Individual Throttle Bodies and Improved Airflow

[Dessertrunner]

Hi Mike,
I have 2 different size heads this one and a larger one. On the old mill I used it to cut gears for work. Also we have electro magnetic vibrators and we need to build the coils in house so we use the 4th axis to make the bobins.



Back to the throttle if you look at the image you can see how the bearings are mounted on each end of the roller.



I need help from someone, do any of you guys have a 2 or 4 barrel carberater and can post a image of how the linkage works to open the second barrel. I am thinking of opening one roller fully then the other to try to help with performance at low revs. I remember Rally Bob and others telling me that rollers have poor performance at low throttle setting.

Have a great day.
Tony

[Dessertrunner]

Given what you suggested Adam about dropping the height of the ram pipes I am looking at going straight with them. Interesting enough there is a cout out in the bonnet support frame that means the ram pipes have a bit more clearance to fit. The last choice is the bonnet bump as suggested so anyway they will be straight.
Tony

[Dessertrunner]

Hi Harvey,
I measure the air flow distances for you. Its a bit hard but its the best I can get for you.

Valve stem to head were inject manifold attaches is 78mm.
Injecter tip to face of head 25mm.
Injector manifold is 80mm thick.

I have measured the intake manifold (throttle manifold) that bolts onto the injector manifold. Its a bit hard to work it out exactly but I am pretty close.
Distances are the best I can figure, hope it helps.

Assume first row front of engine left side left bank, right side right bank.

165mm 195mm
175mm 175mm
185mm 185mm

In other words from the valve stem to the tip of the intake on the front right is
195mm
80mm
78mm
gives a grand total ram pipe length of 353mm total length. so therefor the shortest length is 323.
Hope that helps.
Tony

[Dessertrunner]

The new throttles are
170mm ram pipe.
50mm throttle.
78mm valve to head

298mm total

Don't forget my pipes are 42mm diameter compared to Subaru 45mm.

Tony

[Dessertrunner]

Have been away a bit had to send kids over seas , 1 to UK for 6 months & 1 to US for a month.
Anyway I have been working on the intake design and talking to Harvey as a result he suggested and I accepted that we should have the ram pipes at different length. I have given this close consideration and it makes sense.
What Havery pointed out to me is that if all ram pipes are the same length then the power curve will have a massive spike in its power. If we have each pipe at a slightly different length the peak power may be lower but it will be for a longer time. It should be eaiser to drive. Just incase you were wondering that is why I measured the standard intake we have.

I support the logic and given the problem of clearnace at the front of the motor a lowering of the intake pipes will help. So the plan is 20mm short on front 2 cyclinders & lengthen the back 2 by 20mm. Net result will be a 40mm length range from longest to shortest.

Happy to here what everyone thinks.
Tony

[icingdeath88]

Glad to see you're making good progress.

So I'm curious now. After all the work/research you've done into intake designs so far, what do you think of the stock intake?

[Dessertrunner]

I personally think the numbers we saw from flow benching the intake manifold it is holding the engine back from developing more power. What is surprising me is the number of mods made to engines for not a lot of gain. I think the we need to step through the mods to figure whats best.
Tony

[Dessertrunner]

Weekends are always go for this project. Started framing up the airbox to be used as the mould. Was surprised how well the MDF milled. The parts I have made so far came out really good. I have attached a PDF of the mould with the base left off. The gap between the two halfs is 18mm to allow for the seal and the thickness of the fibreglass. Haven't got enough experiance to say how thick the fibreglass needs to be.
Tony

[Dessertrunner]

Doing some airflow calcs for the MAF units, can someone jump in if they are wrong,

at 8,000rpm the engine draws 4,000 fills of 3.3l's times the effectency factor of 1.15 gives 15,180 litres per min or 910 cuc metres per hour at 20 degrees C 1cubic metre of air weighs 1.204 Kg
There for the engine would use 1,096kg of air per hour.

If we all agree then the largest bosch airflow meter would not do it. Clearly we need 2 of the units that do 640kg per hour. Doing the calc these units will last up to 9,400 rpm which is well above target rev range.
Need bosch unit 0 280 217 531 curve 3

Tony

[svxfiles]

Tony, is 910 cuc the same as 537.7 cubic feet per minute?

[Dessertrunner]

Originally Posted by svxfiles

Tony, is 910 cuc the same as 537.7 cubic feet per minute?

Hi
I think that number is wrong Cuc ft would be a larger number then 910 cuc metres not sure of the conversion.
Tony

[svxfiles]

OK, what is "cuc metres"?

[icingdeath88]

I think he means cubic meters.

Edit: Or maybe cubic centimeters?

[Dessertrunner]

Sorry cubic metres.

[Dessertrunner]

Here are some shoots of the top part of the airbox for want of a better name I have called the job "Oz Power".

This shoot is of the top plate on the airbox being millied, there is a 14mm slope on the plate to give it strength.


Finished plate after sanding.


Here it the assembled airbox I have to put filler in the corners to decrease the radius on the bends.

Have done some of the bottom, had drama sorting it out for the 2 MAF units, figured I will go with units from a SVX as I have a couple of them spare,
Tony