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This would either cause A... a massive boost leak, or B... unmetered air getting into your engine and subsequently it running lean. Would not advise before truly understanding where that air is going.
I don't know much about SC motors, this being my first. But if it's anything like a turbo'd moyor, of which I've had many, then there would be a diverter valve somewhere between the SC and the manifold that would open to let excess boost discharge on throttle close, normally there would be a hose connecting the diverter valve to the intake before the SC, so the excess boost gets recirculated. People often take off that hose and plug the hole in the intake so that when the diverter valve opens it goes whoosh
EDIT: on further research, this doesn't apply to a SC
Depends on the layout of the plumbing. When VW were making the G60 engine, the throttle body itself contained the valve for the return, so you could take the hose off safe in the knowledge that that particular port would only ever blow (so no unmetered air), and without creating a boost leak.
You did have to put a blanking plate over where the other end of the return pipe mounted though.
Depends on the layout of the plumbing. When VW were making the G60 engine, the throttle body itself contained the valve for the return, so you could take the hose off safe in the knowledge that that particular port would only ever blow (so no unmetered air), and without creating a boost leak.
You did have to put a blanking plate over where the other end of the return pipe mounted though.
Correct, which is why we need to fully understand the system before just going to pull lines off.
My m3 has no diverters valve, it plumbs boost back into system to act as an antilag type setup
Just like a turbo motor, the easiest way to get more noise is to run an open filter element - and currently only eventuri have a decent intake kit
Those silencer tubes bw airbox and Tb are more designed to act like harmonic adjustments to the airflow and thus sound, they won't do as much to add whine as an open airbox, but if the price is right via that mina gallery, id be keen to give it a go
Correct, which is why we need to fully understand the system before just going to pull lines off.
There is a bypass valve on the supercharger, but it performs a different role to a wastegate or blow off valve in a turbo.
The bypass valve opens to cut boost when you close the throttle, or when you are cruising with no throttle. This reduces the load on the intake system (i.e. reduces the parasitic losses of driving the supercharger). It opens up a path between the inlet and the outlet of the supercharger internally, so that there is no boost.
On the F-Types these bypass valves are driven by a stepper motor, on the older models they worked mechanically off manifold vacuum.
There is no benefit to be had from messing around with the bypass valve, so don't worry about it.
Originally Posted by domino_z
Just like a turbo motor, the easiest way to get more noise is to run an open filter element - and currently only eventuri have a decent intake kit
Those silencer tubes bw airbox and Tb are more designed to act like harmonic adjustments to the airflow and thus sound, they won't do as much to add whine as an open airbox, but if the price is right via that mina gallery, id be keen to give it a go
On the older supercharged Jags (like my XJR) replacing the plastic intake that has the heimholz resonators on it, with a plain metal tube brought out a lot more supercharger whine, also opening up the air filter itself helps to enhance the noise.
Now that Mina is making these sort of intakes, i'd say go for it.
In the past some people fabricated their own, here's one on a 5.0L XKR that was made a few years ago...
Something like this (in metal) along with open filters like the Eventuri or similar, will go a long way to freeing up the whine.
But you won't get the same sort of whine like the old cars with the M112 blower, the TVS on the newer engines is just not as loud.
Is that diagram from the v6 or v8? Is there a significant difference?
I was just watching a video comparing the v6 & v8. In the 8, you hear more exhaust and in the 6 it seemed like you could hear more motor and SC. It may just be a function of the v8 having a deeper sound and over powering the mic, but I'm not sure that would account for it...
Is that diagram from the v6 or v8? Is there a significant difference?
I was just watching a video comparing the v6 & v8. In the 8, you hear more exhaust and in the 6 it seemed like you could hear more motor and SC. It may just be a function of the v8 having a deeper sound and over powering the mic, but I'm not sure that would account for it...
I think the v6 and the v8 have the same intake part#
There is a bypass valve on the supercharger, but it performs a different role to a wastegate or blow off valve in a turbo.
The bypass valve opens to cut boost when you close the throttle, or when you are cruising with no throttle. This reduces the load on the intake system (i.e. reduces the parasitic losses of driving the supercharger). It opens up a path between the inlet and the outlet of the supercharger internally, so that there is no boost.
On the F-Types these bypass valves are driven by a stepper motor, on the older models they worked mechanically off manifold vacuum.
There is no benefit to be had from messing around with the bypass valve, so don't worry about it.
On the older supercharged Jags (like my XJR) replacing the plastic intake that has the heimholz resonators on it, with a plain metal tube brought out a lot more supercharger whine, also opening up the air filter itself helps to enhance the noise.
Now that Mina is making these sort of intakes, i'd say go for it.
In the past some people fabricated their own, here's one on a 5.0L XKR that was made a few years ago...
Something like this (in metal) along with open filters like the Eventuri or similar, will go a long way to freeing up the whine.
But you won't get the same sort of whine like the old cars with the M112 blower, the TVS on the newer engines is just not as loud.
While noting that we aren't chasing the final few % due to the limitation on throttle valve opening, unless the output bleed pipe is after the Intercooler, feeding it back to before the supercharger will reduce boost due to the increase in temperature...
Here you can see the bypass valve butterfly, it's before the intercoolers, basically just opens a path from the outlet of the supercharger to the inlet.
Is the bypass valve fully closed at WOT in the de-tuned 340hp engine (and perhaps the V8 as well)? Sure would be an easy way to limit output.
I also don't understand how there could be no benefit to modulating bypass valve function if it is indeed controlling boost... presumably this is how VAP and other tuners have managed to increase boost without touching either SC pulley.
Here is what the JLR docs say about it... not too clear...
In any case I don't think this would help any for increased noise...
Is the bypass valve fully closed at WOT in the de-tuned 340hp engine (and perhaps the V8 as well)? Sure would be an easy way to limit output.
I also don't understand how there could be no benefit to modulating bypass valve function if it is indeed controlling boost... presumably this is how VAP and other tuners have managed to increase boost without touching either SC pulley.
Here is what the JLR docs say about it... not too clear...
In any case I don't think this would help any for increased noise...
I would imagine that JLR does not fully close the BPV at WOT, as this would be one of the ways to detune the engines. On the F-Type 400, that valve is probably close to fully closed at WOT.
I would imagine that JLR does not fully close the BPV at WOT, as this would be one of the ways to detune the engines. On the F-Type 400, that valve is probably close to fully closed at WOT.
Is there any reason (other than de-tuning) the BPV would need to be partially closed at throttle positions over a certain % (say 25% throttle for instance, why not just close the BPV all the way and make use of the boost)?
If the engine can take full boost at 6500rpm, then it should be able to take full boost at 2500rpm, etc. since boost is proportional to RPM... of course BPV would still need to take into account deceleration and throttle liftoff.
Couple of reasons I can think why it would remain partially open is unnecessary load on the lobe bearings and heat build up.
But please continue this discussion. I also think that under 100% throttle opening and load the valve should be in the fully closed position, but I don't think it is...
If you look up Mina gallery online there are pictures of the intake tubes ---- mine was the 1st one made for the F type --- and the production pieces are being made overseas --- makes a little more noise because it eliminates the restrictors and looks bad *** !!!
If you look up Mina gallery online there are pictures of the intake tubes ---- mine was the 1st one made for the F type --- and the production pieces are being made overseas --- makes a little more noise because it eliminates the restrictors and looks bad *** !!!
02-04-2017, 09:52 AM
