Faeflora

iTrader: (2)

No, changing the tial wastegate isn't that ******* difficult. At worst have your man lover press down the cap with his fat hairy *** while you bolt it back on.

AbeFM

iTrader: (3)

I'm curious which port does what. Boost pressure in the top port AS YOU DREW IT will close the wastegate, increasing boost. This is backwards. I'm not sure what's wrong, but something is wrong.

Yeah, everyone is saying the same thing here. Do it. You can always run EBC and just have a spring sitting around you don't need.

You know, if you wanted to be clever and spend money, there are caps with a tapped hole in them. You turn a bolt, it pushes on the spring, and you get more boost. See if you can't buy one, if you can't buy one, see if you can make one. Heck, I could even give it a try.

But that's a "MBC" which won't interfere with the characteristics of the stock valve.

(did that make sense? I can draw a shitty picture if you want)

y8s

iTrader: (8)

on the TiAL external wastegate:

TOP port provides CLOSING pressure to the diaphragm

BOTTOM port provides OPENING pressure to the diaphragm

DUMP port provides OPENING pressure to the VALVE

SPRING is on top and holds the valve CLOSED when pressures are equal or greater on TOP.

y8s

iTrader: (8)

I just realized the answer to this question the whole time is that you should be running a bigger wastegate, not a bigger boost controller.

AbeFM

iTrader: (3)

Yay! I'm not totally insane!

Er, and when the pressure on top is slightly less...



Oh yeah, what size wastegate is it? It seems counter intuitive but yes, I had more boost control issues when running higher boost. :-)

What size wastegate is it?

hustler

iTrader: (6)

So you think a 38mm wastegate is too small with a 53.8mm wheel / .84ar turbine on a 1.8 at say 200whp? Seriously? The damn wastegate port is 2/3 the size of the turbine wheel.

y8s

iTrader: (8)

lets see, you say it "overboosts"... is that transient or steady state over time? in other words, with the MBC removed, turbo direct to bottom/side wg port, does it hold steady?

if it creeps up after hitting your set point, then yeah somehow you're outflowing the wastegate. the two solutions are 1) run more boost or 2) get a bigger WG.

if it spikes and settles back down to target, your plumbing (or bc) is cocked up.

hustler

iTrader: (6)

Just running on the gate, it works perfectly. With the boost controller hooked up to the top it overboosts at 5500rpm. With the boost controller on the side port, it spikes.

AbeFM

iTrader: (3)

Spiking will be due to EITHER too big a bleed hole in the MBC, or too low flow in the MBC - this has already been covered.

A better spring in the wastegate will work better because it'll start to open as you get closer to your target. Slower build, but less spiking. This has already been covered.

Putting it on the top port is just plain wrong. This has already been covered.

Why not try some of the suggestions people have made?

hustler

iTrader: (6)

I don't understand why I want to the a spring that will open as I get closer to the target. It opens fine at 11psi

So why do they put a top port in if its "just wrong?" The car definitely drives better with the BC on the top port, rather than just the side port.

I've tried all the different port configurations.

I'm going to attempt to make a ball and spring valve with bigger guts this weekend. I think its related to line size considering that when I switched from 1/8 to 1/4" line on the side port, only running spring pressure, it started working perfectly.

AbeFM

iTrader: (3)

1/8th is pretty small.

I think you want the MBC on the bottom port, and the compressor outlet on the top port. Actually, you know what you really want? You want a solenoid which switches air from the top port to the bottom instead of venting from atmosphere to the manifold.

Sound right, Matt?

hustler

iTrader: (6)

no, you're wrong on the port configuration. I don't really want an EBC either because I like the way an MBC drives.

y8s

iTrader: (8)

I used an MBC on the bottom only and it rocks.

but... using both ports allows you to use boost to hold the valve closed against exhaust pressure.

I dunno, I intend to use the adaptronic EBC at some point, but I'm not sure how I'll wire it up.

AbeFM

iTrader: (3)

It sounds like using both ports will make the two port wastegate behave more like a single port wastegate + MBC.

What do you think about that, Matt, having a switch? So, when you want to close the wastegate, you pressurize the top port, when you want to open it, you pressurize the bottom.

My feeling is it'd be hard to control, pushing too hard on both sides, but still, use the same solenoid but route the lines different.


Right now it would be trying to close the wastegate

y8s

iTrader: (8)

i dunno. i'd say run 3/16 or 1/4 lines but i'm not sold on that being the issue.

I think I'd run comp sourced boost to the bottom all the time and PWM boost source to the top. use the normally closed port on top so it's going to fail safe and use boost to hold it shut in parallel with the spring.

for MBC, I just run it to the bottom.

hustler

iTrader: (6)

well when I had a 1/8" line to the WG it didn't work right at all. When I put a 1/4" line on it, it drove like another vehicle.

AbeFM

iTrader: (3)

Interesting to know. I might look at my own. I think I have a short piece of small tube, and large everywhere else.

As to the normally closed port failing in such a way as to give you a safe mode, that would still work with what I drew, just imagine a little "normally closed" by the orange line. :-)

The nice part with what I'm saying is that closed would really be closed!

hustler

iTrader: (6)

I'm not concerned with this at all. Its making target so low that even when I cruise in 6th w/363 on the highway, its hits target immediately when i stomp the pedal.