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Discussion Starter #1
Good morning fellow Miata friends.

Little run down of spec to give you an idea.

Fully forged engine
STD Cams
Head has been modified quite heavily.
+1mm exhaust valve.
15 thou head skim.
T25 Plus 63ar turbine housing. from ATP. Flows like a T3. So I guess similar to a t25 0.86ar
3" full system
FM manifold
Turbosmart Ultragate 38mm EWG

Photo of turbo setup.

Right.. down to the problem.

EWG has a 1bar spring. Which it was hitting fine every time.

Went down to the dyno and got it tuned. Which we did at 1bar boost.

We decided to up the boost to around 19/20psi as map sensor is only 21psi.

We had a misfire so we changed the plugs to a cooler grade 8 instead of 7. Car then over boosted way above 21psi and popped a intercooler pipe off.

So we turned off the EBC and ran it up and it was hitting 18/19psi. on spring pressure. We refitted the originally plugs but with a smaller gap. Exactly the same problem!?

I've checked everything. Vac lines. changed vac lines. checked EWG hasn't got any problems. it opens as it should.

It's only starts to creep above around 5500 up to 19psi.

I removed one of the springs and it also did the same but to around 12psi on a 7psi spring.

Since playing around last weekend and checking all pipes. it's now hitting 1.5bar which is off my map sensor so I'm running out of fuel.

The diaphragm isn't ripped either.

Does anyone have any ideas. I'm really stuck on what to try. Turbosmart have no idea either.

Could I have a faulty EWG?

How would a spark plug change effect it? As it wasn't misfiring at 1bar previous.

Chuck ideas at me please!

2,586 Posts
Are you sure is not a replica EWG? The chinese market copies everything. I have seen the TiAL Replicas are they almost identical!!! Difference in the metal/materials used but my friend has fake TiAL BOV and I can not tell the difference between his and mine.

for reference see below:
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