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RM Racing Headers/Exhaust Minor Issues

20 January 2004
Just curious if anyone had experienced what I ran into today. I've got several of Randy's parts on the car, including the headers and oval tip exhaust. I know that both pieces are (were, rather) handmade at B&B, but my tech found a couple of issues. We've been replacing every NSX wear item as part of my 'refreshing' program, went to do the O2 sensors and found that the RM headers face the forward oxygen sensor right into the firewall and do not leave enough room for it to be removed. The sensor is also located in a primary as opposed to in a collector, as the other sensor is. Considering this is an OBD1 car, the O2 sensors are used to monitor the two banks (as opposed to OBD2 pre and post cat measurements) and should both measure from as similar a location as possible to each other. My tech didn't exactly love it, but what he really didn't like was having to remove the entire header to change out the O2 sensor (figured i'd really make his day, so I had him put in a new oil pan gasket while he was in there :) ). Also, IMO the welds were not very pretty, though they showed no signs of stress, which is what counts. The other issue is with the RM exhaust...a small crack had developed where one tailpipe exited the canister, and both ends of the can had started to separate at the edges about an inch long. He took it down and welded it, good as new (his welds are much nicer)...was wondering if anyone else had run into these two issues, both items have been on the car for some time and I have no qualms, no big deal, just curious.

By the way, anyone in NY looking for a good shop...I would highly recommend RPM NYC, I have no affiliation but I know how hard it is to find competent guys, tell 'em Jon sent you and they'll assume you're as particular about your car as I am.

- Jon
Re: RM Racing Minor Issues

Glad to hear they did a good job on your car and everything is well now. Did they resolve that other thingy you had going on by the way ?
Yup, runs great and even feels a tiny bit quicker with all the maintenance done. Gearbox is nice with the clutch rod and shift cables adjusted, and Synchromesh installed. Almost have it in showroom condition, going to order new seat leather to get it perfect and maybe update everything to the perforated '00-up pieces. BTW, sorry I couldn't make it this weekend.

- Jon

That is just how the RM headers are, I have then too. What you can do is take the front beam and rear mounts off then rotate the engine slightly to get the 02 sensor out. I agree the welds are not pretty, but mine have been on for 6 years trouble free.

So it goes:)

I installed a set of the RM headers and exhaust about 7 years ago and really like the product.

I just had my 91 in to the dealer to get the front O2 sensor replaced (as well as installing my spanking new HKS HyperMax 2 struts installed!) Last year when the heater in the sensor failed (that's error 41 I believe) I tried to replace it and I couldn't get the thing off to save my life.

The dealer had to remove the header and torch the thing off - it was on there to stay! After cleaning up the threads the new one went in fine. They inspected all the welds and said it was 100%. The sensor could have been removed in place had it not been fused to the header, so that positioning wasn't the big issue. The issue my tech mentioned is that many early NSXs have that heater go out. I'm glad mine didn't let him down.

I was very disappointed with the weld quality on my set of RM headers. Sure they were solid, like Larry B says, but they were rough and covered with slag. Not ideal for improving gas flow which is sort of one of the main reasons one puts headers on an engine. So I spent an hour or so on each header smoothing out the inside welds with a Dremel tool. This is something that should have been done at the factory, not left to the purchaser. I complained about this to Randy Marchetti and he said that should not have happened and 'he would look into it'. But it is a cost cutting measure and I suspect their construction method has not changed.

I also had the same problem with the front O2 sensor. But my Acura dealer was able to get it out - with a lot of cursing! Again this is a cost cutting measure and a necessity because the collector design of the RM header does not allow the sensor to be mounted in the collector where it should be.

If you want top quality buy the Taitec (my first choice) or Comptec (my second) headers. But for a little less money you get a little less quality in a perfectly adequate header.
If you want top quality buy the Taitec (my first choice) or Comptec (my second) headers. But for a little less money you get a little less quality in a perfectly adequate header.

I paid $1499 for my RM's a few years back - Is that the "less money" part? :smile: The Taitec's do look pretty neat, but when I bought the RM's there were OEM, RM and Comptech and that was it!
For what it's worth, here's a link to my recent experiences with the B&B exhaust. I forgot to mention that the muffler seems to be good quality and the flanges that bolt to the cat are really beefy. Maybe I'm just getting old .. my son thinks it sounds awesome and as good or better than the Borla cat-back that he recently put on his car (non-NSX)