4g61t.org

after locating a wastegate actuator for my 14b im just now wrapping up my 14b install on my stock
4g61t colt.

i havent owned this car long and it's really my first turbo car. (i had a tsi talon for a couple months 10 years ago).
Im sorry im not so familiar with turbo systems

my question is that on the original setup there was a vacuum line from right behind the mass air/filter can that went down to
some kind of black plastic "solenoid thing" by the front of the trans and it t' eed into the original wastegate actuator and a port on the original little turbo's compressor outlet. now that i have put on a 14b i no longer have that vacuum port on the compressor side of the turbo. on the dsms was there vac port on the j pipe instead?

im thinking the original vacuum port off the original little turbo was the "boost reference" which would activate the wastgate to get the turbo to quit building boost. its my understanding that the boost pressure is what "trips" the actuator at its calibrated setting
(10psi or so)

since i no longer have that source i have verified that my 14b keeps building boost on my initial the drive (dangerous).
That tells me my wastegate is not being "actuated" lol

so my other question is... do i just need to get a "boost reference" to the wastegate actuator? to get it to open at the factory setting? where would be a good source to grab it from? im t'eed off from the fuel pressure regulator solenoid for my boost gauge signal, i imagine that source would also send a "boost reference to the actuator as well? is there a danger of too many draws from a single vacuum source? or what would anyone recommend i do?

i hope my theory is correct but if im way off in terms of how these systems work or if what i said doesnt make sense
work i will try to clarify more.
and thanks a bunch in advance as from my lurking here some of you guys really know your stuff.

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Black 1989 Colt GT with 4g61t. 200k miles and climbing. Rebuilt 2.0 in the works.....
14b, 450cc's, 3" exhaust, small fmic, all running on megasquirt version: DIYPNP
White 1992 colt-vista wagon 2.4, awd, auto (daily)
Keane

you can just tap in to the line that goes to the BOV and run it to the waste gate. i did thise and took the EGR stuff out.if you want stock waste gate PSI you dont need the MBC.

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08 silverado max
91 Eagle Summit 4g63t swapped

Thanks debow. Great picture.

I thought i read somewhere it was a no no to tee into the bov line?
But if it has worked for you ill give it a shot, easy enough to do.

I want stock wastegate pressure, and to understand the theory better
Is it correct that i am giving the waste gate a boost reference which activates it?

_________________
Black 1989 Colt GT with 4g61t. 200k miles and climbing. Rebuilt 2.0 in the works.....
14b, 450cc's, 3" exhaust, small fmic, all running on megasquirt version: DIYPNP
White 1992 colt-vista wagon 2.4, awd, auto (daily)
Keane

I recommend losing the boost solenoid. Put the MBC between the WG and the vacuum nipple on the charge pipe that feeds intercooler. Definitely recommend not teeing into the BOV source line. It should remain intact and unbroken/uninterupted.

In short:
one solid line from the Intake Manifold to the BOV.
Bottom of MBC to the WG.
One line from source on Turbo charge line (J-pipe) to end of MBC.

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Thom
1991 GVR4 1025/2000 (PTE 1200's, 16g, DSMLink v3, gm-maf, eagle/ross, .020 over, 272's, EVO VIII Wheels)
1992 GVR4 866/1000 (getting everything from above)

hey thanks a lot thomcasey.

thanks for the picture i have no experience with dsms either so i wasnt sure what the j-pipe would have looked like
as i am only using the j pipe from my csm original turbo.

i can see there that the dsm j-pipe has a nipple on it for the boost reference. mine does not.
because it was on the stock turbo housing instead of the j-pipe .

i can see why now when i put everything back together with the 14b installed i lost my boost reference nipple.
so i will just have to weld or braze one onto my stock csm j-pipe which will be easier than trying to find a dsm one.

it all makes sense now and thanks for the routing tips!!

_________________
Black 1989 Colt GT with 4g61t. 200k miles and climbing. Rebuilt 2.0 in the works.....
14b, 450cc's, 3" exhaust, small fmic, all running on megasquirt version: DIYPNP
White 1992 colt-vista wagon 2.4, awd, auto (daily)
Keane