If the catalytic converter is different, then the UK cars are probably a little different.

I know in the US, the 4th gen and 5th gen headers are interchangeable (as long as the 5th gen is a base model).

 

Thanks for your answer but that was not my question, like I allready said, I knew that this header will fit my engine, that is not the problem.

Is there really no one who has any informations for me? :-|

 

I guess I misread your question, lots of question marks.

The Type S/Mugen exhaust system as a whole is slightly better than most other stock exhausts, but it isn't worth the hassel of hunting one down, unless you're only after OEM parts.

A Mugen header is slightly better than your stock BB4 header, in that the factory exhaust manifold was tubular at the top, and the bottom part was a cast piece. The Mugen header is a tubular manifold from top to bottom, with slightly bigger primaries and an ever-so-slightly larger exit at the catalytic converter flange.

If you're looking for a performance gain, the Mugen unit will only probably net you 1-2hp over stock. If you go back to a stock header from a Mugen header, you probably won't notice much of a difference, if any.

If you want noticeable horsepower gains, it's best that you equip an aftermarket header (such as a Vibrant or HyTech unit) with a larger diameter (65mm-80mm) catalytic converter and exhaust for a better breathing system overall.

 

First I like to thank you that you try to help me, you seem to be the only one here, so please dont give me up even when I must say that you missunderstood me again

BUT that isn't a problem, I am from Germany, maybe my English ist to bad so I will try to explain it again:

1. I own a BB6 equipped with a european H22A8 (200hp) engine.
This engine you can see as a detuned H22A (220hp) engine from a Type S / Sir S-Spec. The head, the block (except for little details) and the complete exhaust system (except for the catalyst) of my H22A8 engine are exactly the same like from a H22A Type S / Sir S-Spec engine. The only differences are in the gearbox and the ecu (my ecu is detuned from Honda, thats why I only have 200hp instat of 220hp and I have no ATTS or LSD)

2. This meas my stock exhaust system (except for the catalyst) is the same 2.25" exhaust system like in a stock Type S / Sir S-Spec

3. You sayed: "A Mugen header is slightly better than your stock BB4 header" BUT I have no stock BB4 Header. My stock header is the same one like in a Type S / Sir S-Spec.
(Thats why i sayed you missunderstood me again)

4. The OEM Mugen header & downpipe (the same one you can see at the pictures of my first post) which I want to build on my H22A8 was made from Mugen Power for a 4th. Gen. JDM BB4 model (H22A 1991-1996 Prelude Si VTEC = 200 hp). So unfortunately I dont have the Mugen header and dowpipe which Mugen build for the 5th. Gen. Type S / Sir S-Spec Preludes (H22A engines with 220hp)

5. So the question that now arises me:

Knows anybody about technical differences (like pipe diameter or pipe form) which have influence on horsepower output, between those Mugen headers and downpipes which was made for BB4 models and those which was made for BB6 Type S / Sir S-Spec models?
I mean my Prelude is stock equiped with an 2.25" exhaust system from a model with 220hp and the Mugen header and downpipe I have in my cellar are for a older BB4 model with 200hp. So there are 3 possibilities:

1. Maybe the Mugen header for BB4 isn't better then the stock exhaust header and downpipe I allready have and build on my car and the Mugen BB4 header and downpipe would reduce my hp output?

2. Maybe a Mugen header and downpipe for a Type S / Sir S-Spec would gain more power of my engine than the BB4 header and downpipe I have would did?

3. Or maybe the Mugen headers and downpipes for 4th. Gen. and 5th Gen. are technically (pipe diameter or pipe form) the same so it would dosen't matter and I dont have to worry about it?

That are the questions I like to find answers for!

Primary my intention is not to get as much hp as possible with the Mugen setup, I am a OEM freak and thats why I buyed the Mugen exhaust. BUT I dont need the 4th. Gen. Mugen header and downpipe (even if it is Mugen and it is holy shit^^) when it will reduce my hp output in comparsion to my stock Type S / Sir Spec header and downpipe.

NOTE:

Here are some pics of a OEM Mugen 5th. Gen header and downpipe. When I compare those pics with the pics in my first post (OEM Mugen 4th. Gen Mugen header and downpipe) the only differences I can see are in the length of sections from the downpipe: At the 5th. Gen downpipe the two tubes which come from the header are looking shorter (before they become one tube) to me than the tubes from the 4th Gen. downpipe. Also the flexibel part looks a bit longer and the small tube section after the flexibel part looks a bit longer too at the 5th. Gen downpipe. And the position of brackets also looks different. BUT all that differences seems to be no differences which would have influce on horse power output for me. Those differents are conditioned by the differences of 4.th. and 5.th Gen Prelude chassis. And my 4th. Gen Mugen header and dowpipe is allready made fitted for my 5th. Gen Prelude (last two pictures you see my fitted 4.th Gen Mugen downpipe) so the question of fitment 4th. Gen Mugen header and downpipe at 5th. Gen Prelude Chassis isnt the Problem.

 

The exhaust on the h22a8 and all red top h22 is not the main factor for the power difference. That comes from the cams, pistons etc. The 2.25" exhaust compliments this.

The mugen exhaust that I had not including the header was 2.38" in diameter before I made is fully 2.5" to fit my hytech.

Also the mugen header on a stick jdm 4th gen makes more than 200bhp.

 

The power differences of my h22a8 engine compared to a h22a engine (Type S / Sir S-Spec) only came from the detuned ecu. cams, pistons etc. all parts in the head and block (except for little details) and the complete exhaust system (except for the catalyst) of my H22A8 engine are exactly the same like from a H22A Type S / Sir S-Spec engine

Sry but you mixed the in and out diamter. The in diamter of the Mugen exhaust is 2,25" and the out diameter ist exactly 2.38".

So what you tried to say with "Also the mugen header on a stick jdm 4th gen makes more than 200bhp." is that the Mugen headers and downpipe of 4th. and 5th. Gen. make the same power output right? If it is so, it would be great.

I measured the in diameter of my 4th. Gen Mugen Header and dowpipe:

In diameter header exit (were four tubes become two tubes) = 1,8"
In diamter dowpipe exit = 2.25"

Is there anyone who has the measure data of a 5 th. Gen. Mugen header and downpipe? This could answer all my questions

Also so the measure data of stock H22A (Type S / Sir S-Spec) exhaust system would be very interesting, anyone have this data!?
In my opinion it should be the same like the Mugen exhaust system!

 

Yes the internal parts are the same but the block on the Type S is based an a h22a4 and the head is different being a p13 hf1 head and the a7 being a pde and the s spec being a p5p. S spec and type s blocks are almost the same apart from relocated oil filter.

 

I thought Type S and SiR S-Spec Blocks are different in oil filter location. I thought Sir S-Spec block oil filter location is same like the block of my h22a8. The complete mugen exhaust system i have fitted a Sir S-Spec, i thought (and the seller says the same) it will plug and play fit my h22a8 without any problems. What would you say? I have no ATTS, LSD or 4WS.

 

Thanks for your informations!