# Wastegate Size **URL:** \ **Category:** Shift518 Automotive\ **Created:** [April 20, 2010, 10:47am UTC](https://forums.speedlife.net/t/wastegate-size/251623 "2010-04-20T10:47:03Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![ninety1two40](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ninety1two40/32/6332_2.png) [@ninety1two40](https://forums.speedlife.net/u/ninety1two40)\ **Post date:** [April 20, 2010, 10:47am UTC](https://forums.speedlife.net/t/wastegate-size/251623/1 "2010-04-20T10:47:03Z")
I’m searching for an external wastegate for my RB25 with the Holset HX35 on it. I’m leaning on choosing a Tial 38mm Vband wastegate, but will 38mm be large enough? Will I run into boost control problems if I don’t recirculate the wastegate back into the exhaust? Thanks dude bros ---
**Author:** ![tdi\_logik](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/tdi_logik/32/6310_2.png) [@tdi\_logik](https://forums.speedlife.net/u/tdi_logik)\ **Post date:** [April 20, 2010, 10:56am UTC](https://forums.speedlife.net/t/wastegate-size/251623/2 "2010-04-20T10:56:09Z")
how much boost do you plan on running? on low boost like 8-9psi or so it may/may not creep. just spend the extra 100$ and get the 44. ---
**Author:** ![Boost\_Creep](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/boost_creep/32/6366_2.png) [@Boost\_Creep](https://forums.speedlife.net/u/Boost_Creep)\ **Post date:** [April 20, 2010, 10:57am UTC](https://forums.speedlife.net/t/wastegate-size/251623/3 "2010-04-20T10:57:37Z")
Go 44mm for sure. Or ask Wayne, he’s an expert with WG’s now. ---
**Author:** ![tdi\_logik](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/tdi_logik/32/6310_2.png) [@tdi\_logik](https://forums.speedlife.net/u/tdi_logik)\ **Post date:** [April 20, 2010, 10:59am UTC](https://forums.speedlife.net/t/wastegate-size/251623/4 "2010-04-20T10:59:49Z")
> [@The baby blue shark hood neon tried chasing me down...](https://forums.speedlife.net/t/the-baby-blue-shark-hood-neon-tried-chasing-me-down/30686/355): > > Go 44mm for sure. Or ask Wayne, he’s an expert with WG’s now. a w/g is pretty simple actually… ---
**Author:** ![20wrx09](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/20wrx09/32/6532_2.png) [@20wrx09](https://forums.speedlife.net/u/20wrx09)\ **Post date:** [April 20, 2010, 11:02am UTC](https://forums.speedlife.net/t/wastegate-size/251623/5 "2010-04-20T11:02:28Z")
The theory is that a larger wastegate (44 mm) should be utilized on turbos using low boost vs. turbos that are running high boost which should run a smaller wastegate (38 mm). Where did this theory come from? Remember…a wastegate limits boost. If you want to run more boost, you don’t have to limit it as much. Running less boost means you have to limit it more. ---
**Author:** ![Wayne64SS](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/wayne64ss/32/6365_2.png) [@Wayne64SS](https://forums.speedlife.net/u/Wayne64SS)\ **Post date:** [April 20, 2010, 11:02am UTC](https://forums.speedlife.net/t/wastegate-size/251623/6 "2010-04-20T11:02:59Z")
WGs are very simple, even on the inside!! W/e you get, don’t listen to bryan and buy the wrong spring. LOL ---
**Author:** ![Mk4\_30R\_Ban](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/mk4_30r_ban/32/6347_2.png) [@Mk4\_30R\_Ban](https://forums.speedlife.net/u/Mk4_30R_Ban)\ **Post date:** [April 20, 2010, 11:06am UTC](https://forums.speedlife.net/t/wastegate-size/251623/7 "2010-04-20T11:06:08Z")
is your manifold a twin scroll or single? if its a twin scroll you will need 2 wastegates, or if there is a way of merging the groups into 1 single gate, like the 2JZ hks/greddy headers do. if thats the case, 2 TiAL MVS 38s would work fine. but if you can get away with a single wastegate a single V44 would work fine. just choose spring rate accordingly for the target boost range. .8bar = 10psi opening, and so on. ---
**Author:** ![ninety1two40](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ninety1two40/32/6332_2.png) [@ninety1two40](https://forums.speedlife.net/u/ninety1two40)\ **Post date:** [April 20, 2010, 11:14am UTC](https://forums.speedlife.net/t/wastegate-size/251623/8 "2010-04-20T11:14:52Z")
I’ll be running 10psi for now, so I’ll just get a .8 bar spring. In the future I’ll push it up to 18+ psi via boost controller. I’ll be modifying my log manifold. ---
**Author:** ![Boost\_Creep](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/boost_creep/32/6366_2.png) [@Boost\_Creep](https://forums.speedlife.net/u/Boost_Creep)\ **Post date:** [April 20, 2010, 11:15am UTC](https://forums.speedlife.net/t/wastegate-size/251623/9 "2010-04-20T11:15:36Z")
> [@FS: e28 wheels FS](https://forums.speedlife.net/t/fs-e28-wheels-fs/31170/11): > > WGs are very simple, even on the inside!! W/e you get, don’t listen to bryan and buy the wrong spring. LOL Hey now 40 psi FTW… :shifty ---
**Author:** ![ninety1two40](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ninety1two40/32/6332_2.png) [@ninety1two40](https://forums.speedlife.net/u/ninety1two40)\ **Post date:** [April 20, 2010, 11:16am UTC](https://forums.speedlife.net/t/wastegate-size/251623/10 "2010-04-20T11:16:11Z")
:rofl ---
**Author:** ![Wayne64SS](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/wayne64ss/32/6365_2.png) [@Wayne64SS](https://forums.speedlife.net/u/Wayne64SS)\ **Post date:** [April 20, 2010, 11:33am UTC](https://forums.speedlife.net/t/wastegate-size/251623/11 "2010-04-20T11:33:42Z")
:rofl ---
**Author:** ![Boost\_Creep](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/boost_creep/32/6366_2.png) [@Boost\_Creep](https://forums.speedlife.net/u/Boost_Creep)\ **Post date:** [April 20, 2010, 11:36am UTC](https://forums.speedlife.net/t/wastegate-size/251623/12 "2010-04-20T11:36:51Z")
Wayne, don’t make me drive up there with a 2JZ no turbs. ---
**Author:** ![cazwrx187](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/cazwrx187/32/6388_2.png) [@cazwrx187](https://forums.speedlife.net/u/cazwrx187)\ **Post date:** [April 20, 2010, 11:57am UTC](https://forums.speedlife.net/t/wastegate-size/251623/13 "2010-04-20T11:57:15Z")
> [@WTR: I need somewhere to keep a car!](https://forums.speedlife.net/t/wtr-i-need-somewhere-to-keep-a-car/31153/11): > > The theory is that a larger wastegate (44 mm) should be utilized on turbos using low boost vs. turbos that are running high boost which should run a smaller wastegate (38 mm). Where did this theory come from? Remember…a wastegate limits boost. If you want to run more boost, you don’t have to limit it as much. Running less boost means you have to limit it more. Copy/paste straight from NASIOC. Nice. ---
**Author:** ![ninety1two40](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ninety1two40/32/6332_2.png) [@ninety1two40](https://forums.speedlife.net/u/ninety1two40)\ **Post date:** [April 20, 2010, 11:58am UTC](https://forums.speedlife.net/t/wastegate-size/251623/14 "2010-04-20T11:58:21Z")
Ok so anyway, how do I know what size I need, I don’t want to spend the extra $100+ if I don’t need it. Or does anyone have a used one? Has to be vband though. ---
**Author:** ![Boost\_Creep](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/boost_creep/32/6366_2.png) [@Boost\_Creep](https://forums.speedlife.net/u/Boost_Creep)\ **Post date:** [April 20, 2010, 11:58am UTC](https://forums.speedlife.net/t/wastegate-size/251623/15 "2010-04-20T11:58:38Z")
> [@The baby blue shark hood neon tried chasing me down...](https://forums.speedlife.net/t/the-baby-blue-shark-hood-neon-tried-chasing-me-down/30686/360): > > Copy/paste straight from NASIOC. Nice. ouch caught red handed. ---
**Author:** ![ninety1two40](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ninety1two40/32/6332_2.png) [@ninety1two40](https://forums.speedlife.net/u/ninety1two40)\ **Post date:** [April 20, 2010, 12:02pm UTC](https://forums.speedlife.net/t/wastegate-size/251623/16 "2010-04-20T12:02:44Z")
Diesel guys run these turbos up around 30psi IIRC, I won’t be pushing more than 20psi unless I build my motor. It has an internal wastegate, but unless I bore the opening larger it will just Byran Baykerin on me. But I’d just rather go external. ---
**Author:** ![Boost\_Creep](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/boost_creep/32/6366_2.png) [@Boost\_Creep](https://forums.speedlife.net/u/Boost_Creep)\ **Post date:** [April 20, 2010, 12:05pm UTC](https://forums.speedlife.net/t/wastegate-size/251623/17 "2010-04-20T12:05:24Z")
Internal WG FTL. ---
**Author:** ![Boost\_Creep](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/boost_creep/32/6366_2.png) [@Boost\_Creep](https://forums.speedlife.net/u/Boost_Creep)\ **Post date:** [April 20, 2010, 12:05pm UTC](https://forums.speedlife.net/t/wastegate-size/251623/18 "2010-04-20T12:05:47Z")
And I would like to state for the record you cannot rely on HKS charts for certain boost levels. ---
**Author:** ![Wayne64SS](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/wayne64ss/32/6365_2.png) [@Wayne64SS](https://forums.speedlife.net/u/Wayne64SS)\ **Post date:** [April 20, 2010, 12:07pm UTC](https://forums.speedlife.net/t/wastegate-size/251623/19 "2010-04-20T12:07:11Z")
> [@LS1 evo inside](https://forums.speedlife.net/t/ls1-evo-inside/31180/41): > > Wayne, don’t make me drive up there with a 2JZ no turbs. i dunno bout driving up here with no turbz, but if i see that car again it’s leaving without turbz!!! LOL > [@FS: 1987 BMW 325E](https://forums.speedlife.net/t/fs-1987-bmw-325e/31038/26): > > Diesel guys run these turbos up around 30psi IIRC, I won’t be pushing more than 20psi unless I build my motor. It has an internal wastegate, **but unless I bore the opening larger it will just Byran Baykerin on me.** But I’d just rather go external. bahahahahaha +rep if i can. ---
**Author:** ![Wayne64SS](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/wayne64ss/32/6365_2.png) [@Wayne64SS](https://forums.speedlife.net/u/Wayne64SS)\ **Post date:** [April 20, 2010, 12:07pm UTC](https://forums.speedlife.net/t/wastegate-size/251623/20 "2010-04-20T12:07:44Z")
> [@The baby blue shark hood neon tried chasing me down...](https://forums.speedlife.net/t/the-baby-blue-shark-hood-neon-tried-chasing-me-down/30686/361): > > And I would like to state for the record you cannot rely on HKS charts for certain boost levels. cosigned. [Next page](https://forums.speedlife.net/t/wastegate-size/251623.md?page=2)