whats is a external wastegate??
#2
B1mbo
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obviously the ex wastegate is the wastgate but is not built into the exaust housing but it is built into the manifold
the ex wastegate allows the use off a bigger turbo as you can get bigger exhaust wheel in without the wastegate getting in the way.
i also THINK that because the wastegate in not blocking the exhaust gas flow on a ex wastegated turbo it decreases backpressure ? not 100% sure in that
also you can have very precise boost control you would have to use 2sets of air injectors or play with the spring in the wastgate
a screamer pipe i dont think has any advantage when we do a external wastegate turbo'd enine the exhaust is made at hatward and scott and the screamer pipe is plumbed back iton the exhaust system
hope this helps i think it is all accurate
the ex wastegate allows the use off a bigger turbo as you can get bigger exhaust wheel in without the wastegate getting in the way.
i also THINK that because the wastegate in not blocking the exhaust gas flow on a ex wastegated turbo it decreases backpressure ? not 100% sure in that
also you can have very precise boost control you would have to use 2sets of air injectors or play with the spring in the wastgate
a screamer pipe i dont think has any advantage when we do a external wastegate turbo'd enine the exhaust is made at hatward and scott and the screamer pipe is plumbed back iton the exhaust system
hope this helps i think it is all accurate
#7
Baby Cheesus
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this is an external wastegate, comes off the manifold before the turbo
and this is the screamer pipe exit
my exhaust system was also done by hAyward and scott, but its got to go back at some point, as i cant get full lock to the left, as the fuckwits put the screamer int he way and wheel hits it....
youd have think they may have noticed this
and this is the screamer pipe exit
my exhaust system was also done by hAyward and scott, but its got to go back at some point, as i cant get full lock to the left, as the fuckwits put the screamer int he way and wheel hits it....
youd have think they may have noticed this
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#11
Borg Warner EFR Equipped!
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Other thing to consider is that if you want to tail the boost off at the top end on an internally gated turbo, you can reach the point where the port inside the exhaust housing just physically can't bypass enough exhaust gasses and the boost pressure will creep back up at high revs.
External wastegates when specced properly provide very accurate control!
External wastegates when specced properly provide very accurate control!
#13
B1mbo
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i think its more to do with the spec of your engine weather you go external wastegate or not tbh as if you want over 550 bhp you will struggle to find a good turbo capable of over that
a t4 even struggles with boost creep
you wouldnt put a external gate on a 400bhp turbo even if they did suffer slightly with boost creap because the gain isnt worth it
#14
#1 in Spelling Club
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It's not about what boost you run, more about a point in the airflow scheme, where, as Will said, an Internal Wastegate just can't be big enough to do the job.
That said, it's not a case of biggier is better with External Wastegates, most people go over the top. Gary's 700bhp Evo runs a Tial 38mm Wastegate, same as I run on mine. Mine is sprung at 1.5 bar and I make 1.4 bar absolutely flat with no boost control.
That said, it's not a case of biggier is better with External Wastegates, most people go over the top. Gary's 700bhp Evo runs a Tial 38mm Wastegate, same as I run on mine. Mine is sprung at 1.5 bar and I make 1.4 bar absolutely flat with no boost control.
#23
Advanced PassionFord User
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just dont see how that can work if its after the turbo, surely it got to be before the turbo other wise its venting the exhaust gases after they've already passed thru the turbo
#24
#1 in Spelling Club
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LOL. It's an AMS kit and I think they have at least half and idea what they are doing!!
The Turbine Housing has the normal discharge and Wastegate hole as though it was Internally 'gated, but with no flap. The hole is enlarged too. Then the Turbo Elbow is divided and the Wastegate section of the housing goes directly into a Tial 38mm Wastegate, which in turn discharges directly into the main exhaust.
I'll put a pic up of Gary's new Turbo elbow that Chris has just made next week. Will make sense then.
The Turbine Housing has the normal discharge and Wastegate hole as though it was Internally 'gated, but with no flap. The hole is enlarged too. Then the Turbo Elbow is divided and the Wastegate section of the housing goes directly into a Tial 38mm Wastegate, which in turn discharges directly into the main exhaust.
I'll put a pic up of Gary's new Turbo elbow that Chris has just made next week. Will make sense then.
#29
10K+ Poster!!
If your exhaust is too small and cannot cope with the amount of air being forced through it then venting the screamer pipe to atmosphere would be an advantage, but other than that its just noisier. If your exhaust is too small, the best thing to do would be get a larger/free'r flowing exhaust on the car and plumb the screamer back into that.
#37
PassionFord Post Whore!!
A external wastage has a flap that moves away the same all round so for the same peak lift it can flow more than a internal gate, unless you use a real big bypass hole you cant flow the same, space and packaging is one of the reasons why they can control the boost better but also the smaller hole helps as theres not a instant drop with a hole thats to big.
Mark
#38
B1mbo
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But you need to look at how the flap is attached, a internal gate is hinged like a door and is only opened on one side so this limits the flow of the hole,
A external wastage has a flap that moves away the same all round so for the same peak lift it can flow more than a internal gate, unless you use a real big bypass hole you cant flow the same, space and packaging is one of the reasons why they can control the boost better but also the smaller hole helps as theres not a instant drop with a hole thats to big.
Mark
A external wastage has a flap that moves away the same all round so for the same peak lift it can flow more than a internal gate, unless you use a real big bypass hole you cant flow the same, space and packaging is one of the reasons why they can control the boost better but also the smaller hole helps as theres not a instant drop with a hole thats to big.
Mark
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