Hi guys, i am new to Rx7\'s but i have always wandered how you get the waste gate chatter sound instead of the normal dump valve noise associated with most turbo cars? thanks
On and RX-7 you will need to swap from stock twins to a nice big single turbo.
Fish
that sound is your turbos stalling not good imo,
but if you have some filters and block off a few pipes you can get that sound.
but i would not recommend it
shaQ
QuoteOriginally posted by grigglet33
i am new to Rx7\'s but i have always wandered how you get the waste gate chatter sound instead of the normal dump valve noise associated with most turbo cars?
They are 2 different noises which are not dependant on each other. The BOV goes \'whoosh\', the \'chatter\' is the sound from some types of external wastegate that you have to run when you convert from the stock twin turbos to a larger single turbo setup...
Stock turbos = no chatter.
Thats unless you are running either a rally car or a turbo that can handle being stalled.
Rally cars run without a wastegate, thus where the chatter comes from. But they have a budget for a new turbo at every stage.
A turbo that can handle being stalled on a regular basis are the Mitsi. TD range. ;)
Fish
oh good, i have a huge Mitsi TD08 to go on my project 1st gen 13 b, once i sell my FD i will be on it!!!!
Why would you want to stall the turbo, as I was always led to beleive you maintain the performance levels by keeping it spinning, surely stalling it would mean lag/spool up time being added to every major gear change or when backing off the throttle?:confused:
Steve
^
my exact thought s
:confused:
shaQ
Its a noise thing. ;)
Once you\'ve done it, you want it all that little bit more. :D
Fish
QuoteOriginally posted by Fish
Rally cars run without a wastegate, thus where the chatter comes from. But they have a budget for a new turbo at every stage.
A turbo that can handle being stalled on a regular basis are the Mitsi. TD range. ;)
Fish
Rally cars have an external wastegate - ie a seperate bit of trickery after the tub in the boost circuit - rather than the wastegate being built into the turbo housing. That\'s why they\'re noisier - the gate\'s not buried in the middle of the engine bay somewhere...
They still have a wastegate! Otherwise, there\'s absolutely no way of controlling boost levels - it would build until something went bang. Be nice to be running 10 bar for a fraction of a second, but... :D (Actually the turbo would probably choke on its own boost way before that level and you\'d just end up with ridiculous intake temps and no power and lots of det.)
Even if you have a turbo that doesn\'t mind continuous stalling,you\'re introducing lag every time it stalls, so it hardly helps performance or response.
Recircs give better performance than BOVs unless you\'re flowing stupid amounts of air anyway...
Anyway, NA is the way forward as any fule no. :P
antilag anyone? :god
Si
Wastegates are one way of controlling boost, another is air injectors. Ford have been using these for years. The ECU also controls the amount of boost that a car runs.
The apexi doesnt do it that well, but when you start looking at the money levels of WRC/proper rallying you look at stuff like Motec and Pectel to name just two.
I was running a held 1.8 BAR of boost on my old cortina, using a stock 2 BAR map sensor and a Motec M48 Pro to control the boost. I never had one instance of overboost with it.
As for the high boost levels, this is not a problem with engines that are properly mapped on bench dynos, by people who really know what they are doing.
Fish
QuoteOriginally posted by Fish
As for the high boost levels, this is not a problem with engines that are properly mapped on bench dynos, by people who really know what they are doing.
Fish
Talking of which, what boost r u going to b running then Danny? You given up on mapping on an engine dyno, right?
Yeap, guess I will be back on the M1. ;)
So if you hear a loud noise late at night on that road, dont worry I\'ll be past you before you know it. :D
Fish
PS. High boost levels will not be run!
Thankfully a long way from my manner :D
Be careful dude.
QuoteOriginally posted by Fish
Wastegates are one way of controlling boost, another is air injectors. Ford have been using these for years.
So where do they inject air from / to - and what do they do with charged air they don\'t need?
Inquiring minds wish to know...
QuoteThe ECU also controls the amount of boost that a car runs.
Yeah via the wastegate solenoids :P
I had to have this re-explaned to me, as its been some time.
They are quite simple really. A "set" of air injectors consists of two independent units, on one mounting.
They need two individual PWM outputs from an ecu.
One PWM signal works one of the injectors, which "opens" the wastegate.
The second PWM signal works the other injector, to "close" the watsegate.
On spool up, the "close" injector keeps the wastegate closed, allowing the best spool up.
When you get to target boost, the ECU switches to the "open" injector, to prevent over boost, and then balances the two injectors to maintain the target boost.
They are obviously designed to work with an "external wastegate".
Fish
Thus smoothing out all the transitions and getting rid of spikes...
Doesn\'t matter how clever you think the last thing you learned about performance cars was, there\'s always an even more clever thing you don\'t know about, in\'t there?
And this stuff has been used in WRC and such since about \'85.
Fish