PENROSE

iTrader: (1)

Can you get to all the bolts from underneath the car? Or do you have to remove stuff from the engine bay, and go through there too?

Trying to decide if I can do this myself, or if I should have a shop do it. What would a shop charge?

I am 2010 awd sedan.

Thanks

nickw

youll need a lift to get under the car, or roll it up on the little car ramps and try to get it from there .

godzilla619

iTrader: (1)

if you have a few extensions for your socket set with universal joints you can get to them from underneath, but it will be a PITA to get off a couple of the header bolts. Most shops will charge you <$200 to install HFCs.

DeamonG37s

On my g37s coupe I went through bottom of car and removed the intakes to get mine off. U need a torch to heat them up. Don't even bother if u don't have a torch. Send it to a shop hassle free otherwise ur in for a high flow sweat.

GotAir523

iTrader: (2)

I installed mine in my garage. Put the car on jack stands. The bottom 2 bolts you can get to underneath, the one on the outside you'll be turning for a while as its a tight fit in there. The top bolt however you're going to have to go through the engine bay, it's really the only way. When doing mine, had to look it up on the 370 forum cuz everyone on here took theirs to a shop. Pretty much get about 20" of extensions (I think it was 24) and fish it from either side of the engine onto the top bolt of the cats, and turn. Caution that bolt is a PITA to get off, we ended up breaking both of them cuz we had to push/pull so hard to break it loose. Forewarning, there's going to be a lot of flex when using that much extensions, but it can be done in a garage with some muscle an tools

Black Betty

iTrader: (60)

I paid to have my HFC installed a while back ($250 at the Infiniti dealership) and took them back off and put the OEM cats back on this past weekend. That job is easier than the other way around. I was able to remove all the bolts from the bottom but the HFC had slightly different bolts than the cats do. The biggest potential problem is breaking the bolt that goes in from the top. It is very inaccessible and will be difficult to get out if you break it off. Spray them with PB blaster twice a day for a couple of days before tackling the job to let it thoroughly soak the bolts, it makes breaking them loose much easier. Be very careful removing the O2 sensors, they are easy to damage. Make sure you will be able to complete the job so you don't get half way through, encounter a problem, and find that you need your car but it can't be driven because the job is unfinished. Allow plenty of time. it really helps if you have an air impact gun. Also make sure that you use plenty of good anti seize compound when installing the HFC so that that the fasteners will come off easily when it's time to remove them.