Engine Tuners Opinion Of Sr20 Graph And Potential .

[discopotato03]

For the dyno tuners I have a graph I'd like your opinion on . Its an old one of a warmed ove Nissan SR20 , headwork/cams/good header/ext gate and HKS GT3037 52T with 0.73 A/R turbine housing .

I'm interested to know if such a turbo in a larger 0.82 A/R turbine housing would be responsive and not too shabby on an R33 RB25DET .

The above SR was claimed to get that turbo going at ~ 2600 revs and pump 10 lbs of boost at 3600 rpm .

I know its impossible to make a direct comparison of an SR20 and an RB25 but my guesstimate is that the larger 82 turbine housing and the bigger capacity RB25 might just put everything where you want it turbo operating range over the engines rev range .

If it were possible to drag an 82 3076R's wake up revs say 300 hundred + revs down from where they normally start it puts it into the Hi Flow territory but with greater potential than them .

I can't and I don't think many could use all that a 3076R is capable of so having a compressor that is closer to a 300 WKw ceiling should make a better overall match than one that may do 320 .

Crystal balls ?

Cheers Adrian .

Edited August 1, 2009 by discopotato03

[Dale FZ1]

I can't and I don't think many could use all that a 3076R is capable of so having a compressor that is closer to a 300 WKw ceiling should make a better overall match than one that may do 320 .

I like the general thinking behind this one.

Is there a flow map available for that configuration?

Interesting to see that HKS did not incorporate ported shroud into the comp housing.

Do you know if that cartridge is actually available for purchase?

[discopotato03]

I don't think GCG have it and they are going to chase up the local Garrett franchise to see if they do - which is probably unlikely . It is listed and would be way beyond HKS's "ours only" 6-7 yr honeymoon period .

It may be the same situation we had when the real GT3076R and GT3071R were not locally available , in short supply because there was not much if any interest so low/no stock on hand .

From what I'm told the issue with assembling a turbo with this cartridge is the port shrouded compressor housing . HKS GT3037 52T turbos used both the ported housing and the non ported one depending on the application .

The ported one is more expensive to make and means you have to use a larger diameter inlet hose to go over the 100mm/4" snout .

Two litre fours like SR20's don't seem to be very compressor surge prone unless quite small ratio turbine housings are used . It goes the other way with small capacity engines (small capacity cylinders) like say an RB20 with ~330cc pots and largish turbos for that engine size . I think it's a case of limited torque output from small capacity engines and the need to have the turbo pumping air in as early as possible to get the whole shooting match on the boil .

Have you ever noticed that model specific turbos for smaller RB's have ported housings where the SR version doesn't ?

GTRS's are like this and they do it because they want the pumping capacity of a certain sized compressor and at the same time a turbine housing size that doesn't make the turbo laggy initially .

Usually in this situation the compressor tries to pump more air at than the engine is capable of swallowing at lowish revs and so you get the pressure fluctuations and chuffing antics .

Hope you got a pot of coffee brewing because this gets a bit involved but once you get your head around it the principle is

easy to grasp .

When you look at these compressor wheels they have two sets of blades ie the full height ones and the "splitter blades" which aren't quite as tall . In a port shrouded compressor housing the lower or splitter blades - their inducer outer tips - are at the same height as the inner edge of radial slot machined into the housings snout . The full height blades obviously extend up past the radial slot but back to that in a mo .

For a moment look at both sets of blades as a separate entity . Go back to the above situation of too much air being pumped into an engine at low load/revs .

You get an air pressure differential between the outer faces of the lower splitter blades and the higher full height blades . The pressure becomes slightly higher in front of the lower blades faces and because the full height ones are effectively sweeping over the surge slot there is somewhere else for some of the air that the full height blades are attempting to pump - out through the surge slot and back through the housings jelly bean shaped ports .

Look at it as having optional use of half the blades and nullifying them when their capacity cant be used .

Of course when the engine revs get higher and the surge threshold drops away the pressure differential goes with it and the full height blades are free to pump as much as the wheel speed allows .

There is another bonus in all this , while half the blades are sort of unloaded the drive requirement of the wheel is less so a bit more of the turbines shaft power is available to accelerate the compressor wheel .

So what this port shrouding does is make the compressor less wheel speed sensitive and the turbo better able to cope with a wider range of airflow requirements . A good example is being able to run a turbo like say a GT3076R with its smallest turbine housing size and not have its potentially 540 Hp worth of air capacity surge . A better example is when people run this turbo in HKS guise with their smallest 0.61 A/R turbine housing . They come on early and the ported comp cover keeps the compressor out of the surge range . Another is the smallest optional 0.61 turbine housing on HKS's version of the T04Z , ported comp cover allows you to get away with running a small turbine end on a small motor because I'm sure theres someone somewhere that'd try to run one on a CA18 ...

Anyway back to GT3037 52T's and RB25's , It's a hard one to guess if this combination would surge with the Garrett GT30 0.82 turbine housing . Gut feeling is that the slightly smaller trim compressor is pumping a little less air than the 56T wheel and the middle sized 0.82 A/R turbine housing would not be trying to get the turbine happening as quickly as the 0.63 housing .

People at GCG tell me its not easy to modify the 3076R's comp housing because the 56T wheel is larger at the inducer and the tip height a little wider than the 52T one .

It should be possible to dredge up a T04E non ported housing that was intended for a smaller than 52T "E" wheel , with a lower tip height and profile it to suit the GT37 52T wheel .

In a perfect world Garrett would sell us the 700177-5006 cartridge and the same comp housing as HKS got on their ported 3037S 52T , it is a Garrett housing after all . BTW that "S" is the ported housing 3037 version .

56T versions are 480 and 470 PS .

Just as a little additional info HKS rate the 3037 52T at 440 PS and the 3037S 52T at 450 PS , at the same time they aim you towards having the 0.61/0.73/0.87 A/R turbine housing options on the plain version and the 1.01 or 1.12 A/R housings on the S or ported comp cover version .

So AFAIK the ported 52T turbos Pn is 700382-5010 and the plain snout one 700382-0009 , cartridge Pn as mentioned is 700177-6 .

Happy snaps anyone , cheers Adrian .

[discopotato03]

Click .

Cheers A .

[juggernaut1]

Flow maps would be helpfull. What would be the flow difference between a 3071 56trim versus a 3076 52 trim? Would the 3071 with a .82 rear be like an upsized disco potato?

I've seen stroker SR's 2.2litre make around 315 rwks with a 3071 and .63 rear. So that may give some idea of what it would do on an RB.

I myself made 290rwks with a standard stroke SR with a 3071 .78 twin scroll rear. However compressor surge killed the turbo - it was making 26psi at 4000rpm on the last dyno run it did - more flow than the engine could swallow at those rpm.

Edited August 2, 2009 by juggernaut1

[Dale FZ1]

I'd suggest that if the ported housing were available, or machining could be done, that it should be incorporated. There are a few examples in diesel applications where it is done to assist overall matching - I think Holset call it "band width enhancement" or something similar.

To be honest, a free floating (externally gated) 0.73 A/R housing on a properly designed RB manifold would be close to the ideal from a total flow vs bottom end response balance point of view. Not quite going to be in split pulse territory, but it'd strike a damn fine balance.

Otherwise, the 50 odd hp reduction in peak compressor flow capacity probably wouldn't be sorely missed if a 52T spec 700177-5006 cartridge and matching comp housing could be bought. Slightly less air "grab" might reduce the turbine drive requirements, and give quicker spool-up, while I'd expect the peak shaft speeds to be of no real difference to the 56T version. If that assumption is correct, there is an immediate advantage over the smaller 71mm comp which has to spin appreciably faster.

I'm impressed that the twin scroll 3071 cranked out that much hp, but without even referring to the flow maps I'd have thought 26psi @ 4000 rpm would have things headed straight into surge, and critical overspeeding of the turbocharger. It's a shame to see a failure, but not surprising in the circumstances.

Edited August 2, 2009 by Dale FZ1

[juggernaut1]

I'm impressed that the twin scroll 3071 cranked out that much hp, but without even referring to the flow maps I'd have thought 26psi @ 4000 rpm would have things headed straight into surge, and critical overspeeding of the turbocharger. It's a shame to see a failure, but not surprising in the circumstances.

Your right - accordingly, to my calc's 26psi at 4000 on a SR is off the map for a 3071. Just lucky I found the problem during preparations for its inaugural track day outing.

Surge ported 3037 here I come.

[discopotato03]

Yes my thoughts are also to forsake the 50 Hp (5lbs air) off the top end of an in theory 540 Hp compressor to gain a slightly lower boost threshold at the other end .

Given a choice I'd go for the ported compressor housing because it takes the guesswork out of the surge issue and if you wanted to experiment with housings smaller than that Garrett GT30 0.82 ie the 0.68 Pro S one or even the GT30 0.63 one you can .

With the real GT3071R 56T I sort of had the feeling that the 71.1 mm GT compressor wheel was not really in step with the GT30 turbine , possibly this turbine in 84 trim doesn't spin this compressor fast enough to make it work or if the turbine housing is small and does the comp surges . Again I think it needs that 60mm 76T NS111 turbine that Garrett won't give us .

I have to wonder why Garrett via HKS put into production GT3037's with 48 52 and 56T GT37 compressors and then teamed the 71.1 mm GT35 family compressors , again in 48 52 and 56 trims , with the cropped GT30 turbine .

It almost sounds like they found problems with the full 60mm sized GT30 turbine when combined with the 71.1mm GT35 family compressor wheels .

Why Garrett would then put the real GT3071R into production is anyone's guess , particularly without a ported comp cover . Um also for the record my turbo charts show the highest performance version of the HKS GT2835R , 56T 0.50 A/R T04E comp cover with 100mm inlet so assumes port shrouded housing , shows it as good for 420 PS or 30 less than a GT3037S 52T with the same E family comp housing but in 0.60 A/R .

Turbine housing wise we RB people are really limited to T3 sized mounting flanges and GT30 type ones at that .

Almost everyone that I could get hold of with GT30 family turbos on RB25's leaned towards that 0.82 size and I think Mafia was one of the few who tried both the 0.63 and the 0.82 . Some have had the HKS GT Pro S on 3037 Pro S turbos and at least one changed his 0.68 for the larger 0.87 one .

I'm not sure which would suit me better but its probably a juggle between the 0.68 HKS or the 0.82 Garrett one .

Other factors come into it like whats done to your RB25 ie head cams CR etc .

The head I bought off wolverine was ported by Harris and has oversize exhaust valves plus 256 Poncams fitted and set to give a static CR of ~ 9.2:1 so I think these would improve the off boost torque and throttle response compared to an unopened 33 25DET .

More as comes to hand , cheers A .

[discopotato03]

Just in case you're interested in what a T04E 0.60 A/R port shrouded compressor loks like with its pants down .

This one is off a GT3037S in the US .

Cheers A .

[juggernaut1]

Adrian,

If your running around 9.2:1 comp, smallish cams, bigger ex valves and headwork you could probably get away with the .82 ex housing over the .68 without too much pain, if any.

I picked the 3076 comp and had a bell mouth turned up and welded into the comp housing ala HKS style.

Edited August 3, 2009 by juggernaut1

[discopotato03]

Possibly but I'm going to do my damndest for the 52T GT37 compressor and the ported compressor housing .

Its the challenge of have a "small block" less exy RB30 that's a tad lazy down low - for a three liter ...

I've been in consultation with DaleFZ1 and he's given the pros and cons , yeah I know , of the Garrett vs the Pro S HKS housings . I was saying that the limited value could be its 0.68 A/R size which is in between the GT30 Garrett's 0.63 and 0.82 turbine housings .

I have said in the past that it's possible HKS intended the 0.68 Pro housing for RB20's and the 0.87 for RB25's .

Gary said that in some ways the Garrett housing is easier to fit to the manifold and its slightly more agricultural waste gate style doesn't seem to give anything away to HKS's blinger looking thing . The HKS Pro housing may prove slightly better at wastegating if exhaust gas velocity was very high though the people who've used both don't see any difference other than probably A/R size .

This is great news for most of us because it means we don't have to chase the expensive less common turbine housing or its more involved dump pipes flange/tube setup .

Matter of choice but I think if I was having a dump pipe fabricated to suit the Garrett gated housing I'd try to make it with a narrow divider and the sectioned tube bend just to have the most area and least resistance between the gates "well" and it's outlet passage .

Anyway that's a bit down the track yet .

I'll try and get the non Garrett map I have for their GT3776 and 3782 diesel turbos and scan and post .

I've had this one for some years and put liquid paper over the islands for the other wheels because they are all on the one graph and confusing to read .

To give some idea the left side of the map corresponds to about 15 lbs airflow at the 2 bar line (1 bar positive) which lines up with ~ 49 lbs flow at the RHS of the map . Its island of highest efficiency is 78% and along that 2 bar line spans the 24 to about 38 lbs airflow scale . This island bottoms out at ~ 1.5 bar/20 lbs flow and tops out at perhaps 2.8 bar and 40 lbs of flow .

Granted it probably isn't in a T04E compressor housing and mentions "T04 Housing 76mm , 52 trim , 0.70 A/R" .

I cant remember where I downloaded this map from but I pencilled up the side at the time "HKS GT3037 49 lbs/min or 709 cfm max flow at 2.4 PR and 60% . 33 psi max limited by wheel speed .

Some American site and I'll try to find it later , gotta organise a clutch flywheel and install now .

Cheers A .

Edited August 3, 2009 by discopotato03

[wolverine]

stick your HKS manifold on it while you are swapping the turbo (& replacing the manifold studs that will be broken or about to break) and you will have a sweet set up.

[discopotato03]

That was quick , dunno about that one . Have to wait and see .

Cheers , Adrian .

[discopotato03]

A bit more in this saga . I spoke to Michael at GCG again and it sounds like the 700177-6 cartridge isn't going to be a problem and they've had them before , late last year most recently .

The biggie is going to be can Garrett supply the ported compressor housing they sell to HKS for 52T 3037S's .

Just have to wait and see now .

A .

[discopotato03]

Yes and the map , sorry , best I could do with Digi camera .

Cheers A .

[juggernaut1]

DRRRRUMMMM ROLLLL .

Just got a call from GCG , turbo number 700382-10 with the all important T04E 0.60 A/R port shrouded compressor housing is available in Japan and they are going to air freight one out for me . With luck should have the sucker in my hot little hands in possibly a fortnight .

Now just for the listeners at home . I asked Michael if they are likely to bring any more in for stock and he's not sure , has to bounce that one off Brett . My impatience is going to cost ~ $150 airfreight because going by sea takes around six weeks .

If anyone else is interested in these you can either let me know or go direct to GCG if intending to order .

PLEASE don't take it as granted that this combination is going to be the ducks guts , or come back at me saying I spent good money and it doesn't do what I want . I research these things for myself and if you can wait a while I'll pass on my findings . It SHOULD work just like the Garrett marketed GT3076R in the same sized turbine housing , it SHOULD be a little more responsive and have slightly faster transients but I'm working off the force here not real life experience .

More as comes to hand , cheers A .

So whats the all up damage for one of these, Adrian?

Also is it possible to buy the turbo minus the ex housing i.e. just the CHRA and comp cover so you can slot it into your existing ex housing - it has the T3 60mm ex wheel right?

Cheers

[discopotato03]

DRRRRUMMMM ROLLLL .

Just got a call from GCG , turbo number 700382-10 with the all important T04E 0.60 A/R port shrouded compressor housing is available in Japan and they are going to air freight one out for me . With luck should have the sucker in my hot little hands in possibly a fortnight .

Now just for the listeners at home . I asked Michael if they are likely to bring any more in for stock and he's not sure , has to bounce that one off Brett . My impatience is going to cost ~ $150 airfreight because going by sea takes around six weeks .

If anyone else is interested in these you can either let me know or go direct to GCG if intending to order .

PLEASE don't take it as granted that this combination is going to be the ducks guts , or come back at me saying I spent good money and it doesn't do what I want . I research these things for myself and if you can wait a while I'll pass on my findings . It SHOULD work just like the Garrett marketed GT3076R in the same sized turbine housing , it SHOULD be a little more responsive and have slightly faster transients but I'm working off the force here not real life experience .

More as comes to hand , cheers A .

[wolverine]

sweet!

[discopotato03]

So whats the all up damage for one of these, Adrian?

Also is it possible to buy the turbo minus the ex housing i.e. just the CHRA and comp cover so you can slot it into your existing ex housing - it has the T3 60mm ex wheel right?

Cheers

Yes that's exactly the way it works . Mine will wing it's way here as a cartridge and compressor housing which is probably the way HKS received them , they (HKS) would have put their own turbine housings on them along with the inlet funnel piece and the all important HKS power and response tag . That's worth 10 lbs of boost in the box ...

I think all assembled and with an actuator it'll be a little under two but fluctuations in the Pacific Paseo and Garretts inside leg measurement would all be factors at the time . Can't be 100% sure till it's on the counter at GCG .

I'm just pleased that they managed to find something that's a little different so I'm not expecting a cut throat price .

In the mean time I'll have to think about the turbine housing sizes and what rate actuator to use .

My initial thoughts go to the 0.82 A/R housing and an actuator designed to regulate at - I dunno maybe 12lbs and let the PFC's solenoid boss it around if required .

After that chase up oil and water lines and the dump flange . Lastly the inlet duct to the AFM and the dump to connect to the exhaust .

My R33 is std turbo dump and front pipe so the bit ahead of the 3" cat may need replacing , are they smallish std ?

Cheers all , A .

[discopotato03]

I have a bit more to add regarding the compressor housings on these GT3037/GT3076R type turbos .

According to Turbomaster catalogs the part numbers for the port shrouded compressor housings are 436157-0022 for the 52 compressor trim version and 436157-0023 for the 56 comp trim one .

Unfortunately having the part numbers for these things doesn't guarantee that Garrett can/will sell them to you but at least if you can quote a part number you're in with a fighting chance .

Also BTW the part number for the backplate/adapter ring (the ring located with the large C or circlip) is 448420-0002 and common to both . This fact alone tells us that the housings are T04E family or at least "footprint" .

A little O/T but because I know where to find them , and cross reference them , I'm going to dig up the part numbers of the hopefully Garrett compressor housings used on HKS marketed "GT2835" turbos because it may just be possible to order turbos and or port shrouded compressor housings for the 71.1mm GT35 series compressors .

I can't guarantee this but there is some dumb spud logic in thinking that port shrouded compressor housings on turbos in the GT3071R/GT2835 family could be of benefit .

I remember people having boost creep dramas on 3071R's with the smallest 0.63 A/R Garrett turbine housing and I think the feeling is that with the 0.82 A/R Garrett housing the problem was all but solved . At least one here has told me that in 82 form his R33 (GTS25T) goes quite well but noses over at something over 5 K revs .

The thing I keep seeing is port shrouded comp housings on turbo kits slated for Nissan RB six cylinder engines , you only have to look at the 2530KAI , GTRS , plus the 2835 and 3037 GT Pro turbos . Garrett spec and marketed turbos tend to be generic things where HKS go to some trouble to make them firstly fit and secondly suit the characteristics of the engine being warmed up .

Brett from GCG did say once that a properly made port shrouded comp cover lets some air out in the would be surge phase and actually lets some additional air in when the comp wheel is really hiking and the engine can swallow lots of air .

Back soon , A .

Edited August 9, 2009 by discopotato03