IIRC, yes, the newer NA2 muffler section should be able to be modified to meet up correctly with any year cat. I was presuming we were talking about strictly bolt-on exchanges of parts :smile:
J
NA2 exhaust upgrade?
- Thread starter fastaussie
- Start date
IIRC, yes, the newer NA2 muffler section should be able to be modified to meet up correctly with any year cat. I was presuming we were talking about strictly bolt-on exchanges of parts :smile:
J
Your understanding is correct. All dynos I have seen for NA2 headers on NA1 engines show a 14 to 20 whp gain, depending on the car, dyno, weather, etc. This is usually with a stock exhaust. Aftermarket headers will gain more, but not much, and mostly above 6000 rpm. As for the NA2 update, NA1 was 276 hp and NA2 was 290. 290-276 = 14.
If you want your NSX to "breathe better," headers are the best bang for the buck. A good set of NA2 headers usually goes for $300 to $500 in the marketplace. Occasionally, you can find a nice used set of Comptech headers for $800 to $1000, if that extra 5 to 10 whp is worth the money to you. The Comptech fitment is perfect and they are the best aftermarket option aside from the super-high dollar baller JDM kits like Fujitsubo and GT-One.Exhaust is somewhat of a more controversial topic, but I like to think of it as a sound preference rather than a performance adder. People have put the stock mufflers on a flow bench and yes, there is a measureable drop in vacuum, which indicates a restriction. My issue is the assumption that the restriction is a flaw. Honda spent a lot of time and money on the exhaust design, which uses no packing (to save weight) and is frequency tuned to completely eliminate drone. Because the car is intended to be a daily driven street car, you want to have some backpressure because it improves throttle response off the line. Honda knew this. It all boils down to the design goal for the car. If Honda were designing a race car, where the working rpm is 6000 to 8000, they would remove the restriction to free up as much as 5 whp at the top of the rpm range, since the only time you were in the low range is in pit in/pit out. In racing you are going for every tenth on the track, which means chasing every whp. To assume the same design goal for a street car is illogical to me, especially considering the negative consequences like drone and lack of response at low rpm. But, some people want that shiny dyno chart...different strokes I suppose.
Sorry for the long winded explanation, but the bottom line is the factory exhaust is very good. You can get a little more power from an aftermarket unit, but at the expense of drone and a mushy throttle below 3000. Thus, to me it boils down to a sound preference. Many people do not like the factory exhaust because it is too quiet. That is a perfectly good reason to change it. My RM Racing quad-tip sounds BADASS.
But, it gives my wife a headache. I also think the AP-X, GRF ex-001 and ARC Titanium sound great. The Comptech is decent, too. I think the crazy "F1" pretzel exhausts sound like the fart cans on a teenager's 89 Nissan Sentra, but that's just me.As for fitment, let's assume you find a set of 97-99 NA2 headers. So, your parts are:
97-99 Headers
96 Muffler
91-94 Cats
Option #1 - Headers --> SOS Adapters --> 91-94 cats --> 96 Muffler
You will need to buy the SOS adapters unless you buy aftermarket headers that come with them. 91-96 mufflers are all the same layout. The difference is in the cats, which in 95-96 changed shape otensibly to accommodate the downstream O2 sensors. This required use of elbow adapters to fit the muffler. I suppose you could use 95-96 cats, but you would then need to buy the exhaust adapters:
Option #2 - Headers --> SOS Adapters --> 95-96 cats --> SOS Exhaust adapters --> 96 Muffler
Finally, you could use 97-99 Cats, which would eliminate the need for the header adapters, but you would still need the exhaust adapters:
Option #3 - Headers --> 97-99 cats --> SOS Exhaust adapters --> 96 Muffler
Your cheapest option is #1.
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fastaussie
Suspended
option one was initially the plan, and seems the easiest way to go. i'm not worried about price, just simplicity.
you have excellent knowledge of engine powerband dynamics. back pressure in an engine, especially a smaller displacement engine, helps create low and mid-range torque. Japanese motorcycle engines work in exactly the same way, since they make power with RPM, as does the NSX. torque is more important than people think, as it's what accelerates you to the horsepower, which gives you top speed per gear. torque is what accelerates you from the apex on, not horsepower. since my car is a streetcar predominantly, i'd like to keep some drivability within it.
thanx heaps Honcho. for the thoroughly thorough explanation... :smile:
you have excellent knowledge of engine powerband dynamics. back pressure in an engine, especially a smaller displacement engine, helps create low and mid-range torque. Japanese motorcycle engines work in exactly the same way, since they make power with RPM, as does the NSX. torque is more important than people think, as it's what accelerates you to the horsepower, which gives you top speed per gear. torque is what accelerates you from the apex on, not horsepower. since my car is a streetcar predominantly, i'd like to keep some drivability within it.
thanx heaps Honcho. for the thoroughly thorough explanation... :smile:
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A header involves more labor but it's worth it, much more than changing just the exhaust from OEM to OEM. A 97+ OEM header is a quiet as stock. An aftermarket is maybe a tad louder. Well it was in my case of a Taitec but as Honcho mentioned Comptech or OEM is the better way to go.
A lot of conflicting information on this thread. Let me help you as I've been in the exact same spot as you.
Here's my original post which shows the OEM 1995 NA1 exhaust (1995 muffler, exhaust manifolds & cats) against the OEM 2003 OEM exhaust (2003 muffler, header & cats)
http://www.nsxprime.com/forum/showthread.php?t=86686
Baseline:
After:
Here's my original post which shows the OEM 1995 NA1 exhaust (1995 muffler, exhaust manifolds & cats) against the OEM 2003 OEM exhaust (2003 muffler, header & cats)
http://www.nsxprime.com/forum/showthread.php?t=86686
Well, after hearing all the hype here on Prime about the 1997+ OEM Header/Exhaust combo, I decided to try it after I found out that Vance was selling his 2003 OEM Header/Exhaust/Cat combo in the classifieds. Everyone kept saying that the header design was going to improve overall power.
Since my 1995 has the NA1 exhaust manifolds and OEM muffler on right now, I figured I could get a good jump in performance for pretty cheap (~$1000 for the headers, cats AND muffler) yet keeping it all OEM. So I went ahead and did it and even had it Dyno tested to see if there were any gains.
So I went up to Speed Oracle Performance in Valencia to have it done, since Robert offered me a free Dyno if I got the work done.
Did a baseline run of 233.7HP & 188ft-lbs with OEM NA1 Exhaust Manifolds, NA1 OEM Muffler, NA1 OEM Cats, a Downforce Intake scoop, and the 18/19" Gram Lights wheels on.
After removing the NA1 stuff, we compared it and I was a little surprised to find out that all the diameters of the NA1 exhaust were EXACTLY THE SAME for the 3.0L to the 3.2L. INFACT, the piping diameter coming straight off the block on the NA2 3.2L Header is actually slightly smaller than the exhaust manifold off the 3.0L NA1! See pictures below. I must admit, I was quite surprised and a little nervous that it wouldn't show any gains.
Anyhow, we put it on. . .which took over a day to do the whole job. Here are some comparison pictures.
Front is the 2003 NA2 Muffler. Back is the 1995 NA1 muffler with custom tips. Despite the what it may look in the picture, the pipe diameter is exactly the same.
Here are the front header comparisons. Left is the '95 NA1 exhaust manifold. Right is the NA2 '03 header.
Here is a closer look at the pipe diameter. Note that the NA1 exhaust piping is slightly larger than the NA2 design . . Weird. . . (Again, Left is the '95 NA1 exhaust manifold. Right is the NA2 '03 header.)
Finally here's the dyno. The 3.2L graph is mislabeled. The peak is actually 248.3HP. Torque was ~197ft-lbs. This ends up being a gain of 14.6HP and 9ft-lbs. Gains were across the entire board!
Baseline:
After:
Honcho is correct from my experiance. I had a RM exhaust on my 2000, then a Flowmaster. I DD mine and the volume was just too much. I went stock and noticed the better responce straight away. It is a MUCH better solution for those that DD the car and I think it still sounds good when you wind-it-up.
Your understanding is correct. All dynos I have seen for NA2 headers on NA1 engines show a 14 to 20 whp gain, depending on the car, dyno, weather, etc. This is usually with a stock exhaust. Aftermarket headers will gain more, but not much, and mostly above 6000 rpm. As for the NA2 update, NA1 was 276 hp and NA2 was 290. 290-276 = 14.
Exhaust is somewhat of a more controversial topic, but I like to think of it as a sound preference rather than a performance adder. People have put the stock mufflers on a flow bench and yes, there is a measureable drop in vacuum, which indicates a restriction. My issue is the assumption that the restriction is a flaw. Honda spent a lot of time and money on the exhaust design, which uses no packing (to save weight) and is frequency tuned to completely eliminate drone. Because the car is intended to be a daily driven street car, you want to have some backpressure because it improves throttle response off the line. Honda knew this. It all boils down to the design goal for the car. If Honda were designing a race car, where the working rpm is 6000 to 8000, they would remove the restriction to free up as much as 5 whp at the top of the rpm range, since the only time you were in the low range is in pit in/pit out. In racing you are going for every tenth on the track, which means chasing every whp. To assume the same design goal for a street car is illogical to me, especially considering the negative consequences like drone and lack of response at low rpm. But, some people want that shiny dyno chart...different strokes I suppose.
Sorry for the long winded explanation, but the bottom line is the factory exhaust is very good. You can get a little more power from an aftermarket unit, but at the expense of drone and a mushy throttle below 3000. Thus, to me it boils down to a sound preference. Many people do not like the factory exhaust because it is too quiet. That is a perfectly good reason to change it. My RM Racing quad-tip sounds BADASS.
As for fitment, let's assume you find a set of 97-99 NA2 headers. So, your parts are:
97-99 Headers
96 Muffler
91-94 Cats
Option #1 - Headers --> SOS Adapters --> 91-94 cats --> 96 Muffler
You will need to buy the SOS adapters unless you buy aftermarket headers that come with them. 91-96 mufflers are all the same layout. The difference is in the cats, which in 95-96 changed shape otensibly to accommodate the downstream O2 sensors. This required use of elbow adapters to fit the muffler. I suppose you could use 95-96 cats, but you would then need to buy the exhaust adapters:
Option #2 - Headers --> SOS Adapters --> 95-96 cats --> SOS Exhaust adapters --> 96 Muffler
Finally, you could use 97-99 Cats, which would eliminate the need for the header adapters, but you would still need the exhaust adapters:
Option #3 - Headers --> 97-99 cats --> SOS Exhaust adapters --> 96 Muffler
Your cheapest option is #1.
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