[BMR_GTR]

So I finally got my car up on a lift since I purchased it. A little disappointed. The undercarriage bolts are all badly corroded and some are even broken off so that's going to be fun to get them out.

Anyway the other thing I noticed is there was only 1 bolt from each downpipe to the midpipe. The inner connections were just empty holes. Is there any chance it came from the factory like this? I had it at the GTR dealership for all the 3 year services and the tech didn't say anything? Can it stay like this or do I need to get the right bolts? Pardon my noobness but I've done almost no work on cars myself so this is all new to me.

I'm wondering if the car maybe had a midpipe and then the previous owner put it back to stock. But strange they left the intakes on the car.

 

[Gdzilla_]

Any chance from factory? Highly doubt it.
Any chance from previous owner? Highly susceptible.

 

[crepr12]

Nah...Not factory. Previous owner was a freaking Yahoo...

 

[kholdstare]

Yes you have to install the missing bolts. fuel lines are not far away you don’t want exhaust gas near there. also suggest to do all gaskets new in that section.

 

[GT-Rpilot]

Concur. Previous owner likely half-assed a MP DIY replacement back to stock to sell the part off, and left you with the results, either by not properly tightening the bolts (they came loose) or by simply not putting them back in at all. Did you buy directly from owner or through a dealer? If the former, I would contact this person with questions. If the latter, then it is what it is - get some new bolts put in. Regarding the undercarriage tray fasteners, they have a known history of corrosion - I don't have the thread handy, but there are some companies that sell a titanium replacement kit that includes all new hardware for this very case. You can do a search for that.

 

[NissanassassiN]

Here's the thread for bolts:

Undercarriage Bolt Kit

I searched the forums and most of the stuff that came up was older. I have a MY18 that was actually put into service in 2019 but being in Canada it must have seen some winter. Anyway all the underbolts are rusted and I'd like a kit to replace them. Anyone have any luck with this Kit ? If not...

www.gtrlife.com

 

[L.L.]

If you haven't already, I would also suggest inspecting the nuts behind the flanges on the downpipe side to ensure they're not corroded to the point where a bolt will keep getting stripped, necessitating running a tap through the female side. It just seems strange that the pair were left in that state. It was either a rush job or maybe the previous owner had issues getting bolts in there due to the corrosion.

 

[BMR_GTR]

If you haven't already, I would also suggest inspecting the nuts behind the flanges on the downpipe side to ensure they're not corroded to the point where a bolt will keep getting stripped, necessitating running a tap through the female side. It just seems strange that the pair were left in that state. It was either a rush job or maybe the previous owner had issues getting bolts in there due to the corrosion.

I have the new gaskets, studs and nuts on order at my local Nissan dealership. Any idea what the thread of those studs are so I can make sure I have the right tap if necessary.

 

[L.L.]

I have the new gaskets, studs and nuts on order at my local Nissan dealership. Any idea what the thread of those studs are so I can make sure I have the right tap if necessary.

Should be M10x1.25

 

[Wicked]

Now would be the time for an aftermarket mid pipe!

 

[BMR_GTR]

Now would be the time for an aftermarket mid pipe!

Oh I know!!

 

[BMR_GTR]

As I'm starting to repair this situation that the previous owner left me with I'm starting to believe that the previous owner had a full cat back on the car and then put it back before trading it in to the dealer. There was also an accessport mount in the car which leads me to believe it was tuned. If they left it tuned for the exhaust but put the factory exhaust back on is there any harm? There is a large amount of carbon that gets deposited on the exhaust tips each time I drive.

 

[GT-Rpilot]

More than likely it was tuned, then re-flashed with a "stock" tune when the parts were removed. A tune via Cobb AccessPort or EcuTek is required when adding 3" intakes which is one of the very first mods owners do - typical entry-level mods for "best bang for the buck" power increase is intakes, Midpipe and tune. After that, it's replacing the downpipes and injectors for the basic "FBO" or full bolt-ons upgrade. Adding a catback exhaust system doesn't really yield much power, but a lot of people do it for better sound or to lose some weight (full titanium). When an owner wants to go back to stock, they get a base tune that emulates the stock configuration, so the OEM parts will work again - generally easier to trade a GT-R in if it's not modded, and a lot of owners likely don't even disclose to the dealer that it was ever modded. Even stock, these cars produce soot, but it's much worse when modded.