I don't think the size of the wastegate will fix creeping or spikes.


I own a 34 psi 2.5 Intercooler car and they only thing that cause spikes or creeps as you guys all is is a weak wastegate actuator. The exhaust is pulling against the spring inside the wastegate actuator, that holds back the arm connected to the flapper door. Once it starts to pull it back shut, or partially, its starts to spike.


The real solution is to shorten the wastegate arm, or shim the actuator away, so the spring has more tension on it.


Give me the dimension of the wastegate port and I can tell you, if the size is the problem.

By making it bigger, your losing spool up. Of course there is a time when the size just won't fit any more through it, but it appears like that is not the case here.

 

Well, considering lots of people with years of experience say that boost creep is dependent on wastegate size and flow, no offense, but I trust RETed, NZ COnvertable, Unique TII, and others more than that. If you want to cook your engine just to beat a ricer, by all means do so, Just don't say we didn't warn ya

 

Here's a fact for you GLHS...with my full exhaust, a StageI turbo, and a stock wastegate, I boosted 8 psi. With my new StageII turbo and a ported wastegate (same exhaust) I am boosting 6psi...back down to stock levels. The only difference is the wastegate, and my boost is back where it should be with no boost controller. A full exhaust, free-flowing intake, and stock wastegate has been the cause of many engine failures...we're just looking out for you.

 

I understand what you are saying, but I have building piston engines with excess of 20 plus psi, and never has the wastegate size been a problem for "spiking".

That was always a problem with the actuator for the wastegate arm being pulled back and restricting air flow.


Of course making the hole bigger works, but I don't see how 11 psi is too much for the hole to handle, especially if you're only going 1mm in each direction.


If I could get the actual dimensions of the wastegate port, I can tell you, if the hole is really to small.

I hope you guys get what I am saying, I am by not means questioning what you know and what works.

I am aware of a need for a bigger hole for the wastegate.

But you must know that the wastegate is seeing force applyied to from both directions and the stronger force succeeds, if the wastegate actuator is weak, you will see spiking, as the rpms increase, as it is not strong enough to hold the door fully open.

Does this make any sense to you guys?

 

Boost spkie happens becaue the wastegate opens too slow. Creep happens becaus ethe wastegate does not flow out enough exhaust gasses to bypass the turbine and it continues to spool over the set amount. Plus, you have a series 4. It has a single, tiny wastegate hole. The series 5 has 2. Hundreds of people on the forum can tell you all about how they creep w/ the stock wastegate. The only way to get around creep is to port. Spike is different from creep.

 

So what I need is a External wastgate?

Being the stock is way too small? even for porting.

 

A ported stock wastegate would be fine.