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Elite DSMtalker
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We've had posts dealing with everything BOV. Now, I'm thinking, we have nothing about wastegates. I've searched, and haven't come up with anything. I've checked google, and really didn't find anything. So, I ask the question/open the discussion:

How do you choose a proper wastegate size? (I mean, to achieve zero boost creep, not just by engine size)
I assume you need to know all the specs on the turbo/engine set up you are running, and figure out the estimated amount of maximum "waste" air you will be flowing. I'd also assume you would need to know the amount of air each wastegate can efficiently relieve. From all the info I've seen, it doesn't seem that manufactures really state any of this info. Also, I haven't seen any tuners give guidelines to which wastegate to get.

With all this in mind, what is the best (easiest) way (using readily available specs) to determine your requirements?

(I posted here because, if I get the answers I'm predicting, this will get very in-depth, and technical)
 

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Bigger is better, venting all runners is better than venting one.

Test and tune, or buy the biggest you can afford/fit. It's simple really.

A 40mm will handle what most will put on their car. It really depends on what you want your minimum boost to be. If you plan on min boost of 25psi then you can choose a smaller WG than someone who wants to boost 10psi with the same engine turbo.

example: 34mm flapper on internal 16g min boost w/o creep of 9psi. 28mm flapper on internal 16g w/o creep of 21psi.
 

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Elite DSMtalker
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Discussion Starter #4
Ahh, yes... I forgot about the boost pressure contributing to the amout of waste.
 

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I personally hate when Vendors/OEMs list the WG by HP capacity. In other words, this WG will handle 450 HP engines. The more power you make on a setup the less gate you need. Thats a bigtime pet peeve of mine. I agree with what was said above, try different ones to see what works, or learn from the work others have done before you. In my case I knew I was going to run at least 20 psi street, so even the deltagate (~32mm) would suffice. I got one venting all 4 runners, and I was happy to see it holds WG spring pressure (13lbs) to redline on my TDO6 50 trim. IF it didnt work, my plan was to upgrade to the Tial 35 which uses the same flange. So this was the method mentioned above, testing and tuning. Worked for me :eek:)
 

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how much larger of a gate should you buy if you plan on using nitrous? say a 34mm gate on a 20G @ 20psi, if you add a 75 shot will this same size gate still sufice...this is all theoretical. i do not have the money to just try different setups and see what works for me, as i believe neither do some others.
 

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Elite DSMtalker
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Discussion Starter #8
This is why I asked, many people can't spend a lot of money on wastegates, and would prefer not to have to buy a huge one. I would assume there would be a good way to estimate it size you'd need mathmatically, but there are some specs that we need.
 

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With a 35mm TiAL WG mounted on the #1 runner of a Turbonetics t3 exhaust manifold I can dial my t3/t4 down to about 13psi. No boost creep.
 

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does anyone have any experience with nitrous and larger turbos, how large of a wastegate is needed to eliminate boost creep w/ nitrous.
 

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99GTsc said:
With a 35mm TiAL WG mounted on the #1 runner of a Turbonetics t3 exhaust manifold I can dial my t3/t4 down to about 13psi. No boost creep.
Ditto that setup on a 60 trim stg III I can get down to 8psi no creep.
 

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Generally, the larger the exhaust side of a turbo the less wastegate you need. We are putting down over 500whp on a t3/t4 setup with a tial 35mm. We have run nitrous on this car at the track and it did not boost creep. Location of the the WG also has an effect on how it works. I like to place it on the collector (header app) or off the actual turbine housing, like on a T3 housing (ford 5 bolt pattern style) and make sure all edges are nice and rounded/tapered to allow for smooth flow. Bigger is not always better, but it is almost always more expensive :)

Martin
 

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I had the turbonetics deltagate and it creeped horribly on my 92 Eclipse!!!
I know someone else that likes it and it holds a solid 10psi on their car, but it sure doesnt work on mine!
 

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I ran 7 psi on a br 20g and had no boost creep, but the more boost you run the less exhaust gases will need to vent to control boost. So as stated earlier if you have a big turbo and want to run low boost get a big wastegate.
 

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I don't think anybody has even started to answer the question.

There are many different external gates on the market. I think that Jon is wondering how you can determine what the smallest gate without getting creep you can use on different turbos/engine specs...

Is there any type of numbers to take into consideration beside just saying the bigger the turbo or the bigger the exhaust side, the smaler gate needed.

I think that most of the people that have external gates could probally get by with a smaller one. I will probally go external gate in the future and I plan to by the smallest one that will work the best (like said, smaller ones are usually cheaper).
 

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Here is the answer then.
A 35 mm is the smallest external wastegate you can run. But if you plan to run faster than low 11s ya better buy at least a 40mm. I bought a 46mm Tial because I plan to spray 100 or so.
 

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I would say that it seems there are several people running the 35mm tial on a 60trim (which is pretty big in DSM terms) with no problems. Perhaps its not as simple "how big" but rather, placement, manifold design, turbo specifications, etc. I wish I knew the formula but all I can tell you is the 35mm + profec B on my 60 trim has NO problems whatsoever. I have only been to 23psi so far but my setup NEVER creeps.

I bet there is a big difference in what is needed if your using a mitsu vs a turbonetics manifold and it all goes up in the air with a custom mani.
 

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1 FAST 2.0 said:
Here is the answer then.
A 35 mm is the smallest external wastegate you can run. But if you plan to run faster than low 11s ya better buy at least a 40mm. I bought a 46mm Tial because I plan to spray 100 or so.
what? explain....
 

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Elite DSMtalker
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Discussion Starter #19
stevo said:
I don't think anybody has even started to answer the question.

There are many different external gates on the market. I think that Jon is wondering how you can determine what the smallest gate without getting creep you can use on different turbos/engine specs...

Is there any type of numbers to take into consideration beside just saying the bigger the turbo or the bigger the exhaust side, the smaler gate needed.

I think that most of the people that have external gates could probally get by with a smaller one. I will probally go external gate in the future and I plan to by the smallest one that will work the best (like said, smaller ones are usually cheaper).
That's exactly right.
 

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since this Thread is labeled as "proper wastegate sizing"

lets size up the small 16G

i have a ported small 16G with o2 dump housing.

i want to run exactly 15psi.

i get terrible creep right now.

do i install a 34mm internal flapper or do i go with an external?
 
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