Bonnet scoop

Because it's positioned directly above the turbo and exhaust manifold, a lot of heat gets conducted into the inlet manifold.

After driving the car for a while, the inlet manifold is pretty hot to the touch, which would would surely negate all the cooling that the intercooler has just done?

I'm toying with different ideas for trying to prevent this including, heat wrap, carbon heat shield, and naca bonnet vents and louvres.

Would it be effective to set up some sort of venting system whereby air is taken in through the front of the bonnet, ducted past the inlet manifold, and then use louvres at the rear of the bonnet to exhaust the heat?

I'm open to suggestions and alternatives.

Here's a very rough, and incredibly not to scale diagram of what I'm proposing.

Attachment 30797

With over 230bhp (soon to be more ;)) I've not found the need for it yet. I wouldn't worry about it or waste money on it myself.

I use 1 of these:

https://www.ipdusa.com/products/5210...anifold-spacer

i removed the rubber seal at the rear edge of the bonnet

Quote:

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Originally Posted by JT

I use 1 of these:

https://www.ipdusa.com/products/5210...anifold-spacer

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Be good if they did one for the tdi..

Quote:

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Originally Posted by martin_r_smith

Be good if they did one for the tdi..

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just an idea, I have no idea if they make 1 for the tdi...

unfortunately not, there is nothing really that's made specifically for this engine.

It would be of no performance benefit on a tdi either, the engine doesn't know if it is getting hot, warm or cold air post turbo as it only measures at the maf. And unlike a petrol there is no lambda sensor to tell the ecu what the mixture is doing so it cannot compensate for a greater or lesser quantity/ density of air and adjust fuel accordingly. The fueling is basically metered by inlet temp at the maf, manifold pressure and throttle position (plus a few others like fuel temp etc), so even if you got the post intercooler temps to say 10 degrees but the temp at the maf is 24, it will still fuel for 24 not 10.

Hope that makes sense.

Double post

Thanks guys, some helpful info there.

I didn't know that was the way that the fuelling was ratioed Martin. It seems odd to me to go to the bother of intercooling the charge, and then porting it into the engine via a hot intake manifold.

So the most important thing to consider regarding power is the air/fuel ratio, which is determined purely by the MAF?

If the fuel ratio is unaffected after the MAF, how does the intercooler affect the equation?

Thanks

Quote:

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Originally Posted by petrolh34d

Because it's positioned directly above the turbo and exhaust manifold, a lot of heat gets conducted into the inlet manifold.

After driving the car for a while, the inlet manifold is pretty hot to the touch, which would would surely negate all the cooling that the intercooler has just done?

I'm toying with different ideas for trying to prevent this including, heat wrap, carbon heat shield, and naca bonnet vents and louvres.

Would it be effective to set up some sort of venting system whereby air is taken in through the front of the bonnet, ducted past the inlet manifold, and then use louvres at the rear of the bonnet to exhaust the heat?

I'm open to suggestions and alternatives.

Here's a very rough, and incredibly not to scale diagram of what I'm proposing.

Attachment 30797

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But the inlet is at the front of the engine...

Quote:

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Originally Posted by M-R-P

But the inlet is at the front of the engine...

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Not on the derv, Martin

Quote:

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Originally Posted by Doingitsideways

Not on the derv, Martin

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oh.

:P

The intercooler does not affect the fuelling at all, it is simply there to bring the air temp down to something similar to the air going in at the maf. These old dervs don't have clever management and many assumptions are made rather than using sensors for feed back.

http://i170.photobucket.com/albums/u...227_130457.jpg

Quote:

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Originally Posted by martin_r_smith

The intercooler does not affect the fuelling at all, it is simply there to bring the air temp down to something similar to the air going in at the maf. These old dervs don't have clever management and many assumptions are made rather than using sensors for feed back.

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Cool. So it's basically guess work after the MAF, as the intake temperature can change without the MAF actually knowing.

I think I'm gonna have a stab at some sort of ducting system, purely our of curiosity and the desire to experiment.

Nice Claymore! I think it may have been seeing your design some time ago which has subconsciously inspired me.

Did you have an Integrale vent on your bonnet at one stage?