Damn you cheap Grainger MBC! Boost spiking is holding me back (Grainger users help?)

[Guest bastaad525]

Okay I hit Home Depot... no luck. They had a very small selection of springs, and none of the ones they had was even close to what I needed.

 

They also had NO ball bearings at all, of the type that I would use to replace the one in this grainger valve.

 

I checked mcmaster car but I have NO idea how I would determine what pressure of spring I would need, like inch-pounds or whatever. They are REALLY technical on their spring descriptions too... kinda funny that they give so much detail on such a small (and you would think inconsequential) piece.

 

However, the upshot was that I finally figured out what a turnbuckle is they had them there in that same aisle. So it's basically the same concept as the threaded rod. Looks easy enough to do, and I may do it at some point soon.

 

A few questions though: am I understanding right that to increase boost, you want to SHORTEN the rod?

 

Doesn't this put more stress on the actuator diaphram or spring? What is the most you can shorten the rod like that before it just wont go any further or you can damage components inside the actuator?

 

I also finally figured out what Bernardd was talking about with the spring method he mentioned... you gotta love that one for it's simplicity But yeah, finding the right spring would be a pain.

[mario_82_ZXT]

You want it to put more pressure on the spring, as this makes it more difficult for the wastefate to open, thus more boost. There is a limit to the spring though, that's why you can buy a stiffer wastegate spring.

 

I dunno if these would work for high boost, but what about a spring from a pen? There are wide varieties out there.....

 

Mario

[Guest bastaad525]

Mario funny you mention that about the pen spring, Cygnus mentioned above that he may be running a spring from a pen as well, and I've been taking apart pens looking for something the right size and stiffness but haven't gotten lucky yet. But I will keep looking, lots of pens at my office to take apart

 

It's gonna be a pain in the *** to pull the actuator out, some stuff in the way like my RRFPR. But yeah if this spring thing doesn't work the turnbuckle thing looks like a really good and easy idea, I have a friend who can weld it on for me. I'm just worried that I might damage the actuator this way

[mario_82_ZXT]

Maybe 2 different springs?

 

When I built mine I used a pen spring and it held 10psi, but that's why I don't know if it would work or not for higher boost.

 

Do you have a pic of the turnbuckle?

Mario

[Guest bastaad525]

Well all the pen springs I'm finding so far are way to small in diameter and I dont think any of them will work, though they do seem near the same level of tension/pressure as the spring I already have, so dont' doubt they would hold the boost level I want.

 

nope no pic of the turnbuckle, it's basically just two threaded rods connected by a center section. Rotate the center section one way and the rods extend, increasing overall length. It's the exact same concept as if you just cut the stock rock and threaded it.

[Bernardd]

I messed around a bit with my mbc and the turnbuckle setup I have. I set the turnbuckle to give me 20psi, then I set my mbc to give me about 17-18psi. So I get very fast spool now and a solid 20psi with no spikes. My mbc used to give me a 2-4 psi spike. I've only had it running like this for a couple of rides but it seems to work really well.

[Guest bastaad525]

That's a very good idea... I've read of other dual-setups like that designed to maximize spool and minimize spike, different combinations of boost controllers or dual stage controllers or something I dunno...

 

but never that exact setup. I was actually thinking that going back to just running the stock actuator with some sort of adjustability (like the turnbuckle) would probably hurt spool up a bit, which is one of the advantages that the Grainger valve provides.

 

It's probably gonna be a while before I get around to getting that turnbuckle welded on, but thanks for the VERY good idea, I'll leave the MBC inline set to like 12psi and then adjust the turnbuckle to 14.

[Guest bastaad525]

Cygnus or anyone, about ordering a spring from mcmaster-car, can anyone give me an idea of which spring to order? I can get the length and diameter from the one I'm already running, but what about the actual 'springiness' rating, that is to say, how much the spring deflects for x pressure? If you get a chance can you check it out and maybe give me some recommendations?

[myplasticegg]

Sorry to bring this post up from the dead, but there is a good solution to stop the boost spike. Install a restrictor after the grainger valve but before the wastegate nipple. The restrictor will let the extra air bleed out but still allow for the incomming boost to open the wastegate. The restrictor needs to be cleaned from time to time or have a small filter installed over it (cloth zip tied over it) If you need a pic LMK and i can find one.

 

EDIT: the stock spring from grainger should be good for 18-20 PSI without modification.

[randy 77zt]

i put a t between grainger valve and turbo.the i put a valve on the end of the line running off of the t.i bleed some air off.my opinion is that the grainger valve was designed to regulate flowing air.this is part of the fun of being cheap.it would probably be easier to install 1 of those ready made computor controlled bling boost controllers.

[myplasticegg]

i put a t between grainger valve and turbo.the i put a valve on the end of the line running off of the t.i bleed some air off.my opinion is that the grainger valve was designed to regulate flowing air.this is part of the fun of being cheap.it would probably be easier to install 1 of those ready made computor controlled bling boost controllers.

 

eaiser, yes... but will it cost $7?