Im building and boosting my B18A1 and my HP goal is atleast 350 to the crank. Its just Im not real sure what size wastegate to go with and how to determine it…I figure in between 38mm to 44mm?? Also isnt there different springs internally u choose from?? Please let me know!
a 38mm will be fine. im running 300whp which is in the 350hp crank range and i have absolutely no boost creep. you can change the springs but chances are you’ll be running a boost controller any way. i have a 7psi spring but with my boost controller im running 18psi.
I see thanks for the info man:rockon:
[QUOTE=redtegra;2005247]i have absolutely no boost creep.[/QUOTE]manifold design (location of WG port) has more to do with that then the actual WG/WG size. but you are right a 38mm WG will be fine. a 40mm one will also work. most have the same flange for the 38 and 40mm WG. you will not need a bigger WG for you number then a 40mm.
:werd:
Agreed, a 38mm (Tial) will suit your needs just fine.
Generally bigger wastegates are used to control boost creep (for example, a 38mm on a 16g on a DSM) but this also means they can’t hold as much boost. The stock wastegate on a DSM is around 11-12PSI, if I were you I’d try to find one that opened at like, 4psi and throw an MBC on there to bring it up to what you want, because boost controllers can raise boost over what the WG is set at, but they can’t lower it below the WG psi.
[QUOTE=juanpac0;2010078]Generally bigger wastegates are used to control boost creep[/QUOTE]only as a crutch. the manifold design and DP have more to do with boost creep and its control then the actual WG.
[QUOTE=juanpac0;2010078]but this also means they can’t hold as much boost.[/QUOTE]explain.
[QUOTE=juanpac0;2010078]if I were you I’d try to find one that opened at like, 4psi and throw an MBC on there to bring it up to what you want, because boost controllers can raise boost over what the WG is set at[/QUOTE]its true that boost controllers can increase the amount of psi your able to run. they do this by bleeding off the over pressure to the atmos. BUT there is still a limit, since the WG valve (or flapper if it is an internal gate) still has a spring or diaphram that has to actually hold back the exhaust gas pressure. if its too much, the gas will force the WG open and bleed off the excess pressure. this causes fall off of pressure or irratic pressure control.
edit: its a common rule of thumb to only double the WG spring/diaphram pressure with a BC, anymore could cause issues down the road.
[QUOTE=juanpac0;2010078]but they can’t lower it below the WG psi.[/QUOTE]absolutely true.
[QUOTE=90DB1T;2010458]only as a crutch. the manifold design and DP have more to do with boost creep and its control then the actual WG.
explain.
its true that boost controllers can increase the amount of psi your able to run. they do this by bleeding off the over pressure to the atmos. BUT there is still a limit, since the WG valve (or flapper if it is an internal gate) still has a spring or diaphram that has to actually hold back the exhaust gas pressure. if its too much, the gas will force the WG open and bleed off the excess pressure. this causes fall off of pressure or irratic pressure control.
edit: its a common rule of thumb to only double the WG spring/diaphram pressure with a BC, anymore could cause issues down the road.
absolutely true.[/QUOTE]
First of all, thank you for taking the time to actually respond to my post in a mindful manner.
I agree with the downpipe/o2 housing affecting boost creep more, I was just noting that from my experience, a bigger flapper helps control boost creep since it can dump more exhaust gases (if the creep is related to the turbo, and not the o2 housing/DP). This shouldnt be an issue for most integra owners looking to boost their stock block as at 8psi none of the turbos I’ve seen mentioned in this forum recently reach their flow limits. Larger flappers are known to blow open easier at higher boost (20+ psi, more than most boosted integras will ever see).
I also agree with you on the subject of the boost controller, but if he’s looking to only run 8psi, even just for now, my suggestion falls in line with what you said, and when running this motor at/near its “stock” limits, it helps to have every bit of adjustability.
[QUOTE=juanpac0;2010562]First of all, thank you for taking the time to actually respond to my post in a mindful manner.[/QUOTE]it should be the way everyone posts. clear and to the point. it makes it easier to follow along with the posts and the information being passed out. 
[QUOTE=juanpac0;2010562]I agree with the downpipe/o2 housing affecting boost creep more, I was just noting that from my experience, a bigger flapper helps control boost creep since it can dump more exhaust gases[/QUOTE]ahh… so your refering to internal gates. i figured as much, but wanted to have it clearified.
Yea thanks for the good info! Very understood and clear…makes life easier.