Jump to content
SAU Community

Recommended Posts

  • Replies 84
  • Created
  • Last Reply

Top Posters In This Topic

Fatz you do have a couple of options here , first is to replace the .50 ARR comp cover with the larger .70 ARR T04E cover and keep the backplate .

Second is to use the larger series T04S cover and backplate (adapter ring) which is what Garrett did with their GT3540R turbocharger .

If your finances are limited go the larger ARR .70 "E" cover . If the sky is your limit go the "S" bits . Also remember that the T04S covers are quite large so make sure there's enough real estate where your turbo lives .

Generally compressor covers are sized around airflow rates or speed . So for a given compressor wheel the larger the Area Radius Ratio the lower the gas speed will be and vice versa . Also the larger it is the less chance it will have of being a choke point at high wheel speeds . Someone did tell me that all else being equal going up in comp cover AR brings the boost on a little later and "hits" harder .

With most Garrett turbos there is a set compressor wheel diameter for each wheel/cover family , ie 60mm wheels T3 covers , 71mm wheels T04B covers , 76mm wheels T04E covers , 82mm wheels T04S covers .

In recent years Garrett started going up a size in cover with some of the GT BB series compressors . I think this is because the comp wheels are mechanically stronger , and and can still pump efficiently at much higher rpm's than the bush bearing has beens . This is a win win situation , the small high speed wheels are compact , cheap to produce and more importantly have less innertia so spool sooner .

Examples of this are the little GT28RS (T04B comp cover) and some of the GT2835R series turbos with 71mm compressors and T04E covers .

The Garrett people inthe US tell me that the up sized cover , and a little extra tip height on the wheel , gives extra pumping capacity and a few more points compressor efficiency .

I can only think of two examples of Garrett turbos that went smaller in cover size , they are the HKS GT2540 and the Ford GT3540R . The 2540 is getting on and was probably an attempt to get a bit more flow and power out of a small series turbo , and a low mount compact (convienent) fit for GTR's .

Its safe to say Ford was not looking for serious performance with the XR6T so a compact and probably cheaper adequate cover got the nod . You can bet they knew people would modify them for performance , so the limited cover capacity may have been intended to limit the performance with the std turbo but not affect the standard state of tune .

Cheers A .

yea just stuck a side pipe on the beast and took it out to the drift day

sadly budget has died in the arse so i will have to putt around for some time until a set of cam gears arrive and the powerfc which is probably about 3 months away

im quite happy with the power but as soon as those cam gears are in hopefull it will bring it on a bit better

if cam gears dont bring it down to 4000rpm with power fc and a decent tune then i will consider the upgrade to external wastegate and a .86 rear housing and combine it with the larger front cover

but hey im happy as a pig in shit at the moment and when i win lotto ill do the next big upgrade

ive also got a rb30 complete engine that will be getting a solid bottom end over the next few years to replace the gtr bottom end when or if it ever goes

yea baby

anyone have some cheap cam gears

pete

  • 5 weeks later...
  • 2 months later...

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 mean, I got two VASS engineers to refuse to cert my own coilovers stating those very laws. Appendix B makes it pretty clear what it considers 'Variable Suspension' to be. In my lived experience they can't certify something that isn't actually in the list as something that requires certification. In the VASS engineering checklist they have to complete (LS3/NCOP11) and sign on there is nothing there. All the references inside NCOP11 state that if it's variable by the driver that height needs to maintain 100mm while the car is in motion. It states the car is lowered lowering blocks and other types of things are acceptable. Dialling out a shock is about as 'user adjustable' as changing any other suspension component lol. I wanted to have it signed off to dissuade HWP and RWC testers to state the suspension is legal to avoid having this discussion with them. The real problem is that Police and RWC/Pink/Blue slip people will say it needs engineering, and the engineers will state it doesn't need engineering. It is hugely irritating when aforementioned people get all "i know the rules mate feck off" when they don't, and the actual engineers are pleasant as all hell and do know the rules. Cars failing RWC for things that aren't listed in the RWC requirements is another thing here entirely!
    • I don't. I mean, mine's not a GTR, but it is a 32 with a lot of GTR stuff on it. But regardless, I typically buy from local suppliers. Getting stuff from Japan is seldom worth the pain. Buying from RHDJapan usually ends up in the final total of your basket being about double what you thought it would be, after all the bullshit fees and such are added on.
    • The hydrocarbon component of E10 can be shittier, and is in fact, shittier, than that used in normal 91RON fuel. That's because the octane boost provided by the ethanol allows them to use stuff that doesn't make the grade without the help. The 1c/L saving typically available on E10 is going to be massively overridden by the increased consumption caused by the ethanol and the crappier HC (ie the HCs will be less dense, meaning that there will definitely be less energy per unit volume than for more dense HCs). That is one of the reasons why P98 will return better fuel consumption than 91 does, even with the ignition timing completely fixed. There is more energy per unit volume because the HCs used in 98 are higher density than in the lawnmower fuel.
    • No, I'd suggest that that is the checklist for pneumatic/hydraulic adjustable systems. I would say, based on my years of reading and complying with Australian Standards and similar regulations, that the narrow interpretation of Clause 3.2 b would be the preferred/expected/intended one, by the author, and those using the standard. Wishful thinking need not apply.
    • Yes they do. For some maybe. But for those used the most by abusers, ie Skylines, the numbers are known. The stock eyebrow height for R32/3 Skylines is about 365/375mm or thereabouts. The minimum such heights are recorded in adjacent columns in the database.
×
×
  • Create New...