Boosting problems

[Badger]

Who's mapping?

 

[Besty-FR]

Dervtech have written the map, but as I said they've written about 12 maps now

 

[Besty-FR]

So judging by that the rod needs to be shorter but it's really short as it is and it still isn't boosting til 3000rpm no matter what I do

 

[Badger]

Then it's either;

Map (without seeing it couldn't say)

Or

Turbo stop screw,

As you've already said, if you've wound it all the way out the veins will be as closed as they will ever get so then it's a turbo manufacture issue.

On my GTB, I had to remove the stop screw completely to get the veins to around 1.6mm which was optimum for me. (I disassembled the turbo before installation)

 

[Besty-FR]

I had the stop screw removed when I managed 80mbar difference but never test drove it because I was worried it'd damage it but wanted to see if it was possible to get close to the 120 you said. The actuator has a few more turns in it still but I don't think many.

 

[Badger]

If the stop screw removed produced a better result, try it lightly at first and then monitor boost.

Then go for a WOT in 4th and see if it's better.

Just keep an eye on boost pressure. I'm guessing you don't have an EMP gauge so if you feel the car or engine choke ease off.

 

[Besty-FR]

Ok mate will try it tomorrow

 

[Besty-FR]

Stop screw removed, still slow getting on boost, is that now down to actuator?

 

[Badger]

No, now it's either mapping or the turbo itself.

Has the turbo supplier gave you average RPM for full boost etc? What have others been getting?

When doing the on/off test are you able to watch the actuator?

 

[Besty-FR]

Should be full boost at 2500rpm, yeah I managed to watch it, a friend of mine has a pit in his garage so I jumped under and had a look, seems to move smoothly

 

[Badger]

Definitely held with no movement between? No creep etc... From actuator?

 

[Besty-FR]

Not that I can remember, I'm getting a vacuum pump so I'll be able to test it

 

[Besty-FR]

What would cause me to lose boost between gear changes? I take it over 3000rpm and get 2.2bar but when I change gear it drops right back to 0.8, meaning I need to build it back up, god this is pissing me off!

 

[Badger]

Vanes not closed enough...

 

[Besty-FR]

So stop screw...still!

 

[Badger]

I think we are beyond that! Especially if you don't have it anymore

 

[Besty-FR]

Haha nah I've put it back, I only removed it to do a difference test, I've put it back in lol

 

[Badger]

Was it any better without it?

 

[Badger]

Obviously watch boost levels.

 

[Besty-FR]

Nope not a huge difference, in 1st it crunched...oops