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Tomei dumps are 75mm so unless your front pipes are also 75mm(rare), they are a waste.

However we regularly see up to (and over) 400 rwkw with std dumps.

Have also done back to back tests at 360- 380rwkw with the ONLY change being the dumps and there was NO measurable difference.

We have done this test backwards and forwards several times now (fitting them and removing them, big pipes , little pipes) and again NO measurable difference.

Hard to believe as the std stuff looks like crap, but results are results.

On -7's and 300kw, its not even a consideration imo.

Actually this is the one you want if you like HKS GTSS RB26 performance , everyone everywhere thinks these ARE GTSS turbos with Garrett actuators . Compare the comp maps to the other suggested turbo .

A .

http://www.turbobygarrett.com/turbobygarre...0R_707160_9.htm

http://www.turbobygarrett.com/turbobygarre...0R_707160_7.htm

Edited by discopotato03
not much differance between the 2?

In the real world, there is virtually nothing seperating these 2 (-7 or -9) in terms of power. (both can top out north of 350rwkw)

If anything, the slightly "friendlier" comp wheel on the -7 may spool marginally better than the -9 (SS)...but it is almost too close to call.

You will get great results with either.

The GTSS do come with 1 bar actuators, as do -5s

However -7's come with 11lb actuators (as they are intended to be a bolt in std replacement) which are a bit lamo for the higher boost applications.

It is advisable to upgrade them to the 1 bar actuators if you intend to wind em up past 20lb

Edited by RPMGTR

Well up to you you but if you look closely at the "islands" and the percentage numbers I know which in theory is going to blow slightly cooler air .

Also if you run your eyes up the vertical 30 Lb line to where it intersects the most RHS island note the difference .

It looks to me like the -9's wheel/housing combination is happy to pump air at low pressures as well as high making them a slightly better all round combination . I think these would ultimately make better mid range torque than the -7's .

When you look at HKS spec Garrett turbos you start to see minor alterations to Garretts off the shelf compressors and turbines and they only tend to use non Garrett housings if they found it made a significant difference .

With the -9 cartridge they obviously saw the need to make changes to the compressor wheel otherwise they wouldn't have bothered . I suspect Garrett use their off the shelf wheel rather than alter things because that's a cheaper way to make a generic turbocharger - she'll be right .

IMO HKS went to a bit more trouble to fine tune something to suit a specific application - they wanted the response because people hate turbine lag and they wanted torque to make the engine pull hard without big revs .

All these turbos are really trying hard to alter the state of tune of RB26's , a 4-8 power range is a bit hard for some to stomach in a road car so possibly 3-7 is nicer on the street .

Your calls , I would buy the turbo fine tuned for the app particularly now that you can buy them from Garrett at a Garrett price .

A .

Oh and by the way , Garrett obviously did a cut and paste with the turbine map on that -9 blurbe page because alterations to the compressor side should show up on the turbine map . Lazy pricks .

The GTSS do come with 1 bar actuators, as do -5s

However -7's come with 11lb actuators (as they are intended to be a bolt in std replacement) which are a bit lamo for the higher boost applications.

It is advisable to upgrade them to the 1 bar actuators if you intend to wind em up past 20lb

Ahh thanks for that info; i will be buying the hks kit now as it comes with the better actuators, I was going to buy the -7's.

yep, the HKS kit used to be top value as it includes all the gaskets you need (good qual multi-layer metal ones) and turbos with the heavy duty adjustable actuators pre-fitted and set at 1bar. and all the other little nuts and studs you need and inlet gaskets etc. but sadly it's just gone up a fair bit due to the AUD weakness, but if you can find a kit here you can possible still get it at a competetive price. plus you get the HKS turbos too which are nice.

sounds good but i would definately go the -7s for street use and you may wanna go for a pair of rb25 afm, they are cheaper and you can achieve 400awkw just a thought...:P Eveything else seems good..

im currently at 306kw on stock afms and GT-SS or -9's.... why replace parts if they arnt maxed out? as Benno and Ash are saying about the stock dumps and cams.

i have HPI dumps but my cams are stock and im not going to change them.

yeah you can live without the cams, and if you decide you want them later they can easily be fitted in the car. so no need to buy them now.

I would get the dumps. whilst everything is out and your doing the turbos give them the best breathing you can. the tomei dumps are good and match well with the big boy twin 75mm HKS front pipes.

afms, well same as the cams. you don't HAVE to get them now, and if you find out you do need them they are only a 30 min job to fit down the track. you probably will though. I was regularly hitting 5.115v on mine stock GTR AFMS at only 276rwkw. sure you can still get quite a good tune even with maxed afms, but it's nice to have more scope for more airflow to be measured there.

whilst your engine is out also consider doing sump baffles or a sump extension. good idea if you plan on any track use in the future. and impossible to do with engine in the car.

Like BeerBaron said, afm's take stuff all to change. I had map sensors fitted to my intake while the motor was being rebuilt, just in case i decide to use them in the future. they are simply blocked up for now. the highest ive seen on my afms is around 4.500v. if they ever show that they are maxed out, then i would look at replacing them or maybe looking at the map sensors.

Hmm interestign thread. Thanks guys.

Another option would be to sell the Power FC and get a plug-in Vipec (see the Vipec thread). I've just fitted one to my Stagea 260RS and it's running off a MAP sensor and has brilliant idle control and only took a few hours for the installer to tune. That way you don't need to worry about AFMs at all. Plus it has boost control, launch control and knock control (if you add a signal amplifier).

yeah you can live without the cams, and if you decide you want them later they can easily be fitted in the car. so no need to buy them now.

I would get the dumps. whilst everything is out and your doing the turbos give them the best breathing you can. the tomei dumps are good and match well with the big boy twin 75mm HKS front pipes.

afms, well same as the cams. you don't HAVE to get them now, and if you find out you do need them they are only a 30 min job to fit down the track. you probably will though. I was regularly hitting 5.115v on mine stock GTR AFMS at only 276rwkw. sure you can still get quite a good tune even with maxed afms, but it's nice to have more scope for more airflow to be measured there.

whilst your engine is out also consider doing sump baffles or a sump extension. good idea if you plan on any track use in the future. and impossible to do with engine in the car.

Does the motor have to come out to fit a set of turbos or dump pipes???? Or am i misunderstanding?

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