Jump to content
SAU Community

Recommended Posts

His quote was , "The GT3040 has poor turbine efficiency because the compressor wheel is too big . I (he) would not use it on anything"

At times he's backed up his views with experience gained on their gasflow test stands so I take him at his word . I don't know about new TO4S wheels either , I do know the better E wheels and ALL BCI-18 wheels use six full and splitter blades . Ages ago I put some time into comparing TO4S and BCI-18 wheels (covers off) and there are major differences . If you look at the exducer blades and the rest of the blade you will notice a much better angle of attack on the BCI-18's . The root of the blade is a better shape too . The blades are thinner than TO4S ones , they were designed to be a higher speed wheel with less mass and somehow greater mechanical strength (able to withstand higher rpm without flying to bits) . The original TO4S wheels were not designed for high rpms or pressure ratios . They were intended to be used with large heavy TO4 and TA45 turbines that could flow lots of exhaust gas without lots of revs . I believe the GT turbines teamed with GT wheels of similar OD's can move lots of gass with higher rpm's , less innertial lag and compact overall dimensions .

Oops gotta run (work) To Be Continued tomorrow . Cheers A .

  • Replies 60
  • Created
  • Last Reply

Top Posters In This Topic

Ok back again . Before I start remember these are my interpretations based on my research .

With modern designs there will be a trim size (area of the inducer divided by the area of the exducer or major diameter of the compressor wheel) that gives the greatest pumping efficiency for that series of wheel . Going up or down in trim size goes away from ideal but may suit air flow capacity for particular applications . For example the old T3 wheels ranged in trim from 35 to 65 with the most efficient being around 50/55 trims . Plain bearing 3" or 76mm TO4S wheels from memory range from I think 48 to 60 trim or possibly 63 trim as Chris said . Their design application was Diesel engines which at the time required large volumes of air but not at high (by todays standards) pressure ratios or boost pressure .

There are dozens of different varietys of TO4E wheels but again the highest efficiencies are at about 50 trim . Most of the variations seem to revolve around small trim differences and differing tip heights . Some of the early ones have cropped inducer blades I think to cope with centrifugal forces at high rpms . Both six and seven bladed TO4E's are made including the 57 trim Garrett motorsport special for the Group A Sierra .

All the BCI-18C GT wheels are six bladed and up till recently were the ones specifically designed to work with the GTBB turbines and bearing cartrige . The 3" or 76mm versions (GT37 series) I've only heard of in 48/52/56 trims with 56 giving best efficiencies . The 82mm (GT40 series) I've seen in 50/52/56 trim . HKS's GT3040 has the 50 trim and I'd say this was done because they found the GT30 turbine a tad small so the smaller trim lesser but adequate flowing compressor needed less power to drive therefore less slip losses at the turbine and better spool qualities . I have no idea why Garrett do their version with the 56 trim compressor , maybe it suits some other application . What I would not do is put a .63 GT housing on the back of it to force it into boost on a 2.5 to 3L engine , even the best wheels will surge . Neither small or large housings can help it much because its not causing the problem . I have seen the results of some tests in the US (not by Garrett) comparing the GT3540R and 3040R . These were on 2L 4's with the 3540 giving more power , better transient response and lower turbine inlet pressure . Also not surprisingly it extended the rev range up as well .

Where I fit into this is whether the 3540R will give me the response I want . If it won't the GT30R is probably too small though with a large exhaust housing at least it wont choke to death . Garrett do for HKS a GT3240 which has a GT32 turbine (whatever that is) that size wise fits in between the GT30 and 35 turbines . I've not been able to find out if Garrett use this turbine with GT40 compressors without the HKS price tag or if a housing is available with the T3 flange .

Lastly to rpt the question , is anyone using the GT3540R (with the six blade BCI-18 compressor with a .82AR exhaust housing) on a RB30DET ? Result ?

Cheers A .

its rated at 650hp "apparently"

probably also rated at 600hp..

if the GT35R with 1.06 is rated at 700hp, i think the .82 is rated at 650hp

And looking in the garrett pdf i see the CHRA for the GT35R is 706451-5, so happy days :)

RNS11Z had me worried there :P

MyGT35R.jpg

i am considering purchasing a 1.06 housing once i have it tuned and see if i can bring out more power. Some say the .82 might be too small/harsh for the RB30det... time will tell.

i noticed you have the v-band flange, did u request that or thats how it came? mine has a traditional 4 bolt flange.

This is were the turbo came from. Ray change the internals and said its rated at 700hp.

As he change the original 600hp GT3040 from his lexus and put the new 700hp version on. - You can deffiently notice the difference with the bigger turbo on wheel spin is achiavble easily.

Skyrine-Dave that compresssor is identical. Whats the characteristics of your turbo ?

What rpm does it start to spool up etc.

Any photo's of the exhaust housing ?

http://www.turbofast.com.au/GTseries.html

Its deffiently a .82 rear as it was written on the inside of the exhaust housing were it connects onto the manifold. And its not that big in size.

:P

Jun

http://www.skylinesaustralia.com/photopost.../cat/500/page/2

&

http://www.skylinesaustralia.com/photopost.../cat/500/page/2

You can't really see the exhaust housing but you can sort of tell the size of it.

Looking at ray halls CHRA part number list. Its gt35 compressor a with .82 GT30 exhaust housing how can that be rated at 700hp :uhh: but the 5005 number on the end represents the GT42/45 -704484-5005 which is rated at 800hp :confused:

cameron i dunno if you are refering to me.

But my CHRA is GT35R and my exh housing is .82, i requested it and its also printed on the housing.

and the serial number i read directly off the CHRA serial tag.

i bought my turbo from MTQ Engine services and they listed it as GT35R race 700hp (700hp being with 1.06 hsg)

at the moment it spools at 0 rpm and produces 0 psi of boost as my engine isnt fully assembled yet :jump:

on other specs pages ive read for some reason the gt3545 with the housings, .63, .82 and 1.06 all are rated at 700hp?? they are all the same internally just the rear housings are different

so would they actually all be able to produce the same power? and the smaller housed ones just have better spool?

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

    • Ah. OK. I take it back. I hadn't looked closely at the R33/4 arms and presumed that GKTech did as GKTech do everywhere else, which is to use sphericals there. The poly bushings are made to be 100% interchangeable, should use the standard bolt just fine. Every other bush in every other place in pretty much every other car, does.
    • @silviaz Ok cool, so much easier with a video. I can see why this video would be confusing for new players.   It is obvious that this entire bonnet is going to be resprayed, have a look in the background around 2:05, you can see a bunch of bare metal on the left side of the bonnet.  It's not an issue for the primer being laid down on the non-prepped clear on the bonnet. It will be sanded off at a later stage.  This might not be obvious to new players, but working on bare metal and factory paint in this instance, the factory paint is like a mountain and the bare metal is a huge valley. The bonnet needs to be levelled flat before it receives it's final stage of colour and clear coat. During this levelling process, the primer that is landing on the clear that you are worried about will be removed.  Also, this guy is out of control. Zero PPE while spraying, maybe he is a good example overall about what not to do lol.
    • Ok I FINALLY found a video lol. This took way longer than it should have as I could have sworn I saw multiple videos like this. I kept finding the completely opposite (the correct way of doing this). I wouldn't be surprised if I f**ked this up somehow.  I just realised where I've been getting confused and even with other things I work on. I haven't been doing things the regular way instead I'm going a roundabout way of doing things, like putting epoxy primer first then filler for example instead of putting just filler then primer on top of that, then wondering what happens if I get that primer on the clear coat that I haven't sanded yet. This was a bit of an epiphany 😂  But anyways, here this video. Time stamp, 2:56, some of the primer lands on the paint unscuffed above. You can see from the reflection it looks shiny.  
    • It does, this part circled in red. I assume the OEM bolt might not work well with the poly bushing because the dimensions may be different?
    • The J arm doesn't have bushes either. Assuming that by "J arm" you mean the part of the upright that runs down from the upper arm's outer bushes to the top of the hub. That has a kingpin style bearing in it. If you meant the lower control arm, it has 1 bush, at its inner end. If you have PU in there, that is superior to Nismo rubber. If you meant the caster/tension rod - it has 1x bush at the front end, and again PU is superior to Nismo rubber. But as I said above, I would definitely get the GKTech arms for that, as sphericals slay all other options there.
×
×
  • Create New...