After spending the better part of the past 2.5 days under the car exhaust system wrestling on 2 double plys of cardboard on a cold concrete floor I wanted to write a post with the links I found most useful and some things I noticed when installing a Cantrell header and exhaust onto a '94.
Definitely get yourself a Helms Manual if you don't have one.
Best starting point is the NSX-Wiki:
http://www.nsxprime.com/wiki/Installing_Exhaust
http://www.nsxprime.com/wiki/Installing_Headers
Heavy text based articles so if you want some visual references:
VBNSX's thread: http://www.nsxprime.com/forums/showthread.php?t=74785
* Wear safety glasses: a lot of dirt and grim builds up in all those nooks and crannies under the car. Once you start fussing around under there, it will start falling and more often than not: into your eyes.
*Although if I had to have done it again, I would have removed the central bolt of the front engine mount instead of the 3 little bolts. It makes it easier to slide the front beam out. Page 5 of http://www.tuckerbud.com/Track/Headers/DIYHeaders.doc shows you the exact tool configuration to get to it. Of course in my haste, I didn't get that far in my research.
* Liquid Wrench or similar is mandatory for the exhaust bolts on the catalytic converter if not the header also. I used it sparingly on the O2 sensor despite reading numerous sources stating not to do so.
* I don't know how people remove the front header without moving the AC compressor out of the way. The front heat shield could not be removed no matter how I rotated it, even after removing the O2 sensor. Without removing the heat shield, you can't get to the header bolts.
* No matter how I tried to rotate and shimmy the rear headers in, there was no way they were going to go between the cross beam and the trunk. Lifting the engine by tilting it forward was not going to help. I stumbled upon this thread: http://www.nsxprime.com/forums/showthread.php?t=19936 and i dropped the rear beam by just a half an inch like Larry said and it almost go it all the way in. On my NSX, I had to unbolt the rear sway bar and rotate it out of the way of the outlet of the header to slip it into place: there was only 1 specific series of minute orientation and direction changes for the rear headers to go in. Of course I didn't put the exhaust gasket and lube the bolts the first time I successfully maneuvered the header into place because I didn't want the gasket falling out at some inopportune time or oil dripping onto me...
* Make the investment and get an O2 sensor wrench if you don't already have one. It makes life a lot easier.
* On a '94 you will need to use O2 sensor extension wires. After trying a few combinations of front sensor to rear headers and rear sensor wire to front I stumbled across this thread: http://www.nsxprime.com/forums/showthread.php?t=38631 and found the most satisfactory set up: run the front extension over the engine and down the rear and connect it to the O2 sensor for the rear headers; run the rear sensor down to where the O2 sensor for the front headers will exit behind the oil pan. You can also remove the front bank O2 wire support clips for addition few grams weight savings. The Cantrell kit came with 2 brackets: I used 1 where rear O2 sensors were supported originally: right under the valve cover near the center of the head and the other on the heat shield on the axle to support the front O2 wire.
* On a '94 you will need to use exhaust adapters that will go between the header and catalytic converters. The best way to do this is I found was to loosely install the adapters onto the catalytic converters, then loosely attaching the catalytic converter to the exhaust, and then finally wrestling the adapter piece onto the header before torquing everything down.
* On a '94 you will have an extra hanger on the rear cross beam where the old front header hung on: it becomes vestigial with adapter pipes that do not have a hanger so I removed mine for a couple more ounces of weight savings.
2.5 days probably seems excessive for a header and exhaust install. Mostly because this was the first time I was doing this and took my time to try not to break anything even though I only had hand tools and keep track of all the fasteners. Doing it again, I could probably cut the time down to about a day. I don't know how the guys that do this in 5 hours do it: lots of practice is my guess.
Hopefully this thread pops up a lot in searches to help somebody down the road thinking about or attempting a DIY header install on a NSX. A lot of the observations/recommendations I mentioned were discovered by the wrong way of doing things, head scratching, reading other posts, and thinking things through. Thanks to all the other contributors of the threads I mentioned earlier.
Anybody interested about the fitment and finish of the Cantrell system: my opinion is for the price you pay, it is a good value. My requirements were for a system that produced more power than stock, lighter than stock and not obnoxiously loud. My only gripe on the headers would have been to weld all the way around the outside of the flange and grind down the welds smooth on the inside. The system fits perfectly. I also got the entire system ceramic coated to help keep engine bay and trunk temperatures down.
Time to go for a drive.
--
George
Definitely get yourself a Helms Manual if you don't have one.
Best starting point is the NSX-Wiki:
http://www.nsxprime.com/wiki/Installing_Exhaust
http://www.nsxprime.com/wiki/Installing_Headers
Heavy text based articles so if you want some visual references:
VBNSX's thread: http://www.nsxprime.com/forums/showthread.php?t=74785
* Wear safety glasses: a lot of dirt and grim builds up in all those nooks and crannies under the car. Once you start fussing around under there, it will start falling and more often than not: into your eyes.
*Although if I had to have done it again, I would have removed the central bolt of the front engine mount instead of the 3 little bolts. It makes it easier to slide the front beam out. Page 5 of http://www.tuckerbud.com/Track/Headers/DIYHeaders.doc shows you the exact tool configuration to get to it. Of course in my haste, I didn't get that far in my research.
* Liquid Wrench or similar is mandatory for the exhaust bolts on the catalytic converter if not the header also. I used it sparingly on the O2 sensor despite reading numerous sources stating not to do so.
* I don't know how people remove the front header without moving the AC compressor out of the way. The front heat shield could not be removed no matter how I rotated it, even after removing the O2 sensor. Without removing the heat shield, you can't get to the header bolts.
* No matter how I tried to rotate and shimmy the rear headers in, there was no way they were going to go between the cross beam and the trunk. Lifting the engine by tilting it forward was not going to help. I stumbled upon this thread: http://www.nsxprime.com/forums/showthread.php?t=19936 and i dropped the rear beam by just a half an inch like Larry said and it almost go it all the way in. On my NSX, I had to unbolt the rear sway bar and rotate it out of the way of the outlet of the header to slip it into place: there was only 1 specific series of minute orientation and direction changes for the rear headers to go in. Of course I didn't put the exhaust gasket and lube the bolts the first time I successfully maneuvered the header into place because I didn't want the gasket falling out at some inopportune time or oil dripping onto me...
* Make the investment and get an O2 sensor wrench if you don't already have one. It makes life a lot easier.
* On a '94 you will need to use O2 sensor extension wires. After trying a few combinations of front sensor to rear headers and rear sensor wire to front I stumbled across this thread: http://www.nsxprime.com/forums/showthread.php?t=38631 and found the most satisfactory set up: run the front extension over the engine and down the rear and connect it to the O2 sensor for the rear headers; run the rear sensor down to where the O2 sensor for the front headers will exit behind the oil pan. You can also remove the front bank O2 wire support clips for addition few grams weight savings. The Cantrell kit came with 2 brackets: I used 1 where rear O2 sensors were supported originally: right under the valve cover near the center of the head and the other on the heat shield on the axle to support the front O2 wire.
* On a '94 you will need to use exhaust adapters that will go between the header and catalytic converters. The best way to do this is I found was to loosely install the adapters onto the catalytic converters, then loosely attaching the catalytic converter to the exhaust, and then finally wrestling the adapter piece onto the header before torquing everything down.
* On a '94 you will have an extra hanger on the rear cross beam where the old front header hung on: it becomes vestigial with adapter pipes that do not have a hanger so I removed mine for a couple more ounces of weight savings.
2.5 days probably seems excessive for a header and exhaust install. Mostly because this was the first time I was doing this and took my time to try not to break anything even though I only had hand tools and keep track of all the fasteners. Doing it again, I could probably cut the time down to about a day. I don't know how the guys that do this in 5 hours do it: lots of practice is my guess.
Hopefully this thread pops up a lot in searches to help somebody down the road thinking about or attempting a DIY header install on a NSX. A lot of the observations/recommendations I mentioned were discovered by the wrong way of doing things, head scratching, reading other posts, and thinking things through. Thanks to all the other contributors of the threads I mentioned earlier.
Anybody interested about the fitment and finish of the Cantrell system: my opinion is for the price you pay, it is a good value. My requirements were for a system that produced more power than stock, lighter than stock and not obnoxiously loud. My only gripe on the headers would have been to weld all the way around the outside of the flange and grind down the welds smooth on the inside. The system fits perfectly. I also got the entire system ceramic coated to help keep engine bay and trunk temperatures down.
Time to go for a drive.
--
George
