Design / shape of 16V to quad throttle manifolds

[Sam-Q]

I am trying to work out the best design for a silvertop quad to 4age manifold. To do so I made this amusing looking test fixture:



My main aim at the time with it was to see if it was possible to have something with the throttles the right way up unlike upside down like every other adapter I have seen so far and still clear everything. I found that even if I clears the RWD water pipe the linkages don't clear the fuel rail, so considering I don't wish to supply a linkage kit there went that idea for now.

Angle of throttles: Moving on from that somewhere I read that the reason the later T3 manifolds are angled up is for clearance, and when they had the throttle face parallel to the head (flat) there where problems clearing the water pipes or something. When I did my test fit once I flipped the throttles back to upside down it cleared everything with ease. So am I missing something?

I was thinking why are What are manifolds not angled down? The way I see it is that the velocity stacks would better clear the booster that way. Sure it might look a little odd but it would mean more power from the longer intake. If all goes well I can have a manifold with curved runners no problem.


Apart from having enough vacuum ports for everything, smooth transitions and a nice port match is there anything else that people would suggest in an ideal manifold design?

[Jip86]

The only thing i can see being more difficult is bolting the last trumpet on and removing the socks to clean them would probably require removing a trumpet or two.

Would that part of the engine bay be hotter because a lot of the air from the rad goes down to go out under the car?

A good air box would obviously solve all these problems.

[drift kid]

I just see it being hard to sell because of the fact that they are pointed down, even with theories of how it will flow well people will be skeptical instantly

[LittleRedSpirit]

Consider this table when designing. There is no one ideal setup, it depends on when the inlet valves open and close with reference to tdc. Also the placement of the butterfly has an effect on where the power is made in the rev band.

[Sam-Q]

Jip86: If I do face these down then they should in theory suck colder air and be easier to install everything. Or so I think! hahaha

drift kid: I thought about that but I would think the look of the carbon fiber tubes would have to win them over. Well how about a back to back flow bench test? I am thinking that I post the total measured flow of mine and then the same test with a picture of an un-named but very recognisable manifold from a certain other company. Just like with the velocity stacks people can't argue with the numbers so easy.

Matt: In this very rare example of it I will ignore all theory and instead use the feedback and limited dyno results from my customers in regard to length. Best I can tell anything under 100mm has no gains anywhere with any engine set up. Even the big diameter TRD quad throttle system (N2?) is very long and they run massive cams and big revs. I don't wish to curve this right down so I'm unlikely to be able to fit the 100mm, but 70mm with slide on filters would be nice. I need to find out more.


Someone must have one of the original T3 straight manifolds and know what issues it causes? I suspect it was only because of how short it was that there where clearance problems but until I find out I don't dare go ahead. Otherwise I could have a severely expensive mistake.

[LittleRedSpirit]

You could at least work it back with the table and see where you are in regards to the length it specifies.

[ill-minded]

With the ports, are you designing the manifold to match a Toyota manifold gasket and let users port their heads to suit or do you intend for the manifolds to be able to be ported as well? I'm guessing with carbon runners, this isn't going to be a possibility. Just thinking of the instances where people would be building a more heavily worked engine and are re-modelling the intake ports which would need the manifold modified to suit.

Having the manifold laid down flatter to match the port angles better appeals to me though.

[filfrederick]

just out of interest what construction are you intending to use?
machined or fabricated?

[Sam-Q]

ill-minded: With the carbon fiber tubes the way I think it would be constructed is they would stick through the flanges and then be glued like that. Your questions are something that's been on my mind for a while. With someone fitting blacktop throttles they could port match them via the thickness of the flange, cutting into the tubes and glue for that short section isn't likely to be an issue for such a small length. But the plan was for the ports to match the head with the factory ports. This means no effective porting and it's a pretty big reason why I am still looking at other options. I have not ruled out casting a part, it would make me more confident structurally as it would be a single piece and I could add lots of small changes to make it stronger such as fillets and gussets.

filfrederick: with the concept above, cnc machined aluminium plates for the head, throttle-mount and braces between the two. The braces would be bolted with 2 x M8 through either end off the head and throttle plates. I can't see me doing any welding at all with any option I go for, it's too limiting. Unless I get just the tubes cast and then weld them to the flanges??

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If I am unable to make some progress in what shape I am meant to have I may have both a straight and downward curved manifold 3D-printed, get someone to test fit them with photos and then check for clearances as well as see what people think.

What I suspect is the older parallel face T3 small-port one had clearance issues because it was very short to save costs. This would also explain the WTF photo of someone who had 100mm stacks fitted when that shouldn't even be close to possible. I am going to start digging for that thread, I remember it as being a technical section question on trumpet length so I have something to go off.

If I am right this means if I have a straight manifold or curved down and it's longer than something like 80mm then I will have lots of room. I am hoping someone else will see this thread and help out. I could also post on Toymods I guess.

[Bren]

I hope you have some luck figuring these out. I recently got some silvertop quads but, after our previous discussions, I am not keen on the T3 one. I think the post regarding modified ports is a good one. Eventually I plan on modifying the head, and working the ports, so being able to match the manifold to the head once this is done would be handy.