RB25DET turbo rebuild

[A31_Cefiro]

Hi,

Thought you might be interested in this info. I rang GCG turbos (really friendly people and easy to talk to) to get a quote for a high flow rebuild on the RB25DET standard turbo. Here is what they told me:

They replace the standard ball bearing, replace turbine and compressor wheels with higher flowing steel items. They also machine the housings to suit. They do two different trims. Stage 1 costs $2,200 and they have been able to get 225RWKW, stage two is $2,450 and they have been able to get 257RWKW. In stage 2 trim the tuebo was running 25PSI Boost.

They also told me that Garret GT series and HKS GT series turbos are not rebuildable. The GCG rebuild retains it's rebuildable qualities and comes with a 12month warranty.

[Silver-Arrowz]

Full ball bearing turbo's are not rebuildable. I think the Nissan turbo's are ball bearing on the inlet side only, or other. But it's one side only. Somehow they are rebuildable.

However, I reckon go full ball bearing cause it spools up faster.

[SLY33]

i heard GCG were great and really good to talk to about upgrades, but when i rang i got this old dude who couldnt talk kilowatts, and couldnt give me a rear wheel figure on his st2 turbo rebuild!!

I asked him about rwkw figures, and all he kept saying was his st2 turbo was good for 450hp. He couldnt be specific with me about boost either, so im glad you posted this A31.

I like the power figure at the wheels, but at 25psi, thats way too much boost man. You cant run anywhere near that with the std head gasket.

It sounds like their turbo is inefficient, and ive heard from others that they are a bit laggy too.

Look at whatsisnames turbo. 257rwkw at 13psi!!! damn, thats great power for basically the same boost im running with my std turbo!!

[Silver-Arrowz]

In realiality, nothing and nobody can guarentee you X amount of HP with Y upgrade. The figure he gave you is theoretical in the perfect environment.

He knows it too, that's why he avoided the question cause if he said X amount and it didn't deliver, you'd be on his back in a lighting bolt!

[A31_Cefiro]

They are good points.

I talked to Brett and he didn't guarantee the power but he said that is the power they have been able to get out of it.

He did also state that the stage 2 turbo should be run with other upgrades like fuel pump, injectors etc so he was quite open about this.

What turbo is whatsisname running? I'm investigating options for turbo upgrades and would be interested in hearing about what other people have fitted and the power they make.

[HEL-RZA]

Originally posted by A31_Cefiro

Hi,

They replace the standard ball bearing, replace turbine and compressor wheels with higher flowing steel items.  They also machine the housings to suit. They do two different trims. Stage 1 costs $2,200 and they have been able to get 225RWKW, stage two is $2,450 and they have been able to get 257RWKW. In stage 2 trim the tuebo was running 25PSI Boost.

for that price, possibily less, you can buy a new turbo fitted!!

[Guilt-Toy]

Get a VL turbo $500 and highflow it and rebuild it $650 and install it... You need to modify one oil line and you need to bend a couple of water lines and get a custom dumpie. and bang your ready for 500 hp to the motor..

Thats what i have.. i admit its laggier then standard turbo but bigger turbo allways means more lagg.

[hungry6]

so basically they're saying, they'll keep ur hopusing and swap the entire cartridge for $2200, what a farking rip of !!!!! u can obain brand new gt25 to bolt up for under $2000.

[meggala]

hungry 6 the gt25 doesn't bolt up to the manifold and they are set up for sr's and ca's not rb's.

cefiro dr drift had a vg30 hiflow I drove his car and the turbo was awsome and it was non ball bearing we are talking come on to boost @ 3k ish full boost 4 k rpm when you hit full boost in second the wheels start spinning very nice this was @ 1.2 bar.

disscussing this with him we both came to concluson that we would get a small er exhaust wheel for faster spoolup if we were to get one again. btw this was a non ballbearing turbo so may be the ball bearing option would be better. but the cost difference was big around $800. the car was nuts and it was running stock injecotor bigger fuel pump and z32 afm it ran 108 mph on the track the 1/4 time was slow cause of wheel spin.

the specs were

T3/4 Turbo => Custom made by ATS with 55mm TO4E Comp Wheel and 54mm RX7 Rear Wheel, Oversized wastgate valve, 0.8 Bar Actuator (NEW)

cheers

meggala

[A31_Cefiro]

Thanks. I'll check that out too!!!

[Warpspeed]

If it was me I would go out and buy a brand new or slightly used ball bearing turbo.

There are a lot of myths and BS about concerning the high flowing of turbos.

The old style garrett turbos T2, T25, T28, T3, TO4, and so on are at least thirty year old designs now.

Hell, I was using them 30 years ago, and they were not new designs then.

There is nothing really wrong with them, except the peak efficiency and flow ranges are not as good. The wheels are also larger and heavier than new designs. BUT THEY ARE CHEAP, and if you are on a budget go ahead and have some fun.

Both compressor and turbine wheels tended to be larger diameter, and skinny, with smakller a/r housings. This means the flow range is less, making matching much more critical. They can still make a lot of power though, make no mistake.

Fast forward thirty years to today.

The fact that ball bearing turbos have ball bearings is not the main feature that makes them so good. This point is not generally understood.

What is so good about them is thirty years of computer design simulation technology. The wheel sizes and blade technology is far superior. If you look at modern turbo wheels the major diameter is smaller, and the eye size is larger. The new wheels are fatter, weigh less, and have far less inertia.

Housing sizes now typically have far higher a/r than the old designs, and a far greater flow range, and better peak efficiency.

But the real trick is that the turbines and compressors are better matched for speed and energy. This combined with low inertia is what makes them spool up so fast, and deliver high airflow as well.

All good stuff.

If you think you are smarter than Garrett, or HKS, and can combine bits and pieces from various thirty year old turbos to build yourself a high flow hybrid - well the best of luck. Personally I would not be bothered.

Just go and buy yourself a modern ball bearing unit, and be really happy with the results.

[hungry6]

get a 450hp gt25 and spec it with a 0.64 T3 exhaust housing. it will bolt straight up with intake pipe mods . and u be supprise at the power it generates with other mods. as i remember it came on boost about 3-400 rpm later than the stocko unit. or if u want there is a rarer version of the gt series it's the gt28 that's a lil beauty but also pricey if u can find 1.

[T0nyGTSt]

Why not just buy an aftermarket turbo? Surely this would be less than the $2,000+ cost these guys want?

T.

[A31_Cefiro]

The cost depends. As all the new large turbos I have seen retail higher than $2K then you have to factor in new manifolds (maybe) or new exhaust parts, plus you might need an external wastegate and have it all fitted up which would cost more then the rebuild price....

[dAVE]

was just speaking to a mob up here on the gold coast about it this morning. Didnt really understand what he was saying, but he said that they are not rebuildable, but can be highflowed and new T4 internals or something. He was talking around 1700 for this.

As I said, wasnt really listening or interested as I went there for another reason, so I didnt ask power figures etc.. but if you want to give them a call, look up MR Turbo in the yellowpages.

[Guest INASNT]

isent the biggest turbo that will fit the stock mainfold a 2540?

how much power can u get from that?

[ice180]

mona's beast got 240kw at the rears with a HKS2530... few other minor mods.