Ok I am nearing the finish line on my project but have a question I have not found an answer to. I am bolting up my 500r sp (no instructions of course) and have just about everything ready to re-install the motor. I came across a document that was in the box with my waste gate, which calls for a minimum of 6mm vacuum lines running to the waste gate. Everything makes sense, as the input/output vacuum lines from the Greddy boost controller are 6mm and the two vacuum barbs on the waste gate are 6mm, but then comes the problem. As I understand it one line needs to feed the Greddy box from the intake manifold and then one line out of the Greddy box to the bottom of the waste gate, and another out of the side of the waste gate back to the intake manifold. Problem is the nipples on the intake manifold are sized for 4.4 mm vacuum lines. Can someone tell me if I need to drill and tape my intake manifold to accommodate a 6 mm line? I do apologize if this is an easy search; if it is I am too dump to know what to type in to get the right info. Thanks

 

Are they saying 6mm ID or OD?

 

Read up on installing an external wastegate and make sure you've got the plumbing right. It's been covered before.

That said, you should pull your boost reference from as close to the compressor outlet as possible. Most turbos have a nipple for a boost controller on the outlet of the compressor housing. If yours doesn't, drill/tap a 1/8" NPT hole and screw in a brass nipple that will fit the 6mm hose.

Standard external wastegate plumbing will have a vacuum line going from the bottom nipple of the wastegate to the compressor reference nipple, with a T in that line going to the input on the boost controller. The output of the boost controller will go to the top nipple of the wastegate. Make SURE the boost controller is set up for an external - some you have to flip a switch on the back of the head unit, some you have to put the nipples on the control solenoid a certain way.

Regardless, there's no need to use a nipple on the intake manifold. You CAN, and many have done it, but for best boost control you should always have a boost reference that's close to the compressor's output. The farther downstream the boost reference is, the less boost you see on that reference due to pressure drop. You want the purest reference.

And, yes, 6mm hoses are the way to go. And, ONLY use brass T's and other fittings - NEVER use plastic, they WILL fail from heat and you WILL blow something up when they break.

Dale

 

I run a 500R and had major creep (13psi spring, boosting 20psi+) by getting the pressure source from the UIM. I ended up welding a nipple on the intercooler pipe close to the compressor housing. My welder didn't have an extra nipple so I found Aluminum "spacer" from the hardware store that worked perfect. Boost now holds steady at 17psi.

Now, I'm actually changing the nipple/rubber hose to AN/stainless hose after reading about hose failing on some folks and costing them their motor. My only concern is that I'll be trying -3...which is less than 6mm. But I think it should be fine.

 

Thanks for the input. Just so you know, I have been reading for over a year in order to get as far as I have on my car. To date I have pulled and torn down my motor, installed a Greedy fmic, installed a new clutch and light weight fly wheel, installed a new fuel system with dual pumps and SS lines, relocated my fuel filter, installed a dual EGT probes and gauge, replaced my oil level indicator in the pan with an oil temp sending unit and a bunch of other stuff I can't remember now. I have been able to do almost all of it because of this site and it's members along with some help from Glen Weaver with Arizona Rotary Rockets and a few others. I am very grateful for this site and the generosity of its members. Thanks again for your help. RD