Internal, external wastegate.

[clivegto]

Is there a big advantage to use a external wastegate.

[Leblowski]

I noticed with various build you can control boost better, internal gates tend to boostcreep when you go big or dumppipe exhausts.

So i always go external when building turbobikes.

[homer]

Vote for the external. Better for controlling boost. In low boost/power builds they might be overkill but still I would take external.

[Gixer1460]

Whilst I tend to agree with external gates both of my installs have used internal gates - no boost creep detected and with the big power bike, two port actuator and AMS 1000 boost controller, I have total control and gear dependent boost, all programmable - nice to avoid 30lbs of boost in 1st, 2nd or 3rd LOL!

[no class]

internal gates can be ported to resolve boost creep issues …...and as said above can  also manage  high power outputs . easier to set-up and make for  a cleaner install . External gates can also suffer boost creep when improperly installed ….and I have seen quite a few at bad angles . Properly installed external gates will always manage boost  better at higher levels as well …...but I don't see too many 400+ hp turbo bikes rolling around on the streets...…..to each his own I guess .   

[Arttu]

There is plenty of variation how well the internal gates are done. If internal works in your setup, meaning holds the boost where you want, then there is no advantage with external one. Like mentioned internal gates are often a bit small and that may result boost creep at high rpm. Usually this happens especially if you try to get low boost from relatively large turbo. Quite often porting the gate is enough to solve the problem.

External gate isn't a golden bullet solution to all boost control problems either. There the most critical thing is joining the wastegate connection to the exhaust manifold. If it's at wrong angle or location you may get boost creep no matter how large gate you use. Again the result depends greatly on various factors like turbo sizing and boost target. The worst example that I have seen made 1.3 bars boost even when the whole wastegate was removed

Edited February 20, 2019 by Arttu

[clivegto]

So where & what angle is the best place to mound a external wastegate. Also how is the internal one ported, any pics please.

[Gixer1460]

1 hour ago, clivegto said:

So where & what angle is the best place to mound a external wastegate. Also how is the internal one ported, any pics please.

Look at some of the work from Big CC Racing - that man knows what it takes to make power - attention to detail in the pipework for one.

[MeanBean49]

I know im not running big power, ive had no issues at all using the stock internal wastegate. I have just swapped the actuator for an upgraded one. I use a simple variable electronic boost controller that just restricts the flow to the actuator to set my boost. Never had any boost creep issues at all.

[homer]

3 hours ago, clivegto said:

So where & what angle is the best place to mound a external wastegate. Also how is the internal one ported, any pics please.

Collector or turbine housing. Avoid 90 degree or tighter angle. Figure out how the exhaust gasses flow and try to make the transition to the port as smooth as possible. Usually in motorcycles collector part is quite short so there is no place for the port. I have done few manifolds for cars and did place the port to turbine housing. It works fine.

[no class]

manifold mounted external gate ......

[Arttu]

9 hours ago, clivegto said:

So where & what angle is the best place to mound a external wastegate. Also how is the internal one ported, any pics please.

Homer and no class explained this pretty well. Maybe one additional factor: If there is a bend on manifold just before collector, like on typical bike case, then outer side of curve works better. Most of the flow will go on outer side.

[zedhead]

Some of the drag-specific turbo headers have one of the header pipes pointing directly at the wastegate port - it'll be down to your specific header design / amount of room you have as to how you can do it.

[Brokenbill]

here's mine on my BKing