Thom

What's the stiffness of your wastegate spring?

Paulyy

I've never seen a dual solenoid setup before. Basically it looks as though one solenoid acts as the spring pressure using boost as the spring and the 2nd acting against it to regulate pressure

333pg333

Thom, I believe it's 14psi. We're going to increase this. Potentially to double that.

Pretty much as it was explained to me Paul. The guy that came up with this reckons he had a Cosworth with a similar issue prior to using this method. Apparently gained 1000rpm and was able to reach 8psi more. Obviously many other factors can be involved. I'd be happy with half that.

Thom

I would be curious to see how your tuner gets on controlling the boost electronically with a 30 psi spring. Perhaps with this level of boost and in the context of a full track car where engine loads are probably always 100%, is the precision that an EBC allows on part loads really needed? Just an open question.

Duke

Normally there is no problem running twice the boost of the spring. I've run 1.4 bar with a 0.6 bar spring. With my 0.6 bar spring I only need 11% duty cycle to reach 1.1 bar in the midrange on my 3.1l.

With that said - the wg spring is the natural next step to test on Pat's car given the high duty cycles to see if that helps the situation.

Paulyy

Patrick, Before you go buy more solenoids. There's another method you can try.

1: Try a different rout for the solenoid. (Off the eBoost2 manual)


You can also use a 4 port solenoid.

333pg333

From what I understand, there are actually 3 springs inside these Turbosmart units. Paul measured them this morning and one of them was 5mm short for some reason??

Paul, thanks for those diagrams. I feel that we will still go with the setup suggested by they guy at our end. If we're going to work with him in the future I'd rather do what he's suggesting. For the cost of a Solenoid that doesn't worry me.

We will also make up a metal piece that we can put in the 'gate to lock it. We will take to the dyno if the change in springs and solenoid doesn't yield any gains. Should be back to dyno in the next day or two. Hoping for a simple solution and visible improvement. Holding breath...nah, been doing this too long...

333pg333

Pretty sure this is how we've got it connected now. Thinking that this may actually be working ok but possibly opposite to the way e.g. Gustaf's works?

We're also thinking about changing the hot house from the .82 down the the .63. (GTX3582)
Thoughts?

Paulyy

That's how mine is connected. The one i sent is how to connect to get and hold more boost, it works very similar to the dual solenoid way.


IMO i would try work out everything before changing out turbine housings. Get Xover fixed and work out wastegate boost issue. if boost is still rolling out to slow. Then change out rear housing,
Really no point going to the GT/x30 series. just wont flow the air you want. You'd have to run 30psi to get near 580rwhp with a gtx30r. It just wont keep up at lower pressure.

George D

Interesting comment, and curious with an answer. The spring in most/all the waste gates I've used with EBC's, Electromotive ECU's, and old school black **** won't boost below the spring inside the waste gate. Fail safe deal.

When my Greddy is shut off, failed, etc. the internal boost spring is the limit in my TIAL WG internal spring, or combined springs. I currently use a 12lb spring in case of an electronic issue with the Greddy EBC.

If the Electromotive fails, the car won't run. We've been able to use much higher boost springs with control, but when the Greddy isn't on, or failed (DID) The EMS/Electromotive sees excessive boost - immediate fuel cut. Chose the safer path, as we can run as much boost as the turbo will allow, with control via Greddy EBC and Electromotive EMS knowing the limit set to: Fuel Cut.

Running two solenoid's when your EMS - One of the best available can control the boost seems repetitive. Hey, I'm just typing/curious.

Patrick, killer motor. Looking forward to your car and driver's results/comments.

G

333pg333

Doing a bit of maths on the Xover. Looks like changing it from 2.5" to 2.25" would go from 3.167 ltrs to 2.564 ltrs. So that would certainly change things. It should net a definite improvement in spool without threatening backpressure. The main issue we have at the moment is the old Time and Money chestnut. We have limited time to make any changes and test on the dyno before defending the State Title (fwiw), but having won it we do want to try again this season. The new Xover will allow us to interchange the rear housing to a .63 if we want to gamble on that also. We're changing the layout of the gate and Not to the dual solenoid setup, but like one that Paul showed previously. We'll take a solid filler to fit into the gate at the dyno just to make sure that this isn't the main issue. Also going to change springs but not to 28psi, only 22psi.....






....I think.....

Duke

I found no reason to control both ports on the wastegate. It might work best that way on a low displacement high boost engine though.

I leave the to port open to atmosphere and send pressure to the side port through the solenoid.

Geneqco

Just looking at turbine maps... quite interesting! Whilst the .63 in the GT35 flows an almost identical rate to the .82 in the GT30, it actually builds pressure much more quickly which I guess is why some people find they can change to the 35 without extra lag.

I'm thinking some exhaust back pressure measurements may give you the best insight as to which hotside you need to reach you power goal.

George D

Good. Now I can go to sleep. Patrick, you're one of the few that never gives up, having a analog - basic boost limit is keen. The colored springs for my TIAL, in combination or not is part of the safety margin when electronics fail.

George D

If running a TIAL, the springs with stated max PSI are accurate.

G