ANDYJDMSTI Posted November 4, 2004 Posted November 4, 2004 ....can you fill me in on exactly what an external wastegate does and what the advantages (if any) there are to having one.
the squiggle Posted November 4, 2004 Posted November 4, 2004 For your car there would be no benefit that im aware of The only differance between a normal turbo mounted wastegate and an external is the external wont interfere with the gas flow leaving the turbo when it opens and bypasses the turbo Only when running boost levels of over 2 bar should you consider an external doodah. The Grp B cars of the eighties and the current Indycars run with "Boiler valves". If you look behind the drivers side front wheel on a Grp B quattro there is a small diameter pipe where the external wastegate vents its gases to atmos. The last spec of Grp B Quattro ran at nearly 3 bar of boost on a 6 inch KKK turbo and when the wastegate fired it was about 100 times louder than Antilag as the wastegate exit pipe was only about 2 feet long Grant
Allan Posted November 5, 2004 Posted November 5, 2004 This is a question I have longed to be answered. I (call me sad) love the sound of a wrc car?s wastegate chirping away, Is it poss to have an external wastgate on any turbo?d car? If so are there any benefits of have 1 on your car except from the noise?
ANDYJDMSTI Posted November 5, 2004 Author Posted November 5, 2004 Grant, correcxt me if i am wrong, but one of the best ways to get the chirping/ fluttering is to get an induction kit and run without a dumpvalve. just like Grant does along with Willie (WRC No 1)
the squiggle Posted November 5, 2004 Posted November 5, 2004 After a long three paragraph reply, which my PC has wiped of the face of the earth, which explained why the turbo made that fluttering noise and the technical pros and cons of removing the dumpvalve Short answer Buy a cone filter, K+N 57i/Pipercross/HKS/Blitz, and block off the 3 pipes around where the std dumpvalve would be. Your scooby will chirp just like Sollbergs car Modern World Rally Cars run with no dumpvalve what so ever, the last Rally cars to use an external dumpvalve were the Grp B cars and the early Grp A cars like the Cossie's of Wilson and Delacour Some cars are ok to run without a dumpvalve as the compressor shaft is strong enough to withstand the stresses involved. Classic WRX saloons are good for it, Classic UK cars can be a bit weak in the shaft dept. In general the TD05 and 04 will run without a dumpvalve but the early IHI VF range of turbos are not the best for it. The twin scroll in your car Andy will handle the stress with no problem at all as that is the turbo Subaru Japan fit to the N10 factory rally car It is true that Wullie and myself both run without a dumpvalve, mines for over 18 months and no problems and as far as know Wullie hasn't had any problems on his UK wagon At the next meet/track day/run look for the idiot with the stupid exhaust sticking out an unusual place and i can let you here the noise my imaginary dumpvalve makes. IMHO it sounds better than they £150 HKS blow off chuffer valves Grant
the squiggle Posted November 5, 2004 Posted November 5, 2004 No it reduces lag on mid to high boost gearchanges as the intercooler and manifold still contain pressurised air which is nice, so the turbo has less work to do to get back to full boost pressure Grant
wilky Posted November 5, 2004 Posted November 5, 2004 Hmmm, okay Ive got a pace and TD05 FE on an STI 7 block in a stI RA V2 getting rebuilt as we speak, the DV is on the hard piping, would I see advantage from removing it and blanking the piping??
the squiggle Posted November 5, 2004 Posted November 5, 2004 The TD05 will handle the stress involved as it has a heavy duty turbine shaft. The drag cars from Japan run huge turbos without any dumpvalve with huge front mounts and they guys dont put anything on the car which may impede performance but as i have not driven a car with a front mount and no dumpvalve i could not say wether or not you would notice any effect. At a guess i would say the principle would be the same as a top mount, the manifold and intercooler would still contain the pressurised air so it would take less time for the turbo to spool up to reach its desired boost level just that the induction tract is a lot longer on a Fr mount than a top mount You would not do any harm in trying it out to see if the turbo hits its boost target quicker on a fr mount Grant
wilky Posted November 5, 2004 Posted November 5, 2004 Ill get a plate made up and give it a whirl, pardon the pun! Callum
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