Setup and application is a boat with a 540 BBC that has a blower currently and want to change to twin turbos. RPM range 3000-6500. For turbos I am looking at either S472sx-e or S476sx-e with 87mm and Tial SS 1.02 turbine housing. Intake also needs to be for EFI since I'm running a Holley HP.

With current setup I don't have an intake to start with. The more I read the more configurations I come across and have no idea which way to go. I'm considering either an Edelbrock PRO FLO XT or Victor Jr so far unless there is a better recomendation. I would love to have a billet intake from like Steve Morris or Nelson Racing but I can build the whole system for that much.
Of the two I am leaning towards the PRO FLO XT but have read about the casting quality being questionable even though they perform. It also seems to loose a little torque down low which is fine for a boat and has more HP up top over the Victor Jr. Then just add a throttle body and be done. It also seems to be the right RPM range.
With the Victor Jr is where things get lost. I can do an elbow to TB, 4150 with a hat, adapter to single port TB. I have read plenty that say the elbow causes distribution issues unless it has a divider and 4150 has lower flow then a single 90mm. Not sure on the adapter to single though. Yet most setups I see are elbows.

So what is the recommendation here?

Thanks

 

Well dang two weeks and no love here, lol.

Anyway if anyone has any feedback on which way for an intake I would appreciate it.
I am leaning towards the PRO FLO XT since it seems cheaper and in the right RPM range but if it really has distribution problems I will look at the other route with Victor Jr. But that also seems to have distribution problems unless running a divided elbow and I only found two off the shelf so far.

I was considering the intercooler on top of the intake like a lot of boats have but that isn't cheap and I thinking the intercooling is limited.

What other info would be needed to help choose?
Thoughts?

 

You might post this under the advance section.

All I can do is offer my opinion since I dont have experience with the proflow.
From what I have learned about intake design only from listening to experienced peeps, the proflow will most likely get more flow to the rear cylinders.
With HP i believe you can tune cylinder to cylinder.

When it comes to the elbow, based on my experience with hats and blowthru carbs, the back side radius of the 90 deg elbow will have the most air flow. What ever cylinders are on the side of the backside radius will get the most air.

Neither design is perfect. Both have been used many times.
Based on the HP range im guess your going for, just pick which one is gonna work best for you.

If this was max effort, like you where gonna have two turbos and a bunch of boost on this, I would say hold out and get a morris or visner intake.

 

Thanks for the reply.
I did decide to probably change to the Edelbrock 70855. I posted up in the intake design something I came up with for a top.

 

I did read this before but I have no BBC experience. The intake manifold design thread is great to read. I agree with tbird, those proflow intakes with the flat roof would tend to force the air to the back cylinders unless they have something on the inside that directs the flow. It needs a Holley high ram type lid according to what I read. Guys here will answer no problem but only if they have experience.

 

..Bringing this over from the Advanced area. I had looked at the drive by wire setup. The issue that I was having was the LS drive by wire throttle bodies seemed too large to use two. The drive-ability on a car might be an issue. I don't think you would have an issue on a boat, unless it became an issue of low throttle maneuvering. Instead of going with smaller throttles, I ended up with Holley 112-589 90 mm with tapered ramp at the bottom to reduce the flow at part throttle. Unfortunately they are not drive by wire.
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anything above quarter throttle should be crazy anyway.
As far as "stealing", none of what I am doing is new. I have been "collaborating" with anyone that is willing to share! At this point all that I have done is rough in the design. I still need to decide on exact sizes for the inter-cooler bricks. I have been toying with the idea of using A/C to cool the water for the Inter-coolers to improve efficiency. Making the Inter-coolers longer (6") would be easy to do, the angle of the inlets may need to be adjusted to clear the valve covers. There is room to go strait off the sides, but it might look a little top heavy. how much room do you have vertically in the boat? I want to keep the whole thing under my C10 hood.

 

That is an interesting idea with the Holley. I would like to see a CFD analysis of the flow at wide open.
As for the DBW I was thinking of the stock 78mm LS. Can get them cheap at the junkyard. They got plenty of them.
I am using a Holley HP EFI and I just checked if it would do DBW. Nope have to get the Dominator one. I would like to have the Dominator for dual wide band but it just keeps adding up.

You are right about the weight though. Fill those up with water and I'm sure they get heavy. Were you thinking of all sheet metal or doing some machined pieces on the tunnel ram to weld to?

As for room, my blower setup is 2' tall so I got room. I would like to bring it down to lower my hatch though.

Here is a really nice setup that Shearer is doing.

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How do you end up too large on a dbw? Just let the ecu open it less. OE's will run an DBWTB that will deliver 300% the required air mass and have 100% drivability. Is there some limit of the DBW algo in the ecu you are running?

 

That Shearer set up is pretty cool! I have been all over the map with what I am doing on the manifold. I have a guy that can 3D print the lower manifold. I toyed with making a casting off of the 3D print, and then I was thinking billet and I would provide the CAD model for milling. The latest was just to build the thing and get it done. So many people I know have bad azz cars that have never seen the road. Direction has been keep it simple with known components or at least minimize the risks of having something that does not meet the desired goal of every day driver. Part of keeping it simple is to keep the intake tract about the 3.5 inches of the turbo outlets and as short as is reasonable. The 90mm throttle bodies keep close to that, but when I inquired here (The Turbo Forums) and at work (OEM), I couldn't find anyone that recommended it, let alone had actually done it. And then like you I would have had to trade my computer system for the Holley Dominator or such. It will be much cooler to drive it than keep working on it to make a space shuttle.

 

Well I am torn between the Shearer setup or my plenum design with separate IC. I really like your design but it seems to costly with the additional upgrades.

Yea you gotta do what works for you and your time and budget. Sounds like you have the skills and friends to help out with design and printing things which really helps. If I was at my old job I would have much more access to equipment to CNC whatever I wanted. I was thinking though as for a TB with the twin inlets on your design you can do like an X pipe with the TB at the cross. This way it is only one 90mm. I think if done right might look kinda cool.

After talking to Shearer be happy you have that intake. They have been on back order for many months and no one has any in stock. Sounds like it will still be a few months before Edelbrock produces any.