Individual Throttle Bodies and Improved Airflow - Page 23

oab_au · #**331** 04-14-2011, 06:27 PM

Quote:

Originally Posted by Dessertrunner

Hi Mike, these are going on the race engine you built for me, should look good.

I am trying to get my head around were to get the air from, Matt just fitted socks to his ram pipes and got the air from the engine bay. I want to get it from the outside, under most race rules we are not allowed to cut a scoop in the bonnet. That leaves me with,
Front above radiator (my prefered)
Or back of bonnet at the base of the windscreen.

My prefered option is front of bonnet, the reason is that I am going to change to a cross flow radiator, meaning side tanks with the cap on the outlet side, on this bases I might be able to let air in at the top of the radiator. This may mean that I have to move the alternator to were the aircon compressor was to let a clear air parth into the filter for the ram pipes. Also I maybe able to get better flow down the centre pipe of the cooling system by moving it to the centre as well. Tonight I will post photos of what I mean.

Tony

You will have to have an air box, of a big enough volume, for the six intakes to work from. You could use a two piece box, of fiberglass, with one piece under the intakes and the top piece to enclose them. The rear of the box could have two holes to connect to the original air pipe and air cleaner box. The box doesn't have to be 'vacuum tight', so the ram tubes to the box, can be sealed with foam.

The injectors can be just above, and aimed at the rollers. The injectors above the ram tubes would be inviting a fire. OK with open intakes, but with enclosed intakes, a backfire would be nasty.

Harvey.

Dessertrunner · #**332** 04-15-2011, 02:33 PM

Hi Harvey,
I agree with you about going in the bend of the ram pipe with the injectors I just need to wait till they arrive. If the pipe is thick enough then thats way I will go other wise I will have to rethink them.
Looked at the existing air box and its all to small for the high volume we need, going in through the front is the best option, its just a matter of do I make one large airbox or 2 smaller ones.
Tony

oab_au · #**333** 04-15-2011, 05:28 PM

Quote:

Originally Posted by Dessertrunner

Hi Harvey,
I agree with you about going in the bend of the ram pipe with the injectors I just need to wait till they arrive. If the pipe is thick enough then thats way I will go other wise I will have to rethink them.
Looked at the existing air box and its all to small for the high volume we need, going in through the front is the best option, its just a matter of do I make one large airbox or 2 smaller ones. Tony

The air volume will only be a bit more than the engine consumes now, it is still only a 3.3 lt. The rate of flow will increase with the rpm, but I don't believe it is too small. Are you going to fit an air cleaner?

Use one large one, the air box has to be large enough to allow the sound waves to completely expand, as if the ram pipe opened into the atmosphere. If it is too small the wave will not deliver the same intense pressure wave to the cylinder.

Harvey.

Harvey.

Dessertrunner · #**334** 04-15-2011, 06:21 PM

Quote:

Originally Posted by oab_au

The air volume will only be a bit more than the engine consumes now, it is still only a 3.3 lt. The rate of flow will increase with the rpm, but I don't believe it is too small. Are you going to fit an air cleaner?

Use one large one, the air box has to be large enough to allow the sound waves to completely expand, as if the ram pipe opened into the atmosphere. If it is too small the wave will not deliver the same intense pressure wave to the cylinder.

Harvey.

You would go and give me a good reason to change my direction. Your point about 1 big air box is right on the mark. I didn't consider sound waves. I can buy 3 mm thick carbon fibre sheet (cost a small fortune) this will enable me to build up a strong base for the air box.
I have measured the restriction in the air box and its pretty bad at higher revs, so I will change it. Yes I will run a air cleaner my guess 2 of the current ones side by side. The other plus side of the bigger air box is if I have to install the injectors at the top of the pipes I can use the air box frame to do it.

Does anyone know of any road cars with injectors at the top of the intake pipe?

Tony

Boxersix · #**335** 04-17-2011, 12:14 AM

Quote:

Originally Posted by Dessertrunner

Does anyone know of any road cars with injectors at the top of the intake pipe?

Tony

Yeah the S70-2 engine in the Mclaren F1

Dessertrunner · #**336** 04-17-2011, 12:54 AM

Hi Adam,
What do you think, were would you put the injectors?

Boxersix · #**337** 04-17-2011, 08:41 PM

Quote:

Originally Posted by Dessertrunner

Hi Adam,
What do you think, were would you put the injectors?

The primary injectors, or secondaries?

Realistically, you may run into packaging issues with your roller throttles, and the tract length that you prefer to run. Due to the short tract expected and the spacing required to conceal the roller barrels inside the billet housings you'd likely find the current OEM location unfit as they simply cannot fit in the current orientation. Moving the injectors outwards(away from the port) results in poor feed angle and will certainly result in poor fuel injection into the airflow and poor atomization.

This is where one may have to look into alternative injector style for better packaging.

One cannot simply move the primary injectors pre-throttle plate/roller. The motor simply will not run at low throttle input. Many high RPM engines(super sport bikes, F1, the Mclaren F1 I mentioned) have a full set of secondary injectors that atomize directly into the ITB velocity stacks for proper fuel atomization at high intake velocities associated with short tract ITB setups, but still retain a full set of primaries at the port for low speed operation.

The large diameter side feed style SVX(Sti) type injector may not be the best suited for this application where one is not retaining the OEM lower runner/injector boss casting and one may have to covert over to a more common bosch(Ford Motorsports) style top feed injectors and fuel rail setup that would allow a proper feed angle, still be able to clear the mechanics of the roller throttles, and allow you to retain a shorter tract length. There are also long nose injectors as well which allow for increase injector standoff distance form the actual throttle mechanism.

One has to take into account that you're setting up a system onto a HEAD that was never designed for it, and more importantly the intake port was never designed for it. Impossible?, no. But one just has to realize there may be a compromise necessary that one really doens't want to take.

Dessertrunner · #**338** 04-17-2011, 10:19 PM

Thanks for that Adam, I am waiting on the ram pipes from the UK to work out how much height I have left under the bonnet. If I can get a further 20mm I should be good to put the injecter in the standard location. I will aim for that first.
A further question you cut the web out from between the two rollers so they could touch, on mine I have a .3mm gap between the two rollers. I am becoming concerned that this might be to much to enable proper idle.
What do you think?

If this is the case I can either make the rollers each .3 mm larger diameter or make the roller off centre so they get closer as they rotate.
Was there any learnings you can pass onto me when you did yours?

Tony

oab_au · #**339** 04-17-2011, 10:23 PM

I agree with Adam.

Harvey.

Boxersix · #**340** 04-18-2011, 01:41 AM

between .15 and .25mm(~.005"-.010") is the range to try and work with but .3mm isn't that far off so I'd say you should be fine. Remember you can always machine things off further though.

Try and use either brass or graphite composite rod for the rollers. Avoid aluminum and ferrous metals.

Dessertrunner · #**341** 04-18-2011, 01:55 AM

I went with brass as you suggested.
Tony

Dessertrunner · #**342** 04-20-2011, 04:23 AM

Might have to try the graphite as the brass is just to heavy and doesn't move very easily. Also I think I may have to redesign the throttle so I can use a reamer to make sure the roller pockets are the even. Also looking at putting bearings on each roller but that will be a pain in the ass.
Tony

longassname · #**343** 04-20-2011, 09:09 AM

It amazes me I still don't own one of these. I was eyeing the SPI version back when it took me several tries over several days to get the spindle on my machine truly square. I'm going to redo some stuff on my machine and think I'll get one this go around.

Have you used a mist system that was effective at clearing chips out of your parts?

Quote:

Originally Posted by Boxersix

It's a very handy indicator tool, and even if your head is trammed in properly, it's still excellent and accurate for parallelism of the material or machined parts into your bed vise(s)

Well with the money spent. Their squaring tool is nice too. I have used their tool height setter, but now have digital touchoffs for all my machines.

zaueugen · #**344** 04-20-2011, 11:45 AM

do u guys think that not having the cover under the front part of the car on would effect the air flow to the airbox? newb question.. but jw. (by cover, i mean that huge plastic piece that is place under the car where the engine is, to block out rocks etc)

icingdeath88 · #**345** 04-20-2011, 12:15 PM

Quote:

Originally Posted by zaueugen

do u guys think that not having the cover under the front part of the car on would effect the air flow to the airbox? newb question.. but jw. (by cover, i mean that huge plastic piece that is place under the car where the engine is, to block out rocks etc)

It's usually called a "belly pan". More for aerodynamics than airflow ether to the intake or cooling the engine. The airbox pulls air from inside the right fenderwell, so it wouldn't be affected either way.