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I am trying to get my boost down to a reasonable level to work my way up from a low boost setting , tuning then gradually adding more...
what i have is a 5.3ls with 317 heads , 231/239 cam , 1 3/4 stainless headers and twin garret 60-1 hi-fi turbos... air to air intercooler , dual 2.5" in one 3" out into a 90mm throttle body mounted on an edelbrock hi-ram intake. Wastegates are dual Turbonetics racegates plumbed into the side of the "elbows" that connect the 3" header collectors to the turbos.
right now im running on the wastegate springs, but i am easily making more boost than the springs... i started out with 7 lb springs, then 5's , then 3's and now i am running springs out of a starter solenoid (even lighter) to TRY and get the turbos to reduce in boost - and its like nothing has changed whatsoever. I have to throttle it like mad, but the boost will jump up to 8-9 lbs super easy (i even bumped 11.5today)
They are big wastegates , vented to atmosphere via screamer pipes - i just dont see why they act as if they are not even there?!? I have my vacuum lines attached directly to the charge pipe heading into the throttle body and plumbed underneath the wastegate diaphragm so that boost pressure will open the gates... i have pressure tested the gates and they start opening at like 2 lbs of pressure, full open by like 7lbs.
I have uploaded a pic to this post earlier this morning and then again , hours later and for some reason its not making it onto the thread.. here i will try uploading it as an attachment.
Where does the red pressure signal line go to/from ?
And there appears to be some sort of adjusting not on the gate ? These usually heavily restrict travel of the gate if screwed in, which would massively reduce flow ability.
Forcefed, i cant see the picture that you linked to. Someone else tell me if they can see it or repost it.
stevieturbo, those are direct to a vacuum/boost manifold that i built onto the bottom of the main 3" pipe that is coming into the throttle body. the hoses are of exact equal length to each wastegate. I will post pictures just to clarify this.
Btw, you will see another red hose that is just looped. I put this on tho plug two extra ports for when i need them in the future.
about the adjustments on the gate that you speak of, all there is is a gate spring preload adjustment. i have it set to as light as possible. i have bench tested the gates as well as pressurized them while on the car as you see, and they start to open at 2 lbs and are full open by 7, and they are as equal as i think they could get.
How much travel does the actual valve inside the gate have though ? The top chamber looks very small, add to that the adjustment bolt...it just looks like actual opening could be very small ?
The gate is listed as 1.85" or 47mm. the actual travel of it, i didnt measure it precisely but id say it opens about 5/8".... i just used a hand held vacuum pump to see the travel (connected on top of the diaphragm instead of under it ) and it took about 5" of vacuum to move it half travel and about 10" to make it full open.. again that was vacuum and not pressure... I dont have a hand held pressure pump that takes a little more to be able to measure that than i have accessible to me today.
i am about to mount a go-pro and make sure than when i am in boost that they are indeed working.
hey btw, turbonetics rates these racegates @700 hp apiece so i would think if anything they would be too big not act too small. other places i see rate them up to 900 hp each. go figure
The turbo should be perpendicular to flow, and the WG should be inline/parallel with flow. The setup you have is not optimal for WG priority. Twins usually have less back pressure and are more sensitive to placement. I've seen worse placements than your's work as well, but it would help to set them up like so IMO.
Forcefed86, i have never noticed an install as parallel in flow as yours. I will be looking closer from now on but id say , while picture perfect as it may be all the successful installs dont look quite so perfect. I am not disputing you by any means im just saying surely thats not the only way they will work...
*update* When i wedged the gates open (around 90% open) , it was literally HARD to make any boost at all and id say it made 4-5 lbs at the most and this took place at a higher rpm at like top of second and into the shift transition to 3rd (high rpm to high load)
It's the most ideal location and pretty common if you look around. Thats just a random pic I found but I suppose mine is similar. Here is mine... I use 2 38mm gates and can hold 8lbs on a 370' motor with 2" piping and 1 small t4 housing.
Forcefed86, i have never noticed an install as parallel in flow as yours. I will be looking closer from now on but id say , while picture perfect as it may be all the successful installs dont look quite so perfect. I am not disputing you by any means im just saying surely thats not the only way they will work...
*update* When i wedged the gates open (around 90% open) , it was literally HARD to make any boost at all and id say it made 4-5 lbs at the most and this took place at a higher rpm at like top of second and into the shift transition to 3rd (high rpm to high load)
When you say 90% open, is this open the same amount as when you are manually applying pressure to the gate to open it ?
All I am saying about the 90 percent is the wedges I put to hold the wastegate open only held the gate open approx 90 percent... I could have built wider wedges and held it open more but they would have been harder to get in and out..
I was only trying to see if the gates were indeed effective while open... The answer is a definite yes , now to get them to open under boost pressure..
Do you think that my reference line location could be being affected by "Venturi effect"? There is air rushing past that orifice at high speed , do you guys think it could negate what I am trying to use it for ?
Sounds like your springs are either too tight or the wrong rate for your setup. If they aren’t opening enough (fully) to control your boost, put a lighter spring in and try again.
I'm quite sure they aren't opening fully , but I'm gonna come closer to saying they are barely opening of any at all.
I have springs so light in there , they are smaller than the smallest spring turbonetics makes for these gates which is a 3-5... I have springs that I got from a local starter repair man out of some vehicles start solenoid, in an effort to just make them do something !
No, I do not have any ports at the compressor housing but that doesn't mean I won't make some ..
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Wastegates not effective? 
