NA2 headers on my NA1 - what additional parts do I need?

[Chemical1]

Hi forum!

I have accuired NA2 headers to be fitted to my 1991 NSX. I also have the sos-adapters. My shopping list so far consists of:

O2 sensors
O2 sensor extensions

Is there anything else I should get, like new gaskets? If so, what fitment? For a NA1 engine?

I have searched the forum but cant find any specific information. Sorry if this is quote obvious but my mechanical knowledge is limited. Also, Are there any specific places I should by the sensors/extensions from?

Cheers,
Jon

 

[goldNSX]

Yes, gaskets. I had NA1 ones but having it done some years ago I remind that they had to be modified slightly, not sure. Add some nuts and studs (2 of each) just for the case you break one or two, depends on how old an rusted your old header is.

 

[solidol]

I would get:

18115-PBY-J02, 2pc
90217-657-000, 14pc

and spare studs just in case like goldNSX mentioned.

 

[Honcho]

+1

Hi Jon, since those are my old headers , you should use NA2 gaskets and the revised NA2-style nuts, which solidol has listed above. I would definitely also get a few extra studs, since they do break quite easily when removing the old manifolds.

 

[Chemical1]

Hi and thanks for the replies! :smile:

I think my shoppinglist is fairly complete and will get the NA2 gaskets and nuts as well as oxygen sensors + extensions!

When I get these I look forward getting the headers installed! I will keep you posted!

/Jon

 

[charlee]

Just to be sure, these NA2 headers are from 97-99 correct?

 

[JLCoolman]

When I did my NA2 headers (from an '05) I reused my NA1 gaskets (the ones between the manifold and the heads). Is there a reason not to reuse the NA1 gaskets?
Or are you guys talking about the gaskets between the header and cats/adapters?

 

[Honcho]

When I did my NA2 headers (from an '05) I reused my NA1 gaskets (the ones between the manifold and the heads). Is there a reason not to reuse the NA1 gaskets?
Or are you guys talking about the gaskets between the header and cats/adapters?

The manifold gaskets to the head. NA2 uses a slightly larger port opening that matches the ports on the NA2 manifolds. It's not much of a difference, but when you are NA, every bit counts.

 

[JLCoolman]

I was wondering about that. But your NA1 heads still have the same size ports unless you port them....
So just because the NA2 gasket has larger ports doesn't help if the NA1 head ports are the same size, right?

 

[Honcho]

It's a better fit on NA1 and NA2 head ports. Kaz always recommends NA2 gaskets and nuts.

 

[kaede]

+1

Hi Jon, since those are my old headers , you should use NA2 gaskets and the revised NA2-style nuts, which solidol has listed above. I would definitely also get a few extra studs, since they do break quite easily when removing the old manifolds.

I am doing the same job soon! Any idea what part number the studs are? try finding it on oemacuraparts.com put couldn't =P Thanks!

 

[DDozier]

I am doing the same job soon! Any idea what part number the studs are? try finding it on oemacuraparts.com put couldn't =P Thanks!

Nuts and gasket are here:
http://www.acuraoemparts.com/delray...=EXHAUST+MANIFOLD+(MT)&ListAll=All&vinsrch=no

Studs are here item #19 :
http://www.acuraoemparts.com/delray...y5=CYLINDER+HEAD+(FR.)&ListAll=All&vinsrch=no

Dave

 

[kaede]

Thank you very much Dave!! I am guessing get the newest model year studs and bolts are fine as they're just better versions of the same thing. (my car is a 94 NA1). Unfortunately i already bought the NA1 gaskets, so will use those instead of buying newer NA2 ones. Thanks!!

 

[kaede]

It's a better fit on NA1 and NA2 head ports. Kaz always recommends NA2 gaskets and nuts.

Should i just replace all the studs as well then? One question i have is on the NA1, the studs are 8x43 while the NA2 is 8x33. Since i am there, might as well just replace all the studs with NA2 8x33 studs and new NA2 nuts. Those will work right? Thanks!! just want to make sure i have everything ready before i take it apart!

 

[B2FiNiTY]

Exactly. I would recommend you replace them to NA2 studs as well since they are shorter. This will leave less thread exposed and this will help prevent them from being affected by the elements.

Just buy the new gaskets and sell the old ones.

 

[kookoo4nsx]

I did the same upgrade and could not get the leverage to remove the old O2 sensors. Finally had to place the new factory na2 header on my driveway, park my volvo on the header and then stand on my o2 remover tool. That sucker was in there!!!!

I personally feel the na2 header makes more torque on a turbo system all things being equal than a high dollar custom header.

 

[trainingrevolution]

Just thought I would add some info to the discussion....

Here is my .02, I installed 1997 headers on my 1992. Take it for what its worth. Having known then what I know now I would have purchased a nice gently used set of CompTech headers.

If you are getting OEM headers consider the following:

1. Spend $ on aftermarket headers
Labor is the same or more if you use factory headers.
2. Re-Weld the Factory OEM Headers
The factory OEM headers are tack welded and can crack at the seam, I brought my headers to turbochargers.com in Houston and they put a bead weld all the way around.
3. Jetcoat them (ceramic coating)
Jethotcoatings.com
4. Install them yourself
Tons of great write ups here on PRIME

David McDavid Acura in Austin did my headers.

Here were the costs involved (it was GROSSLY more expensive than I had anticipated when all was said and done).

NSX Prime Used Heades 19K Miles $350

SoS EAP-665 1997-99 Header Conversion Kit ($274) (required to keep my 1992 catalytic converters), O2 Sensor Extension Harness Kit ($79) + Shipping ($8) Total $361.

Delray Acura Zanardi Rear Sway Bar (required if you plan on using catalytic converters from 1997) ($82.39) + Shipping ($8.95) Total $91.34

Turbochargers.com Labor to weld headers Total $150.

Jet-Hot Ceramic Coating ($235.00) + Shipping ($34) Total $269.

Gaskets
(2) 18115-PR7-A02 Gasket, EX, MAN ($53.84), (2) 18212-SA0-003 Gasket, EX PIP ($19.04) (2) GSKT 52.5MM-53 ($28.86) Total $101.74

David McDavid Acura Labor $735.00

Grand Total $2,058.08

 

[kaede]

OP, since we are removing the headers anyways, I am also replacing the oil pan gasket as well as all new studs, bolts, and nuts associated with that job. If you track, also a great time to put in the oil pan baffle! Of course that calls for a new oil change as well. A little bit of preventative maintainence since we're down there =D

 

[MileHighNSX]

Just thought I would add some info to the discussion....

Here is my .02, I installed 1997 headers on my 1992. Take it for what its worth. Having known then what I know now I would have purchased a nice gently used set of CompTech headers.

If you are getting OEM headers consider the following:

1. Spend $ on aftermarket headers
Labor is the same or more if you use factory headers.
2. Re-Weld the Factory OEM Headers
The factory OEM headers are tack welded and can crack at the seam, I brought my headers to turbochargers.com in Houston and they put a bead weld all the way around.
3. Jetcoat them (ceramic coating)
Jethotcoatings.com
4. Install them yourself
Tons of great write ups here on PRIME

David McDavid Acura in Austin did my headers.

Here were the costs involved (it was GROSSLY more expensive than I had anticipated when all was said and done).

NSX Prime Used Heades 19K Miles $350

SoS EAP-665 1997-99 Header Conversion Kit ($274) (required to keep my 1992 catalytic converters), O2 Sensor Extension Harness Kit ($79) + Shipping ($8) Total $361.

Delray Acura Zanardi Rear Sway Bar (required if you plan on using catalytic converters from 1997) ($82.39) + Shipping ($8.95) Total $91.34

Turbochargers.com Labor to weld headers Total $150.

Jet-Hot Ceramic Coating ($235.00) + Shipping ($34) Total $269.

Gaskets
(2) 18115-PR7-A02 Gasket, EX, MAN ($53.84), (2) 18212-SA0-003 Gasket, EX PIP ($19.04) (2) GSKT 52.5MM-53 ($28.86) Total $101.74

David McDavid Acura Labor $735.00

Grand Total $2,058.08

Holy @%$# I didn't realize that the NA2 headers could cost that much to install?

 

[kaede]

well thats because he got it re-welded, rested it with ceramic coating, as well as getting parts and services at the local dealer. If you skip on couple of those u should save some shipping cost as well as labour costs =D His scenario is like the worst case scenario!

But i also agree with him, by spending that much might as well get aftermarket that fits right to begin with (no adapters to deal with) and have it done at a reputable NSX mechanic store.

 

[bruckner]

Resurrecting thread! I'm contemplating installing a full NA2 setup (headers, cats and muffler) from a 1998 on my 1991, I went through many threads discussing mostly headers. I have a few questions:

- Will the 98 exhaust setup work with my 91 rear sway bar? If not, is the Type-S sway bar the bona fide replacement?
- Which O2 sensors require extensions, upstream or downstream?
- Am I correct in thinking the NA2 O2 sensors will work fine eliminating the need for extensions?

Thanks,

 

[socalx]

I have them on my 1993 with the stock sway bar
I am using my stock o2 sensors with sos extensions
See answer number 2

 

[socalx]

Also. Having previously used and having first hand knowledge of more,then one premium aftermarket nsx header, I chose to stay with the factory stainless tubular header 6 years ago and have not regretted it

 

[bruckner]

I have them on my 1993 with the stock sway bar
I am using my stock o2 sensors with sos extensions
See answer number 2

Which catalytic converter setup do you have? I do remember reading somewhere that some years aren't compatible with the 91 swap bar.

Which o2 sensors need extensions? There are 4 of them, up and down stream.

Thanks,

 

[socalx]

I am running the stock 1991-1994 cat converters. To run these you need adapter pipes that go between the header and the cats and o2 wire extensions. There are only 2 02 sensors on 1991-1994 nsx’s. Now if you have a 1995-1996 nsx you don’t need the adapter pipes mentioned in my 2nd sentence, you will use your factory adapter pipes between the cats and your exhaust but you will need o2 extension wires for the front two o2 sensors , your rear sensors on a 1995-1996 nsx are in the cats and will stay in the same place.