Dump valve on an auto?

[Anarchi-H]

Ok; I'm asking this for my uncle as he is looking in to buying a 2.0 litre twin turbo supra with an automatic transmission...

He wants to know if he can put a dump valve on it, and since I know about as much as car mechanics as I do sewing (not alot), any advice would be appreciated. I can't seem to find any relavent matches from google, but then again, I could be looking for the wrong keywords.

[nism0]

Ofcourse you can, the dumpvalve is part of the turbo system, not transmission.

[Anarchi-H]

Ofcourse you can, the dumpvalve is part of the turbo system, not transmission.

That is the reasoning we came to, but then it occured to us that we didn't know how the actual valve is actuated. Is it purely based on pressure building up, or is it actuated in some manner?

[nism0]

I can't say too much, as I'm not a technical buff, but from what I know, it's actuated when the pressure is released from the gas, so it will acuate when you release the gas pedal.

[tristancliffe]

Normally done solely on pressure... But some cars have a dump valve that can be set to high or low boost on the ECU, so fitting an aftermarket one might not be really easy (I don't know that car).

Just don't get one that goes "wissshsshshshshshsisisdsdisdis]djaspd" everytime you move your foot.

[Anarchi-H]

Ahah, thanks :)

A little googling for how they actually work gave me the answer I was looking for... unless anybody else can think of any technical reasons why you can't put a dump valve on an automatic

http://www.seatcupra.net/review_forgedv.htm

[96 GTS]

I'm pretty sure the car already has a dump valve. AFAIK anything with a turbo or supercharger needs some way to bleed of excess boost, or else it'd damage the engine.

[nism0]

Yes, most stock turbo cars will have wastegates, and most are internal.
If you want the "ppshhh" sound, thats when you get the dumpvalve/blow off valve.

[atledreier]

All turbo cars have wastegates, and most have some sort of recycling valve that bleed off excess boost when it's not needed. They are not the same thing, though. In most cars this bleed valve vent back to the intake, and the valve is vacuum actuated. The difference between the stock bleedvalve and a dumpvalve is that the dump valve bleed air to the outside of the intake tubing, creating the characteristic hiss.
There should be no problem using a dumpvalve on an auto that wouldn't also present itself on a manual. You will not get the hiss on shifts though, as you don't lift between gears. You'd get it when you lift off, though.

[Huru-aito]

Replacing a bypass valve with a dump valve can cause very rich mixture when lifting off - air that has already been measured is vented out of the system -> ECU calculates fuel injection according to a wrong amount of air. But that depends on what kind of a system the ECU uses to measure the air.

[DodgeRacer]

Is this a Supra Celica or a Supra ? I beieve the regular supras were 3 Litre Inline 6's not 2 Litre, just for future referance.

[pb32000]

Is this a Supra Celica or a Supra ? I beieve the regular supras were 3 Litre Inline 6's not 2 Litre, just for future referance.

Seems not (http://www.carfolio.com/search/results/?terms=supra)

[Anarchi-H]

Is this a Supra Celica or a Supra ? I beieve the regular supras were 3 Litre Inline 6's not 2 Litre, just for future referance.

We had that ponderance; since the inusrance company refused to believe that it was a 2 litre when he tried to get a quote.

Anyway; thanks for all the info guys. I'm a total noob when it comes to cars, so your help is much appreciated :shy:

[DodgeRacer]

Seems not (http://www.carfolio.com/search/results/?terms=supra)

this is why i asked if it was a supra celica or not, >86 ones are supra celicas, with 2L and >86.5 are 3L ;)