Jump to content
SAU Community

Recommended Posts

hey guy's just asking the turbo guru's here if its possible to correct the massive mix match in housing/wheel design that is present in the gt2876r... the turbo is strapped to a rb25 and is rediculusly laggy for not alot of power or "punch" spec's are :

Turbine

-Wheel: 53mm w/ 62 trim

-Housing: .64 ar

Compressor

-Wheel: 76mm w/ 48 trim

-Housing: .70 ar

4inch front mouth

its for a moded std manifold...

please no suggestion's of changing turbo's etc at this time, as i would like to explore the possibility for changing housing's etc...

Link to comment
https://www.sau.com.au/forums/topic/213319-2876r-downsize/
Share on other sites

say for example, 1 bar actuator presure. 2nd and 3rd gear approx fullboost @ 4500 rpm... this is untuned though, running old tune from std turbo, however i cant see the turbo getting anywhere below what i'd be happy with...

Link to comment
https://www.sau.com.au/forums/topic/213319-2876r-downsize/#findComment-3768006
Share on other sites

Your call but your not going to fix that thing with housing alterations , the only genuine option is a larger .86 A/R turbine housing and that will only give it more turbine lag .

The problem is it has a modern low blade count light weight 54mm diameter turbine trying to drive a dinosaur 76mm T04S compressor wheel . Changing housings won't alter the fact that its compressor is a really bad match for its turbine .

Why Garrett continue to sell those POS things I'll never know .

IMO it has to go if you want you car to be lots better .

Sorry , A .

Link to comment
https://www.sau.com.au/forums/topic/213319-2876r-downsize/#findComment-3768439
Share on other sites

Are you sure about that turbine trim? It should be the same as a 2871 rear end.

The only way you could make that turbo usable is to replace the whole front end. I would suggest .5 A/R generic t04e comp cover and backing plate, with a 71mm 52 or 56 trim compressor.

By the time you get the work done and supply the parts it'd be cheaper and easier to just find a second hand replacement 2871 on NS and sell yours. They all seem to be going bigger these days for some reason, you may even find a sucker to buy yours :thumbsup:

Link to comment
https://www.sau.com.au/forums/topic/213319-2876r-downsize/#findComment-3768884
Share on other sites

By the time you get the work done and supply the parts it'd be cheaper and easier to just find a second hand replacement 2871 on NS and sell yours. They all seem to be going bigger these days for some reason, you may even find a sucker to buy yours :D

no way.......NS members are way too astute than to buy a 2876 - thats only something a skyline driver would buy :laugh:

Link to comment
https://www.sau.com.au/forums/topic/213319-2876r-downsize/#findComment-3770950
Share on other sites

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


  • Latest Posts

    • For once a good news  It needed to be adjusted by that one nut and it is ok  At least something was easy But thank you very much for help. But a small issue is now(gearbox) that when the car is stationary you can hear "clinking" from gearbox so some of the bearing is 100% not that happy... It goes away once you push clutch so it is 100% gearbox. Just if you know...what that bearing could be? It sounding like "spun bearing" but it is louder.
    • Yeah, that's fine**. But the numbers you came up with are just wrong. Try it for yourself. Put in any voltage from the possible range and see what result you get. You get nonsense. ** When I say "fine", I mean, it's still shit. The very simple linear formula (slope & intercept) is shit for a sensor with a non-linear response. This is the curve, from your data above. Look at the CURVE! It's only really linear between about 30 and 90 °C. And if you used only that range to define a curve, it would be great. But you would go more and more wrong as you went to higher temps. And that is why the slope & intercept found when you use 50 and 150 as the end points is so bad halfway between those points. The real curve is a long way below the linear curve which just zips straight between the end points, like this one. You could probably use the same slope and a lower intercept, to move that straight line down, and spread the error out. But you would 5-10°C off in a lot of places. You'd need to say what temperature range you really wanted to be most right - say, 100 to 130, and plop the line closest to teh real curve in that region, which would make it quite wrong down at the lower temperatures. Let me just say that HPTuners are not being realistic in only allowing for a simple linear curve. 
    • I feel I should re-iterate. The above picture is the only option available in the software and the blurb from HP Tuners I quoted earlier is the only way to add data to it and that's the description they offer as to how to figure it out. The only fields available is the blank box after (Input/ ) and the box right before = Output. Those are the only numbers that can be entered.
    • No, your formula is arse backwards. Mine is totally different to yours, and is the one I said was bang on at 50 and 150. I'll put your data into Excel (actually it already is, chart it and fit a linear fit to it, aiming to make it evenly wrong across the whole span. But not now. Other things to do first.
    • God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
×
×
  • Create New...