Upgrading Rb25det Turbo

[bibsteys]

hello my name is brian and i am new to the forum. I have a 1990 gts-t type m with rb25det. Currently i am without a drivers licence for the next 6 months. i will be doing some modification and would like some advice. currently on the car i have a greddy downpipe with an apexi cat back for my exaust. i also have an old blits sbc witch will only allow me to boost to 12 psi. the parts that i have but are not on the car yet are brembo brake roters an hks bov and an intake manifold. the next things on the list to order are a greddy oil cooler/relocation kit along with a trust fmic. what i am wondering is witch turbo i should go with? i would not like to retain my factory manifold and i would like a turbo that can run at least 2 bar safley with a decent responce. any suggestions i was looking at a used hks gt2540 but its gone now. dont want to spend an arm and a leg on a turbo. ill wate untell i get it and spend some doh on a nice stand alone ecu.

any suggestions on the turbo or general good ideas whan adding boost are appreshiated thanks brian!

[jase-r34]

G'day Brian and welcome to SAU! There is a wealth of information on here. If you have some time just have a search through and I'm sure you'll find some good stuff relating to what you're looking for

As far as running 2 bar... Hope you are planning on rebuilding nice n strong!

[andymoocow]

gday Brian.

best place to start reading is here:

http://www.skylinesaustralia.com/forums/Rb...yno-t55845.html

There are HEAPS of pages of reading but its extremely helpful and i read from page 1 to the end before i chose my turbo. You can see LOTS of dyno graphs for response plus other mods people have done to get the results they have posted.

Good luck mate, and enjoy.

[Lachlan33]

2 bar lol. Thats like 28 psi mate.

You need to be aware that you can't just buy a bigger turbo, whack it on and have instant power gains. You need to have all sorts of supporting mods, from a decent exhaust, to engine managment, different Air flow meter, fuel Injectors, etc.

Instead of aiming at a particular level of boost, let us know what sort of power your looking for and people should be able to give you all sorts of info in regard to what you would need to do to get that. For example if you are looking at the 200-250 kw range then your choice of turbo is going to be very different to if you were chasing 300kw or more.

And remember, 12 psi from a small turbo is not the same as 12 psi from a large turbo.

[bibsteys]

Thank you for the helpful reading. sorry i did not to go into more detail about the build i would like to do. I would like to make 400 rwhp. but i would also like to retain a turbo with a good responce. im looking at some faily cheap manifolds i looked at using the stock one but thats just not the way to go. I plan to upgrade to top feed injectors with fuel pump ect but i am still reaserching my fuel system. not sure exactly wat i am going to do yet. As far as engine managment goes im realy hoping to be able to afford the haltech. I am oredering things slowly and making sure i buy the right stuff as time realy isnt a factor. considering i have no licence(drifting in parking lot bad idea).

Any tips usfull thanks brian

[joeyjoejoejuniorshabadoo]

a 2540 wont get you to 400rwhp... and will be out of its efficiency range before 2 bar

look at a garrett 3076. this will get you to 400 without losing that much response.

for referance...i'm running an HKS 2835, which is basically modified a garrett 3071 and i get 285rwkw (380rwhp) on 98 ron with near stock response.

[Pattygtst]

for 400rwhp or 300rwkw best turbo option for response is a gt3076 in a 0.82 housing a 0.63 might get there but i doubt it.

[Turbz RB-25]

HKS GT2835, I got 274 rwkw (about 370rwhp) with that baby!

Bloody good response!

[Lachlan33]

I am myself looking at going to a GT3076 with a .82 housing. From what I have found through searches and the dyno results forum, this should get 400rwhp quite easily provided you have the supporting mods.

Be aware though that it is generally regarded that 300rwkw is hovering around the limits of what the stock internals can reasonably take.

You mention going to top feed injectors, I may be wrong but I don't think that is required. I think some 550cc injectors and an upgraded fuel pump should meet your needs.

Then you just need some sort of aftermarket ECU, a decent cooler and exhaust and you are on your way. My stock clutch gave out not long after 200rwkw, I suggest upgrading that if you have not already.

[joeyjoejoejuniorshabadoo]

top feed injectors are not needed if you keep the stock plenum. nismo 555's are bolt in

for an aftermarket plenum you'll probably need top feed of same size and a new rail

manifold wise the stock one is well within its efficency range @ 3oorwkw and is not worth replacing unless you really want a highmount.

there are low mount ones avail, but the results vary from nothing, to a slight gain, to even a slight loss in some cases.

the stock plenum is also good for these numbers, and will only really aid you in cosmetics at that power level

you will also definately need:

fuel pump - i run a nismo item, drop in... highly recommended

clutch - single plate button - nismo supercoppermix single plate is good but expensive

fmic - look @ hybrid or jjr for good cheaper options that are well capable of 300rwkw or ARC if you like spending

ecu - power fc / vipec / link / haltech / microtech / remap (power fc probably best option due to price and tuners)

also a good idea:

diff - there is no point having 3oorwkw and a single spinner... trust me! i have a nismo 1.5 way gtlsd pro tt - VERY VERY highly recommend

guages - oil pressure and temp, as well as water temp and boost are good

EBC - greddy profec b / blitz dsbc is good for a cheaper option that will hold you pretty well

also while the turbo is off rip off the mani and replace the gaskets with metal ones, will only cost a little and is cheaper than fixing later.