what is the"hess" sound when ppl release the gas padel on sport car ??

Question

what is the"hess" sound when ppl release the gas padel on sport car ?? did ppl mod their car or does it come with it from the manufacturer?

Answer 1

the loud "hiss" or "pssh" sound when the pedal is released is caused by released excess or back pressure also known as "boost" from a turbo (turbine) . The excess boost is let out through something called a blow off valve (BOV) which vents into the atmosphere, or a Bypass Valve (BPV) which vents it back into the air intake system.



The purpose of this is to prevent "overboosting" and "boost surge". A turbo uses PSI (pounds per square inch) to force more air into the engine (forced induction) by using the exhuast gas routing through the turbo housing ie the more exhaust (higher rpm) the more boost (power).



Over boosting is exactly like it sounds, if an engine is set up to handle let's say 15 PSI of boost, the BOV can be set to 15PSI and will vent anything over that when it reaches to prevent damage to the enigine.



The main reson for a BOV or BPV though is to prevent boost surge. In short and simple Boost surge is when the air being forced into the engine through the piping actually comes back through when the pedal is released, if a valve is not used to vent it before it reaches back to the turbo you risk bending the fins inside it, or possibly detonating it all together.



Valves also come in a variety of different sounds depending on the company, the stock BPV on my mr2 sounds like a rattle snake, others just make a really lound "psssh" sound, and even one that sounds kinda like a seal. Either way when you hear a sound like a lot of air going through a small hole it's probably a turbo.

Answer 2

I believe what you are describing is a turbocharger blow off valve. This is usually an aftermarket add-on that is on the compressor side of the turbocharger. Simply put , this is how it works, The turbocharger rapidly accelerates producing boost ,when the driver changes gears, they let off of the accelerator pedal and the throttle plates snap shut thereby trapping a lot of rapidly moving air and stalling the turbo causing it to almost stop. This results in less power. Now if you add a blow off valve, When the driver changes gears and throttle plate pressure builds, it is released through this valve allowing the turbo to stay spooled up untill the throttle plates open again. Makes the car faster ,so thats why they do it.

Answer 3

Yea! i theory each and each of the solutions I study were solid. you'll merely journey some inconvenience. you may bypass to the aspects homestead and get a bottle of octane improve. this can help and there are different tricks yet you shouldn't be desirous to apply any of those in this motor vehicle. i ought to upload, via the indisputable fact that is prudent, that it really is assuming that an issue did not get up that has no longer something to do with the gas. you probably did not element out what variety of transmission you've. If the engine r.p.m.'s are intense, on acceleration, and the vehicles ahead action seems decreased, there would properly be a grab problem or a stopped up clear out.

Answer 4

i believe you are referring to engine breaking, it sounds like the car purrs a little, right? I used to drive big rigs and they had a pedal on the floor(some models)called a jake brake. what it did was cut the fuel and oxygen getting to the engine. you more than likely have heard this on the highway when there is a lot of stop and go traffic. it sounds really cool, I think. but to answer your question about modifying the car, no, you only get that sound with a manual transmission.

Answer 5

it is the turbo charger that they installed on the vehicle, mostly on japanese or other foreign cars. i believe the best ones are known as wastegate turbos, they are known to boost your hp up to 400%, they cost boocoos of money to install cuz lots of parts come to them, intercoolers,flagilators,the turbo itself, and controls for it. some diesel trucks use turbos as well. most of the time its that whining sound the truck makes when it is sucking in air through the turbo charger when the engine is being wound up. they are hard to maintain, because you can easily mess one up

Answer 6

I couldn't tell you exactly but it is a definate mod!!! Car manufactures don't make cars that way from factory!! It is people trying to believe they are cool and all that!! lol