Intake plenum and 911 throttle body

[tommy583]

This is an interesting thread. Being that I have a non e-gas model the only way I can find to get a larger throttle body is the Pedro's bore service. His site says they bore the stock one out to 75mm. So if I do this I would be in the market for one that would fit that. Is that a possibility?

[edc]

Non e-gas 3.4 911 throttle body.

[tommy583]

Originally Posted by edc

Non e-gas 3.4 911 throttle body.

Thanks edc, I was thinking this would work as well. But I was unable to find one online last night to be sure.

[Reebuck1]

Kram36....What size engine are you running?? 996 3.4 or 3.6?? and what size throttle body are you using?? Thanks....I too am waiting to see how Ben does !!

[Ben006]

Yes I can do one for the 2.5 too, but since the 2.5's plenum is very different from the 2.7 and 3.2's plenum I will need to take the mesurement from a 2.5L one


My friend told me Monday, I hope I will be able to do it and that all my measurement were right !

cross your finger with me

[KRAM36]

Originally Posted by Reebuck1

Kram36....What size engine are you running?? 996 3.4 or 3.6?? and what size throttle body are you using?? Thanks....I too am waiting to see how Ben does !!

Stock 3.2, 76mm TB.

[Ben006]

Hi !

As planned I found a garage Monday to finally work on the intake !

and... it doesn't fit ... nothing bad, but the straight T shape makes the TB bump against the starter and force the intake elbow to stick too far up.

Nothing that a slight angle can't fix

I will make another one soon.

I also noticed that the temperature in the engine bay was higher than I thought on a hot Florida day !
So I put the T back into the oven to see if it can handle 240F ... result, it can I will just make it thicker in some place for added strengh and peace of mind !

It takes time, but I'm on the right way

Ben

[Ben006]

I also think that I will try a flow divider like in the 987 :

without the flap, but it's a great way to ensure that both sides receive the exact same amount of air despite having to make a tighter turn on the left side !

[KRAM36]

Curious why the air is making a tighter turn to the left side?

[Ben006]

because I'm not going tu use a straight T shape any more, it will be tilted 10°

I will show you as soon as I'm done with the software.

The shape will look weird, but I'm trying to direct air equally on each side, not that easy ...

I'm going to try another route, like the oem (longer tube after the TB), and see if I can come up with a better, more balanced shape

also, the problem with a big divider is that it's going to "seal" the to banks from each other, and makes you loose top end power (sorry, I lack technical vocabulary to explain it correctly in english).


So ... I'm working on it

If anyone has any idea, feel free to share

Ben

[KRAM36]

TRK (The Radium King) would probably be the one to consult on that.

[Ben006]

Hi !

I made modifications to the T, with an angle, the TB should point slightly to the left.
this way it should clear the stater solenoid.

Now I need to see if the engine cover will clear the intake elbow.

I want to get it 100% right before printing it.

[Jake Raby]

Remember, the short radius is what matters with any normally aspirated engine. I see people wasting their time with induction components, because they don't understand how dry flow really works.

[Ben006]

Yep
But the space is tight, and the TB is really bigger than the 986 one, so I try to find the best shape with the room I have.

[Ben006]

Hi !

I did have a lot of free time to work on the intake, but I think this time I'm good !
I realise that trying to make it simple in shape ... would making it harder to fit ...
So I copied the stock shape. It took me some time to get the angles as clos as possible to the stock T, but I think I'm close.

This way, It will clear the starter solenoid, and the engine cover




tell me what you think

Ben

[Reebuck1]

Great Ben!! When will you be able to make a few??
What material will you use (heat sensitivity)?

[Ben006]

I will make one, test it, then, I can make as many as I want with a 2 week delay between

the material will be nylon, I tested it up to 240F without problem so I'm not worried about it, it will be 4mm thick (3mm for the one I already have, and tested) and I will wrap it with heat insulator for further protection

Ben

[jaykay]

Nice design! Has the bend to the left been designed for use of the stock 3.2 intake pipe? Does have it have captured nuts as would be found in a stock piece? 74mm TB?

The material also needs to be impervious to oil..

[Ben006]

The material will resist to oil and fuel

I don't know yet wich intake pipe will fit.
I tought the 3.2 used the same 68mm TB as the 2.7 ?

The nuts are hold in place in four hexagonal holes in the back of the mouting part.


Ben

[Ben006]

Hi !

Finally, after tens of hours behind the screen and in my engine bay, I think I have the right shape !

It has the same angle that the stock one has, so it must clear everything in the engine bay, it has the largest radius possible without affecting the fitting (larger the the stock one).

I added two ribs on each side to have a better sealing with the boots.

A groove in the mating surface to make applying silicon sealer evenly (I tossed the idea of using the Porsche seal, it's going to be just as good, but 4 times cheaper to make and change (20$ for the OEM TB seal...)).

I tilted the EVAP connector to be as close as possible to the stock location (do you know where I can get a new hose for this ? mine broke ...)

It's also 1mm thicker that the first one I made, so even stronger and resistant to heat (I will wrap it in heat shielding tape anyway).

It won't be black as the first one, but white. Why ? cheaper, and it's not the same black as the stock parts so ...

Finally, for information, nylon as been used for timing sprocket on some OHV engine, so in the engine bloc heat !
I think I will be safe in the intake

Oh and, it does not have the wedge but I can easily make one with a wedge !





Ffffff I'm really stressed to now if all my measurement are right ^^


Ben