for those with experience…
what seems to be the limit of a tial 38mm wastegate before you get creep?
im trying to decide between the 38mm, the 41mm or the 44mm.
Brian
it depends on the setup. Depends on what turbo on what engine size at what power level. In general, the more boost you run, the less chance of creep you have. Wastegate placement has a huge effect on this too. What plans do you have for your setup?
What CFM are you looking to flow w/ what turbo?
the displacement of the motor and the expected HP are also needed…
In general its best to go a little bigger then be too small, just go with the 44…t he differance in price isnt that much, and you get vband…
2.5L 16v. 4.09" stroke, 3.44" bore. borg warner s200, divided inlet turbine, single wastegate off of a Y before the turbine. equal length header… have not determined the primary and secondary lengths yet.
probably something like this:
Brian
I don’t know if it helps you at all but my 3.2L SHO engine is putting about 400hp to the ground and I never get any spikes or creep even durring shifts (automatic trans). If you have to get the 44mm to get the V band then do it. I snapped one of my wastegate bolts off in the flange on my car and the way it is designed I can’t do shit with it untill the subframe comes out.
word and word
go with the 44…
the main thing is, how much boost?
also a pic of the mani/wastegate placement would be nice… if its like a 90 and u can tell exhaust wont “easily” flow to the WG then u might see some creep, but if its something like this, then there’s more flow to the wg and less chance of creep
for that flow rate tho, i think a 38 should be fine, but like viper said, the 44 is nearly the same price (esp if u find a lightly used one) and its vband…
fyi i dont think there’s a 41mm tial…they used to make a 40 back in the day but not anymore.
ill probably start out with the 38 and if i have any issues, ill use it on another project and get the 44mm.
Brian
the calculator link that i posted estimated around 25psi for 500hp with the setup im building. (still gathering some parts) for the most part, i probably will run 15-20. this is a street car project and im not going to be running psycho boost all the time.
yeah I plan on trying to incorporate the gate at a bend so it will have an easier time venting the excess exhaust energy. but then again, i dont want to put a tight bend real close to the turbine inlet just so the wastegate flows well and compromise the smoothness of flow into the turbine itself.
i wonder if it makes much of a difference if the wastegate is right before the turbine or in a bend further upstream in the secondary piping. shouldnt make much of a difference but i want smooth entry into the turbine.
last i checked the 40 was done and the 41 was still available. http://www.tialsport.com/prod_wg_41.htm
i dont have a TIG welder but i do have a mig and a miller arc and im doing this all at home in the garage so its going to be a mild steel coated setup, so finding a vband flange that is steel is probably going to be extremely difficult though i havent looked hard yet. i did find a steel adapter to go from 38mm flange to 44mm vband so i could hack that up and weld it to the manifold piping and use a stainless discharge tube to a stainless flex to my downpipe which is a mild stainless. that little bit of fab wouldnt be bad to do elsewhere. i hate dump tubes but i could stand it just to get to my buddies house with the tig for the final merge back into the downpipe further down the exhaust stream.
Brian
if ur gonna run 15-20 then u should be fine.
a lotta ppl try to run 7 psi w/ huge turbos and small gates and then wonder why they’re creeping.
merging the wastegate dump further down is “Better” anyway so :tup: to that idea
and cool on the 41…ive been outta the game for too long 
The larger gate is nice if your running a large turbo and low boost. This is where creep seems to be the largest issue. Thats why fullrace upgraded from a 38 to 44 on their manifold. But if you plan on running high boost on a moderate sized turbo you should be fine.
it all depends how low of boost you want to run
the idea is that you want a bigger wastegate so you can run a smaller spring to get less boost
with your setup i would go with a 44mm depending on your power goals
if you want really low psi for daily driving your should do twin 38’s, but a 44mm should be good enough
FYI, they just released a new 38mm that is vband and flows a bit better.
Nothing wrong with welding mild steel to stainless. Just use 308 rod. I do it all the time.
If you need Tial stuff or tig welding just gimme a hollar dude.
Also, convert your mig to 309 wire and run Tri-gas. You’ll migweld stainless all day.
thought id share my experience:
i have a turbonetics 38mm WG on a cast log manifold running a 50 trim on a 2.4L.
i had pretty substantial boost creep, 2-4lbs at 12-21psi boost settings with a .48AR turbine housing running an aem truboost. after installing a .63AR housing on, boost creep was pretty much gone.
I’ll share my experiences as well… i’m running a 38mm Tial on my car. The engine is a bored and stroked 2.4 liter now about a 2.6 liter. The turbo is a Garrett t60-1 .82 a/r. At 25-26psi I was seeing zero boost creep and have pushed it as high as 28psi on some race gas with no creep as well.
you guys all realize that the wastegate is a limiting factor at low boost only, you can run 40psi with a 42r on a 38mm and work fine (with co2) but that same turbo and 38mm gate will not let you run 7psi w/o creep
Good point… guess i’ve never tried running low boost on my setup though. The lowest i’ve went with it was 1 bar and didn’t notice creep there either.