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Best Turbo for RB25DET

Guest Sphyncter

By Guest Sphyncter,
in Engines & Forced Induction

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sweetr33 Experienced

sweetr33

Posted
Posted

oh and i forgot to add. I believe that the highflow comes in 2 stages if u wish. Stage 1- 450hp rated and stage 2- 500hp rated. I mean realistically people are getting within 50hp of the claimed hp limit so i reckon 400 ponies is more than enough to satisfy most

heno Collaborator

heno

Posted
Posted

what else are you planning on doing to your car? nice big hp turbos are gr8, but if you dont have a good pump, injectors, ecu, front mount, depends on what turbo, custom manifold. and maybe lowering the compresion, if you already have this stuff i would go 2535 or 3040.good for 250-270rwkw+, if you dont have this stuff i would just get your old one high flowed from gcg. good for 230-240rwkw

predator Grand Master

predator

Posted
Posted
e stock one is good at low spoolup, even faster if you fit;

1. lightweight flywheel

2. exhaust cam wheel (retard 4 degrees)

3. 3" dump pipe straight off the turbo to a decat or 3" cat pipe

4. hks exhaust camshaft

5. learn how to use the search tool tool.

yup.. exactly.. no point in getting another turbo unless you're getting the most out of what you already have. With "Everything else" you should be able to get down to a low 13.x 1/4 mile which is very respectable. Turbo should almost the very last thing on your shopping list.

KamikazeR33 Grand Master

KamikazeR33

Posted
Posted
yup.. exactly.. no point in getting another turbo unless you're getting the most out of what you already have.

meh :cheers:

there r plenty off good turbos out there for the hp u want

u can pick up some good 2nd hand turbos cheaply - look around

SLY33 Mentor

SLY33

Posted
Posted
yup.. exactly.. no point in getting another turbo unless you're getting the most out of what you already have. With "Everything else" you should be able to get down to a low 13.x 1/4 mile which is very respectable. Turbo should almost the very last thing on your shopping list.

hi guys, i would disagree with this.

im not sure it would represent bang for buck once you add it all up. I was going to do the flywheel, cam gear and all the little accessory power things etc, but the cost plus fitting of all these just do get small gains works out to be as much as a new turbo. And only for low 13's.

I ended up selling my cam gear and forgetting the flywheel for now and went straight for an upgrade turbo. at 1800$ plus fitting/tuning and the car should run easy 12s.

Granted you will still need a couple of extra things like a Rising rate reg, but the stocky turbo wont match the midrange and top end increase in huff over of upgrade/highflow. Im quite happy at the moment with how the car drives, and dont desire a whole lot of extra power, and now i can still add the little things like the cam gear if i want a bit later on.

(if you go a highflow of the stockie you can probably "get away with" the standard dump pipe too. I made ~230rwkw with stock dump but with an HKS2530 it wasnt real suitable. A good dump is always a good idea though)

Im not saying cam gears, flywheels etc arent worth it, and eventually id like to add them all. Even if you get up near 220rwkw with the std turbo, the torque wont compare to an upgrade turbo. To get the most out of any modifications you'll need an ECU in any case.

Steve Grand Master

Steve

Posted
Posted

perfect turbo eh? well, you really need to think about what sort of hp you want, what support systems you have or will get, what sort of money you want to spend, etc

soo many variables, the problem is, what is 'perfect' for you may not be what is perfect for the next guy, also, by the sounds of your post above, I dont think you have a great grip on how turbos work - dont think I am having a go, cos I'm not.

BIG hp will mean lag - no way around it - to flow well top end, means they wont flow well bottom end, its a compromise. For example the stock turbo is designed for mid range, come on boost early, but runs out up top. Big turbo will come on boost alot later, but will have top end, medium/big will have some mid range with a good top end, but still come on boost later.

A really good alrounder is the HKS2530 - just ask sly33, so if you are after a turbo that comes on boost early, is responsive and gives a decent increase to top end, go something like this, or an equivelant. But remeber also, that a turbo needs support systems upgraded to show its true worth.

I would recommend, as Rob77 has, that you do a search. there is a fair bit of info out there on turbos. then when you are thoroughly confused by it all, ask again, and be more specific, stuff like rwkw goal, where you want good boost to be made, how hard you want it to hit, etc and tell us what support systems you have or will be getting. Lastly, an indication of budget is a good thing too.

rs73 Grand Master

rs73

Posted
Posted

I've had two opposing views of the 2530, 2535, & 2540 on RB25...

One side definitely go for these turbos as stock injectors can still be used with this range, and it spools up faster... Although for 2540 might be on the limit of injectors and better to upgrade them. Fuel pump still needs to be upgraded.

The other side is against this turbo as it's too small, keep spinning the wheels on 2nd, 3rd gears and the power curve drops off before building enough desirable power... This side recommends to go a minimum of 2835 or above like 3037. Upgraded fuel pump and injectors are a must.

Which one is which now...

predator Grand Master

predator

Posted
Posted
im not sure it would represent bang for buck once you add it all up. I was going to do the flywheel, cam gear and all the little accessory power things etc, but the cost plus fitting of all these just do get small gains works out to be as much as a new turbo. And only for low 13's.

Problem is quite a few people stick a bigger turbo and still only get high 12's. As they have neglected much of the handling and support issues like good tyres, handling items, etc because they're dont want to waste money on that.. but when you consider the total costs (AFM, ECU, turbo, fitting) there is not much way to get it all done for much change out of $5k. That buys a lot of other stuff. But yeah, big turbo gives the most instant hp no doubt about it.. but if its just "bang" spin, spin on the wheels.. stupid.

Other option to the HKS 2530 which is looking nice is the Trust 517z (for around 230rwkw).. or 518z (for around 250rwkw).. Pretty much same torque curve, just the 517z drops off a little earlier. Depends whether you believe in trusting plain bearing vs ballbearing. Trust has been building plain bearing turbos for a long time, obviously they see no need to go for ballbearing. I've been looking a little, these turbos can be had for under $2500 shipped from japan new. Not too exxy.

lol - you've got a silvia anyway! what u talking about.. different turbo combos you need for the silvia. Generally you can get away with smaller for same power as the rb.

  • 4 years later...
teng Rising Star

teng

Posted
Posted (edited)

Old thread but.....

Does hi-flowing need to be done professionally or can just buy the Hi-flow kit from a vender and bring your turbo to the local machine shop to make it fit?

Edited by teng
GtstCoupe Proficient

GtstCoupe

Posted
Posted

Hey Teng,

Highflowing must be done professionlly, As its balanced and the housing is machined for bigger wheels etc.

There area few companies, But GCG is very highly spoken of and recommended. :D

Usually you send off your existing turbo and usually within a week you recieve it back for to bolt back on.

If you carnt have the car off the road for long, they may be able to sent one out done for you and you simply send

your old one back to them, And away you go.

The above applies not only to GCG but other turbo builders too.

Check the RB25 Dyno thead to see results of the highflow and

may other turbo on the RB25. :D

:) Cheer

  • 2 years later...

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