Rusty's Renix Performance Mods Any Good??

1989 XJ 4.0, AW-4, OEM exhaust. 323,000 miles. Running great.

Would like it to run better. Looking at Rusty's throttle body spacer and air tube, aka, "poor man's FIPK". Are these mods worthwhile?

--Karl

save your money, or spend it on a more worthwhile upgrade. The limiting factor of the Renix motor intake flow is more the head than the intake. If you really want to do the intake then spend that money on an HO intake, and mate it to your Renix.

ok here's my opinion: An airtube is easy to make, just buy one of those cheap ricer air filters at the parts store, get a piece of pipe, stick it on the end of the rubber tube, then make a bracket to hold it up. Add hose barbs to the pipe so you can hook up the vaccum lines, or use breather filters on the big ones. then take the money you saved and get a better muffler instead of the spacer. Rusty's has a muffler/tailpipe package, I've heard it fits well and there's a few muffler choices. I just got a 20$ thrush turbo muffler and clamped that on.

323,000 miles? wow. my renix blew up at 211,000, but I helped it a little. the "new" motor is at 220,000

Rusty's air tube is a good deal IMHO. I have the saws and welders necessary to build my own and I still went with Rustys. I also think his catback exhaust system is pretty tough to beat. I would do the exhaust and air tube first then the throttle body bore and spacer. Is the spacer or a bored out throttle body needed? - No probably not, but neither is TV, but necessity and enjoyment are two different things. Good Luck

Woody