legacycentral bbs

The subject says it all. Boot B is $95 at the dealer. F that noise. I don't need a BOV return line, and I can put the other two fittings on my coffee mug. I need a flexible bend with both of Boot B's diameters, inexpensively. Anyone?

How badly is yours damaged? Are you pretty sure it's not salvageable with room-temperature vulcanizing silicone and Automotive Goop?

I'd be nervous about trying to hack together replacements for the PCV fittings because I don't understand how the PCV system works; it's possible that you'd lose some important properties of the fittings.

no, not damaged yet. Just 10 years old, and quite stiff for a "flexible" boot. The bottom is currently expanded and the top compressed (on the convolutes, of course) to give the turbo inlet side a slight angle to meet with the not-so-vertical inlet clock angle. I know thats not gonna last long....


Oh and the only special thing about that boot was the fitting facing the driver side, and I've already replaced that (the car CAME with that piece busted) with some aluminum, just cut out the bottom of the edge to mimic the shape of the old fitting's mouth (assumably for a venturi effect or something) and it works fine.

Do we even know the sizes of boot b's in/out? I didn't think to check while mine was out...

How did you attach the aluminum to the rubber?

I know the outlet of the resonator has an outer diameter of 65mm. I don't know about the size of the compressor inlet.

well, that particular piece that I replaced with aluminum was actually just a plastic fitting (shaped the same way I made the aluminum) that was inserted inside boot b's fitting, which sticks out a bit like the other PCV fitting. So I just replaced broken plastic with aluminum and re-used the hose clamps that were there to begin with. I don't think I've got a good photo showing that, but I did take quite a few photos during the turboesectomomotomy. I'll go through them and post some when I get half a chance.

So 65mm, good at least we've got one measurement. Next time Boot B is off I'll grab the other measurement.

Ohh... You replaced the end of the plastic pipe with aluminum. But the little nipple on Boot B was still intact. Gotcha.

The other measurement of Boot B might not be so important for you if you're trying to hack something together for your hybrid turbo... What you really want to know is the outer diameter of the compressor inlet. Or are you using the stock compressor inlet elbow?

well, the t-bird inlet is bigger than the stock inlet, but I had to use the stock elbow for clearance reasons. Had to have the compressor inlet surface and the stock elbow flange milled down to clear the intake runner. The t-bird inlet elbow was a 45 degree, not a 90, and it would probably require both intake runners on the passenger side of the engine to just not be there. That's a good restriction in the intake path, I have 3" run all the way from the fender to the coffee mug, where it gets to 65mm for Boot B, and then it necks down really small by the time it hits the turbo. But that air going in has good velocity, at least.

The inlet flange shape on the t-bird compressor housing is exactly the same size and shape and everything as a standard Chevy thermostat. In fact, my buddy happened to have a few Chevy thermostat gaskets lying around, good thing since I didn't have one for the turbo

Hey Chris, do you remember if you made the measurement of the outer diameter of the stock compressor inlet elbow?

Boot B:

to turbo ID: 2 1/4"
to intake ID: 2 1/2"

Regards
Rene (from Chile)

By the by - Boot B can be replaced with a 90 degree formed radiator hose section of the proper size to fit on the end of the coffee mug (or the turbo inlet - of which I forget the size right now but its friggin small) and then just adapt the two sizes with a standard exhaust adapter found at any Discount Auto Parts or Autozone. Move any fittings you care about (PCV venturi fitting, BOV recirc inlet) onto your coffee mug, and WHAM! No more $95 Boot B problems.

As I stated earlier: F that noise.

I believe I have a good photo of the Boot B area in my FMIC routing pics, which I am still waiting to get copies of. I can post a photo if anyone wants to see. But no ideas on the sizes, I'm not planning to disassemble that area any time soon. If I do I'll try to remember to measure. I do remember that they are two standard sizes that are both available in exhaust. Might be 2 1/4" and 2 1/2" as Rene states above....

The two PCV fittings are 12mm. The BOV fitting is 19mm. The inlet to Boot B is 65mm, and the outlet is 55mm.

But if you're replacing Boot B and also the coffee mug, you might as well try to make it so you only have one size transition between the MAF and the compressor, right?

I'm skeptical about the venturi-type PCV thing working after being moved to the mug though...

Hey hey, there are the sizes... lol! Like magic.

well, the mug itself is a smooth size transition... the exhaust adapter is relatively smooth, isn't too drastic of a change. I have my doubts about the PCV venturi fitting but we made sure to imitate the shape of the old plastic opening that was on the end of the stock one. It's better than nothing, and man I love not having a Boot B on my car.

I didn't replace the mug, just added more fittings to it

Hmm. How did you orient the venturi? The stock configuration had it right at the compressor inlet. Do you have any pictures?

I was thinking before about using a silicone elbow instead of Boot B and then cutting a small hole maybe 10mm in diameter for the PCV venturi, placing it in the stock spot. It seemed to me that the pliability of the silicone would provide a good enough seal, particularly since the interior would always be under a very slight vacuum.

Thats a possible way to re-create that venturi-like effect that is supposed to occur at the turbo down-bend... currently it is in the center of the mug inserted perpendicular to the mug surface, and aimed with the open side of the V-cut facing airflow, but it's not totally secured. The aluminum venturi shape is clamped onto by the hose on the outside, but is only held in the coffee mug by a grommet. It slides out if I want it to, but it doesn't do it on its own. I don't believe it rotates either.

I've got a shot of the mug in some of the FMIC photos I'm waiting on, I'll post it up soon.

Facing airflow? You mean facing away from airflow, right?

on my intake i had to recrate the pcv system. the venturi isnt there anymore. its connected by a hose clamped to the outside of where it acutaly went. there may be a leak there because the hose is a little bigger than the od if where the hose went.

could that cause gas milage to go down drasticly? it idles just fine and runs normal under all conditions.

I don't know if the change would be drastic, but under load you're probably ending up with a pressurized crankcase, which does cause a loss in efficiency.

oops my mistake, it was getting late... I meant facing away from the air-flow.

can you elaborate on this positive crank case pressure

Well, it's just that when there isn't sufficient vacuum at the intake manifold, the stock PCV system relies on the venturi to pull a slight vacuum on the crankcase. Without it, the combustion that leaks past the piston rings fills the crankcase and pressurizes it. This in turn makes the rings seal worse.

I think.