Jump to content
SAU Community

Recommended Posts

Hi Guys

Been advised a couple of times now that my turbo is holding me back , engine is capable of more .Now for a while ive been resisting this notion its a fairly new garrett GT3040R the spec's on this turbo are turbine -wheel-60mm w/84 trim and a .82 housing.....Compressor-wheel 82mm w/56 trim and .70 ar.Been advised to uprate it to the garrett gt3540r this turbo has been updated to the new garrett GT3582R there's not a great deal of differance between these two turbo's gt3582 specs are ,turbine-Compressor wheel 82mm w/56 trim and 0.70 ar, turbine wheel 68mm w/84 trim but here im thinking of going to the 0.63 houseing

as you can see very little differance .

The engine is a built rb20det ,specs are rb25 crank, rb26 rods, aries 40thou oversized forged pistons.hks cams, ported head ,hks cam gears ,1mm oversized valves and all the bolt on goodies engine is making 306rwkw at the moment and I'm pretty happy with that .At UAS dyno day it made 250rwkw at 4250rpm and full boost by 3800rpm so the power is there but more than one tuner has said get rid of the turbo u need something bigger while thats fine and dandy to say get this turbo it will do the trick thats what I was told when I bought the gt3040 well now I'm being told something differant so I thought I'd throw this up here and get some advice on what poeple think would be a better turbo for my setup even been looking along the lines og the tdo6 .

cheers Peter

P.S did a search but not realy a lot of info on this power level with an rb20 ,well its an rb2.1 thanks

Link to comment
https://www.sau.com.au/forums/topic/189996-advise-needed-from-turbo-experts/
Share on other sites

what sort of boost are you running to make the 306? What happens if you add more? Has anyone determined that it's the turbine side thats limiting the set up? Have you played with turbine housings to see what effect it has?

I've seen your dyno sheet and, to be honest, it's pretty bloody impressive to have the midrange and top end you have considering the relatively low capacity and relatively large turbo (and turbine housing A/R). Personally i'd leave it, unless you are chasing a number.

Wow your turbo is as responsive as when its on RB25's, how much pre-load is used to get it like that?

edit - just looked @ your graph, whats 136km/h on your setup?

Anyways, how much power/response are you after exactly? Purpose of the car?

You kinda haven't really said, so sorta hard to look at what turbos might fit your requirements... without listing them :P

Also, how much boost was needed for 300rwkw/RB20? And was the 250rwkw with the same boost and thats the reason its holding back?

I'm running 23psi boost for that power level ,the tuner has said to me more boost made very little differance so he left it there but seeing as it was a fresh engine (1600klm) then he played it safe as I told him I'd be happy if it made the 300kw mark.

BHDave I played with smaller housings on earlier turbo's (cost me a small fortune) and consulted with a turbo builder who had done the mods to previous turbo's for me ,though he did originaly suggest the gt3540 he thought the gt3040 with the .82 rear housing would be enough so went on his advise.Dont get me wrong I'm real happy with the way it is atm I drive it around on low boost which is 13psi and its maken 240rwkw at that .

Reason im thinking more is I put alot of work into getting boost to come on as early as possible and in building a solid engine ,it has the running gear for alot more hp the trick is getting it ,im not doing it for numbers im doing it for myself to see what I can get out of it and still make an enjoyable car to drive

R31Nismoid I dont understand what you mean by pre-load ,I'll have to check the graphs when I get home for the power at 136klm's .(edit)Power at 136km/h is 280rwkw @ 5100rpm going of the dyno sheet.I have not set goal on power level since I made the 300rwkw mark except how much more is it capable of ,wasn't that long ago that 300kw was unheard of in an rb20 ,now there's quite a few pushing that mark so how much more can they go.The 250rwkw mark was on same boost level but at 4200rpm the 300rwkw at 6500rpm

I like using the car at the drags although I will be doing some track days with it .It has run an 11.7 at wsid but think I can better that yet.

I can build an engine and fully rebuild a car but I'm afraid undersatnding turbos atm is a little beyond me and how they flow so I'm trying to find a better solution and some more info on what is going to work best without going stupidly large turbo thats usless execpt on superhigh rev's it is still a weekend driven car,

cheers Peter

I see where you are coming from re the bigger turbine in a smaller housing, you are trying to trade off any extra lag as a result of the larger rotating mass by having a smaller turbine housing to force it to spin up quicker.

It's the way i'd do it, despite knowing full well that high exhaust manifold pressure is the enemy.

Just consider you have the extra torque a bigger turbine can provide spinning up the same compressor so i don't think you will be stepping backward significantly in response even with the same sized turbine housing. The potential is there to choke at the top end with the small housing.

All i can suggest, if you decide to go ahead, is be prepared to step up on the turbine a/r.

  • 7 months later...

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

    • Welcome to Skyline ownership. Yes, it is entirely possible parts websites get things wrong. There's a whole world of inaccuracies out there when it comes to R34 stuff (and probably 33 and 32). Lots of things that are 'just bolt on, entirely interchangable' aren't. Even between S1 and S2 R34's. Yes they have a GTT item supposedly being 296mm. This is incorrect. I would call whoever you got them from and return them and let them know the GTT actually uses 310mm rotors. Depending on where you got them from your experience and success will obviously vary.
    • Hi...a bit a "development" on the brakes. I spoke to the guys where i get brakes from...and they are saying that 296mm EBC are for R34 GT-T. I then went to their site: https://www.ebcbrakes.com/vehicle/uk-row/NISSAN/Skyline (R34)/ and search for my car(R34 GT 1998 - it has GTT brakes) and it show me this USR1229 number and they are rly 296mm rotors... So now iam rly confused... The rotors i have now on the car are 310mm asi shown... So where is the problem? Does the whole EBC got it wrong or my calipers are just...idk know what?  
    • Oh What the hell, I used to get a "are you sure you want to reply, this thread is XX months old" message. Maybe a software update remove that. My bad.
    • This is a recipe for disaster* Note: Disaster is relative. The thing that often gets lost in threads like this is what is considered acceptable poke and compromise between what one person considers 'good' looks and what someone else does. The quoted specs would sit absurdly outside the guards with the spacers mentioned and need  REALLY thin tyres and a LOT of camber AND rolling the guards to fit. Some people love this. Some people consider this a ruined car. One thing is for certain though, rolling the guards is pretty much mandatory for any 'good' fitment (of either variety). It is often the difference between any fitment remotely close to the guards. "Not to mention the rears were like a mm from hitting the coilovers." I have a question though - This spec is VERY close to what I was planning to buy relative to the inboard suspension - I have an offset measuring tool on the way to confirm it. When you say "like a mm" do you mean literally 1mm? Or 2mm? Cause that's enough clearance for me in the rear :p I actually found the more limiting factor ISNT the coilover but the actual suspension arms. Did you take a look at how close those were?
    • @GTSBoy yeah sorry i know thery are known for colors bud those DBA are too in colors 🙂 Green will be good enough for me  
×
×
  • Create New...