DIY ZSpeed NISMO 370Z Aluminum Under Pan Diffuser

[wind.zero]

I ordered this from Joe at ZSpeed as soon as it was available. I also have the GTM SC Stage 1 installed which caused some installation hassles. In other words, it is not a perfect fit because of the IC piping and the oil filter relocation kit, but it is pretty close. I appreciate the help and excellent customer service from ZSpeed.

First, the product is of exceptional quality and is shipped in a quick, safe, and professionally manner. I literally had the items in hand 3 days after ordering them over a weekend.

Second, I had some install and fitment issues due to the GTM SC kit. These issues DO NOT apply to a NA NISMO. Please don’t let my issues hinder your order of the kit.

The GTM SC kit uses the vacant space on each side of the bumper which makes fitment challenging. In fact, fitting the OEM plastic piece is really tight. The IC piping/air filters occupy the passenger side, and the oil filter relocation kit, oil filter, and oil cooler are stuffed into the driver side. Thus, installing something less pliable like aluminum is a little difficult. Joe has some variance in the mounting points but not enough to perfectly cohabitate with the SC pieces.

The install is as simple as removing the obnoxiously expensive (~$930 USD) OEM plastic piece and replacing it with the three pieces from ZSpeed. The only real tip I can give is to install the side pieces first, then align and install the middle piece. Also, since I am SC’ed the oil change access panel gives a great view of a sandwich plate and oil lines, but I knew this from the start. However, oil changes can be performed by just removing the center piece rather than all of the pieces so it is still simpler.

I am tired of seeing this:


So the primary reason for ordering the ZSpeed kit was for the vent to pull in air directly to the oil pan. Plus, I think it looks better than plastic and provides a greater degree of protection from road debris. I know that I could have cut a hole in the OEM plastic piece, but that thing is expensive and I was not motivated to cut it. I will keep it to return the car to stock if that day ever comes.

This is the $930 OEM plastic under tray


Packaged ZSpeed Aluminum Under Pan Diffuser


The side pieces


The center piece


The problem areas because of the GTM SC kit


The biggest problem is the IC piping on the passenger side. This contact causes a cold start vibration which goes away after reaching operating temperature. I am going to try and isolate the vibration with some cut radiator hose between the IC piping and the diffuser.


I used some high temperature resistant loom for now, but still have the vibration.


One mount point had to be zip tied on each side piece due to tight fitment with SC parts. This shows the driver side. It is the same location on the passenger side. It is the deepest hole so the wheel/tire hides the view of the zip tie area. On the driver side, the bolt would hit the oil lines, on the passenger side, they just do not line up due to the IC piping skewing the ZSpeed part.


Also on the center piece, these holes do not align. With all of the other mounts tightened down securely, everything still appears to be very secure. There are still 6 mounting points in the front and 4 along the back. I do not think missing these 2 is the end of the world. Again, this alignment issue is due to the GTM SC kit and not ZSpeed.


This shot shows the air vent and flow to my GReddy oil pan.


Driving Impressions:
It has only been on for four days. I have a cold start vibration which I believe is from the IC piping contact. It goes away after driving about 5-10 minutes. I hope to cushion or isolate the vibration with some split radiator hose where the metal on metal contact is occurring.

The highest oil temperatures I have seen so far have been in the 220 range. However, it has only been in the low 80’s and I have not really gotten on the boost yet. So far so good.

I encourage anyone with a NA NISMO to get this kit. I think it is well worth the price of admission. If you are FI (SC or TT), you might give it some thought.

Thanks Joe @ ZSpeed.

Oil cooling efforts so far ….

1. GTM 25R Oil Cooler
2. GReddy Turbo Oil Pan
3. Venter Fender Lining
4. ZSpeed vented Under Pan Diffuser

Coming soon: SPAL pusher fan on the 25R Oil Cooler.

[Cell]

Even with an oil cooler you still hit 260... Is that with mild boost or hard driving?

[wind.zero]

Originally Posted by Cell

Even with an oil cooler you still hit 260... Is that with mild boost or hard driving?

^^
Yes even with a 25R oil cooler. The NISMO bumper has very little air flow and the oil cooler is stuffed into the driver side pocket of the bumper.



260 is an exception and not the norm. But I still do not like seeing that on the gauge. In the heat of the summer, cruising on the highway, I run 220-240. Get into boost and 260 is easily achieved. Depending on the ambient air temperatures and humidity, sometimes temperatures come back down to a reasonable level, sometimes they don't.

260 happens with hard driving combined with ambient air temperatures as low as 80 degrees though. I am confident that the SPAL fan will cure the problem.

I saw 260 last week and it was 78 degrees after some spirited, high speed driving.

[Joe@ZSpeed]

Thanks for the write up! I appreciate your time and effort.

A couple vents in the drivers side panel maybe? That would help get some air coming across the oil cooler...

[wind.zero]

^^
Affirmative

This would fix it, but I just cannot cut a hole in the NISMO bumper, yet.

GTM Oil Cooler NACA Duct

[koffeegy]

Originally Posted by wind.zero

^^
Yes even with a 25R oil cooler. The NISMO bumper has very little air flow and the oil cooler is stuffed into the driver side pocket of the bumper.



260 is an exception and not the norm. But I still do not like seeing that on the gauge. In the heat of the summer, cruising on the highway, I run 220-240. Get into boost and 260 is easily achieved. Depending on the ambient air temperatures and humidity, sometimes temperatures come back down to a reasonable level, sometimes they don't.

260 happens with hard driving combined with ambient air temperatures as low as 80 degrees though. I am confident that the SPAL fan will cure the problem.

I saw 260 last week and it was 78 degrees after some spirited, high speed driving.

I was under the impression that the 25R oil cooler was designed to be open to the direct air flow being forced in through the opening in the bumper at higher speeds. Just like the radiator has to in the path of the best air flow. Just my opinion... But I think if you relocate the oil cooler to in front of the radiator, you should probably see better results. I just don't see it getting the proper amount of air circulation through the coils hidden off to the side. Just like the radiator needs the air to cool off the coils... so des the oil cooler.

[wind.zero]

I can't relocate the oil cooler to the front because of the FMIC.



I have the SPAL fan and relay, but I have not had the time to install it. I have already vented the fender lining. The fan should push air over the oil cooler and out the vent in the fender lining. This should be a problem solved on the high oil temperatures.

Vented Fender Lining

[Joe@ZSpeed]

Originally Posted by wind.zero

^^
Affirmative

This would fix it, but I just cannot cut a hole in the NISMO bumper, yet.

GTM Oil Cooler NACA Duct

I meant in the corner piece of the aluminum pan wing.

[gy954]

As to air flow, etc., might one get a front fender similar to the Branew (pic below) or hot wheels? But as I wrote that, I realized you may have some mod on your car that makes fitment of the Branew impossible. <sigh> Heck of a problem to have!

[gy954]

I was surfing around and came across the following. Hope it helps.

DIY: Fender Lining Vent for Oil Cooler GTM Supercharger Stage 1 on NISMO

[koffeegy]

Originally Posted by gy954

I was surfing around and came across the following. Hope it helps.

DIY: Fender Lining Vent for Oil Cooler GTM Supercharger Stage 1 on NISMO

Lolololololololololololol. Look who posted both of these. Good try.

Sorry, I meant no offense.

[gy954]

Oh brother, I just re-checked the posters. Yup the same person. LOL! What a doofus!! Wait a minute--that's ME we're talking about.

[theDreamer]

Looks good, interesting about the rubbing with the SC kit, I still want to order this since I am getting the Nismo front but wondering about the vibration.
The zip tie fix does not seem that big of a deal if it can hold the under tray properly.

[wind.zero]

Originally Posted by theDreamer

Looks good, interesting about the rubbing with the SC kit, I still want to order this since I am getting the Nismo front but wondering about the vibration.
The zip tie fix does not seem that big of a deal if it can hold the under tray properly.

Thanks

If you look here, the right circle shows where the IC piping was on the OEM piece. The left circle had to be zip tied with the OEM piece because of the oil lines. Everything is just really tight with the SC kit.

It has been on a week now and no issues. The vibration is only on a cold start. I got on it Wednesday and today and nothing flew out from under the car

[wind.zero]

UPDATE

I purchased a Spectre silicon coupler ($7.99) from Autozone and split it down the middle. I then cut that into 2 pieces. I zip tied the pieces to the IC piping and that eliminated the cold start vibration.

This picture shows where the direct contact was made with the IC piping. This contact occurred with the plastic under tray and the ZSpeed diffuser. Again, this is NOT a fitment problem with the ZSpeed part. It is a fitment problem with the supercharger IC piping.


This picture shows the coupler zip tied to the IC piping to eliminate the metal on metal contact and cured the cold start vibration.