Saxperience - Citroen Saxo Forum - My Throttle Bodied VTS *23/09/09 *Pics and Video of Engine Added*

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Quote:

Originally Posted by AlexR (Post 3488672)

The thing is though, with the rubber seal there it's directing the air down the back of the engine bay, with lifters more air is entering meaning that there is more air in the engine bay that needs to escape.

Aerodynamics is pretty simple really. Imagine a wedge shaped piece of metal, flat and level at the bottom, the top side is angled. The bottom has negligible aero in isolation, the top part will create downforce as it needs to compress the air for the air to pass over it, putting pressure on the top side, obviously the further back you go the more pressure is created so the extra pressure is higher the further along the wedge you go. As the wedge finishes there is now an area behind it that is vacant space, for the air to fill that it would have to expand again, this creates a low pressure zone as opposed to the high pressure zone where air is compressing. The air will flow into this zone, imagine this is now the shape of your bonnet(sloped with a drop off at the end) The air fill flow into the gap.
Inside the engine bay the air loses most of it's speed passing through the rad and around the engine, and the majority flows under the engine & gearbox but some goes around the sides and over, very little but some. With bonnet lifters most of the air will be sucked in when moving and have nowhere to go, it will try and lift the bonnet further creating lift.

Rear splitters are usually designed to create a low pressure zone under the rear of the car by providing a tuned shape to channel the air and create downforce. Just like a front splitter(or wing like in F1) is always sloped to compress air and provide additional downforce. The larger the angle the more downforce.

Just think logically on the basic rules and you can predict the effect of anything.

Bosh - hole in one! I does make sense now - I don't think it'll make a huge difference on the road? And in terms of acceleration?

Apologies is derailed the prog thread

Quote:

Apologies is derailed the prog thread

Dont worry bout it, obviously its a topic that effects me too and itll be interesting to see what you temp sensor says.

Naturally an air temp sensor will show cooler from the air being induced above the bonnet, usually if running bodies. Wouldn't see much difference using a full inlet.

No on a road car it's not that bad. It will only really affect high speeds.

An enclosed airbox around throttle bodies with a filter sucking cool air is idea, it improves low down running although it does affect top end. A minor remap is recommended if changing to an airbox. I've seen direct rolling road comparisons with and without airbox on the same car. 5% difference on that one with the bonnet open ;)

Out of the two which is better on track/road ? Bonnet raised or not? Ignoring the option of an airbox?

Are you running filter socks?

I'd stick with it raised providing you're not indending on doing high speed runs.
Be safest using it in the standard position with some filter socks(which will account for nearly the 5% loss of an airbox anyway)

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Yea I do have filter socks, so its better leaving it raised until i get round to airboxing it then?

Yep it'll be alright if the lifter kit is decent :)

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Yep it'll be alright if the lifter kit is decent

Cheers alex, well we modified a ebay one to make it stronger as the washers etc were extremly thin so me and my dad changed all the bits for some man metal.

I just bought a new steering wheel from AlexR

I hope he doesnt mind me using the pic.

The plans for the car now are to get some weight shed. Im going to buy new (matching) buckets, remove rear seats, replace door cards with carbon etc.

I am also toying with the idea of having NOS installed. Running 50 jets, the main thing putting me off at the minute is where to but the gas from.

Heya mate, check out my progress thread:

I had a little look an the inlet temperatures, and with a coolant temperature of 88 degrees - ambient of 15, I was reading an inlet temperature of 18 degrees at around 70mph - was a lot lower than I was expecting !!!

lovin the new wheel, how much it set you back??? really want one.

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lovin the new wheel, how much it set you back??? really want one.

£75 it cost

looks in really good conditon! smart :)

Not really a update but I need to buy a oil cooler thermostat. I have mocal 13row oil cooler and now the bonnets raised I think the oil is probably a bit cooler than it should be, so for those that know, is this the sort of thermostat I want?

http://cgi.ebay.co.uk/OIL-COOLER-PLA...3A1%7C294%3A50

^^^ that's the bad boy!!

Cheers raunchz, Ill that ordered now.

Well its been an eventful day in the world of the saxo.

I picked up some new seats today, Corbeau Targas from Farry on here along with some sabelt harness'. So they will be going in tomorrow.

I also found my lost power lol, when it was on the dyno it only made 157.7, I have found out why. Cylinder 2 was losing compression through the spark plug so I tightend it up and the car ran and sounded much better.

BUT...since coming back from collecting the seats something has happend to the car, I dont know what but it sounds like shite, and the idle has started to bob up and down a bit which it has never done before. Also has started running rich the majority of the time and slight smell of petrol when stationary. I really dont know what it could be?

One of the bolts on the inlet manifold has fallen off, so the inlet might not be sealed so I will sort that tommorrow but surely that wouldnt cause all the problems above?

An inlet leak would cause it to run dodgy, so sounds like the problem!

^^ Yeah what he said.

Irratic idle is a major symptom.

im hoping its just that bolt then, its one I forgot to put a washer on so I will do it tommorrow.

If not then I think im just going to cry.