New Garrett Gt3540 Internal Gate Is Here + Dyno Results

[dangerman4]

how does this look?

fits in the right spot and plenty of room for the ox sensor

[Cubes]

Looks very nice..

From a flow perspective; would it be better to place the location of the join on the inside of the bend instead of the outside?

Or if possible on a straight section.

I am visualising the air flowing through the pipe and as it follows the bend it tries to push up hard against the outer edge of the bend, it then approaches the join as the air is pressed up against the outer edge of the bend and causes turbulence as it tries to flow in to it a touch. If that join were on the inside of the bend I would think there would be less turbulence as the air can follow the outer edge of the pipe without interuption.

Is that the correct way to think about flow dynamics? I've done ZERO studies on flow dynamics so really have no idea; simply an attempt to visualise how the air flows through the pipe.

Reason I ask is I have seen many dump pipes done like this and always been curious.......

[dangerman4]

the other trouble is this is made out of a 3 inch mandrel bend and a 2 inch mandrel bend.

its a hell of a lot bigger then a normal low mount dump pipe.

so room becomes an issue.

the size of the pipes should more then compensate for the slight turbulance..

i hope

[dangerman4]

fits nice and neat.

[Cubes]

the other trouble is this is made out of a 3 inch mandrel bend and a 2 inch mandrel bend.

its a hell of a lot bigger then a normal low mount dump pipe.

so room becomes an issue.

the size of the pipes should more then compensate for the slight turbulance..

i hope

Don't get me wrong I wasn't trying to pick the design; in fact every other dump I've seen has the join on the outer edge. I'm hoping some one with a little flow dynamics knowledge will stuble upon my post shed some light as its always bugged me a little.

I have Never seen a dump designed the way I stated in my previous post.

But omg.. your dump pipe does look nice; the fit is very tight.

The .82 definitely looks smaller than the 1.06 iw i've seen.

[dangerman4]

it looks a lot worse then it actually is.

there is about 2 inches between the turbo and the guard and also about 2 inches surrounding the dump

pipe. once i cover it all in heat wrap and mount a stainless heat shield above and behind the dump it should'nt be an issue.

[Bliksem]

love reading about this sortof thing.

I was considering one of the turbo's when racespec announced them a while ago

Another question regarding your dump pipe, would the wastegate pipe cause any turbulance issues where it is plumbing back in? I'm just asking this because I was reading about BATMBL's pipes when they were first released and he tried to keep the wastegate pipe as long as possible to avoid turbulance.

keep up the great work!

[Cubes]

Its also best to run a 12.5degree angle matched the size of the back of the turbine/wastegate to the desired final pipe size.

Where does it end... arggg.

[Dale FZ1]

At the moment I'm a little ignorant of the cartridge/s that this turbine housing is designed to mate with. Hence the question about the CHRA - I want to see what impellers this particular baby has...

Good work on getting the turbocharger part numbers. Pleasing to see that Garrett have brought out two A/R sizes; more options. Notice that the pics look remarkably similar to a HKS design with the divider cast between wastegate outlet and turbine discharge?

Was there any solid/reliable info from GCG as to what sort of power rating or service application (ie road, circuit, drag) these things should have with a Skyline?

the CHRA number would be the same for any cartridge with the same comp/turbine so its the complete assembly or unit number you want . Something worth noting is the part number stamped on the side of the exhaust housings mounting flange in the second shot . This would almost certainly be the turbine housings part number .

What I want to know is can these housings be grafted onto the GT37R cartridges because they have the potential to be better than the GT3540R cartridge for the larger/est RB - just need a suitable exhaust housing .

[rb26s13]

if it was me doin the pipework for that internal gate turbo i'd almost be tempted to run the wastegate pipe seperately.. i really like the internal gate exhaust housing design makes it easy for pipework i guess you could say.. on the design of your dump pipe.. if you can i'd be running the wastegate pipe a bit further down.. not a fan of running short wastegate pipes.. or plumbing them back in

[shonen]

hmm just out of curiosity how much power are you expecting from this setup ??

[discopotato03]

At the moment I'm a little ignorant of the cartridge/s that this turbine housing is designed to mate with. Hence the question about the CHRA - I want to see what impellers this particular baby has...

Good work on getting the turbocharger part numbers. Pleasing to see that Garrett have brought out two A/R sizes; more options. Notice that the pics look remarkably similar to a HKS design with the divider cast between wastegate outlet and turbine discharge?

Was there any solid/reliable info from GCG as to what sort of power rating or service application (ie road, circuit, drag) these things should have with a Skyline?

Dale as a generalization the GT3540R should make similar power to one with a free floating housing (meaning non gated) unless the gate cannot pass enough exhaust gas to properly regulate turbine/compressor speed and boost rise .

We now have all three AR sizes .63 .82 1.06 with IW so have some flexibility . The important thing to remember is that its not possible to run the smaller AR housings and expect the waste gate to make up the flow difference of a larger AR housing . Boost pressure is regulated by the waste gate actuator which uses a pressure signal from the compressor side not the turbine side . Exhaust manifold pressure/turbine inlet pressure/back pressure is dictated by firstly the turbine/housing and everything south of the turbine inlet . different sized exhaust housings are made to taylor turbine/compressor speed from the available exhaust gas velocity . It really is a juggle of turbine/housing size vs compressor size/capacity to pump air . If you use small AR exhaust housings on turbos with large high flowing compressors (GT3540R's one is capable of 70+ lbs airflow so 700+ Hp's worth of air) the higher exhaust gas velocity though the smaller volute passage brings the compressor up to positive air pressure type revs and if the engine is not running fast enough to swallow it you end up with either compressor surge or medocre low boost performance .

Its my opinion only but a .63 housing on this turbo is too small given its air pumping capacity , if the .82 is too laggy its trying to tell you its too much turbo - or compressor anyway . If smaller trim compressors were available in this turbo it may just work . Another maybe is to use port shrouded compressor covers to avoid the surge issue .

RB30DET's seem to handle the 1.06 ok and even the .82 for a roadie that does not use huge boost pressures . I hear people say that it works ok on RB26's as well though they are probably expected to lift their skirts at 4000+ rpm . I guess a serious track Rb25 with gearing etc to suit could use a .82 version . Gary and others have said that even GT3076R's can be a bit much on a daily driven RB25DET so the GT3540R being larger could be expected to have a higher boost threshold . This is normal when comparing a 500 to a 700Hp capable turbocharger . Power numbers are impossible to quote because the same turbo will give vastly different results on a real race engine compared to the production version it was based on . You can base turbo power potential off the maximum airflow it can efficiently pump (this is usually expressed as pounds per minute) though exhaust flow and turbine efficiency is just as important .

Out of here now , need some sleep (I know how Roy feels) .

Cheers A .

[dangerman4]

its all done..

i havent driven it yet, as i still have to put on all the heat wrap, and a heat shield.

but it all fits and sounds really smooth.

i will try and organise a tune for early next week.

[rb26s13]

very nice keen to see results

[lukits01]

What is the spec/mods of the engine?

[Dale FZ1]

Thanks Disco. All very accurate and correct observations/opinions. Definitely clears up some perceptions about the value (or otherwise) of various A/R combinations.

I had been considering whether this housing would at last allow a suitably flowing/efficient driving bolt-on 71/60mm cartridge out of the GT3071 family, and also for those wanting something around 5-600hp but still internally gated (82/68mm?).

It's almost like the different A/R is available so that we can use different cartridges according to the power:response balance being sought. Just a matter of determining the optimum compressor spec, then getting the turbine impeller + housing sized to suit (as per normal matching processes).

I'd just like to gauge what it has been designed to mate up with, and if the range of options available to us has been opened wide up. It is a really good development and hopefully will satisfy a demand that has existed for a while now.

Dangerman would you do us a favour and post up the CHRA number? Since you're one of the first (the first??) with this unit I'd just like to see what spec impellers it uses.

cheers

Dale

Edited September 15, 2006 by Dale FZ1

[dangerman4]

i didnt write them down before i put the turbo on but from what i can see its chra no. is

706451-5015

i dont know if thats of any help as i cant find much info on them as yet

[garage-tuner]

i didnt write them down before i put the turbo on but from what i can see its chra no. is

706451-5015

i dont know if thats of any help as i cant find much info on them as yet

CHRA No. 706451-5015 = 61.36mm, 56 trim compressor wheel and 62.32mm, 84 trim exhaust wheel.

Cheers.

[dangerman4]

where did you get that info from?

cheers

[discopotato03]

You can find it and its maps at turbobygarrett.com . Click products/turbos and scroll down .

I don't think it shows these housings yet - .63 , .82AR ratio IW GT35 turbine side .

Cheers A .