Your opinion?

[arjunior45]

what do you think of that on a Q4? Not the Zender front spoiler of coarse.
155 GTA had something similar as far as I can recall.

It's on a Japanese 155 V6.

[wrinx]

Similar idea to a Zeatek undertray but they don't make one for 155s ,they are supposed to be very good (but check no pipes are rubbing!).

Zeatek site: http://alfastumper.dk/oscommerce_st/...products_id=61

wrinx

[Brul(tm)]

What about air flow and possible heat build up?
And how does this effect the air flow?

Greetings,
Marc

[arjunior45]

What about air flow and possible heat build up?
And how does this effect the air flow?

Greetings,
Marc

These are my concerns Marc. That's why I'm asking for your opinion!

The heat build up during summer time in Athens city traffic is the No 1 concern of mine. But heated/warm air goes upwards and I have the ventilation hole in the front bonnet, just above the exhaust manifold! Probably in the city traffic I won't have serious problems. But that's something to confirm during summer time.

As for the air flow I do not know either.
With a Zender front spoiler and the car moving, probably more air will enter in the engine bay. Both from the central lower part of this spoiler and the vent hole at the front bonnet {which is in an area of positive aerodynamic pressure - see picture attached}.

But then? What?
Do you think it will be better to 'guide' all the hot air, from the water radiator and the turbine, further backwards? And how this can affect the 'aeordynamic' under the car? That's the million dollars question!

[Evodelta]

The only way to know is to test it, you will find lots of info on this kind of thing on autospeed.com. You will need a Dwyer Magnehelic gauge and may find that the undertray helps the cooling of your car aswell as your fuel consumption.

If you need to test before buying or even get your own cheap then the local vehicle breakers is a good place to start, you will be surprised at what you can find on newer vehicles, not only aerodynamic undertrays, but lots of cheap heat shield material too.

[arjunior45]

So, I take as 'positive' your comment!

Wish I had the time and the mood to search the local breakers but ... I have some health problems lately and I'm trying to avoid driving my car as much as possible.

[Evodelta]

Sorry to hear about your poor health and hope you get better soon, while you are convalescing you may have some time for some reading then.

Definately worth thinking about and testing anyhow.

[Brul(tm)]

Definately worth thinking about and testing anyhow.

Does this mean repositioning and/or modifying the air vents aleady present?

I started looking around on the autospeed website.
I hope it rain's a lot when I am finally finished building (baby)rooms at home This also means I will be able to spent some time working on my Q4

Greetings,
Marc

[Evodelta]

Does this mean repositioning and/or modifying the air vents aleady present?

I started looking around on the autospeed website.
I hope it rains a lot when I am finally finished building (baby)rooms at home This also means I will be able to spent some time working on my Q4

Greetings,
Marc

I'm not totally sure what you mean there? What I am really trying to point out is that these kind of improvements or testing need not be beyond you as the knowledge, tools and material are easy and not too expensive to come by.

I'm sure you'll be doing the painting soon.

[Brul(tm)]

I'm not totally sure what you mean there? What I am really trying to point out is that these kind of improvements or testing need not be beyond you as the knowledge, tools and material are easy and not too expensive to come by.

I'm sure you'll be doing the painting soon.

Okay, I'll try again.
The undertray in the picture has some default vents on it.
I think it needs some adjustments before it's suitable for under
a Q4? Otherwise you migth create a heat problem instead of trying to get more air trhough

Greetings,
Marc


Greetings,
Marc

[Evodelta]

Ah, I see, the vents on the undertray, not on the car.

Without testing it we could talk about it for years and never know, but to point you in the right direction of theory the air passing along the underside of the 'tray actively draws the air out of the engine bay and from behind the 'rad and intercooler.

Do you remember the in-depth thread discussion we had on intercoolers? It was mentioned by me near the end, here are some pics of what is going on, but on top ofcourse:

[Brul(tm)]

Ah, I see, the vents on the undertray, not on the car.

Sorry for my confusion.
No, not the car.. this would do no good the the design of te car in my opnion But I would consider it, if it would help to improve the performance and can be subtly done.

Without testing it we could talk about it for years and never know, but to point you in the right direction of theory the air passing along the underside of the 'tray actively draws the air out of the engine bay and from behind the 'rad and intercooler.

You are absolutly right, but with a little help from those who have more experience in this matter in the right direction
I have seen this under tray before and didn't see the "value" of it then. Now I understand it could help getting more fresh/cool air through.

The testing is for me also the hard part, I don't have all the right equipement to do this

Do you remember the in-depth thread discussion we had on intercoolers? It was mentioned by me near the end with (I think) some pics.

Of course I do, very interesting subject. After reading that thread, I really don't know what to do anymore with the intercooler
Had some ideas there, but after reading the intercoolers thread that would be really bad one

Greetings,
Marc

[arjunior45]

Concerning the vent hole on the bonnet I can assure you both that it works. I can 'see' the hot air coming out of this hole as I can see the burned oil smoke coming out of there {as I have an oil leak from cam cover gasket, dropping oil on the turbine}.

The undertray I'll test it during summer time and I'll try to check the efficiency or not, concerning hear development in the engine bay.