My 3B to RS2 project

[newsh]

Now that the boost is not creeping I've wound the spring down to give 1.5 Bar boost, these GT turbos spin up bloody quick don't they

[Acidburn]

We need some videos

flyby's etc.

[Rusty]

Ah, that's a new one but now I've read it, it makes sense.So if your WG is too small and isn't flowing enough gas to stop the turbo spinning faster then I guess that it's all about path of least resistance. If the WG is more restrictive than the turbine & exhaust assembly then it ain't gonna flow that way. What you need is some exhaust gas that enjoys taking the long wy round, a sort of petrolhead's exhaust gas

Are you going to get a larger WG on there?

[newsh]

Yeah, seems like the guys who run internal wastegates get this all the time, it shouldn't happen to us unless we go GT35 and larger..
My WG is original with over 200,000 miles on it so may not be opening fully, so I think I'm going to try a new wastegate first, I can borrow one , if that doesnt work it might have to be a Tial, unfortunately the prices on 034 seem to have gone up recently, they do a drop in 44mm one IIRC.

[gedu]

hrmm, with internal wastegate you are begging for problems with small garretts

Stock WG might start putting things into disarray quite easily, as it doesn't flow _that_ much, and if you want to run low pressures, you really have to be able to divert lots of gasses from turbine. Putting back-pressure into exhaust is just "wrong" way to tackle it, get a larger WG that can divert enough gas from turbine

Of course, loudness is also quite tiring, and yes, you almost always get more back pressure when quieting things down.

[Jamo]

hrmm, with internal wastegate you are begging for problems with small garretts

Stock WG might start putting things into disarray quite easily, as it doesn't flow _that_ much, and if you want to run low pressures, you really have to be able to divert lots of gasses from turbine. Putting back-pressure into exhaust is just "wrong" way to tackle it, get a larger WG that can divert enough gas from turbine

Of course, loudness is also quite tiring, and yes, you almost always get more back pressure when quieting things down.

I agree, I'm sure someone said earlier the wastegate was too small, can't imagine who.........

The wastegate really needs porting, the gasket to gate is shocking there is so much that can be taken off.

I'll take a picture some day if I can.

[A80Avant]

it could be that the 200.000mpg old wastage needs some servicing rather than needing a bigger one.If that wastegate was indeed the problem of it being too small,then why is it that everyone of us using the same turbo,isnt having the same problem so far?...It could be a mixture of things as well and not just one thing.Low backpressure from your exhaust+ years of muck in the wastegate making it actually smaller than it can be...

Logic says though that if there was an issue with the wastegate and this level of turbos,then all I5 engines with bigger garretts should have been using Tials already.I have seen the boost being a problem on a GT35 garrett,not the 3071 or the 3076 so far

[gedu]

Yep, there is always the possibility that original WG is past its due date. Spilt membrane could do that.

Full throttle boost control is one thing, part throttle usually is the hard part. I want my engine to be able to keep that ~1bar boost stable to redline if there comes a need to do it

[newsh]

it could be that the 200.000mpg old wastage needs some servicing rather than needing a bigger one.If that wastegate was indeed the problem of it being too small,then why is it that everyone of us using the same turbo,isnt having the same problem so far?...It could be a mixture of things as well and not just one thing.Low backpressure from your exhaust+ years of muck in the wastegate making it actually smaller than it can be...

Logic says though that if there was an issue with the wastegate and this level of turbos,then all I5 engines with bigger garretts should have been using Tials already.I have seen the boost being a problem on a GT35 garrett,not the 3071 or the 3076 so far

Absolutely correct.

[newsh]

Bit of a breakthrough in the wastegate dept. It turns out that my WG not only has a smaller valve (early 3B WG?) but is not correctly machined, so the valve cannot open fully, you can see this in comparison with the replacement, its 1/4 inch shorter in movement.

[madwolf_Uk]

Thats interesting then mate, wonder why the earlier 3B's had a smaller one

Something to bear in mind, wonder when the change over for larger omes is...

Good to see making progress as well

[newsh]

Thats interesting then mate, wonder why the earlier 3B's had a smaller one

Something to bear in mind, wonder when the change over for larger omes is...

Good to see making progress as well

Cheers Gary, not sure of the change over or if this car has had a WG fitted from a 10vt at some point in its life Very relieved to find the cause of the problem. Mid box should be in by tomorrow too.

[madwolf_Uk]

Nice one, whats left to do after that then mate, just a remap for the current spec?

[newsh]

Nice one, whats left to do after that then mate, just a remap for the current spec?

Think I might just go for the reverse IM before remapping

[madwolf_Uk]

Think I might just go for the reverse IM before remapping

was that with the (un)helpfull suggestion of mine at ADI then?