking at doing is finding a set of cheap flowtech 4.6 dohc headers, cutting the flange off and welding on the VH flange that I made similar to the way this guy makes LS1 longtubes from 5.0 headers.
Re: Headers (pmpmstrb)
It depends on your target hp, I'm hoping for 400-450 rwhp and think twin 2.5", > X pipe then straight through mufflers should be about right but I gotta look into it some more when the time comes.
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doctorchee
- Posts: 168
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- Car: BMW 318IS
Re: Headers (defrag010)
Hi
how about the following headers:
SR20DETCA18DET
you think by changing the flange, this header will be more suitable and properly fits easier?
how about the following headers:
SR20DETCA18DET
you think by changing the flange, this header will be more suitable and properly fits easier?