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

    • Thanks for posting, your engine bay looks tops. I'm fairly sure you posted the wrong video though, I think you were supposed to upload the one from your "private test road" where it's banging off the limiter with the gate open?
    • This is something to be careful of. I did a bit of digging on the NM35, as I spend a lot of time on near brand new cars and CANBus related stuff, which uses the same "OBD2" plug for a fair chunk of making my life easy. The NM35, does NOT support OBD2. The data pin is actually on Pin3, which is a manufacturer specific pin, and requires Consult3 to connect to the NM35. Your low voltage, is either because the NM35 doesn't have 12V to the constant power pin on the J1962 (OBD2) connector, OR, it is attempting the standard comms, (CanBus, K Line, etc) and can't see any voltage on those pins. Some people have had success accessing SOME data from the vehicle on OBD2 specification, using a module that supports KPW. My assumption, like Duncan has stated, it will likely actually be JOBD, where there is some cross over with the OBD2 and JOBD standards. Note, lots of "OBD2" dongles, do NOT support KPW, which is what you need for a lot of Japanese vehicles of this era (And even up until recent years!), EG, Subaru, Suzuki, etc.    The end of this thread is probably worth a read, as some people did find a way to get a display up in the NM35 recently, looks like someone implemented all the stuff needed to make it work. (The right protocols).  
    • Depending on the purpose of the car, and how much more fabbing you want to do, and what clearances you have, you could look to raise the motor, which will raise the front diff up. Likely would mean altering the chassis rails etc etc, hence the more fab work you'd need to do. However, this can create issues, not just in clearance with everything fitting under the bonnet, but you've also raised a LOT of weight up in the car, and this will DEFINITELY alter handling characteristics (But, so will how much weight you've already added to the front end). You'll also have to deal with the fact the gearbox to rear diff is now out of alignment too for the tail shaft, and alter the angle of the diff, or deal with a bit of potential vibration. Raising the motor an inch up, is effectively the same as making the whole car sit higher by not lowering it as far. So one inch higher motor, theoretically means you can drop the car an extra inch lower, and maintain the same angles in the CVs. Again, depends on the purpose of the car. If it's a just cruiser on the street car, maybe won't be an issue. If it's meant to be a time attack car, I can see you not wanting to raise the motor. This is just for you to ponder as an idea.
    • Have you not seen geospy.ai? It can now give GPS co ords to within a metre from a photo, even if it's a random photo you take inside. Supposedly at the moment only the government/law enforcement has access to that... Supposedly...
    • I've got the rear ones, they're certainly beefy. I need to take them to my driveshaft guru to check over, he's very fussy about the quality of components so I'll let you know if they are made of cheese by a blind man.   Are you in Australia? A mate just had a set of EN26 shafts made for his K20 Lotus by our fabricator which were quite cheap (compared to Driveshaft Shop) so if you can procure the CV's and draw what you need he'd make them for ~$800 for the pair.
×
×
  • Create New...