Jump to content
SAU Community

Recommended Posts

Hi all , I've been looking at Garretts GT3540R for a while now with the idea of using one on an RB2631DET low mounted .

Peoples experience with these things seems to show that the 82mm GT40 compressor in 56 trim is often a bit over the top for realistic power goals so what to do ?

I don't like the idea of the GT3040R's , either 50T (HKS) or 56T (Garrett) though the 50T is the better of the two . I believe the GT30 turbine is a little small for a 3L anyway so it wouldn't matter what compressor you hung off it , a reasonable alternative may have been the GT32 turbine but Garrett don't offer it in any ball bearing cartridge I know of . I think HKS had Garrett crop their GT35 68mm turbine down to ~ 64mm 84 trim for the GT3240 - so had a "sort of" BB GT32 turbine . That turbo had a 54 trim GT40 comp but more on that later . Essentially the GT3240 is a bit like a GT3540R with an in between sized turbine (between GT30 and GT35) and a slightly smaller trim compressor of the same family . It seems to have been an effort to have more wind than their GT3040 and a bit more exhaust flow for a bit more squirt . They are being used in single form on high performance fours such as Evo Lancers the odd Toyota 3SGTE and in twin form on Nissan RB26 drag specials .

Back to my situation . I think when HKS were having their GT BB turbos developed there was less in the way of wheels around than there is today and anyhow it was 90's thinking .

More very soon , cheers A .

Link to comment
https://www.sau.com.au/forums/topic/106033-garrett-gt3540r-modified/
Share on other sites

In more recent times some turbos have been optioned with turbines closer to the compressors major diameter or if thats not possible smaller trim compressors . I think this is done to minimise exhaust restriction and concentrate on moving lots of air but not at high boost pressures .

There are lots of examples of HKS optioned GT BB turbos with mid trim compressors while Garrets nearest equals have the big trim comp . Many say HKS turbos are optimised to work at higher boost than their Garrett cousins but I reckon they are simply optimised to be a good balance when loaded up rather than a hell fired attempt to find a couple of pounds of boost at cranking revs .

So from some of their examples we can learn that lag and response can be moved around in a couple of different ways . The old standby if a turbo was a bit lazy was to throw on a smaller a/r turbine housing to wake it up earlier . I think the better way to do it is to reduce the compressor trim which takes some load off the turbine and for same exhaust energy input can spin up earlier in the scheme of things . This is all fine and well as long as the smaller trim compressor still has the pumping capacity required .

To the GT3540R , finally they say ...

These turbos use the 82mm GT40 compressor of the BCCW18C family in 56 trim . From some sniffing around I found 50 , 52 and 54 trim wheels of the same family as well . The HKS GT3040 uses a GT40 50 trim as does the bush bearing GT4082 . The bush bearing GT3782 uses a 52 trim and finally HKS's GT3240 uses a 54 trim version . Interestingly the HKS's use a .60 a/r TO4S comp cover except for the GT3040 optioned with the largest 1.12 a/r turbine housing (thanks Fantasy) while Garrett plugs on with the larger .70 a/r TO4S cover .

What I have in mind is to use a 50 or 52 trim GT40 compressor on a GT3540R to optimise whats probably a Diesel cartridge for a petrol engine . I don't need 650Hp's worth of airflow when 500's worth will do nicely . Now Brett from GCG tells me that the 52T wheel is available though from over seas and would require machining operations so it could fit . The comp cover is also around but as a new component is a tidy sum . So it seems that the only "easy" way out is to somehow obtain a "cheap" or damaged HKS GT3040 and rat it for the compressor and comp cover . Even then the wheels centre hole would need to be drilled as the GT30 turbine shaft is smaller than the GT35's . If anyone has one of these for reasonable money can you let me know - remember its just the wheel and housing I need .

It it eventuates it could be called the GT35RS . How much better it would work than a std GT35R is hard to say but I'm sure it would suit my purposes and close the gap between GT30R and GT35R enough while having no less exhaust restriction .

Opinions ? Cheers A .

ive been following this for a while too. :) GT30r too small and the gt35r is too big for what i want.

I have seen the gt32's and wondered if bush bearing would make that much difference to a ball bearing turbo. Roy says his td-06 spools faster than smaller turbos, so it makes me wonder...

I always like reading your opinions disco, let us know how the gt35rs goes :(

Edited by Bl4cK32

Its hard to put a number to it so if I had to guess probably around 450 , more interested in average power . The car will almost certainly be 2WD and have to live with production gearbox ratios , also don't know what I'm doing with rods yet so maybe SK's 475Hp may be the ceiling . Its doubtful if a road driven R32 with street rubber on sane rims could harness even this . So a free reving torquey engine with good throttle control is the aim . I want to use a reasonably tall ie 3.7 final drive with 16" wheels and tune the thing to make best mean part throttle torque because I think that feels good and pays off at the bowser .

I don't think making good power with this kind of engine will be difficult but getting a smooth transition from cubic inch power to forced induced power may be interesting .

Cheers A .

Edited by discopotato03

with a 26/30 it'll make up for the gap by using the GT35 IMO.

GT35 works well on the 2.6 as it is...

Plus if you use cams...

very meaty power range indeed i would imagine, and it shouldnt be too "twitchy" really when you think about it if your not going the tiny rear housings, should be very progressive

ive been following this for a while too. :D  Roy says his td-06 spools faster than smaller turbos, so it makes me wonder...

Mine doesnt spool quicker then smaller turbos. Thats for sure. But the way the thing drives when comapred to similar sized ball bearing turbos, then well the combination of the manifold and everything else suggests that there is more in the wheel sizing then the fact that its plain bearing or ball bearing.

I have compared it to a few 2535s etc on Rb20s, and from memory it spools about the same /better. I understand the 2535 is rated less the TD06 and is BB...so ?????????????????

The bearing type probably plays a part in the power delivery. Where a BB turbo has better transient response, so mine is a bit duller when i open the gates...which is ok by me as it seems to help traction.

Ppl always say Trust turbos hit hard, mine doesnt really seem to. It doesnt really ramp hard onto boost and terrorise passengers, i actually like how it gets its power down. Perhaps thats the cam gear settings,...lol i got no idea :D

LOL...im confused, yeh BB turbos. No doubt are better, but the wheel sizing and matchin it to exhaust flow would seem more important...how thats done i got no idea :P

...but with all the cool BB turbos floating around at a steal...id only consider a plain bearing turbo if all avenues hit a dead end...though i did see an animal Hybrid turbo once gettign tuned on a friends car. It used the Trust TD06SH turbine, with a big Garrett front wheel, still using the Mitsubishi cartridge...the thing was very impressive and was marching easily past 300rwks on an RB25. It was very surprising how responsive it was and it was with something like 18psi at less then 4,000rpm...it was near maxing out the 550 injectors so was making good power...so perhaps look at the TD06SH turbines...???

I want to use a reasonably tall ie 3.7 final drive with 16" wheels and tune the thing to make best mean part throttle torque because I think that feels good and pays off at the bowser .

I don't think making good power with this kind of engine will be difficult but getting a smooth transition from cubic inch power to forced induced power may be interesting .

Cheers  A .

I recently drove a friends VLT that made 187rwkw running a 2.5" exhaust, fmic and 14psi, it had a compression test resulting in @ 150psi in all 6. A little high for 7.8:1 comp I thought. :)

It was rather impressive to drive. To be honest I didn't notice any lack of down low torque despite the high 3.45:1 ratio at part throttle, it did feel a little slower getting up in the rev's where boost would build but once boost was in it really hauled arse.

To cut a long story short don't for one minute be worried about the 3.7:1.

It will work fine and be a much nicer easier car to drive. :(

Darren... I shiet you not it felt as if it pulled as hard if not a little harder than yours through the mid range, it did however feel as if it died a little past 4.5k, due to the head I assume.

The longer ratio felt as if it allowed you to use the torque of the motor.

Much much nicer and quicker feeling to drive than the 4.363:1 ratio.

For a streeter Sky30 expressed his concern with regards to how savage the gt35r is on the rb30det. Do remember its making ~550nm of tractive effort torque in order to make ~300rwkw where as an rb25 on the same dyno requires around 390nm of torque to make ~313rwkw.

Mine made 390nm of torque to make 180rwkw. :S

We can see why traction is such a problem on a rb30det making decent power.

Interesting torque figures, get the transition as linear as possible and it will be a very quick car.

Back on topic... discopotato03 do you mind being my guineapig.. lol

No thats not a question. ;)

Your goals are the same as I and you do understand turbo matching just a little (lot) better than I.

I just went back from 4.11 to VL turbo 3.45's and really noticed no difference in

normal driving, But obviously was a lot nicer on the freeway. Actually feels a lot

faster

on boost aswell, i think bigger capacity turbo motors like gearing, IMHO,

4.11 and 4,44 are to short for a RB30 motor, they don't rev hard enough .

If you are using a twin cam Rb30 the 3540 .82 is quite linear in it's delivery

with poncams, compared to the single cam motor, i would just use that.

cheers

darren

Yeah Cubes LOL I was sort of wondering if I should get someone to host the "GT35RS" if it was a practical proposition . Seriously though the car should come before the turbo otherwise the economics of the project get all out of hand .

I'm pleased it was noted that the VLT's gearing works out ok and think its a combination of the box and final drive ratios that suit the RB30 and I spose the approximate weight of a VL or R32GTST . When I crunched the numbers the all up gearing of the VLT looks better than the 33 box and taller diff . Its most likely a case of Nissan wanting that short 1st ratio so an R32/RB20DET combination or R33/RB25DET could idle around in Japans bumper to bumper without being snatchy or needing to ride the clutch . I'm probably starting a war here but either of the above would not be the most torquey things given what they have to haul around at low revs in std tune .

The RB30 with its longer stroke and rods I'd say makes better use of its capacity than the 20 or 25 so its capable of significantly more torque at lowish revs . The difference between 1st - 2nd is better (closer) in the VL so this makes a big difference in how a car launches from start . One of the most infuriating things I find with Nissan transmissions is the big 1-2 gap , kills baulk rings and makes motors bog down . The VL has the wider gap 2 - 3 where it is better off because winding up 2nd is more likely to get most where they want to be and anyhow the 2-3 change across the gates takes a little longer and gives the syncro hub a short spell before it takes up . Also 3 litres would be less fussed pulling the taller 3rd gear . I should really try and locate a VL box before they dry up though I suspect the Navara V6 version of this box may have the same ratios - may even have the Skyline style shift and clutch slave mounting point too .

Anyhow the combination of appropriate gearing and engine torque characteristics makes or breaks these conversions , I dont need upper end turbo torque because mid range pull makes the arguably tall gearing work - well on the road anyway .

Latest thinking for "GT35RS" is maybe reprofiling the 56 trim GT40 compressor for 54 or 52 trim . Doing it this way means its (maybe) possible to use the original wheel which you have and its guaranteed to bolt back on . If this mod gained a following it would be nice to keep costs minimal on an already expensive bit of gear . Not sure what to do about the comp cover as there are a few options . We could use a TO4E cover like Ford did with the XR6T in .50/.60/.70 a/r or machine/press/stake a new section of aluminium into the original .70 a/r TO4S cover and profile it to suit . Thinking about it this gives the opportunity to play with port shrouding like HKS tends to do at times and could bolt in like their version of the TO4Z . The .60 a/r TO4S cover like HKS used on their GT3040/GT3240 is available os but in the mid 400's .

Av a good weekend cheers A .

Cheers A .

As Nathan said when he drove mine with its 4.363:1.

It feels as if it doesn't get time to 'use' the torque from the motor to accelerate the car.

Darren, how do you now find throttle control/traction?

That's exactly what i was going to write but didn't know if it would read write,

At 100km i only went back to second and bang into stop to stop wheelspin,

but it felt like it stopped pulling hard at 160km

I had exactly the same problem with our 1.5L turbo rolla years ago with 4.44, then

went to 3.9 and it was a weapon, the problem there also was worse, revs would rise faster than boost in 1st gear as it woudn't load the motor up enough, It feels exactly

the same with the RB30 even though i can see it has fullboost at 4250rpm in first.

I guess with 4.11's it fells revvy, but with 3.45 it pulls/feels torquey wheel spin is tamed down a fair bit, still spins all the way through second on low boost

but you can also feather the throttle which you coudn't do with the 4.11's, the whole car

felt like you were pushing/pulling it, highly annoying.

If i had a R32 i would putting the tallest ratio i could get with a RB30 in it.

Changes the car, defibitly for the better

So bang a 3540 .82 on it and gets some diff gears:)

Oh yeah totally agree with disco on the torque of the Rb25/20, i might

upset people aswell, but i can not stand them, they both feel like 4cyl to me

compared to the 30, and a big turbo makes them worse, and i have driven plenty

stock and with big turbos

cheers

darren

Edited by S3_Girl
  • 3 weeks later...

Been thinking about compressors and housings again for the mythical perfect GT35R turbine based turbo for an RB26/31DET . After much research into small ie 50 trim GT40 compressors it turns out that the larger trim ie 56T GT37 76mm wheel from the real GT30R and 3037 56T has similar pumping capacity in a more compact TO4E type compressor cover . I need to go back and compare the maps specifically the speed lines of the maps to see if they're similar enough to work at same-ish shaft speeds . If so I then need to ask Brett if a GT35R turbine can fit up the guts of A GT30R turbo with its heat shield so that the cartridge seals in the front of the turbine housing . If it worked it technically makes it a GT3537R or GT3576R . I also need to find out if the 50mm outlet is large enough to feed a 3L up to 300Kw and if not are their .60 or .70 a/r versions with the larger 60mm outlet . Does anyone know if the XR6's turbo will go 300Kw + because this would answer some of these questions . I really would like to see its comp map but being a local development probably unlikely .

Cheers A .

Thanks Chris , its good to know the integral gate and housing can pass the exhaust gas at 400Kw on an angry 4L 6 , the torque must be pretty good .

Latest information is that the GT35R's turbine shaft will fit in the GT30R cartridge , apparently the GT25 through to GT35 BB turbos all use the GT25 BB centre section/bearing cartridge/shaft BUT the journal where the compressor mounts is different/larger on the GT35R turbine shaft . So this means it can work but the GT30R's compressor bore needs to be enlarged to suit the shaft .

Cheers A .

Thanks Chris , its good to know the integral gate and housing can pass the exhaust gas at 400Kw on an angry 4L 6 , the torque must be pretty good

But how much is it passing is the question.

Most of it would be going down the dump you'd think to get the boost required to get to 400rwkw

Hi all , I've been looking at Garretts GT3540R for a while now with the idea of using one on an RB2631DET low mounted .

Peoples experience with these things seems to show that the 82mm GT40 compressor in 56 trim is often a bit over the top for realistic power goals so what to do ?

I don't like the idea of the GT3040R's , either 50T (HKS) or 56T (Garrett) though the 50T is the better of the two . I believe the GT30 turbine is a little small for a 3L anyway so it wouldn't matter what compressor you hung off it , a reasonable alternative may have been the GT32 turbine but Garrett don't offer it in any ball bearing cartridge I know of . I think HKS had Garrett crop their GT35 68mm turbine down to ~ 64mm 84 trim for the GT3240 - so had a "sort of" BB GT32 turbine . That turbo had a 54 trim GT40 comp but more on that later . Essentially the GT3240 is a bit like a GT3540R with an in between sized turbine (between GT30 and GT35) and a slightly smaller trim compressor of the same family . It seems to have been an effort to have more wind than their GT3040 and a bit more exhaust flow for a bit more squirt . They are being used in single form on high performance fours such as Evo Lancers the odd Toyota 3SGTE and in twin form on Nissan RB26 drag specials .

Back to my situation . I think when HKS were having their GT BB turbos developed there was less in the way of wheels around than there is today and anyhow it was 90's thinking .

More very soon , cheers A .

We run Gt 30/40 on a couple of customer cars, very streetable and make 285kw at the tyres. would be ample. If you are looking for something a little different you could go a GT35/66R-SPL. Its got a

0.8ar front cover, 66mm comp wheel and the choice of .63, .82 & 1.06 exhaust housings. This is a single upgrade for RB26. Im installing this setup in a GTR next week, let you no how it goes.

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

    • From there, it is really just test and assemble. Plug the adapter cables from the unit into the back of the screen, then the other side to the car harness. Don't forget all the other plugs too! Run the cables behind the unit and screw it back into place (4 screws) and you should now have 3 cables to run from the top screen to the android unit. I ran them along the DS of the other AV units in the gap between their backets and the console, and used some corrugated tubing on the sharp edges of the bracket so the wires were safe. Plug the centre console and lower screen in temporarily and turn the car to ACC, the AV should fire up as normal. Hold the back button for 3 sec and Android should appear on the top screen. You need to set the input to Aux for audio (more on that later). I put the unit under the AC duct in the centre console, with the wifi antenna on top of the AC duct near the shifter, the bluetooth antenna on the AC duct under the centre console The GPS unit on top of the DS to AC duct; they all seem to work OK there are are out of the way. Neat cable routing is a pain. For the drive recorder I mounted it near the rear view mirror and run the cable in the headlining, across the a pillar and then down the inside of the a pillar seal to the DS lower dash. From there it goes across and to one USB input for the unit. The second USB input is attached to the ECUtec OBD dongle and the 3rd goes to the USB bulkhead connected I added in the centre console. This is how the centre console looks "tidied" up Note I didn't install the provided speaker, didn't use the 2.5mm IPod in line or the piggyback loom for the Ipod or change any DIP switches; they seem to only be required if you need to use the Ipod input rather than the AUX input. That's it, install done, I'll follow up with a separate post on how the unit works, but in summary it retains all factory functions and inputs (so I still use my phone to the car for calls), reverse still works like factory etc.
    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
    • But first....while I was there, I also swapped across the centre console box for the other style where the AV inputs don't intrude into the (very limited !) space.  Part# was 96926-4GA0A, 284H3-4GA0B, 284H3-4GA0A. (I've already swapped the top 12v socket for a USB bulkhead in this pic, it fit the hole without modification:) Comparison of the 2: Basically to do the console you need to remove the DS and PS side console trim (they slide up and back, held in by clips only) Then remove the back half of the console top trim with the cupholders, pops up, all clips again but be careful at the front as it is pretty flimsy. Then slide the shifter boot down, remove the spring clip, loose it forever somewhere in the car the pull the shift knob off. Remove the tiny plastic piece on DS near "P" and use something thin and long (most screwdrivers won't fit) to push down the interlock and put the shifter down in D for space. There is one screw at the front, then the shifter surround and ashtray lift up. There are 3 or 4 plugs underneath and it is off. Next is the rear cover of the centre console; you need to open the console lid, pop off the trim covering the lid hinge and undo the 2rd screw from the driver's side (the rest all need to come out later so you can do them all now and remove the lid) Then the rear cover unclips (6 clips), start at the top with a trim tool pulling backwards. Once it is off there are 2 screws facing rearwards to remove (need a short phillips for these) and you are done with the rear of the console. There are 4 plugs at the A/V box to unclip Then there are 2 screws at the front of the console, and 2 clips (pull up and back) and the console will come out.
×
×
  • Create New...