Hypergear Turbochargers and High flow Services Development thread

[zebra]

Twin Scroll = Larger turbine housing a/r needed, as the effective volume inside is reduced by the divider.

so instead of a .82 GT30 housings you would use a 1.06 in twin-scroll form

[hypergear]

I'm pretty sure the .82 equivalent in a twin scroll is a .84 rear housing. So by cutting in the divider I probable ending up with a .80 rear.

[zebra]

whats the internal volume of the twin scroll .84 hosuing comapred to the single entry .82?

in cc's or cm^2

[ARTZ]

have you seen Garretts Quad scroll Hypercharger...

Stumbled across it the other day, i think its for motorbikes though

[sriver killer]

You can find FNT feed back from Random in page 87. Check index on page 1.

Any way. lots of talk about twin scroll turbine housings. At this stage I'm not convinced that they has a "major" affect but welling to do some tests.

So, we all know the air gap inside the turbine housing is the height of the inducer blade of the turbine wheel.

By placing a metal strip in between and half the gap is actually reducing the area of the gap enabling higher air velocity. To me this is another way of sacrificing top end power for down low response unless the size of the turbine wheel and housing is in a reasonably large size.

Theoretically I can archive this behavior by reducing the gap height at only 60~70% of the turbine wheel top without the divider in the center.

I've done a drawing converting single scrolled turbine housing into a twin scroll item, internal or dual gate bolt on to stock setup of course. Good thing is I can setup dual effective FNT nozzles inside that housing for even better response. I'll be doing a back to back tests using a G3 core. hopefully it's worth the effort.

Any way, Do post up if you have any experiences or back to back tests with single to twin scroll turbine housings.

I had a look at that chart on page 103 ( I think)of all your turbo's on the power/drivability chart.

The atr43SS seems to really walk all over the g3. Is the difference between these two turbo's only the billet comp wheel.

stao can you get a single scroll housing for your atr45 and adapt fnt nozzles to suit?

When are you testing the dual nozzles in the G3?

[hypergear]

The SS series is a turbo that is very specifically made for RB25det. Won't work on your Rb30det. Also the G3 result used on the chart is not based on the current version. I should have some current G3 results this weekend.

[sriver killer]

The SS series is a turbo that is very specifically made for RB25det. Won't work on your Rb30det. Also the G3 result used on the chart is not based on the current version. I should have some current G3 results this weekend.

I am very interested to see these results stao.

What is on the cards this weekend?

[chocco]

where is all the info for all the turbos available??

[89CAL]

where is all the info for all the turbos available??

Here

[lilcrash]

Is this car still racing today?

Pretty sure the new owner is or will be racing it still.

[siksII]

Who is using the stock R33 blow off valve? Has anyone had a problem with them after their turbo upgrade?

Im looking to install my SS1PU next week and im not sure if I need to buy an aftermarket one. Would prefer not to in any case to keep it stock as possible.

[dori34]

Who is using the stock R33 blow off valve? Has anyone had a problem with them after their turbo upgrade?

Im looking to install my SS1PU next week and im not sure if I need to buy an aftermarket one. Would prefer not to in any case to keep it stock as possible.

you can mod the stock BOV to hold more boost anyway if you have issues

[Rolls]

Who is using the stock R33 blow off valve? Has anyone had a problem with them after their turbo upgrade?

Im looking to install my SS1PU next week and im not sure if I need to buy an aftermarket one. Would prefer not to in any case to keep it stock as possible.

If it is working fine now there is no reason why it should stop working with the new turbo. The way the BOV diaphram works means more boost doesn't make it more likely to leak, as more boost means you have more boost on both sides of it, eg there's more boost in the intake, but there is also more boost in the vac tube holding it closed.

You can mod them to change their behaviour on light throttle/going from full throttle to half throttle so they don't open as easily, but there isn't really any need imo.

[Hanaldo]

Can also upgrade to a GTR item if need be, cheap and the best option available.

[GTScotT]

Am not sure how a 20 year old diaphragm would cope with a 30+psi setup lol

They are out there now, big boost is becoming more and more acceptable and most manufacturers are producing big boost wanting replacements to their older models (BW and the big G inclusive).

I would compare the situation to using an expired rubber straight out of lock up. Asking for trouble.

[SargeRX8]

Ive got the stock BOV and under 20psi it doesn't open up. Remember, as said above, there is also a line to the top of the BOV applying Xpsi to the top of the valve to keep it shut.

[Rolls]

Am not sure how a 20 year old diaphragm would cope with a 30+psi setup lol

Go look at a diagraph of a BOV, the 30psi is on both sides of the diaphram hence it doesn't open, you could put 100psi through it and assuming the piping itself could take it there is no reason why it would open either.

The force holding it closed is identical to the force on the inside pipe. As both sides of the diaphram are the same size, and there is identical pressure on both sides the force is the same hence it doesn't open, doesn't matter how much boost you run, it will never open.

The only reason it ever opens is as when you close the throttle there is a huge pressure spike near the bov, this spike is greater than the pressure at the intake manifold end, hence one pressure is greater than the other, hence the force allows the diaphram to open, there has to be quite a large pressure differential to open it though due to the spring.

Depending on the design of the BOV you can get a pressure differential on vac conditions, this allows the bov to open on low throttle bypassing the turbo completely which imo is a good thing.

There is a fantastic diagram here on wiki

http://en.wikipedia....i/Blowoff_valve

Have a look at the on throttle vs off throttle picture, it becomes blatantly obvious why it won't leak even with say 30psi.

Edited October 6, 2011 by Rolls

[siksII]

Ive got the stock BOV and under 20psi it doesn't open up. Remember, as said above, there is also a line to the top of the BOV applying Xpsi to the top of the valve to keep it shut.

Thanks Sarge, this was the answer I was looking for - someone who has tried it already Stao was not completely confident there would be no issues when I asked him on the phone and I have seen first hand problems with the stock item on SR20s (looks similar, not sure if its the same as rb25). I will get my tuner's opinion as well.

[Rolls]

Mine has been running ~15-20psi for about a year as well without issue. I think you'll find 95% of them are fine.

[GTScotT]

Go look at a diagraph of a BOV, the 30psi is on both sides of the diaphram hence it doesn't open, you could put 100psi through it and assuming the piping itself could take it there is no reason why it would open either.

There is a rubber seal inside that will come in contact with fuel and other crap floating around in the motors system.

Think: rubber, fuel, oil, heat, pressure, AGE.

It is guaranteed that the thing has a used by date, and Im pretty sure 20 years of regular duty will have an impact. Especially when a lot of imports sit around on shipping docks forever before their final fate is determined.