Page 1 of 2

RoadsterSport 4 Install

Posted: Tue Sep 03, 2019 2:58 pm
by MitchellD778
New member to this forum. I'm installing a RoadsterSport 4 and a MagnaFlow Cat on my 1990 Miata. I got the original exhaust off of the cat pretty easily and now trying to disconnect the Cat from the front pipe. I got one bolt off barely, it turned, but I could tell it was frozen up since it really never felt like it was loosening and then it snapped off. Thankfully enough of the bolt came off so I can get that side of the CAT off. The other bolt i'm having the same issues, was able to turn it (btw, used Kroil the night before) but it has stopped turning. I can turn it back some but still can't get it to break free. Leverage is rather poor, and the Cat is spinning back towards the car so I put a piece of wood in between the Cat and the car but still can't get it to budge. I'm worried about breaking the front pipe, any suggestions on loosening this bolt other than more Kroil, waiting and trying again? Should I try some heat on the bolt?

Thanks!

Re: RoadsterSport 4 Install

Posted: Tue Sep 03, 2019 6:27 pm
by jboemler
You probably can't break the header or cat, but you might end up twisting the bolt in two. No big deal, just replace it. Using some high-temp (copper) anti-seize will prevent having the same problem again.

Re: RoadsterSport 4 Install

Posted: Wed Sep 04, 2019 7:13 am
by MitchellD778
Another night of soaking and a fresh start did wonders. Made me wonder why I had such a hard time yesterday getting it off. This time I was able to unscrew it with out snapping it off. :)

Re: RoadsterSport 4 Install

Posted: Wed Sep 04, 2019 9:25 am
by Greg @ GWR
Since you need to replace the broken bolt you might as well get a pair and also replace the one you had to soak. Fresh bolts/nuts will be easier to handle. The anti-seize is also a good idea.

Re: RoadsterSport 4 Install

Posted: Wed Sep 04, 2019 10:18 am
by MitchellD778
Definitely new bolts since i'm replacing the CAT with a direct fit Magnaflow and I have to get bolts for the connection to the mid pipe (OEM Cat has the bolts threaded into the CAT). I already have some anti-seize, but I was wondering if you need washers or not? I'm assuming it wouldn't hurt to use washers since the bolt heads and nuts are not that much larger in comparison to the holes they go through. Probably a stupid question but have never done this before.

Re: RoadsterSport 4 Install

Posted: Wed Sep 04, 2019 8:05 pm
by Brian
First, I suggest hold on the cat swap...and try just the exhaust for now. After a few hundred miles of adding carbon on inside of new exhaust perhaps then add the Magnaflow cat, that will also let you hear the exhaust with stock cat, it will be different/louder with the Magnaflow.

Re: RoadsterSport 4 Install

Posted: Thu Sep 05, 2019 11:18 am
by MitchellD778
Hey Brian, i would have to drill out one of the bolts that is stuck in the Cat. Even if i get that out the threads might not be in the best of shape and i don't have a tap. And i have already done alot of secondary stuff like taking off the heat shield above the muffler and cleaning up the rust and painting and other general cleaning on areas that i can reach easier with the exhaust out of the car. I guess what i'm saying is not sure i want to do get under this car again in a month. Understand the car will be louder with the magnaflow and i got the extra baffle in case I need to dial it back some. Will replacing the magnaflow at the same time let too much carbon through initially and cause some issue or are you just thinking the sound will be alot louder and using the old cat would get me used to the change?

Re: RoadsterSport 4 Install

Posted: Sat Sep 07, 2019 8:36 am
by MitchellD778
I got the Magnaflow direct fit cat and RoadsterSport 4 installed and when i leak tested the cat has no leaks on either side but there is a leak between the muffler and the midpipe. The fit isn't great between these two sections; it is off angle and if i push up the muffler i don't get the tip clearance of 1/2 inch recommended in the instructions. I can't push down the midpipe any further either. Do i have to get the two flanges on the pipe completely parallel before tightening the v-clamp all the way down? Or will the v-clamp if i tighten as far as it will go eventually line them up enough so it won't leak?

Initially before tightening the bolts at the Cat i had all the bolts loosened up and still could not get the flanges parallel between the midpipe and the muffler. It could be the magna flow cat is not at the exact angle as the OEM CAT.

Suggestions?

Re: RoadsterSport 4 Install

Posted: Sat Sep 07, 2019 8:43 am
by Brian
We have seen same issues with Magnaflow cats. Back to stock cat if you need to, VClamps don't have much forgiveness, but if take turns on hardware before/after converter you might get it to compromise enough for both ends to seal up.

Re: RoadsterSport 4 Install

Posted: Sat Sep 07, 2019 8:56 am
by MitchellD778
I was a little gun shy on continuing to screw down the vclamp but I still had maybe an 1/2 inch or more left on the threads. What happens if i only have a 1/4 inch clearance on the tail pipe to the body, i have a feeling if i keep tightening the vclamp there is no way that i will have 1/2 inch of clearance, something has to give.

I'll try one more time, then i guess i'll start trying to get the bolt out of the cat so i can hopefully reuse.