Which headers?

[lotusolly]

Hi all,

Looking to replace my headers (Still the original cast ones!) but not quite sure which ones I should purchase to fit my car?
Mine is a 1995MY 3.0 so 16/17" wheels and japan spec gear ratio's. Looking at the headers on my car, they have the metal flexi-joint at the end and appear to be the same as the early cars but the american listings show 94 on as being the newer style! Did they update their spec at a different time to us?

Many thanks

Olly

[Senninha]

Hi Olly,

Without question I would receommend a discussion with Kaz. When back in Japan earlier thi syear he was able to evaluate via b2b2 testig the many options avaiable. If you check his health check thread you'll see which way he went.

HTH, Paul

[Kaz-kzukNA1]

Hi, Olly.

All NA1 engine with MT/AT on pop-up or face lifted models have cast iron ‘manifold’ and not the later spec ‘header’ style one.


‘Header’ style was introduced only for the NA2 engine so it would be early 97 for almost all of the countries.


I don’t think the info of ’94 onwards’ is correct but possibly it was referring to something else and not the header???


The introduction of OBD-2 was different between US Acura and UK models so you need to be bit careful when dealing with the parts around the exhaust and ignition area.

In US, OBD-2 was mandatory from 96 onwards but for NSX, it was already introduced from Acura 95 models whereas for UK, the full spec was only introduced from 00 models yet four O2 sensors were already on the pre-00 models.

Already confused??


For the selection of the header, almost any headers from well known manufacture/supplier will produce noticeable power increase if you have changed it from NA1 manifold.


I heard that Honda used ‘manifold’ design in order to honour the so called ‘gentlemen’s agreement’ of limiting the max power at 280PS among the car manufactures in Japan but don’t know the truth.


Some of the well known Japanese headers are designed in-house but out-sourced to the special welder/bender for the manufacturing process so you may see several headers with different brand name but manufactured by the same company.


As mentioned above, almost any headers will show increase in the power from NA1 manifold so you are pretty much paying for the quality, material, durability, ease of installation and the sound effect combined with your exhaust and CAT.


In my personal view, if you look at the rear bank header, it will tell you how much effort was paid into the R&D for the design and manufacturing jig.


Because of the limited space and the position of the rear bank CAT, almost any headers have to bend the tube 180deg and it is not easy to do this using the singular tube design.


Thus, many headers use lots of short length tubes welded together for the rear bank to achieve this design restriction and ease of manufacturing.


Lots of short tubes means lots of welding points and each short tubes are very likely to be in different length means different stress points.

So, if the design was not optimised with the expansion rate of the material in mind, these headers are more likely to crack than the singular tube ones.


Having said this, if it cracked, your local exhaust shop should be able to weld it at very low cost.


Depending on the design, the installation of O2 sensor could be tricky and also future service around the engine/suspension area may require extra hours.


Just don’t use stainless nut on stainless bolt during the installation because I can 100% guarantee you that they will seize.

If you want to use stainless, make sure to use it on one side (nut or bolt) and not on both sides.


If you are after the exhaust sound, best to consider the header, exhaust, CAT as a package.


CAT/De-CAT will have significant effect on the throttle response and the sound but very little on the power figure and only a few at WOT.


You can find additional info at the ‘Header installation’ section of my ‘NSX Technical and Service Index thread under the Technical section.

Kaz

[lotusolly]

Thanks Kaz,

Just wanted to make sure I didn't order parts that wouldn't fit.

Olly

[nationofzeros]

Hi Olly

I'm not sure this will be helpful, but I am running MUGEN tubular headers, Random Technologies hi - flo cats and a TAITEC GT (I think) back box and I couldn't be more pleased with the throttle response, sound etc although I know no different. Kaz is familiar with the setup.

Best regards

Chris

[NSXGB]

There's a FULL Tubi setup on Pistonheads if you are interested.

http://www.pistonheads.com/sales/list.asp?s=328

[lotusolly]

There's a FULL Tubi setup on Pistonheads if you are interested.

http://www.pistonheads.com/sales/list.asp?s=328

Thanks Simon

[matpp]

There's a FULL Tubi setup on Pistonheads if you are interested.

http://www.pistonheads.com/sales/list.asp?s=328

It's a Tubi exhaust but the headers are Top Speed......they came off N11 NSX which is currently for sale.

Cheers,

[NSXGB]

Ahh, slightly misleading then. Nothing wrong with the top speed headers though, they give good dyno results.