General engine questions/issues that aren't specific to the other categories
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By lip_vtec
#28206 im after a manifold now im not sure what would be better for acceleration 4-1 or 4-2-1 :? help maybe lol and also i need a place in the uk to order form im looking to get a decent one but nothing too expensive any advice or alterantives greately appreciated guys:thumb:
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By BAXTER_EJ1
#28208 4-1 is illegal in all of Canada and most if not all of USA I think, I would check to see what your laws are over there regarding that.

I'd be interested to see how 4-1 and 4-2-1 compare though too :thumb:
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By lip_vtec
#28210 as far as i know there are no laws against either so really i just wanna know whats gunna give best results for acceleration and where i can get a manifold ata decent price
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By Graham
#28214 Nah theyre definetaly not illegal here - didnt 96 spec integras come with 4-1 manifolds as standard? :?
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By JLau
#28216 Niether is illegal in the US. I went w/ the JDM ITR 4-1 based on the fact that Honda's are pathetic in NA form as far as torque goes so why not improve where they are more impressive and make most power? In the heavenly high end of the RPM band.
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By Greasedmonkey
#28217 4-1 manifolds arent illegal in the US.
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By BAXTER_EJ1
#28223 :?

Call me stupid and kick me in the teeth then lol. I think they are in Canada, but I'd rather now risk my credit yet again :P

So 4-1 will give more torque than a 4-2-1, any numbers? By how much?
User avatar
By york62
#28229
MKennedy86 wrote:4-1 is illegal in all of Canada and most if not all of USA I think, I would check to see what your laws are over there regarding that.

I'd be interested to see how 4-1 and 4-2-1 compare though too :thumb:


i didnt know that, so i wonder about the open header i will be running?
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By ohDirka
#28230 i run open headers :D
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By suspendedHatch
#28235 This is silly.

First of all, illegal? Why? What are you talking about? SMOG illegal? That's the only sense I can make.

Legality of parts is pretty much a concern in California only, and most name brands have applied for and received CARB legal status.

You used to be able to generalize that 4-1 headers made higher peak hp at the expense of low end torque, and that 4-2-1 (tri-Y) headers made more power overall at the expense of peak hp. Thus the 4-1 would be better for drag racing and the 4-2-1 would be the best choice for a daily driver. But after being stagnant for a decade, import header technology made a leap and now the generalizations are not so accurate. You need to compare dyno graphs.

Chances are that if the header you're looking at costs $600-1200, you're on to something.
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By BAXTER_EJ1
#28255 Don't quote me on anything, I just threw out what I heard somewhere sometime, if they're legal in Canada too then :woot: , after doing research now I see that yes, 4-1 headers are usually 50-state legal in the US, so my bad.

I guess anything that you pay top dollar for generally can be considered good quality lol. Thanks for that info though :thumb:
User avatar
By vtec_gloucester
#28276
lip_vtec wrote:im after a manifold now im not sure what would be better for acceleration 4-1 or 4-2-1 :? help maybe lol and also i need a place in the uk to order form im looking to get a decent one but nothing too expensive any advice or alterantives greately appreciated guys:thumb:


what engine is it?
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By lip_vtec
#28286 its a d16z6
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By Ej2-B16a
#28927 from what i know.. you can have a header thats like 10-9-6-3-1 if it exsisted.. and it wouldnt be illegal if it had a C.A.R.B #.......

atelast in cali i think it doesnt matter wat it is as long as its carb legal..
User avatar
By suspendedHatch
#29100 What are you talking about?! A 10 cylinder motor? Not in a Honda. The header wouldn't break down that way either.

Do you understand that there are four cylinders, hence 4 pipes, they collect in pairs, you then have 2 pipes, then they collect into 1. Or you can start with 4 and have them merge all into 1 at the same time, hence 4-1.