Need Help with my intake design

[MrN2OBelvedere]

Hello all,

I've got a bit of a dilema with my intake design, and I'm finding this out after I have already designed and had most of the fabrication finished. The design is for a hot Mopar 360 and uses a tunnel ram base as the foundation. I am basically at the point of welding it up but I need to work out a couple more details before I finish it. Here's a pic of the intake (throttle body adapter not shown in the image):



As you can see it has plenty of plenum volume already, which brings me to my first "problem". Should I attach the throttle body to the front opening (the circular cut out at the front of the intake) or should I attach it to the end of the cold air tube? The reason I ask this is because I am interested in trying to mitigate the effects of the turbulent air flow behind the throttle butterfly by giving the airflow some time to become more developed. The problem with this is that the intake tube will in effect become an extension of my plenum and increase the already large plenum from about 450 cu in to about 590 cu inches (this is assuming a 20" intake tube length, I'm not sure on the exact length yet, but I'd like to feed the tube to an outlet box in my fenderwell). Do any of you guys think I should keep the throttle body at the entrance to the plenum or do you think it might be worth it to place the TB at the end of the tube?

The second problem I have is that the welder told me he can't weld in my injector bungs because of the tight angle of the bungs in relation to the outer walls of the ports. You can see this here:


I took a look at the bungs, and it appears that if I cut off the large bulge at the top of the bung that I would gain a great deal of clearance for welding. As far as sealing goes it doesn't appear that it would affect anything, as the o-ring interface is below this bulge. At that point it would look more like the setup pictured here:
http://www.rossmachineracing.com/images ... slarge.jpg

Any ideas? I appreciate any help I can get here guys.

[Vicoor]

I think the issue may be with the proximity of the front ports to the opening. I'd be inclined to extend the plenum forward an inch or so and radius the opening to allow for a smooth transition.

[MrN2OBelvedere]

I think the issue may be with the proximity of the front ports to the opening. I'd be inclined to extend the plenum forward an inch or so and radius the opening to allow for a smooth transition.

This is the current throttle body adapter that will transition from the Infinity Q45 TB to the plenum:


So what you are suggesting is that I should try mounting the TB about an inch or so before this transition into the plenum? What I might do is create both scenarios and just see which feels better once I get it running.

[Vicoor]

I was talking about the whole "front" wall moving forward a bit. Of course that could be dependent on space limitations.

Besides that it looks great!

[fury fan]

I’d recommend putting the TB on the plenum and not at the end of the tube, but my reasons are hunches and not fully scientific: Aftermarket intakes of this type put the TB at the engine (as do most OEM setups). Putting the TB on the tube might lower the RPM range of that intake system (think of the 59-61 Chrysler crossrams). Also, that Q45 TB is fairly heavy, it might not be a good idea to have it hanging off the end of a tube – might lead to cracking of welds on the plenum?

For the welding of the injector bungs:
If you remove the bolt-on plenum does that give enough room to get the welding nozzle in? I’ve seen pics of tunnelrams with injector bungs installed, so it’s a do-able installation.

[Vicoor]

here's a link to some very...very cool intakes that might help you with your design

http://www.yellowbullet.com/forum/showt ... t=marcella

If you go to weldingweb.com in the projects forum you can search and find more

[MrN2OBelvedere]

Hey guys...quick question

Where is the best place to run the MAP sensor hose to? My main concern is that I want to minimize MAP fluctuations caused by cam overlap and reversion in general.

I think there is a place on the throttle body, one of the nipple fittings just after the butterfly could be used. This would certainly be the easiest route.

Would it be better to place the MAP sensor hose attached somewhere in the plenum? I have a couple of options if I attach the nipple fitting to the plenum:
1) weld a bung in the side of the sheetmetal portion. If I go this route where is the best place to place the bung?
2) I can drill and tap the base flange from the underside with npt threads and screw the bung in directly. This hole would be located centrally in between the two large openings in the base flange. I kind of like this option because it will lend a somewhat cleaner appearance; the hose would route into the open area under the runners.

By the way I'm finally sending the intake out next week to be welded up.

[Matt Cramer]

We're using a Holley Stealth Ram - basically a ready-made version of that sort of intake - on one of our project cars. IIRC, we put the MAP sensor hose on a bung on the back of the plenum.