Jump to content
SAU Community

Recommended Posts

HI GUYS,

i have found a good n cheap GT3040 for $1300 and was wondering how well this will go on a standard RB25 engine. I got stock internals, stock cams, stock plenum however got a powerfc, fmic, big injectors n pump, intake etc. I am aiming at 260rkw which i know ill get but will my internals hold and will i get lag from this turbo?

Is it tooo big for standard RB25, will i stress it, or will i just get lag?

thanks

john

Link to comment
https://www.sau.com.au/forums/topic/167495-gt3040-on-a-standard-rb25-yes-or-no/
Share on other sites

compressor is larger the exhaust? what the? are u sure ?

Very common Paul :P

The engine should be right, if the tune is kept SAFE and a little on the conservative side. This should be half decent on a rb25. The smaller ext housing will provide a faster spool up, but will limit peak power. At a later stage, if you thirst more power, you can always upgrade to a .83 ext housing, which is a better match for this turbo.

All the best. Make sure the flange is suited to a rb25 manifold.

Very common Paul :P

The engine should be right, if the tune is kept SAFE and a little on the conservative side. This should be half decent on a rb25. The smaller ext housing will provide a faster spool up, but will limit peak power. At a later stage, if you thirst more power, you can always upgrade to a .83 ext housing, which is a better match for this turbo.

All the best. Make sure the flange is suited to a rb25 manifold.

thanks mate but what u mean the right flange. its a t3 flange however this turbo came off an sr setup. doesnt any t3 exhuast falnge bolt up to the rb25 t3 manifold.

thanks

john

Very common Paul :P

The engine should be right, if the tune is kept SAFE and a little on the conservative side. This should be half decent on a rb25. The smaller ext housing will provide a faster spool up, but will limit peak power. At a later stage, if you thirst more power, you can always upgrade to a .83 ext housing, which is a better match for this turbo.

All the best. Make sure the flange is suited to a rb25 manifold.

^ wat he said!

the only time u will see the exhaust housing bigger then the compressor housing will be on a rotor or a bigger engine eg. V8, truck even ur standard turbo has a smaller compressor housing then ur exhaust housing

being a .63 rear exhaust housing it will provide very fast spool on a 2.5L engine BUT will limit power up high in the rev range but if ur only looking for 260rwkw this turbo wont have a problem giving it to u, this turbo will make alot more power then that i made 276.6rwkw with a standard bottom end with a SR20

the rear exhaust housing has a .86 option so u can always change it at a later date if u want more topend power but the price u pay for more power will be lag

oh im the one selling the turbo by the way :)

Edited by STR8E180

lol the pic gave it away lololol ill make my decision based on wat else i need to install but should be a problem

^ wat he said!

the only time u will see the exhaust housing bigger then the compressor housing will be on a rotor or a bigger engine eg. V8, truck even ur standard turbo has a smaller compressor housing then ur exhaust housing

being a .63 rear exhaust housing it will provide very fast spool on a 2.5L engine BUT will limit power up high in the rev range but if ur only looking for 260rwkw this turbo wont have a problem giving it to u, this turbo will make alot more power then that i made 276.6rwkw with a standard bottom end with a SR20

the rear exhaust housing has a .86 option so u can always change it at a later date if u want more topend power but the price u pay for more power will be lag

oh im the one selling the turbo by the way :P

well i can give u a list of wat ur going to need

because the turbo is external gated ur going to need an external gate

and because u need an external gate to control boost ur only to need a manifold with an outlet to fit an external gate onto

and ur going to need ur intercooler pipe moded to suit the compressor housing outlet, ur also going to need a new intake pipe because the compressor housing inlet is 4inch so ur going to need a new 4inch air filter (K&N fits perfect)

ur also going to need new oil and water lines made up and a new dump pipe

if are u are in sydney i will be able to make up all the new intercooler pipe + intake pipe + dump pipe for u

im a fabricator by the way

A couple of things I'd be concerned about .

1) Personally I'm not a fan of the big 82mm OD compressors on the 60mm turbine .

2) Advertised as a "4 bolt" turbine housing . Make sure its got the conical stand off on the back of it or its not a propper

GT30 turbine housing . Only available in T3 flange .63/.82/1.06 from Garrett , both integral and external wastegate .

No offense but I think its brave to compare turbine and compressor housing A/R ratios because they live in totally different environments . The difference in temperature of the gasses let alone pulsed exhaust gasses make their requirements very different .

Its entirely possible to run quite large divided turbine housings because the whole expansion of the hot exhaust gasses across a pulse divided system means venting into an area of lower pressure and ultimately volume on the way from the exhaust valves to the turbine blades . The single scroll turbine housing forces you to size its A/R ratio to work a bit like a venturi or nozzle to accelerate the gasses into the turbines inducer blades . If you have to do it this way the roads to rapid transients and acceptable boost threshold is to use conservative compressor wheels that need the least turbine energy to get them cracking .

This may make you laugh but Garrett would have been better off doing the GT3082R the other way round compared to a GT3582R ie the GT35's turbine with the GT3076R's compressor making it a GT3576R . That way you get the larger turbine shaft torque to drive the 76mm GT compressors power needs . THEN if you have to pull back on turbine housing A/R at least you get sufficient power from the 68mm vs 60mm turbine .

Funnily enough Garrett do make the GT3576 and GT3576R but its in the larger centre section (the ball bearing version) and I believe its the diesel spec HP turbine rather than the petrol performance spec UHP turbine . A "GT3576R" would be like an upsized real GT3071R ie turbine diametre closer to compressor diametre . The real GT3071R is 60/71mm diametres whe a "GT3576R" would be 68/76mm . One who worked for Garrett Aftermarket US did tell me this combination would be good but there is also going to be a slight turbine innertia issue . I think you could get around this easily enough with well thought out manifolds/turbine housings and as always tuning .

Off the topic , IMO the GT3082R is the wrong way round and tries to drive a 680 Hp capable compressor with a 500 Hp capable turbine . I think people find the things laggy because the turbine can't develop enough shaft power at low engine speed/exhaust gas velocity to supply the power an ~ 62lb/min (air) capable compressor . The real GT3076R's compressor is good for ~ 53-54lb/min and the real GT3071R's ~ 50lbs/min .

I reckon using the .63 A/R turbine housing on a GT3082R merely forces higher exhaust gas velocity into the turbine which my get it going but prematurely chokes up the exhaust side - its the engine that suffers .

Cheers A .

I reckon using the .63 A/R turbine housing on a GT3082R merely forces higher exhaust gas velocity into the turbine which my get it going but prematurely chokes up the exhaust side - its the engine that suffers .

Cheers A .

Which is generally why the GT3082's make bugger all if any more power over the GT3076's UNLESS they are pumped full of 100+ron fuel and or water meth injection.

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

    • Seat of the pants assessment of the new intake: The car is way less "doughy" when hitting the loud pedal, especially off idle when stopped or in traffic, I did use a cheapo lazer thermal thingo to measure the temp around where the pod filter got its air, it was between 55 - 60°C, in saying this the car was shut off and not moving, so the OEM intake pipe was not supplying any fresh air to where the pod was when the car was at least moving A weird bonus was induction noise on the throttle in the cabin increased a bit,  I was worried that I was actually going to lose some of that induction noise I love so much, outside though, when I got the daughter to do a WOT drive by pass for me, the induction noise has increased alot when on the throttle, not quite ITB doort, but well up there I'm extremely happy with the results and have been exploring the country roads in the region  As for house mods: 1.New front fence is up and is awesome, it really upgraded how the joint looks from the street, and the added security is nice 2. Electricians have replace some interior lights, and with more lighting in the garage, a few new motion detecting lights out the front above the garage, front room, and at the front door, which I have already found heaps helpful coming and going, also now has fancy pants CCTV all round the house The only hold point for power though is the solar and batteries due to supply issues, although this will happen over the next few weeks 3. I have done a heap of landscaping out the front and I'm almost ready to do a new small retaining wall with some nice blocks to replace the brick and cemented in rocks around the raised garden beds cemented in river stone "was the fashion at the time" the house was built. I currently have a pallet of retaining wall blocks and 2 bulka bags of 20mm blue metal to replace the wood chip that is in the raised garden beds around the house 4. I now have 3 big raised garden beds for out the back to grow some vegetables, about 70cm high, 200cm long and 100cm wide 5. My 2 compost bins are already pretty full with brown, green and kitchen waste from the landscaping I'vedone so far, but they will probably take a few months to break down, so anything else that gets chopped, trimmed, and kitchen waste will just start filling the base of the raised garden beds to about 30cm before I start throwing 40cm of good compost, and stuff, for the vegetables to grow in, I'll need a few ton of compost and soil, but the local supplier can sent me bulka bags of the stuff Basically the logs, wood chips and a few strategically placed rocks for drainage, will give the beds some good organic materials down low to break down over time, and they will hold moisture during the warmer months to save the water in my big arse water tank if we don't get alot of rain So, all in all, the car and house mods are going well, and I'm really enjoying being retired, I sleep in too 0700 and slowly plod around inside until I feel like actually doing anything, and only work in the yard for as long as want, which has actually been alot over the last few weeks,  although when you look at it, it seems that not a huge amount of work has been done,  until I look at the before I started the work pics Happy days and good times indeed 
    • hahaha yeah. Plan is to get side skirts and probably just rear pods. But going to do them one-by-one. I've got a set that I really like from RHDJapen, but that one isn't shipped to AU. So need to find someone who can get it for me
    • Here's an idea, answer the questions I asked you as they are trying to work out WHY the LSD will be binding up in a straight line.
    • You haven't driven many modern cars then have you? Most of them have sfa steering feel with their stupid electric bullshit steering systems.
×
×
  • Create New...