Hi, I removed the undertrays a number of years ago due to the usual issue of them loosening off and dragging - drove me mad squeezing under it on the side of the motorway trying to resecure them. Anyway now I'm thinking did they actually serve an aerodynamic purpose? If so at would speed would they have an effect?? Every so often on my driveway of course the car will sit at 120/130 and feels pretty planted. Or do they act purely to stop dirt/debris covering the underside of the engine? I'm curious about this and wonder how many of you guys run without the undertrays?

Cheers

Thomas

They definitely help to keep the engine bay clean. I don't think they have a real world aero benefit as they're too flimsy but they do help to control the airflow across the engine from the viscous with the pressure difference at the back helping draw the air across and out.

 

The forward undertray helps to guide the air across the radiators, preventing the airflow from bypassing the matrix so that one is also beneficial to have installed.

 

The side sections of the undertray are part of the forward section of the inner wheel arch trim so I assume they're still in place(?). They house the naca ducting that draws out exhaust air for the intercoolers so they are also important.

 

You probably wouldn't notice any difference by not having them fitted, but collectively you could be slightly down on performance with potentially heat soaked intercoolers and with an already hot engine bay not being cooled as efficiently as it could be, the thermostat would have to be further open, meaning you're potentially closer to an overheat situation. Keep them all fitted I say.

I have the front section fitted.

The rear section is in the garage & has been off for the past year.

Not noticed anything about keeping the engine clean as I have just done an oil change.

My view is if Nissan disigned it it must be fitted for a porpoise, maybe protection?

My view is if Nissan disigned it it must be fitted for a porpoise, maybe protection?

 

Not so sure about that Art.

 

porpoises then Andrew:)

I should have paid more attention at school!

They definitely help to keep the engine bay clean. I don't think they have a real world aero benefit as they're too flimsy but they do help to control the airflow across the engine from the viscous with the pressure difference at the back helping draw the air across and out.

 

The forward undertray helps to guide the air across the radiators, preventing the airflow from bypassing the matrix so that one is also beneficial to have installed.

 

The side sections of the undertray are part of the forward section of the inner wheel arch trim so I assume they're still in place(?). They house the naca ducting that draws out exhaust air for the intercoolers so they are also important.

 

You probably wouldn't notice any difference by not having them fitted, but collectively you could be slightly down on performance with potentially heat soaked intercoolers and with an already hot engine bay not being cooled as efficiently as it could be, the thermostat would have to be further open, meaning you're potentially closer to an overheat situation. Keep them all fitted I say.

 

Well described from an aircraft engineer :yes:

 

I have removed mine and fitted the aluminium under tray.

 

The front tray acts to drive air in the right place, air is fickle and will compress and redirect if not directed properly. The rear portion as Joel points out probably has purpose here too to create pressure difference, esp in idle conditions. However the fan cowel I suspect will have greater duty here. I would say it's main purpose is to protect the ancillaries items and thier belts as well as the engine from grime and debris. The alternator is in a particularly vulnerable location for water damage etc. Imagine how inconvenient it would be if a bit of flint flicked up, caught in the crank pulley and sheared a belt, you could quickly find yourself stranded, then you could die or worse. :lol:

Well described from an aircraft engineer :yes:

 

I have removed mine and fitted the aluminium under tray.

 

[ATTACH=CONFIG]104133[/ATTACH]

 

My next project :yes:

* Both my trays are still very much intact and have never failed in nearly 13 years of ownership.

 

* Z32s with no trays always look a little weathered / incomplete

 

* It protects the sump from road debris and chipping.

 

* Channels airflow

 

I see absolutely no reason not to have these fitted.

Thanks for your response guys you have pretty much reinforced what I thought. Better on than off! Mine were pretty damaged when I got the car which sped up their removal.

I like the look of the aluminium one would it be possible to post a link to that?

Thanks again.

Thomas

Google Z1 Motorsports they have them. USA company so it can be expensive on postage and import duty. I bought mine from a member here.

Thanks

Thanks

 

No bother Thomas and I would send you the link but my work computer wont let me open the site for some reason.

No worries I have used z1 a few times in the past. Thanks again.