My Throttle Bodied VTS *23/09/09 *Pics and Video of Engine Added* - Page 7 - Saxperience

makaveli144 · 9th July 2009, 22:27

Quote:

the figures dont seem that bad the peak power very high, what the rev limiter set to?

have to really rev it some to get round to that dont you, bet you love it though wish i had thorttle bodies now

i got a standard vts gearbox on mine at the moment and you can tell that the gearbox is too long for cammed vts as when i change gear i always come out the power!!

so god know what it like with thorttle bodies does it fell ok?

also what was the price for the re map?

andy

The limiter is set at 7900. The peak power is very high and you do have to rev it but obviously it flies towards the limit up until 4th id say and 5th is a useless gear lol.

The remap cost me £285 and I do really want to change the box, i wouldnt say the VTS box is too bad but with the way the engine is the quicker the revs climb the better it will be.

AndySAXO^p · 10th July 2009, 07:25

yer sound good to me, bet it sound nice when you rev it that high

andy

kevin_172 · 10th July 2009, 15:58

you do know that fitting bonnet raisers will actually give you a higher temp inside the engine bay?? you create a pocket of air that cant flow out and it just gets hotter.

raunchz · 10th July 2009, 16:36

Quote:

Originally Posted by kevin_172

you do know that fitting bonnet raisers will actually give you a higher temp inside the engine bay?? you create a pocket of air that cant flow out and it just gets hotter.

how come ? I don't understand?

kevin_172 · 10th July 2009, 16:42

the airflow when the bonnet when standard is areo dynamic and allows for the air to flow out the bay through the scuttle unhindered as such. when the raisers are put on it raises the rear of the bonnet. now when the air passes over it it's not so aero dynamic and hot pockets are created when the air is rushing over the car. this has been tried and tested. as he has said he is now getting flat spots..... thats because the actual air intake is hotter because of these hotspots created!

raunchz · 10th July 2009, 16:54

Wouldn't the air rushing over the bonnet pull the air from the scuttle area as it passes over - making it cooler?

I'll have a look at my manifold air temperature, iirc it was slightly cooler - mine was the car that had a flat spot from raising up the bonnet.

I'm just looking to perfect my setup so any help is appreciated!

kevin_172 · 10th July 2009, 16:56

it dosent "pull" anything its a flow system.....

AlexR · 10th July 2009, 17:00

The low pressure zone to the rear of the bonnet sucks air in, stopping the air from the grille from escaping. It may provide cooler air to the bodies but as an overall thing it's not good.

You need a nice steering wheel to go in there

kevin_172 · 10th July 2009, 17:01

thank you alex

raunchz · 10th July 2009, 17:04

Quote:

Originally Posted by AlexR

The low pressure zone to the rear of the bonnet sucks air in, stopping the air from the grille from escaping. It may provide cooler air to the bodies but as an overall thing it's not good.

You need a nice steering wheel to go in there

I see what your saying about the low pressure area - standard, the bonnet has a rubber seal that goes inbetween the bonnet and the scuttle top, so as standard there's no area at the back for hot air to escape, so even with the bonnet raised the air not escaping would be just like standard?

Next time im out i'll have a look at the intake temperatures to see the difference between ambient and when driving.

I don't know one thing about aerodynamics as you guys can probably tell

makaveli144 · 10th July 2009, 18:05

Quote:

you do know that fitting bonnet raisers will actually give you a higher temp inside the engine bay?? you create a pocket of air that cant flow out and it just gets hotter.

Hmmm, I have no way of measuring my intake temp, I just assumed it would help.

Having said that my water temp and oil temp is much cooler?

Bickerton · 10th July 2009, 18:21

Quote:

Originally Posted by raunchz

Wouldn't the air rushing over the bonnet pull the air from the scuttle area as it passes over - making it cooler?

I'll have a look at my manifold air temperature, iirc it was slightly cooler - mine was the car that had a flat spot from raising up the bonnet.

I'm just looking to perfect my setup so any help is appreciated!

This may work as an example...

When you drive along and open your window a little bit to let cool air in and warm air out you end up just causing a massive pressure pocket and the outta air hits the inner air and proceeds to vibrate and usually hurt your ears causing you to open another window to ease the pressure, this help atall or just confuse the issue more?

AlexR · 10th July 2009, 18:30

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.

raunchz · 10th July 2009, 18:31

Quote:

Originally Posted by Bickerton

This may work as an example...

When you drive along and open your window a little bit to let cool air in and warm air out you end up just causing a massive pressure pocket and the outta air hits the inner air and proceeds to vibrate and usually hurt your ears causing you to open another window to ease the pressure, this help atall or just confuse the issue more?

It's sort of making sense a little - I think I won't try to understand it as it'll just confuse me . . . . time for a beer

makaveli144 · 10th July 2009, 18:31

Quote:

When you drive along and open your window a little bit to let cool air in and warm air out you end up just causing a massive pressure pocket and the outta air hits the inner air and proceeds to vibrate and usually hurt your ears causing you to open another window to ease the pressure, this help atall or just confuse the issue more?

No I understand the principal, but the gauges seem to say the car is running cooler. Really I need someway to check...

makaveli144 · 10th July 2009, 18:33

What would you guys recommend as getting more cold air to the bodies then? The bodies dont quite reach the scuttle so cutting it would just create the same problem wouldnt it?

Bickerton · 10th July 2009, 18:34

Quote:

Originally Posted by makaveli144

What would you guys recommend as getting more cold air to the bodies then? The bodies dont quite reach the scuttle so cutting it would just create the same problem wouldnt it?

Cold intakes?