Simmy's Naked Turbo Project

I think there are two kinds of manual boost controllers:

1. Boost Controllers that bleed off air from the compressor before it gets to the wastegate. This means that some of your boost is always bleeding off to atmosphere. Setting these is counterintuitive, the lower the spring pressure the more boost you bleed off and the less pressure your waste gate sees (more boost). I think it's supposed to be smoother (i.e. the wastegate will eventually see the 7psi it requires to fully open), but it's a more gradual result. These are most common.
2. Boost Controllers that work as a check valve, adding spring pressure to the compressor pressure. This will delay a signal getting to the wastegate until the compressor pressure exceeds the spring pressure. Increasing spring pressure increases boost. I made a bleed boost controller into one of these by plugging up the hole. There may be some "flutter" in the waste gate, as when you set say 12 psi on the spring pressure, the wastegate sees nothing at 11, then BAM 12 psi and swings open, dropping boost below 12psi. Then the ball valve shuts and the wastegate sees 0 psi, closing it again. However, in running it on my own turbo, it didn't seem like a problem, and I usually only boosted to 11psi for short bursts. Maybe there was no issue at all.

Also a note on the powerup kit. It's just a delay valve that delays the signal to the wastegate. This means you can reach a higher peak compressor pressure (12psi) but the bike falls flat on it's face if you try to hold it there. When the wastegate gets the signal, it opens and drops the boost to 7 psi. I did not like that feeling and it didn't help the one dyno run I did.

 

Thanks @k-moe I think at this point it might be just as easy to try another boost controller as they’re pretty cheap. Maybe this spring is too stiff.
The 8 psi would be ideal for a 900, while I’m riding it as a 650 the higher boost is nice, they’ve certainly proven to survive this abuse.

 

yes, below is straight from BoostValve's website:

Camparison of a BoostValve and a bleeder valve

The BoostValve prevents boost pressure from opening the turbo's waste gate until the desired preset boost level is reached. Inside the valve is a precision stainless steel ball that is held in place by spring tension. During the turbo's spool-up (as pressure is building) spring tension in the valve is greater than the boost pressure pushing against the ball, so the ball prevents the air from flowing to the waste-gate actuator.

A bleeder valve is open all the time. Bleed valves work by fooling the waste gate into only seeing some of the boost pressure. The rest of the pressure is vented off, sometimes completely wasted by blowing out an open hose. Just like an air leak in any other hose this wasted air can cause problems with modern computerized engine controls. Additionally this causes the waste gate to open before maximum boost which can create turbo lag.

Mine seems to be leaking at low pressure contrary to what BoostValve are claiming.

 

Don't forget they are plumbed in differently. Most manufacturers went over to wired, electrically pulsed controllers years ago - you can buy them as kits.

 

yes and below are the different schematics.
The lower schematic is how I had mine installed.
For such a simple device I have not yet figured out why it is restricting my waste gate from opening.

I like those but at $400 a little pricey.

 

Simmy, did you try running the manual boost controller, in your current setup, with the dial screwed all the way in instead of out?

 

No I did not. That would for sure just hold the wastegate closed.
I think I know what you're getting at, which would make sense if it was plumbed in as per the bleeder set up.
My BoostValve outlet is connected to the wastegate actuator.
I've been conversing with the BoostValve manufacturer.
They have different rate springs, its possible they sent me the stiff one.

 

Sorry, I didn't read your previous post closely enough as to which setup you used.

I see you tested it and showed that it would let air by at 1psi, is there any chance that you plumbed it backwards on the bike?

Where are you getting the boost signal from? The airbox nipple or the compressor? I remember a cap on the compressor port. Not sure if that makes a difference

 

I’m coming directly from the compressor to the controller. I have Tee in this hose to the boost gauge but that won’t matter.

 

Where the boost signal comes from might be the key thing here.

This is what Ric Gillis from BoostValve just wrote me, he is suggesting the same thing you have;

I usually like to set up the Boostvalve where there's negative pressure (vacuum) going to the inlet side of the valve so when you let off the throttle it snaps the Boostvalve shut. Turbos tend to keep spinning after you close the throttle delaying the response of the Boostvalve. I would cap off the port at the turbo. Tee into the boost sensor line and route that to the inlet of the Boostvalve. You might want to run your boost gauge off this port too. Keep in mind we really don't care how much pressure comes out of the turbo itself. What matters is what is at the intake, that's what is actually going into your engine.

For anyone else still following along, here's a schematic of what Ric Gillis has suggested.
Hopefully this is insightful for anyone else considering upping the boost pressure of their Turbo.
I hope to get some time this weekend to make these changes and test it.

 

So my setup (not saying you should do it) left the "green" line stock (i.e. running the port on intake #2 just to the boost sensor for the dash gauge and TCI ), and plumbed a T off of the "red" line from the intake to the pressure regulator. But I was also more worried about the stock fuel pump not keeping up with the boost as I adjusted the manual boost controller, and the fuel system cares about the compressor output, not the manifold pressure.

So I guess it all depends on what pressure you care about more. If the boost valve shuts with throttle, then the waste gate stays closed and the compressor will keep building pressure until the blow-off valve pops (I guess that's what it's there for, for the sudden closing of the throttle). I understood that in general, if you aren't using the boost pressure, (i.e. throttle closed) you want the wastegate to open to reduce the drive on the turbine side. Popping the blow-off valve means that the compressor isn't working against anything at can overspeed (and it already spins very fast as is).

Manifold pressure drop due to the venturi and will also vary with throttle opening. So you can be building more pressure behind the throttle plates than you see at the intake manifold and your boost gauge. Furthermore, there's a bleed port on that boost controller, which may function as an air leak at times on intake #2 through the green line. The stock setup won't have a leak (as long as the line going to the sensor doesn't have any holes in it.

 

I had this line dedicated to just the engine timing also thinking best not to disturb that signal with any T's.

this line I've left alone as I did verify my FPR is functioning and my upgraded pump will always exceed any boost pressure the turbo is capable of producing.

You're right the only time the BOV will pop open is when the butterflies are closed, and instantly removing an resistance to spinning may allow it to spin even faster.
Combustion is reduced which will slow the turbine but I agree there will be a time lag for this.

The hole on the controller is only to release pressure and ensure the wastegate is able to close. It should only leak when the wastegate is activated.
It would be nice to have 3 pressure gauges, one for fuel, one for surge tank and one for manifold pressure.
If I had a fairing I would consider it. Once I have control of my boost pressure and set to a reasonable limit I do intend to remove it entirely though.
Hopefully I can just ride it and focus on the rapidly approaching horizon. Not there yet.

 

On Friday I reconfigured the boost controller as per my diagram above, ie; tapping the #2 cylinder intake.
I set the preload on the spring near the limit for lowest boost.
Rolling the throttle on in 5th gear the boost went to about 12 psi and remained very controllable until I had to back off anyway.
Once I got to a back road I took it to 6,000 rpm in 3rd gear and whacked it open.
Same thing as before, the gauge spiked to >20 psi and popped the BOV valve open.
I'm not sure what to try next.

As I demonstrated before when I took the boost controller out of the circuit the bike ran perfectly with the OEM actuator controlling things.
Boost would climb to 7-8 psi and hold, even when accelerating in lower gears.

 

Rick at BoostValve is sending me a replacement unit to run at low pressure with a low pressure spring (0-20 psi) replacing the standard spring.
I'll wait and see if this does it.

 

one of my favourite threads from any bike forum..looking forward to updates...i cant help thinking that the xj6 front end would be a perfect match for the rear wheel?

 

I bought a turbo parts bike.
The motor looks good but it might be seized.

If the bottom end looks good I’d like to fit my 900 cylinders to it. This makes a 738.
The 900 crank and cases I have can be another motor later.

Loki is sniffing the intake for mice, LOL

 

Awesome oil cooler for someone's project. If anyone needs anything just PM me.
Turbo, carbs, body work are all gone.

 

I’m currently running the bike without the boost controller. I have the pressure tap on the compressor plugged off and take the pressure signal from the nipple on #2 carb. No.2 is the only carb with this nipple.
From there it goes directly to the turbo actuator and opens the wastegate.
It builds a solid 9psi but most importantly holds that pressure when I accelerate through the gears. I can ride faster because it’s all so controllable.
When I had 16 psi it still quickly hit that in the lower gears.
When it popped the wastegate the stock actuator was overwhelmed, all this is happening just when you’re looking for the next gear.
I’m just now pulling the boost gauge and putting the other mirror on.
At 9psi it’s still a wicked fast ride, and totally illegal when ever on boost anyway.

 

Oh and also repositioning the Yamaha badges on the tank. I had them level with the ground and it didn’t look right. Finally got up the nerve to remove them from that beautiful paint. WD40 helped.
And I still have a pulse from the front brake.
I had these discs powder coated and they look awesome, I’ve not wanted to make the realization that one might be warped.
I’ve seen some Brembo floaters listed for a Virago, maybe time for that splurge.

 

Commuted to work today on the Turbo.
I repositioned the Yamaha badges, removed the boost gauge and mounted the LH mirror. I got everything the way I want for now.
The winter project will be building a bigger motor for it.