I ordered a Magnaflow cat back for my 1990 L-98. They were running a promotion giving a free hi flow cat with your order. So today I pulled my Y pipe and cat. Every thing is real clean under the car so it all came off easy. I had to move her back into the garage and WOW! Loud, but man it has some power now. Anyone use the open cat and cat back system? Will she still breath near this?

 

I didn't dotice any bad effects. My rear y pipe was rusted through where it adjoins the mufflers so I replaced it. The motor will rev quicker. The sound at cruising speeds is the same and the resonance is still present. On cold mornings when I crank it up and let idle for the warm up, I have noticed that the passenger side exhaust draws in air and the drivers side exhaust blows out until the pipes warm up and then they both expell the gasses the same. My rear Y-pipe has the cross over tube thats supposed to equalize the pressures. I hate all the gimmicks. In my opinion the best bolt-on performance mods that you can do is make sure that all of the stock emission system, sensors and fuel delivery systems are working properly. Everything that is claimed to boost HP is at WOT and will never really be realized at normal or spirited driving. My motor has 186K miles and still runs as strong as the day it was new. Just do the routine maintenence stuff and drive the car for what it is. If you want a race car then buy one and change the motor and work on it all the time. The custom chip will show some gains on a stock motor, but add one with the correct hardware(T-stat). Learning the hard way.

 

You should do it with open long tube headers and no front y-pipe. I had to back the vette out of the garage while my exhaust was off. The stuff on the walls was rattling just idling.

 

Lucky you didn't melt anything, I speak ffrom personl exp!