Rear aero mods?

Post by **Merlin** » Tue Jun 26, 2012 12:55 pm

The Prelude has a huge cavity underneath the rear of the car. Some Luders like Phil have "speed holes" in the rear bumper and I have seen a few US 5G's with rear difusers fitted. Any ideas what I could do to my 4G?

Speed holes on Phils car:

Rear diffuser on 5G's:

This one is a photoshop

Im not really up for the holes in the bumper but what does everyone think the diffuser?

Is it a worth while mod for my, what is essentially a track only, car? The car is sitting low and has a deep front lip and sides. Would a big bit of perspex sheet do the same job? Something like this?

Ideas please.

nitin_s1 · Post by **nitin_s1** » Tue Jun 26, 2012 1:03 pm

This one looks awesome. Tempted to do it in my Type-S when time comes.

A1ex · Post by **A1ex** » Tue Jun 26, 2012 1:04 pm

I love the profile on the last diffuser!

To my understanding the low lip at the front high rear combo creates a vacuum under the car and sucks it down to give more downforce. I guess the diffuser would help the air slip under the car better rather than catching on the rear bumper and improve the downforce along with reduce the drag a little further.

I think it really depends what kind of speed you get up to around the corners. There many highspeed corners on tracks you go to?

A1ex · Post by **A1ex** » Tue Jun 26, 2012 1:07 pm

Oh just remembered, a guy I work with did a degree in automotive design. He was telling me the best thing to reduce drag is to have a lip spoiler on the boot to take the air away from the back of the car

Post by **Merlin** » Tue Jun 26, 2012 1:09 pm

Thats where the Lude is at its best, in the corners. Most corners at Knockhill are around 70mph for me but I'll have a better idea after my track day next week (telemetry app will give me a near enough speed). Im not after this for looks, only if it will give a benefit, even just a small one

A1ex · Post by **A1ex** » Tue Jun 26, 2012 1:14 pm

It should give some benefit, are the touring cars using them?

Post by **Merlin** » Tue Jun 26, 2012 1:19 pm

I would assume so. I suppose I really should check out the builds of the other cars in my track club and see what ones are using them. Up the straights I'm about 20mph down on most of the bigger boys, with me topping out around 105mph. Through the corners I am quite competitive.

Really I would like to know if this is worth persuing or if its a waste of time

A1ex · Post by **A1ex** » Tue Jun 26, 2012 1:23 pm

It'll reduce the drag of the rear end as it'll skim under rather than catching in your bumper. This will lift your top speed a little, how much tho I don't know.

stk prelude · Post by **stk prelude** » Tue Jun 26, 2012 3:30 pm

im doing this at some point

dont care if it dont work but if it looks cool it will stay

A1ex · Post by **A1ex** » Tue Jun 26, 2012 3:42 pm

stk prelude wrote:im doing this at some point dont care if it dont work but if it looks cool it will stay

Same here. Not that I get to take it on track and see if it makes a difference mind but it looks good.

I found this a few weeks ago;

http://www.ebay.com/itm/120811990871?ss ... 1423.l2649

with a bit of modification it could be adapted quite well to this