Makes sense...so, I was probably overworking the turbo as it is just to get my 19-20psi...hmm. So, should I not incrementally tighten the turnbuckle, but rather go down all the way (or at least close to the end)?

 

Do it incrementally!

I can't say that ALL of the actuator rods are 100% consistently the same length as they are all bent, cut, and threaded by hand. There are undoubtedly variations between one rod and the next.

Yours may not require that you go all the way down, so it's best to do it incrementally just to be safe.

 

Every one that we have done, required going down all the way. In fact like I stated, we shaved another few mm off our rod as well. The threading continues much further than where the turnbuckle cannot turn any further without cutting. I would go all the way down IMO. You should have to pull up on the arm to slip it on the flapper door. This may require pliers or vicegrips.

 

I will do it incrementally if we are able to manipulate the nut and turnbuckle without removing the radiator and such, but if we can't, then I'm going to shoot for one big adjustment and hope it works. I don't want to have to drain the coolant, remove the radiator, and then put it all back together each time, but if that's what it takes in the end, then we'll do it.

 

Hmm, so you can't even get to the end of the threads? Where it sits now, you already have to pull it up very slightly to get onto the flapper pin, but it's not enough that it closes the flapper at rest. Hopefully, I am able to go much further down the remaining threads...

 

Warr: you definatly want significant preload on the WG flapper. There is a significant pressure differential that the flapper is trying to seal against. The exh manifold pressure is probobly atleast the same as your intake manifold pressure. Idealy the pressure in the o2 housing/exhaust pipe is atmosphere or just a tiny bit higher.

I would try and get a resting "interferance fit" between the flapper arm' pin and teh hole of the WGA rod to be about 1/4". IE: you have to pull against the WGA spring that 1/4" distance to slip the rod onto the pin.

The worst you are going to see by setting it "too tight" is a bigger than normal boost spike as the MBC opens.

 

It's impossible to make more torque than horsepower after 5250rpm's
Your torque and horsepower will always cross at 5250rpms.

 

Um, that wasn't the point of the drawing, man. So I was off by a few centimeters or whatever. I wasn't even talking about that part of the graph anyway; I was focusing mainly on where the normal torque spike would be and what the resulting line would look like (obviously, it wouldn't be perfectly straight, and I know that it would intersect HP at 5252rpm).

 

I'm not sure that this is correct. The only way the turbo would be spinning faster than necessary is with a leak on the intake side of the engine. In this case some of the energy from the exhaust gas is always allowed to bypass the turbine wheel, so it is being sent out the exhaust. The turbo is still only spinning at speeds required to support 19-20 psi. Once the problem is fixed (assuming it is the WGA preload), spoolup should happen slightly faster and boost should hold even better.

-Paul

 

I know you probably know that, but for the sake of useless knowledge i figured i would let everyone else know.. Also you did say they would come back together at 5700rpms.

 

Yes, I did, but I was referring to the revised HP curve and the original one. HP would follow suit accordingly and still intersect at 5252, so that's not relevant to my 5700rpm comment (referring to old and new torque curves only).

 

Paul is 100% correct on this. If you have low boost due to the WG opening early you by defenition are not spinning the turbo too fast, or working it too hard trying to make more boost than you are actually seeing. The boost is low because the exhaust gases are bypassing the turbin causing it to spin slower than it needs to for your desired boost level.

Keith

 

Any time a new actuator (or new exhaust, intercooler, etc) is installed, the wastegate arm should be adjusted until you get the desired wastegate pressure, though that isn't always the stock pressure.

It's a bit weird, to me anyway, that so few people seem to bother doing this when they instal the new part(s) in the first place.

 

First I have a question You posted a dyno graph of before and after. The before you posted is that the power your car was making when you ran your best times to date?

The increase in those graph are from the last time you were on the dyno to this time right? I know there are a lot of mods done since them but considering the boost levels the car has picked up a lot.

BTW, rather than messing with the pre-load try the heavy spring. I have used the Forged boost controller a few times and not been able to get over 19 psi on the light spring. That is my guess.

The preload. I usually pre-load it half the thickness of the pin you put it on.

David Buschur
www.buschurracing.com

 

Thanks. Good luck with the adjustment(s).