it seems like my car is loosing power after some really spirited driving (when it's extremely hot), and exhaust noise changes too (it becomes more "softer").

so, I guess, maybe it's Berk's HFC dying? some time ago both gaskets on them were burned and I changed them to the metallic rings and when mechanics looked inside of the cats they saw some deformation of the metallic web inside, though not very bad (to their opinion).

are there any other reasons for my car to loose power after the spirited driving?

 

have you replaced the stock intakes with pod filters by any chance?

if it's a restriction in the exhaust you *should* feel it all the time

 

hmm.... how old are the hfcs?

 

I have my HFC's for year and a half and I have stock intake!

My exhaust is: Berk's HFC -> Moroso spiral flow resonators (to reduce rasp and drone) -> Borla true-dual cat-back H-pipe.

I'm not sure if it's Berk's fault in power loss, when the car is extremely hot, but I don't have any other clues...

 

Borderline limp mode?

The hotter the car gets past the threshold, the more it cuts power...

 

Oh, it can be this way! Thank you for this idea

Maybe I should remove my huge custom fiberglass engine undercover, though it has all the holes as a stock plastic...

What else can be done to not going into that borderline limp mode?

 

invest in an OBD scan tool that will show you engine temps as well. these needles dont move enough to show us if the car is just warmed up, or getting to a point of where it reaches temps it shouldnt.

see the temps that it sits at, when driving is normal.
then compare the temps when you feel the car is losing power....

 

Welcome to limp mode.

 

FYI - Loose is the opposite of tight, lose is the opposite of win.

 

Get the largest oil cooler that is available to you. You can cheap out and get a small one now, but as your driving develops, if you hit limp mode again, you're just gonna wish you had the larger one.

Undercover? As in underbody tray? Leave it in place. A vented hood could help.

 

A oil temp gauge will help too

 

If your tooth is LOOSE, you will probably LOSE it


anyway, get an oil cooler. that will help/prevent limp mode

 

don't you have a G35 HR? Cuz the HR does not suffer from oil temps as bad as the VHR. I would recommend checking the coolant temp though.

 

Yes, I do have g35 vq35hr and recently I added Stillen transmission cooler.

My custom fiberglass underbody cover is thick and rather heavy, so I replaced it today with the stock thin plastic. But now I feel my front end is rather loose (strong undercover works like brace), so I will drill some vent holes in it and return it to the place!

And yes, I will remove upper engine cover (with infiniti logo) for summer.

P.s. English is not my native language, so i make mistakes sometimes

 

Larger radiator, oil cooler, vented hood. The underbody panel shouldn't make a difference unless it is smaller than the factory one. It's not a load bearing member