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Previous Next Up Topic Engines / Subbug - Subaru Power / IC to TB Tube - what hook-ups to add? (7810 hits)
By @Jeff GS Date 2009-07-08 16:22
OK, I'm fitting up the Intercooler to throttle body tube, one more section to cut and it'll be ready for the first round of welding.  2.5" OD aluminum tube - some very nice quality mendrel bends from Treadstone.

For reference - this is going on a megasquirted Suby turbo engine.

So the end connections are the "easy" part (TB & IC).  Now thinking - what else needs to be plumbed into this tube?  So far I've got:
Blow off valve connection - 1" hose connection (Jay - I know you recommended plumbing this off the intercooler, but I'm not doing any more cutting/welding on the IC!  There's just enough room underneath for a BOV with careful planning.)

And that's about it?

What about any sensors?  MAT?  This sensor looks like about a 3/8" pipe fitting (standard GM sensor)
Anything else?  Now is the time to begin planning for this stuff, so I can figure out the hose routing and general placement of whatever needs to go on there.  Any vacuum/pressure tube fittings?

Figured I'd come of the intake manifold plenum on top for general vacuum/pressure sensing (MAP connection, FPR, cockpit boost gauge & BOV?).  The turbo has an integral tube fitting in the outlet port that looks ideal for connecting directly to the wastegate.  I can always fit a manual boost controller later if I want to "tweak" this up a little.

Anything else I'm missing?

By Jay H (X-20) (ManxVair CC) Date 2009-07-09 21:51 Edited 2009-07-11 02:49
Water/methanol injection nozzle? How about nitrous? I think you hit all the needed tie in points. Megasquirt needs the map sensor. I needed two map sensors because the progressive water/meth inj used it's own 3 Bar Map sensor.

The BOV will likely come off the turbo housing and possibly be routed via a solenoid boost controller, but all that is separate from the plumbing you are discussing.

That's all I can think of at the moment.

Jeff, you put the BOV where YOU are going to be happy with it! :-) I like shoehorning things into tight spaces, as long as I have serviceability later on. I'm always thinking of that when designing placement of any components.

10 July 09 EDIT: I typed bad info here, so I'm editing it out so other people who read this don't get confused.

By @Jeff GS Date 2009-07-10 01:20
OK, now I'm confused......
Thought the BOV needed to see vacuum at the sensing line in order to open?  At least everything I've read indicates so???
The wastegate, OTOH, needs to see that boost signal to operate properly!

I'm going to route the BOV "flow" sides to the tube we're discussing and to the intake tube upstream of the turbo (between turbo and air filter).  Trying to keep all the hissing and popping to a minimum while driving!

Thanks Jay!
By Jay H (X-20) (ManxVair CC) Date 2009-07-11 02:38
Maybe I got confused! Now, I'll have to go out and look mine over... Be right back.
By Jay H (X-20) (ManxVair CC) Date 2009-07-11 02:47
Oh my God... I gave you bum information. I have no idea what I was thinking. You are right... the vac line needs to go to manifold vacuum.

I originally typed BOV location and re-read your post. I realized you were talking sensing line, and In changing my text all around apparently I confused myself.

I'm sorry I confused you. You were thinking correctly all along. My apologies. I'm going to go edit my post so it doesn't confuse more people that read it.

By @Jeff GS Date 2009-07-11 12:19
Whew!  Seeing how you have (had....) a running & driving (at least hundreds of miles!) conversion buggy, I was really doubting my own knowledge Jay!  Me - aka: coming from a non-driving, never even ran "project" person!

Going to measure all the fitting sizes today, as I've noted there are at least 2 or 3 different diameter nipples on the intake manifold, turbo, wastegate, FPR, Megasquirt MPS, and the BOV, etc...  Time to begin figuring out what size hoses I need to get.

Back to the intake tube, so for right now I'm planning fittings for the BOV (1" hose connection), the MAT sensor (pipe fitting), and probably go ahead and put in a spare 1/8" female NPT to have "just in case" I want to use it for pressure sensing later on.

Going to do some finish cutting on the aluminum tube sections today, then begin re-fitting the body back down on the chassis (will need more clearancing around the turbo and intercooler).

So on a somewhat related topic - the cockpit boost gauge:
What is considered to be the correct size tubing to run from the engine - all the way up to the cockpit/dash for the boost gauge?  1/8" seems to be a bit small for good gauge response?  Thinking along the lines of running a 3/16" metal line for the longest section (inside the center tunnel), connected at either end to flexible hoses to gauge and engine.

By Terry F Date 2009-07-12 01:15
1/16" should be fine Jeff, I'm running 10' of vac line off a tee at the ECU port which is 6' from the intake manifold port and it works great. Just make sure you use quality silicon vacuum hose.
By Jay H (X-20) (ManxVair CC) Date 2009-07-12 22:43
Yah, really sorry about giving out bad info. I pride myself on giving good advice and obviously let myself down on this one.

On to other things: I have 1/8" plastic line run from the manifold through the tunnel forward of the bulkhead, out the tunnel, up the front outside of the bulkhead then back to the gauge in my dash. I was thinking along the same lines as you wondering if it would be too small.

The gauge response seems just fine, but now I'm wondering if I shouldn't feed it with a larger diameter hose the length of the tunnel for a trial and see if I get faster response on the gauge. It seems fine, but maybe it would be faster than it is now.... Hard to tell... I have nothing to compare it to.

Previous Next Up Topic Engines / Subbug - Subaru Power / IC to TB Tube - what hook-ups to add? (7810 hits)

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