More than one way to address a potential issue. I will have to remember that one, when I am helping others, like some of the Cobra R Intake guys.

Tom V.

 

Is this due to the increase in pressure or the change in turbulence? I assume (incorrectly?) the manifold was designed that way for packaging rather than flow optimization, and that even in the blower application there would be gains to be had with some manifold changes. I don't mean to question you, this stuff is largely beyond my depth. I am just trying to grasp what I can.

 

Can you post up the whole cam card for the camshaft specs listed above.

Tom V.

 

Factory cams can vary, but the general consensus on the 03/04 Terminators are as follows:
184 degrees @.050 with .394 valve lift on the intake, .004 of 240 degrees
196 degrees @.050 with .394 valve lift on the exhaust, .oo4 of 250 degrees

centerlines vary, as do Lobe Separation, but the LSA is *said* to be 108

Actually quite frustrating tying to find accurate information.

I can tell you we have our cams degreed/dialed in with accuracy.
I've been a camshaft guy for 20+years....

The intake cams on my particular engine are:
274 @.004
230 @.050
176 @.200

109 Centerline

Exhaust cams are OE stock at 211 @.050 on a 123 centerline

I have FULL TiVCT (twin independent variable cam timing) active and can move the intake and exhaust cams independently of each other VS RPM, with a sweep of 50 degree each.
Currently moving the intake from 89 degree centerline for peak torque to 112 at peak HP and the exhaust fairly stable at 113.

 

More than likely packaging is the #1 reason they did this.
I just find it 'interesting' the power and RPM are quite robust given the pkg restraints.

 

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You might want to consider bell-mouthing the exit of the vertical tubes. As the air exits it will immediately expand. The cut edge introduces turbulence completely around the perimeter and a bell-mouth will smooth some of that transition. Regardless of the velocity at the exit, you have unnecessary turbulence. I realize it will all hit the roof but a smooth, laminar impact has got to be better than chaotic eddies everywhere. The new hole on the wall of the tube to “relieve pressure” has also introduced unwanted turbulence and is surely affecting flow. And since they are all in line you may be at risk of some kind of resonance at an unknown rpm. Think organ pipes here.

It might be interesting to drill around You Tube seeking DIY smoke machines. I think some wind tunnel type smoke testing might show interesting results. I thank you for sharing your project and I love the interesting design. There is more potential to unlock once the flow discontinuities are cleaned up.

 

Yes, I've been thinking about this.
Trying to find CFD data on Brass musical instruments actually......as that does apply here.
Data is hard to come by. Wouldn't want to create noise (music) but would like to cut down on the turbulence for sure.

We know the plenum will see dramatic pulses as the intake valves open/close. And the incoming air from the turbo should be relatively pulse-free.

Oh......so many variables here....

 

I wanted to get some advice from the experts here. I was starting to design a plenum for the top of the Edelbrock 70855. Not much different than what Wilson or many others do. I have seen others that have done one but I haven't seen the back and that is where my concern is. It has an "S" shape to it. It looks best to follow the natural design just not sure how it effects air distribution.
I didn't finish off the connection there since I have changed it a few times.

Any thoughts on this? Or even overall design? Is there any angles for these front fed plenums to stay within?

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[QUOTE=". . . Any thoughts on this? Or even overall design? Is there any angles for these front fed plenums to stay within?"

If you are referring to the front angle look at the first page of this thread. (posts 1-3) Tom has drawings of flow as it pertains to the TB butterfly(s). I think Wilson and others angle the front to suit flow conditions caused by the TB. The back angle is compromised due to package space. I have never seen a rule-of-thumb.

 

saltfever: yes that is what I was referring to. I set it up to 20deg. I know Holley does 25deg. I did re-read those first few post and I have read pretty much most of this thread and while there is no hard numbers I figured I would ask. I would think in the 8 years of this thread someone might have some more general guidelines to follow that have been proven. Thanks though.

 

I have know John Marcella from the time he was in high school. He has a real good "feel" for what it takes to build a proper intake for a engine. Some experience from working for others in the early years and a LOT of experience from owning and building custom intakes when he started his business.

I see nothing wrong with the design you have posted, BUT every engine is a bit different and very hard to give specific answers
to general questions. Thinks like engine size, throttle body size, boosted or not boosted, large engine vs smaller engine, very high rpm vs basic 7000+ rpm type parameters.

1st question: what is this intake going on? With one set of injectors we are probably not talking a boosted large engine.

Tom V.

 

Tom, I was hoping you would chime in.

This is going on a 540 twin turbo in a boat. Only looking to make 1350 or so at around 6200 with a max of 6500.
I am running 96 lb injectors now for 1000 hp so upping to 120 lb should fit the bill.
For turbos I was considering the S472sx or S476sx plus intercoolers.
Currently it is setup with a blower and i'm wanting to change over for the cool factor and make more power.

Hope that covers it.

 

Back in 1996, a friend and I put together a little engine 406 cid with twin turbos in a 1970 GTO drag car.
A TV Guy named Chief now runs that chassis on his TV program.
The little engine was on methanol so we ran two sets of the 160 lb/hr Bosch injectors.
The engine made 1600 horsepower and ran in the 6s (in 1996).

We used two throttle bodies as there were no large throttle bodies available in that time period.
We made a intake manifold that was crude in appearance compared to your manifold design
but it worked well enough to run 6s in the quarter. The heads were warmed over cast iron heads.
Barely flowed 260 cfm per port. One set of injectors were on the outside of the intake and one set were installed on the inside
(opposite wall) of the intake. Worked really well for what it was. The chassis would do sub 1.0 60 ft times in 1996.
One reason why Chief has great short times on his program. The chassis was a double tube Pro Mod Chassis.
Fiberglas front end and doors but a steel roof and rear half of the car. A builder named Jeff Covey built the car.

So for you to make 1350 on a twin turbo 540 cid boat engine should make nice hp. Mercury Racing has had a engine
in that power range for years and their engine had great durability.

Here is a link to their engines which you may be aware of being a boater:

https://www.mercuryracing.com/qc4v-jet-king/

Tom V

 

yes I am familiar with the Mercury 1350's. That's what got me thinking about using more of a tunnel ram style setup since that is kinda what they are doing with the long runners and plenum.
I was original thinking of using a Whipple intake with the intercooler on top then a front fed plenum on top of intercooler but the cost is outrageous. I also think the intercooler isn't big enough to fully take advantage of unlimited lake water. Then there is Carson Brummet that has the old Gentry stuff that works well and the intercooler is probably better sized but I am sure it's not cheap either. See attached.

So sounds like the rear "S" shape of the plenum is of no concern for distribution? I guess it is just minor details of the overall design. Same goes for the angle of throttle body and hump size.

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What is the front to back dimension on the tunnel ram intake you posted a picture of?
Might have an large water to air intercooler brick that would work for you.

Tom v.

 

If you are referring to the Edelbrock I am coming up with 18".
I don't have it in hand as I wanted to make sure I was going the right route so I think that is close.

 

I have one on hand I can measure up for you. I will post up some pictures and dimensions tomorrow.

 

Thanks to all and be safe out there.
Tom V.

 

let me know if you need any other measurements! First set of 3 are the Inside dimensions, the second set of 3 are outside. be careful of the injector rails, they stick up slightly above the mounting plane.


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Thanks TTurbo565 for the awesome close ups of dimensions. That helps with my drawing efforts.
Have you got a chance to run this manifold and what are your thoughts of it? For something of the shelf it seems hard to beat if I can fab up top plenum for it.