Corksport turbo boost creep

[Speed403]

I'm looking to get the cst4 turbo, does anyone know for sure if the boost creep issue has been fixed or is it still a problem for some people. Thanks!

[Fstrnyou]

Doubt it.
My Corksport turbo was part of the "2nd batch" that supposedly was revised to solve the boost creep, but that wasn't the case. I imagine if I had an upgraded exhaust manifold, it would be even worse.
I have not see any discussion, documentation or claims stating the the newly named CST4 has received revisions to address boost creep...aside from the EWG housing option/upgrade.

[LenSpeed6]

I havent noticed any boost creep with my CS turbo

[Fstrnyou]

Originally Posted by LenSpeed6 I havent noticed any boost creep with my CS turbo

What intercooler are you using?

[LenSpeed6]

stock for now because im weaksauce, hoping to run the rerelease of the fmic from CS if that ever happens.

[Fstrnyou]

Originally Posted by LenSpeed6 stock for now.

There it is.

Have fun with boost creep later.

BUT, the boost creep isn't as bad as I've led on. Wastegate is about 12psi or so and it creeps to 18ish psi. And 18 isn't unusually high, so it's manageable.

[LenSpeed6]

I'm pushing around 23-24psi threw that shit stock top mount and a small intake. Already maxed out the intake and I'm sure the IC isnt very happy. I am running the EBCS in factory bleed set up rather than interrupt, thinking about changing that in the near future.

As always I learn more when you post @Fstrnyou;

[Jeff23spl]

at 23-24psi it is why you didn't notice any creep if it is below 18 psi lol

Why would you install a BT and run it below 18psi ?
Stock bloc can handle 18 all day if properly tuned and if you are still afraid, add meth and a larger IC

[Fstrnyou]

When I was still on stock TMIC with 3.5" intake and turbo-back exhaust, I didnt have any creep and ran 20psi.
My WGDC was flat all the way to redline even if I targeted lower boost.

However, when the CP-e TMIC went on, it was just enough increase in intake flow to overpower a full open wastegate. 0% WGDC would get to 12psi pretty quickly and was flat for a very short while before tapering smoothly to about 18psi at redline.

Now, I was originally targeting 20psi with the stock TMIC anyways, so all I had to do was play with the WGDC table to get back to targets. But what I ended up with was a negative taper WGDC to result in a flat boost curve.
I don't have it in front of me, but as an example, the WGDC might be at 50% at 3500 and taper to 15% at 6500.

The real issue with boost creep is you now have no way to limit boost on the top end other than throttle control... via your foot or some tricky business with the throttle tables in the tune.

To continue, if you want to run higher boost, that's obviously not an issue. Just increase the WGDC. But you will find as you increase boost targets that there comes a point you start to notice the WGDC isn't tapering off as fast as before to achieve targets. And if you turn it up high enough, the WGDC will be flat again. The reason for this is because you are getting closer to the choke point of the CS turbine housing. My current tune has the WGDC very near 100% near redline trying to hold 28psi. I emailed Corksport about it and they told me that's all she's got in her. Oh well.

[Speed403]

Thanks guys. So it seems for about the same price and same Power the bnrs3 would be the way to go?

[Fstrnyou]

A buddy of mine had an S3 and loved it.
Changed to a PT5558 and loved that too but wasn't as fun for a daily.
Was going to go back to the S3 but found a sick deal on an S4.

Short version, you'll probably really enjoy the S3.

[Speed403]

I'm not going to be using e85 or meth, so I figured the s3 would be the best turbo to take advantage of the stock fuel system. Probably aim for 350whp give or take

[Fstrnyou]

Yep. You'll be all set with S3

[Speed403]

Awesome. Thanks for the advice!

[LenSpeed6]

According to Cork, the now CST4 can do 28psi but happier at around 25-26 which is probably the max of what I'd do for my particular car (for now). I wish that the CST5 was available when I was building my car, who knows what I'll end up doing in the future but upgrading the manifolds would be priority over a different turbo for me.

Unless its a chinese knock off it doesnt seem like you can go wrong with either CS or BNR.