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mark
06-07-2007, 09:29 AM
i'm having problems boost spiking.. it seems worse when I put in a restrictor (the yellow one, i cant find my mint green one) I'm spiking to 30+ pounds, then it falls off to where it should. I am using the computer to control boost (trimcal) it did it manually as well.

I am wondering if the yellow restrictor is too small an orifice for the turbo I am running (50 trim t3/t4 e housing w .48 housing) I'm guessing the 48 housing is causing fast spool up and the restrictor is slowing down the WG opening up as fast as it should... I am running a brand new WG actuator also, it did the same thing with the old one as well. I sort of recall the boost not spiking like that when I left out the restrictor, but I thought that a restrictor was necessary...

is my theory wrong, or in the ball park.

It just makes me nervous when i see 30+ pounds for a second.

if a restrictor is necessary, I'm going to take a piece of round plastic stock, and drill a hole in it, then see how it spikes, and if too much spike, ream the hole out more until there is no spike. good or bad idea?

Turbodave
06-07-2007, 03:40 PM
The restrictors are designed around the stock turbo and plumbing, with a bigger turbo and custom calibration I wouldn't expect the stock restrictor to work properly. Your idea about experimenting with with plastic stock sounds like a good way to determine how much, if any restrictor is needed.

mark
06-08-2007, 12:04 PM
ok great. i just always thought a restrictor was necessary... awsome.

thanks!

Millerman340
06-08-2007, 10:51 PM
I don't run a restrictor with my Holset. I have just the G-valve & a .020 MiG tip as a bleed. It spikes about 5 lbs over then settles down.

Tony Hanna
06-08-2007, 11:43 PM
Come to think of it, I don't think there was a restrictor anywhere inline on mine either. The way I understand it, the TI is a solenoid regulated "bleed", so when the solenoid opens it raises boost and when it closes, it lowers boost. I'm pretty sure that setup has to have a restrictor to work properly.

If I'm not mistaken, the TII and I would assume TIII boost control works more like a computer controlled g-valve in that the solenoid opens to lower boost and closes to raise it. I wouldn't think a restrictor would be necessary in that type of setup.

Charger R/T
06-09-2007, 08:54 AM
I have read a bunch of threads on this stuff and have only experiments once for a short time on my R/T. But what I see is the plastic tubing every one is running is to small. When you want to cut the boost level off you need to fill the wastegate can with boost. The longer it takes to fill the longer boost will climb. Its like you want to fill a swimming pool does the pool fill quicker with a 3/4 inch garden hose or a 2 inch fire hose?

When I ran a mbc on my R/T to raise the boost to 15 psi on a stock computer I put a T in the brake booster hose (I think it is a 3/8 inch line) with a 1/4 inch T. I refitted the mbc with all 1/4 inch fittings and used 1/4 inch rubber hose to plumb it up and used a mig tip for my bleed. I used no restrictor anywhere. While I had that set up on it would go to where I set it and just stay there. The mbc eventually jammed up but by then I had a 15 psi computer and +20 injectors so I swapped that in and have it running right now on the computer but have been thinking about putting it back on.
Tim