External wastegates.

**Steve Webb** · 07-04-11, 20:19

Does anyone on the forum run with an external wastegate? I've just been reading through some techy stuff about them and would be interested to hear peoples real world experiences.
Did it improve response, cut down lag etc.

And if you have got one fitted, lets see some pics.

Cheers

**SteveNZ** · 09-04-11, 03:18

They definately make it easier to control the boost.

**Steve Webb** · 09-04-11, 08:06

I was interested more in where people plumb them in in the real world, I've seen all the theory, but real world installations rarely follow the 'best practice'

**SteveNZ** · 09-04-11, 14:54

Well a friend of mine has one mounted off the turbine housing.

http://www.fiatcarclub.co.nz/forum/v....php?f=13&t=25

Fitting it to the turbine housing is considered good but his setup was less than desirable and he suffered boost creep. It was probably due to the "take of pipe" that was needed to clear the radiator.

The whole system has now been redesigned with a new turbo to have the wastegate mounted off the beginning of the scroll at a good angle (actually no angle it projects straight from the manifold collector). The wastegate will end up pointing straight down under the turbo.

Wastegates were once the "must have" bling accessory on a turbo car. I've seen some terrible installs but surprisingly they still usually work very well. Most just got welded to the standard manifold at some obscure angle.

**mpampis_** · 11-04-11, 05:28

Well, for sure you can control better the boost pressure, the point is what is the best size of the external and the best spring for working well. You will tell me it depend on the car's setup. I have a T3/T4 turbo with stage3 wheel. Something like Garrett 30.71! I am use this turbo at 1.1 - 1.2 bar boost because I have stock pistons. Any idea? I am thinking about 38mm external and spring opening at 0.8- 0.9 bar

**SteveNZ** · 11-04-11, 12:29

The spring is easy. How low will you want to run the boost? Get that spring. If not get the one closest to the pressure you want to run. You really want to use a spring that is as close to the boost you want to run. This will make it easier for the boost controller if you want to use one at all.

How big? T3/4's run on a stock internal wastegate OK. A 38mm should be large enough. Don't believe the speal about using a small wastegate for high boost and a large wastegate for low boost. Basically, more power = bigger wastegate. It's really a little trial and error though. If you want to be sure get a larger one, its only costing you more money.