Whos Interested In The Gt3076r/gt3037 In 52 Trim ?

[discopotato03]

Hi all , I need to know how many would be interested in having a Garrett GT3076R/GT3037 in 52 compressor trim . This option as far as I can tell was only ever offered by HKS and was the "non laggy real GT30R" .

I understand that some will be available in March next year though how many and built or supplied from Garrett I don't know yet .

The acid test would be putting one of these up against a BB Hi Flow and seeing the differences in all round performance . It may not be beyond the relms of having RB housings on such a cartridge so that at least it would air/exhaust wise bolt to an RB20/25 .

If serious get back to me , cheers A .

PS have some comp performance figures to add when I can look them up .

[discopotato03]

Here's part of an article from RC of Garrett North America for turbo sizing Nissan Sentra SR20's .

GT3037: This is the mother load of turbos , get the 52 trim compressor and the .73A/R housing for good streetability and ` 400-425 whp . Get the 56 trim and .87 A/R housing if you can live with a little more lag and want 475 whp .

Note that this was on 4 cylinder SR20's and with T28 flanged HKS exhause housings . Things are going to vary a bit with a six cylinder RB and Garretts exhaust housings are .63 and .82 A/R ratio in T3 flange .

My gut feeling is that these should do similar things to the BB Hi Flow but with more modern wheel and housing designs so you'd think the transient response would be better . My opaque crystal ball reckons this would be the one for a good street RB25DET so we'll have to wait and see .

Cheers Adrian .

[lukits01]

I've been looking for the HKS3037 kit for sometime, this seems like a good alternative, any estimate on price? Im guessing external gate version only?

Was planning on using it on a street RB30, aiming for response and flat torque delivery, too much power just overpowers the the street tyres.

I know you recommend this for RB25, how do you suppose it would perform on a RB30?

[Lithium]

Here's part of an article from RC of Garrett North America for turbo sizing Nissan Sentra SR20's .

GT3037: This is the mother load of turbos , get the 52 trim compressor and the .73A/R housing for good streetability and ` 400-425 whp . Get the 56 trim and .87 A/R housing if you can live with a little more lag and want 475 whp .

Hm. Mother load of turbos for SR20 - wouldn't one think that a bit more aggressive trim would be more suited to a 2.5l? So far I love the 56T GT3076R on the 2.5 - so far I'm not sure where the lag people talking about them having is, though mine is only at .6bar at the moment (Reached <3000rpm)... though would be interested to hear how a 52T goes on an RB25 if someone goes this combo.

[Sammie]

im a bit dumb but by trim do u mean front cover? i just got my turbo today gt30r a/r 50 .82 housing slide said its good for 270-300kw's oh yea and its IW

[discopotato03]

Lithium its hard to tell because everyones perception of no lag is different . People I know of say that the "GT30R" is laggy on an RB25 but as we know there are many variations of the GT30 ball bearing turbine based turbos and the real one is more the exception to find than the rule .

What I found people saying in the US was that its not difficult to stay in cross over (higher boost pressure at compressor outlet that turbine inlet pressure) with this 52 trim GT3037/GT3076R . Granted they were using mild cams and headwork plus good exhaust manifolds but the turbo has to be good as well . They were quick to add that not very many years ago it was thought this impossible to achieve with production based turbo engines .

I look at the GT3076R/GT3037 56 trim as a maximum ie the largest trim compressor wheel of that GT37 family made . As most know turbo manufacturers generally offer more compressor trim variations than they do turbine trims so in this case its largest trim GT37 wheel for that GT30 turbine . So in other words they are pushing the upper end pumping capacity at the expense of low end and lower mid range . The 52 trim compressor is the middle of the range and as far as I'm concerned can move enough air for the 250-260 Kw that most could get to the tarmac on street rubber . I also think these larger trim compressor variations want to drag their feet while the turbine gets enough shaft power up then build boost very rapidly ie medeocre torque then in with a wham and wheel spin city . To my way of thinking the mid trim compressor stands a better chance of being a bit more user friendly and easier to modulate power delivery with the hoof .

If RC was right and the 56 trim version is good for high 400's Hp wise it could be way beyond what an RB25 with production con rods and pistons can withstand . I think SK once mentioned that internally std RB25DET's are living on the edge at much over what 270-280 Kw so any extra compressor capacity is adding lag for zip .

For me I think this would be a nice road turbo and user friendly in an R33GTST with one of Garretts IW housings .

The one to work on for a torquey RB30DET is I reckon a 52 compressor trim GT3582R but I'm leaning on the RB25 first .

Gotta run , cheers Adrian .

[discopotato03]

By front cover I mean the aluminium compressor housing or what some call "snail" .

.50 A/R ratio ? All the GT3076R turbos from Garrett I've seen use .60 A/R port shrouded compressor housings . Check the ID tag , should say 700382-12 and or 700177-5007 for the 56 trim version .

Pics usually tell the story

Cheers A .

[Busky2k]

I would be very interested in the 52 trim GT37 compressor, mainly because I have an SR20. I'd love to see a compressor map, but it'll be ages before we get to see anything. Granted, I would have thought the 56 trim would still be quite good for the RB25.

[Cubes]

I've been looking for the HKS3037 kit for sometime, this seems like a good alternative, any estimate on price? Im guessing external gate version only?

Was planning on using it on a street RB30, aiming for response and flat torque delivery, too much power just overpowers the the street tyres.

I know you recommend this for RB25, how do you suppose it would perform on a RB30?

Torque overpowers street tyres.

Run a small turbo with lots of boost, massive mid range and traction is a big issue.

Run a larger turbo such as the GT35r and traction is just that bit more controllable.

A set semi's and mechanical diffs will go a long way.

*subscribes*

[lukits01]

Torque overpowers street tyres.

Run a small turbo with lots of boost, massive mid range and traction is a big issue.

Run a larger turbo such as the GT35r and traction is just that bit more controllable.

A set semi's and mechanical diffs will go a long way.

*subscribes*

I was thinking that, would explain my current problem RB30+2535

Though I am enjoying the instant boost and response

But Im wondering how the GT3037 compares to GT35 compares in terms of response

[discopotato03]

For those interested the inducer or front of the compressor wheel diametre is a monstrous 2mm smaller with the 52 trim wheel vs 56 trim ie 55mm and 57mm .

Also the HKS model specific version (HKS GT3037 52T) for the SR20 used at times a .50 A/R TO4E compressor housing . Others I've seen and assume specific for Nissan RB have a .60 A/R port shrouded compressor housing .

I have a non Garrett map which is very similar to Garretts GT3076R map but with everything shifted left about 3.5-4lbs on the grid . The title says TO4 housing 76mm , 52 trim , 0.70 A/R . Its actually three maps overlayed on the one graph for the Diesel bush bearing GT3776 and GT3782 series turbos including the one mentioned as well .

I can almost hear people thinking why all this fuss and bother over 4-5 lbs air flow . Well the point is that any workload you can take away from the turbine means the whole rotating assembly will have faster transients meaning a well trained hoof can get turbine response closer to throttle response . Personally I reckon its a better match of air to exhaust flow than the 56T version .

Call it copy cat or monkey see monkey do but some of HKS's turbo options have used mid trim compressor wheels ie GT2835's , GT-RS's . Their GT3040 and GT3240 also use smaller trim compressors than Garretts closest marketed option . If HKS's reputation rests on its customers success or failure then success means they're doing it better than others in the market place . If they're doing it better with smaller trim compressors and shrouded comp housings than Garretts generic offerings then I think there's something in it .

Cheers for now , Adrian DP03 .

BTW I have no financial interest or any real info on this offering but testing the interest waters .

Edited December 16, 2006 by discopotato03

[Busky2k]

Hey disco could you explain to us how compressor housings and the A/R affects compressor flow/lag and performance? Eg the 0.50A/R vs the 0.60 A/R for the GT37 compressors.

[discopotato03]

I'll give it a go .

Air being centrifuged off the compressors exducer area (squared off outer tips if you like) enters the diffuser area or channel between the flat inner side of the compressor housing and the inner side of the housings back plate . This is designed to slow the air down and convert velocity energy into pressure energy .

Now you need to understand the difference between static pressure and total pressure . To read static pressure you can tap into a compressor housing and run a pressure gauge . To read total pressure you would need a Pitot tube or an upside down "L" shaped tube with its hole facing the approaching air supply . So static pressure on one hand and total pressure on the other .

Getting back to the compressor housings Area Radius ratio , the higher the ratio the larger the cross sectional area of the housing becomes . So with a larger passage the gas speed will be lower than it would be with a smaller one .

The rest is my own theories .

Firstly the compressor housing has to be able to pass sufficient air for the engine to breath properly in atmo and supercharged states . Secondly depending on the desired state of tune of the engine the AR ratio shoud vary to give acceptable total pressure between the torque peak and power peak - so many variables .

Garrett has had most of the present families of compressor housings for some time . They seem to like the idea of going up one family size (ie T3 to TO4B or TO4B to TO4E etc) when they began using ball bearing cartridges and GT series compressor wheels . By this I mean for example some T3 comp wheels are approx the same outer diametre as the 60mm GT wheels but in performance apps get TO4B comp housings and dimensionally same backplate/diffuser diametre . This probably sounds confusing but TO4B comp wheels are usually 71mm diametre . I have to assume that 60mm GT compressors being true high speed wheels were capable of more airflow read higher that suitable gas velocity and therefore too restrictive with the T3 compressor housing . The 71mm (GT35) series comp wheels can have TO4B or TO4E series comp housings depending on required total airflow/velocity . The larger diffuser of the one size up housings can make for larger and wider areas of high efficiency though wheel trim can have a large say in this as well . I reckon that HKS did a sneeky on their custom TO4Z comp housing to cheat a little here ie not have to make a custom backplate and adapter ring to get the GT40 style comp housing on the std cartridge .

Have to go out and recharge my brain ATM , back later cheers A .

Edited December 17, 2006 by discopotato03

[Sammie]

disco the tag says 700177

[discopotato03]

Yep and should have a dash "-" followed by more numbers . 700177 I believe means GT30 turbine in GT25BB centre section , the dash numbers mean compressor spec generally .

Cheers A .

Charge light still yellow .

[Sammie]

yea pretty much looking forward to it getting fitted which should be soon cant wait to see the results

[discopotato03]

Anyhow the upshot is that the larger A/R housing can pass the gas off the compressor at peak revs a little more easily than a smaller one if flow capacity of the wheel is reaching its limit . Note that with std RB20 and 25 turbos the compressor housing grows markedly for the same wheel size .

Depending on what you read into it , HKS USA's website shows their GT3037 as having a .60 comp housing with 70mm inlet boss and 50mm outlet boss and claim 440 Hp potential in 52 trim . The next up HKS GT3037"S" 52T shows 100mm inlet boss and 50 mm outlet boss and claim 450 Hp . I think they may have made a typo in the first instance and meant .50 A/R and plain or non shrouded housing . They don't mention it but I've never seen a GT3037S or GT3076R without the 100mm inlet boss and port shrouding thought HKS always use the trumpet mouthed insert probably to cut down the "jet turbine whine" that ported shrouds often produce . What this feature does do is widen the maps particularly in the upper left hand side of the graph (in other words high pressure at low gas flow rates which is what turbos with small turbine housings do when boost rises sharply at lowish engine speed - low airflow rate) .

For your SR20 the .50A/R housing should not be a problem because often four cylinders are less likely to surge than sixes - the pots are of greater capacity than a similar capacity six so can get away with slightly larger A/R turbine housings without being too laggy . The small inlet boss/plumbing is also easier to house in tight spaced four pot engine bays particularly front wheel drive ones .

For an RB six I'd prefer the ported shroud and .60 A/R ratio particularly on the 2.5 litre engine because its probably going to windmill fairly fast if the turbine housing A/R is sized to bring the thing on in the 2500 + rpm range . If it had the .63 A/R housing and you floored it at low revs the ported shroud should just about cope with surge issues but thats only a hunch . A bit wide that .63/.82 A/R gap , the HKS GT3037 Pro S .68 A/R housing is probably a little better sized for street 2.5L .

Time will tell , cheers A .

[wolverine]

disco, would using using a GT3071 with .82A/R and the largest trim 71mm compressor end up being about the same or similar spot as a .63A/R on the GT3076 52 trim?

[tridentt150v]

DP3,

I'd be interested in the 52 trim 3037/3076, I've held off buying a turbo [for several reasons, $$$, hunting down a HKS cast manifold, getting it honed and coated etc], but would be very interested in this turbo set up for my RB25. I can wait a bit longer, but would have to reassess my options if March drags into april into may etc. If Garrett have them out by March, the timing would be spot on.

BTW I'd be looking at an external wastegate, but if they are internal then I guess I could plate over the external mount on my HKS cast manifold. But an external wastegate should be no big deal because the changes are on the comp. side, not the turbine side.

[discopotato03]

Someone was always going to ask that one and its its a good one because these two wheels in theory are good for about the same sort of airflow .

The real GT3071R is not a bad thing but when teamed with the GT30 turbine its a bit of a juggle getting the wheel speed right to put the pumping capacity where you want it in relation to engine speed . This turbo is good example of being biased a bit more turbine wise than most . You will have noticed that this turbo does have an optional port shrouded compressor housing available but you don't tend to see it in this form probably for cost reasons from a suppliers point of view . The available compressor map shows that to get the most from this turbo takes a bit more shaft speed and the area of highest efficiency begins and ends a bit higher than the 76mm GT compressors do . I'm pretty sure this ties in with the compressor housings A/R ie .50 vs .60 and the fact that the 76mm GT wheels use ported inlet shrouds .

One of Garretts engineers once mentioned that this real GT3071R was sort of a production based version of Garretts competition TR30R but IMO that one used a 60mm version of the NS111 turbine (same family as GT2860RS/GT2530) and if it was in 76T a better thing - very open bladed light weight compared to 84T GT30 . That turbine with the 71mm GT compressor in 52 trim would have been very likely better than the GT2835 52 trim cartridge and similar but slightly better than the GT-RS . Garrett should be shot for not using that turbine more often .

Back to GT3076R 52T vs GT3071R 56T . Provided you can get the required airflow the mid trim size usually gets the best efficiency with compressor wheels . Larger or smaller trims are there to tune the wheel families pumping capacity to suit the engine . Production economics step in at this point and turbo manufacturers who use a common wheel/housing family often try to have the same part/s used in different units to keep costs down . Market trends also dictate what sells in volume and sales are what its all about .

In this case the demand for the GT3076R/GT3037 in 48 and 52 compressor trims has not been high so the aftermarket section of Garrett North America went with the larger 56 comp trim version . Very probably a moores law thing - more air guys , more power . Also more boost lag ...

Anyhow I can keep on spieling on but the bottom line I feel is that a GT3076R in 52 comp trim is a better road car turbo that a real GT3071R in 56 comp trim . I can't show back to back test results because I don't have any . Somewhere in the mists of wheel tip speeds and compressor housing design there will be reasons why the 3076R/3037's map is better . This is not to say that with a bit of mucking around you couldn't get something similar out of the 3071R but without the maps its a case of spending money and hoping it works . As I said before HKS has opted for mid trim compressors and ported shroud type compressor housings on some their successful turbos and they appear to work very well . Its also important to note that they used a cropped version of the GT30 turbine in their GT2835 series turbos (very similar to real GT3071R cartridge) probably to keep the wheel speed up a bit at the expense of top end exhaust flow . That is a workable formula provided the turbine housing is GT30 based because the GT28 housings bored out stuff it all up .

There have been interesting reads at SR20 sites where they have compared the GT3037 56T to the GT3071R 56T , they did not find the 1000 rpm lower boost threshold that ATP was claiming in the US . Another significant thing is that the Sentra mob (Sort of Pulsar 4 door sedan B15 rather than N15 as we have) race transverse front wheel drive cars and there are limits as to how much torque you can feed through the wheels that drive and steer their cars . The ones that can get their hands "on pretty much any turbo they want" like the GT3037 52 Trim . Surely its a throttle response vs boost/torque response thing here . I will put it to them and get back on this .

Turbine housing and A/R ratio . Again the real GT3071R is a bit particular here so don't know about the .82 on this turbo on a Stagea . They are rather heavy and being automatic probably thrive on low down torque depending on how the stall speed of the torque converter is set up . Engine management is an issue for them and Gary SK is probably the one to ask about Stags .

If I had to make the choise for an RB25 it would most lilely be the GT3076R/GT3037 52T .63 exhaust housing and the port shrouded .60 A/R compressor housing on an R33 spec engine , if I had the luxury of an R34GTT spec RB25 (I wish) I'd be brave and opt for the .82 because the variable cam timing and better aftermarket cam profiles available (slightly shorter duration and a little more valve lift) would probably pull up the off boost and low end torque . If and when these things land here hopefully the supplier will be keen to test both housing sizes which is to their own benefit because a happy customer is great advertising - grape vine shakes and reaches far and wide .

Cheers A .