Why the plastic cover over the bottom of engine?

jakoye · 07-17-2009, 12:23 PM

Here's a reader review of the 370Z off of cars.com. Funny, because I have a Mustang GT too and I'm thinking of doing the same thing: giving up the 'Stang for the Z!

I'm curious if anyone can answer his question about why Nissan put a plastic cover over the bottom of the engine? Is it as simple as "low car, protect the engine from pavement scraping"?

Quote:

"I gave up my Mustang GT for this little gem (Silver touring with nav and 6 speed)and don't regret it. It handles like no other car I have ever driven and even the ride is better than expected. The power rush is unbelievable for 3.7 liters and just about ever one gives it a double take, little wonder, it's probably the only one in town. I am unfamiliar with the overall reliability of this particular machine which appears to be very technical and closely packaged.

My only gripe at this point is why the 16 bolt plastic pan covering the entire engine bottom including the oil drain plug and filter??? Why 16 bolts for a plastic cover, it costs an extra $10.00 for an oil change due to the labor required for removal and reinstallation!!!"

2009 Nissan 370Z Consumer Reviews

kdo2milger · 07-17-2009, 12:29 PM

I had a 04 mach1, gave to my brother and got a z, i dont regret it at all, but i do miss the mach...

airflow restriction.

its there to create less drag, less drag=less air restriction=more stick to the road ...

6MT · 07-17-2009, 12:32 PM

Duhhh ... isn't fer those back woods trails ... and them four by fours? Ta keep da mud an' guck out?

(just kidding)

Modshack · 07-17-2009, 12:37 PM

Quote:

Originally Posted by jakoye

Is it as simple as "low car, protect the engine from pavement scraping"?

Ummm...No. less than 1/16" of plastic isn't gonna protect anything. It is for aerodynamics. Reduces turbulance and lift. Many modern cars emply a similar cover (I wouldn't put Mustang in that "modern" category)....

OMGWTFBBQ · 07-17-2009, 12:38 PM

I'm not sure which piece you're talking about because I've never actually looked underneath my car, but I think that piece is there to create a "flat-bottom" type effect? It's a somewhat functional aerodynamic piece I believe.

Edit: Just read Modshack's explanation haha.

Trips · 07-17-2009, 12:49 PM

Like kdo2milger said it's an aerodynamic piece most other manufacturers do it also like Mercedes and Bmw, it is there to keep airflow from goint up into engine compartment to a minimum this is part of the less drag test they do at high speed, is there someone who can chime in and correct me if I'm wrong?

kannibul · 07-17-2009, 01:31 PM

It'll also keep dirt and junk out of the engine bay...

Might be a PITA to get off and have to deal with for oil changes, but from what I've seen, at least they put the filter and drain in the right spot...unlike my Honda Civic - reach up passed the exhaust, between the steering components to the back of the engine...way up there where your arm is basically a straight shot to your arm pit...where hot oil will cause the MOST pain...with that, I've taken to removing the front driver's side tire/wheel, and going in through the side to get around that hurdle...

zZSportZz · 07-17-2009, 01:34 PM

You can just take off the back four bolts and fold the plastic along the designated crease (it was made to do this) if you are lazy. I take off all 16 bolts and remove it during an oil change.

AK370Z · 07-17-2009, 01:37 PM

Quote:

Originally Posted by OMGWTFBBQ

I'm not sure which piece you're talking about because I've never actually looked underneath my car, but I think that piece is there to create a "flat-bottom" type effect? It's a somewhat functional aerodynamic piece I believe.

jakoye · 07-17-2009, 03:40 PM

Quote:

Originally Posted by Modshack

Many modern cars emply a similar cover (I wouldn't put Mustang in that "modern" category)....

Haha! Yeah, I can see why people would think that, especially with the solid rear axle.

I can't really complain though. The 'Stang has been a good car for me. I'd always wanted a Mustang (growing up, that was THE car) and when they redesigned it, Ford had me hooked. I just put some FRP axle-backs on it too. Nice sound. Not too loud and no drone. And no "fart" sound either!

I owned a Z back in the day. An '86 300. I loved the car, but it was kind of a POS. Soooo many problems with it. But with the 370 model... well, Nissan's got their hooks back in me! I've got new car fever again!

But I'm trying to be good and wait until it makes financial sense. With the economy the way it is, big purchases of any kind seems like the wrong idea. So I'm waiting for a bit. We'll see how long I can hold out.

kannibul · 07-17-2009, 04:28 PM

If it were me...with a Mustang - the last thing I would do to that exhaust is anything but make it sound like a AAA Dragster...or a classic muscle car with glass packs...

I heard a buzz-box exhaust on a Mustang the other day...

I just laughed. What a waste of a good sounding engine. Save the buzz boxes for the FWD 4-bangers with the huge wing.

av370 · 07-17-2009, 04:52 PM

Ive got a 04 gt convertable, damm good car. If ford would have put a 6 speed in this year instead of a two decade old 5 speed there would have been one in my garage instead of the Z,kinda glad that didnt happen.

mrarroyo · 07-17-2009, 07:42 PM

My 02 Audi TT had one and it was a pain to change the oil/filter. But you live with it due to the added performance.

Modshack · 07-17-2009, 07:49 PM

Quote:

Originally Posted by mrarroyo

My 02 Audi TT had one and it was a pain to change the oil/filter. But you live with it due to the added performance.

The Aud part was a little more substantial (had one too). The Z piece is really a thin piece of plastic...
Pretty cheezy..

RCZ · 07-17-2009, 08:16 PM

Modern cars makers try to keep the bottom of their cars as flat as possible to minimize drag and maximize downforce. In the case of the drag, obviously a smooth surface will create less drag than an irregular one (such as the bottom of your car). For downforce, its used like an upside down airplane wing. Airplane wings create lift through their shape because the shape of the wing causes air to move faster above it than below it. That creates low pressure and essentially sucks the plane's wing upwards. Same thing applies to undercar surfaces and rear diffussers, except instead of creating lift ABOVE the car, you create the low pressure underneath the car, so that it sucks the car towards the ground.

A rear diffuser creates the same effect underneath the rear of the car. It creates negative lift and cleans up the air underneath the rear, effectively adding stability and downforce.

Here's s pic of modern day supercars to give you a better idea...

Enzo:

GT-R

In the 70's they tried installing big fans that would suck the air out from underneath the car, effectively vacuuming it to the track. That got outlawed quick... heres a quote:

"Lotus, in 1978, developed a fully shaped underbody to its Formula 1 car that, along with sliding side skirts, created a low pressure area under the car allowing cornering speeds to soar. The side skirts would wear and often break and the sudden loss of vacuum would result in catastrophic accidents. This technique of ground effects was also banned."

"

Makes for a fun read.

http://jimsgarage.wordpress.com/2007...round-effects/

07-17-2009, 12:29 PM	#2 (permalink)
kdo2milger OG Priesthood Join Date: Feb 2009 Location: Fargo, ND Posts: 17,859 Drives: NISMO T Rep Power: 59	I had a 04 mach1, gave to my brother and got a z, i dont regret it at all, but i do miss the mach... airflow restriction. its there to create less drag, less drag=less air restriction=more stick to the road ... __________________ Project *NISMO*

07-17-2009, 12:32 PM	#3 (permalink)
6MT A True Z Fanatic Join Date: May 2009 Location: ITU Zone 2 Posts: 22,459 Drives: Reliant Robin Rep Power: 1790	Duhhh ... isn't fer those back woods trails ... and them four by fours? Ta keep da mud an' guck out? (just kidding) __________________ Andrew 2009 370Z Sport/Touring 6MT sold 2013 Honda Civic Si coupe D/D

07-17-2009, 12:38 PM	#5 (permalink)
OMGWTFBBQ A True Z Fanatic Join Date: Jan 2009 Location: the OC Posts: 1,886 Drives: 08 SGM IS350 Rep Power: 4549	I'm not sure which piece you're talking about because I've never actually looked underneath my car, but I think that piece is there to create a "flat-bottom" type effect? It's a somewhat functional aerodynamic piece I believe. Edit: Just read Modshack's explanation haha. __________________ Zele Performance \| Varis \| Powerhouse Amuse \| Craftsquare \| Tommy Kaira \| Top Secret \| HKS \| Defi \| Volk Racing \| Cusco \| SPL \| Never ending build thread.. PM me if you have rare JDM parts for sale!

07-17-2009, 12:49 PM	#6 (permalink)
Trips Administrator Join Date: May 2009 Location: Disneyland, Ca Posts: 8,730 Drives: 🔰 Rep Power: 10	Like kdo2milger said it's an aerodynamic piece most other manufacturers do it also like Mercedes and Bmw, it is there to keep airflow from goint up into engine compartment to a minimum this is part of the less drag test they do at high speed, is there someone who can chime in and correct me if I'm wrong? __________________

07-17-2009, 08:16 PM	#15 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1118	Modern cars makers try to keep the bottom of their cars as flat as possible to minimize drag and maximize downforce. In the case of the drag, obviously a smooth surface will create less drag than an irregular one (such as the bottom of your car). For downforce, its used like an upside down airplane wing. Airplane wings create lift through their shape because the shape of the wing causes air to move faster above it than below it. That creates low pressure and essentially sucks the plane's wing upwards. Same thing applies to undercar surfaces and rear diffussers, except instead of creating lift ABOVE the car, you create the low pressure underneath the car, so that it sucks the car towards the ground. A rear diffuser creates the same effect underneath the rear of the car. It creates negative lift and cleans up the air underneath the rear, effectively adding stability and downforce. Here's s pic of modern day supercars to give you a better idea... Enzo: GT-R In the 70's they tried installing big fans that would suck the air out from underneath the car, effectively vacuuming it to the track. That got outlawed quick... heres a quote: "Lotus, in 1978, developed a fully shaped underbody to its Formula 1 car that, along with sliding side skirts, created a low pressure area under the car allowing cornering speeds to soar. The side skirts would wear and often break and the sudden loss of vacuum would result in catastrophic accidents. This technique of ground effects was also banned." " Makes for a fun read. http://jimsgarage.wordpress.com/2007...round-effects/ Last edited by RCZ; 07-17-2009 at 08:26 PM.

07-17-2009, 01:31 PM	#7 (permalink)
kannibul A True Z Fanatic Join Date: Jun 2009 Location: Jenks, OK Posts: 2,281 Drives: 370z Touring/Sport Rep Power: 267	It'll also keep dirt and junk out of the engine bay... Might be a PITA to get off and have to deal with for oil changes, but from what I've seen, at least they put the filter and drain in the right spot...unlike my Honda Civic - reach up passed the exhaust, between the steering components to the back of the engine...way up there where your arm is basically a straight shot to your arm pit...where hot oil will cause the MOST pain...with that, I've taken to removing the front driver's side tire/wheel, and going in through the side to get around that hurdle...

07-17-2009, 01:34 PM	#8 (permalink)
zZSportZz A True Z Fanatic Join Date: Mar 2009 Location: Maryland Posts: 1,095 Drives: 370z Blk on Blk 6MT Rep Power: 18	You can just take off the back four bolts and fold the plastic along the designated crease (it was made to do this) if you are lazy. I take off all 16 bolts and remove it during an oil change.

07-17-2009, 04:28 PM	#11 (permalink)
kannibul A True Z Fanatic Join Date: Jun 2009 Location: Jenks, OK Posts: 2,281 Drives: 370z Touring/Sport Rep Power: 267	If it were me...with a Mustang - the last thing I would do to that exhaust is anything but make it sound like a AAA Dragster...or a classic muscle car with glass packs... I heard a buzz-box exhaust on a Mustang the other day... I just laughed. What a waste of a good sounding engine. Save the buzz boxes for the FWD 4-bangers with the huge wing.

07-17-2009, 04:52 PM	#12 (permalink)
av370 Base Member Join Date: Jul 2009 Location: antelope valley CA Posts: 70 Drives: 09 370Z Rep Power: 264	Ive got a 04 gt convertable, damm good car. If ford would have put a 6 speed in this year instead of a two decade old 5 speed there would have been one in my garage instead of the Z,kinda glad that didnt happen.

07-17-2009, 07:42 PM	#13 (permalink)
mrarroyo Base Member Join Date: Jun 2009 Location: Heaven on Earth Posts: 211 Drives: 09 Nissan 370Z M6 Rep Power: 16	My 02 Audi TT had one and it was a pain to change the oil/filter. But you live with it due to the added performance.

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