What would happen if I built a grainger cut out eliminator..

[Subliminal]

And didn't use a restrictor? I think I have all the pieces, sans the restrictor. What's the point of said restrictor?

I'm confused!

[Subliminal]

Well, I tried it. I took my grainger valve from the turbo, and put it on the map. I don't care if my turbo spikes a little, i'll just watch the a/f gauge. However, I can't get the damn thing not to hit overboost. I unscrewed that thing almost all the way, and it still hit overboost. Kind of annoying. Maybe there's something to that reducer business.

Argh...and i thought this getting around the overboost cutout would be easy...nothing's easy...grin. Luckily, even with the wastegate unplugged (small can) I only hit overboost at wide open. If I give it 3/4 throttle, no funny business.

I will get this, though...oh yes, I will!

[mwinkle353]

I use a grainger valve on my 89. I have it as my only source of boost control. It's between the barb outlet on the compressor and the wastegate actuator. It seems to work out pretty well for me. But then again, the Mitsu turbo isn't really doing me much justice on the 2.5L motor.


Wink

[Subliminal]

I don't think anyone reads these posts anyway, but I just built one of these:

http://www.fwdmopar.com/sites/dennis/howto.html

They say third time is a charm!

[Subliminal]

Huh...so nobody's going to answer the simple, original question.

[ludwig340]

What benefit are you looking for or drawback are you trying to eliminate?

[Subliminal]

Well, right here, I'm just curious as to the restrictor. I don't know how that will change things.

But, the problem I'm trying to deal with is this:

My van has a garrett on it with a small can. The can seems to allow for a maximum boost of right around fuel cut off (it only hits it every now and again). I don't currently have a boost gauge, as I broke it (DOH!) but I do have an A/F gauge, so I can safely watch the fuel. I want to let the turbo do it's max, and just not hit overboost. My guess is I have plenty of fuel for the extra little tidbit of boost that I get over the shutdown.

I tried a zener, and it quit supplying fuel too early. My guess would be around 10 psi. No good.

I tried a gvalve bleed on the map, but without the reducer. Also, no good. No matter how far I screwed that stupid thing out, I still hit overboost. I'm guessing that reducer actually helps somehow, but I was looking for an explanation.

So, I ended up building the 'adjustable zener' which I plan on throwing on tonight.

So, in a nut shell, I'm trying to eliminate overboost, while allowing for the maximum amount of fuel that my current system can supply.

[ludwig340]

Don't want to sound too obvious, but are you sure the diode you installed was what you thought it was and was working correctly?

[Subliminal]

Yeah, it was a 4.3v diode. The cutout on my van is probably closer to 4.7 v.

[ludwig340]

Hmm, good question. Of course, I don't know why the zener diode wouldn't have worked if it was working properly, either.

Good luck with the new gizmo, anyway!

[lametec]

Yes, the restrictor is a major part of a cutout raiser. It won't work without it, as the engine has more than enough breath to "overpower" the hole in the ball-valve.

With the restrictor in line, it limits the amount of air let into the valve, and as such the little hole in the valve can bleed off more than enough air so the MAP doesn't see too high pressure.