1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

making a boost regulator

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Old 06-19-06, 11:04 AM
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making a boost regulator

Here's a cheap and simple way to build your own mechanical boost regulator - total cost about $12.00. This regulator holds back the signal from a manifold vacuum/pressure source to the wastegate until desired boost is reached.

Start with a check ball valve with adjustable spring tension (McMaster Carr part #48935K25)



...and a brass barbed end fitting (McMaster Carr part #5346K51)



...and a 90 degree brass barbed elbow (McMaster Carr part #44555K142). This will become the wastegate signal output. Drill a .020" hole through the elbow to create a vent - you don't have to put a filter on the hole, as it never sees vacuum.



Disassemble the check ball valve....



...and move the ball to the other side of the spring.



Before reassembling the check ball valve body, add the straight barbed fitting...




...and using a Precision Calebrated Single User Multi Percussion Whackometer (aka hammer) drive one barb of the 90 degree elbow through the hole in end of thecheck ball valve body top. The fit should be snug and take some effort - that'll ensure it stays in place and self-seals once you're done.



So now you have all your parts ready to go....



just screw it all together, and you're done.



To install, connect the vacuum hose providing boost signal pressure to the elbowed end, and the straight barb to the waste gate line end.

To adjust boost, simply twist the elbowed end out of the check ball valve body and lock in place using the locking nut. This will change the overall length of the assembly. A longer assembly = lower boost, a shorter assembly = higher boost.






Old 06-19-06, 01:42 PM
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Good information Manntis
Old 06-19-06, 03:39 PM
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I have made a few of these and found they like to leak around the ball bearing. so what I do is find a flat punch that fits down inside and take an extra ball bearing and tap it a few times with a hammer and flat punch into the brass where it seats. pun new ball bearing back in and it should seal really well.

I have never used a vent in any of my homemade ones and my friends $50 one dont have a vent either. what is the vent for and is it something neccesary??

if you solid mount it you usually only need one wrench to use it and I keep my adjustment wrench right next to it also.


cant wait for my EBC
Old 06-19-06, 08:26 PM
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These parts already have flat seats (identical on both sides of the valve - one acts as a seat for the spring, the other for the ball) and the ball seals fairly well... when I tighen it past a few threads and try blowing into it, it's sealed tight as the spring keeps the ball compressed against its seat. YMMV.

The vent provides relief to atmosphere for the "wastegate actuator" pressure when you let off the throttle...
Old 06-20-06, 02:30 AM
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hmm. Thought there'd be more interest.
Old 06-20-06, 02:57 AM
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good write up.............I dont know anything about this so what exactly is the gain on a stock engine, just a better regulator
Old 06-20-06, 03:00 AM
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It's just a way of taking control of your boost and decreasing lag if you have an instant-open wastegate, like the one on my Garrett. When I floor it, boost builds slowly because the wastegate starts venting immediately (stock config). By adding this valve, the wastegate doesn't see the 'open' signal till the valve opens and lets the pressure through, thereby allowing the turbo to spool up quicker
Old 06-20-06, 03:01 AM
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yea i wish i had a turbo so i could do this, maybe on the nexted engine
Old 06-20-06, 07:23 AM
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So you found teh right vacuum line D'arcy?
Old 06-20-06, 10:24 AM
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there is a site that sells these too but the cost alot more than $12 not trying to steal your thunder Manntis, its just that i was wondering how they workd and everything, when i get my car and go turbo i will be using this method!
Old 06-20-06, 12:42 PM
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good write up Manntis
Old 06-20-06, 01:24 PM
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if there were more turbo 1st gens im sure thered be many more thank you's and responses in general
Old 06-20-06, 09:13 PM
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manntis thanks for the write up, I need to make another one real soon so I will try this for sure.
Old 06-21-06, 01:52 PM
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Originally Posted by MosesX605
So you found teh right vacuum line D'arcy?
I've eliminated 9, 3 to go. Why Chrysler decided to not onlu bundle them together in a covered harness, but twist them within the harness, was a good idea, I'll never know...
Old 06-21-06, 01:55 PM
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Originally Posted by 3rd and final 7
there is a site that sells these too but the cost alot more than $12 not trying to steal your thunder Manntis, its just that i was wondering how they workd and everything, when i get my car and go turbo i will be using this method!
There's a chap who sells 'em for $47. Seemed high for hand-screwing together a couple of parts,drilling a single hole, and tapping one bit into the other. Only took me about 8 minutes to build this one, so he's charging $12 in parts, $35 for 8 mins labour
Old 06-21-06, 02:18 PM
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So, I have a question pertaining to the spring. If I replaced that spring with a spring that holds more pounds before giving way, would that in return increase the amount of boost running? Just out of curiosity, as I won't be going turbo anytime soon.
Old 06-21-06, 03:34 PM
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yes, stiffer spring will give you more boost, but that is the reason that these are adjustable. you just turn the pressure either way you want and it lowers or raises your boost. it only goes as low as your actuator will go from the factory(or modified) .
Old 06-21-06, 04:08 PM
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yeah, you just screw the end with the elbow deeper into the housing (shortening the assembly and compressing the spring against the ball), then lock it into place with the locking nut. No need to change parts to change max boost - just loosen the locking nut, tighten or loosen the upper assembly, then lock it back in place.
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