Jump to content
SAU Community

Recommended Posts

And didn't you lift a head or blow your motor?

Squeezing all that pressure into a tiny T3 flange, then releasing all that pressure after the restriction is counter intuitive. That's why as soon as people go to high mounts they pick up power but it's not so much the high mount it's more so the exhaust gasses be bleed off before the collector.

Boost control is subjective, and your 6tits probably doesn't have twin gates off it or the merge between both scrolls to the gate was poor.

If you ever have an exhaust pressure sensor or gauge on the collector you'll understand.

1 minute ago, Griffin said:

Is there any difference having wastegate on manifold at / before collector over the turbine housing?

Yep, you'll reduce exhaust back pressure, make more power, less things glowing on the hot side.

I did that only mod and with the same timing map, same boost, same turbo (except it was a BB centre this time round, same comp/turbine wheel) and made extra 20kW off the bat. 

4 hours ago, Dose Pipe Sutututu said:

And didn't you lift a head or blow your motor?

Squeezing all that pressure into a tiny T3 flange, then releasing all that pressure after the restriction is counter intuitive. That's why as soon as people go to high mounts they pick up power but it's not so much the high mount it's more so the exhaust gasses be bleed off before the collector.

Boost control is subjective, and your 6tits probably doesn't have twin gates off it or the merge between both scrolls to the gate was poor.

If you ever have an exhaust pressure sensor or gauge on the collector you'll understand.

Wouldn't the actual restriction be the actual turbine housing itself?
By my understanding of pressure, the pressure inside the manifold would not be altered depending on where the gate was, as long as it's between the head and the turbine wheel.

I had 1 gate in both setups, and a 45mm gate off the housing vs a 50mm gate off the 6boost. You can tell just by looking at it which gate is in the better spot for flow.

I agree with you, going external gate does free up power, once you start to really get the most out of any specific turbo. IWG's of any kinds (Even on EFR's!) seem to just not cut it once you really, really want to get the most out of a rear housing.


In this example though, the engine is likely to let go before the turbo or gate really even gets involved as a point of discussion

Here's a thought experiment.

Let's say that the exhaust gas needs to be split 50/50 between the gate and the turbine.  If the ext gate is on the turbine housing, then you are shoving double the amount of gas into the housing than if the gate was on the manifold somewhere.  Either way, we want the same 50% to make it all the way to the nozzle, but in the region between the flange and the housing mounted gate, the gas velocity must be double.  Pressure losses go up with the square of velocity.  So whatever frictional losses occur, they are doubled.  The exhaust gas is losing energy before it has even made it to the turbine.  It must therefore not be as good as if it was vented before the housing.

The difference might not be large, but it will be there.

The one big advantage of putting the gate on the housing is that it is easier to put it in a spot where the gas is definitely flowing towards the gate (because all the gas is flowing that way anyway) which makes it a little harder to f**k it up the way that people do when they put ext gate offtakes onto manifolds at bizarre angles.

  • Like 1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • I was 99% sure the standard one is long enough to get there, you might just have to change the throttle orientation. If not, I remember someone having used an r31 cable instead, but that is probably harder to find than r33 by now...
    • HELP   Hey all, Is there an accelerator cable from another Nissan that can be used on the R33 GTST RB25DET with a Greddy forward facing plenum?  Thanks in advance  Rob 
    • Or do we think it was installed to give 1 bar of boost max, all day, everyday?
    • So could it be assumed it has been installed intentionally with potentially a power FC boost controller kit? 
    • Had my rig on Matt's dyno at PITS the other day. After a few years between tunes I added a few sensors and swapped intercoolers. Result. 553hp at 26psi. Not bad for an FJ20 that was built in 2007. The problem.. It filled the overflow bottle on hard runs which leads me to believe the head gasket isn't sealing. I have a coolant pressure sensor which was reading cap pressure at 22psi and occasionally overrunning to 23/24 psi on deceleration after a pull. It was not spiking. It has arp2000 head studs and a cometic gasket. As its been 18 years in service, I pulled the engine out and head off. Everything looks good but we obviously have an issue. Where I'm at.. Years ago I had the same issue, I checked the stud tension and they were all over the place. Some at 60 to 70 and some up near 90. I nipped them all to 100ft lbs and this stopped the water push until now. I believe this compromised the gasket back then. What do I do? 2 options are..  1) I bought arp 625+s, which I could put in with a new gasket. Thinking Kameari this time, reassemble and try again. 2) strip the block, get fire rings machined in with copper gasket and try that. I do not want to push it more than 28 to 30psi. I think the turbo will be out by then anyway. (G30-770). My other concern is the long term ability of a copper head gasket. Are they streetable for years? I feel like a new gasket with the new studs will probably suffice, but I don't know. Any thoughts welcome and advice on copper gaskets and fire rings. Thanks!
×
×
  • Create New...