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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 .

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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?

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