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I am looking at replacing the standard turbos on my 1996 R33 GTR since they are now over twenty years old. What would you recommend as a direct bolt on replacement? The car is basically standard and still runs the stock ECU with only the exhaust and air filters being modified. The car is very original so I'm not looking at modifying the car but I would like to run a little more boost than standard. I see that there are 3 Garrett turbos for the GTR being the GT2860-5, GT2860-7 and GT2860-9. What would be the best for my setup and that would bold directly on. What I have heard so far is the -7 are the best for a standard engine and add some HKS actuators so I can run a little more boost. What do you think?
 

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GT2860R-7 is equivalent to R34 N1 turbos. I believe that they're actually fairly comparable to the stock R34 ceramic turbos but can run more boost without falling apart. GT2859R-9 will give you a little more power at the top end as the compressor efficiency remains near max even if you run 1.4 bar whereas the -7s mostly start making heat around ~1.2 bar.

The downside of the -9s is that you will lose ~100-200 RPM in boost threshold at the low end relative to -7s. Hard to say exactly how much because I've never really seen anyone do back to back runs.

Both turbos will bolt on without issues.

I would also say put the air filters back to stock, paper filters are there because they protect your engine. Going with anything else usually reduces the life of your engine due to increased silica content in the oil.

If you want to run the -7s I'm pretty sure the stock actuators are fine, 14.7 PSI means your wastegate boost pressure is 1 bar, if it comes with a 6-7 psi spring you'll want to upgrade to anywhere between 10 to 14 psi rated springs as the wastegate will only hold up to about 2x the rating unless you use CO2 boost control at which point a 5 psi spring is more than enough.

If you plan on running ~1 bar of boost then you can probably get away with just buying a Haltech Elite 2500 + plug-in harness and nothing else, as long as injector duty cycle stays below ~90% the fuel system should be ok. However, if you plan on running more boost than that you need more injector, more MAF, and more fuel pump. R35 injectors are cheap in most places as are R35 MAFs. Tomei and Nismo both make drop-in fuel pumps, probably a few more out there like Walbro and other common names.
 

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Im in the same boat and will watch this with interest
I'm just going single turbo.
So have bolt on set what includes 2x Hks gt-ss, hks elbows and baffled twin turbo pipe which are extra now. Going to but sales advert soon, but if interested pm me.
 

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I don***8217;t think that***8217;s true, as mine has an OEM ECU and is definitely not standard, on GT-SS. Not a bad option in this case, great spool.
 

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I don’t think that’s true, as mine has an OEM ECU and is definitely not standard, on GT-SS. Not a bad option in this case, great spool.
The R33 and R34 ECUs from the factory are read-only. Once you commit the map to the H8/534 it cannot be modified again. There are a number of solutions out there to convert the ECU to be rewriteable but they’re very hard to find these days as all of these components are out of production.

The R32 ECU is easy to rewrite with a Nistune board. Most people sticking with a “stock” ECU end up going to R32 ECU + Nistune. That takes some work as the O2 sensor is a different type and some other things need to be done. I personally think you’re better off going with a Haltech as it supports just about everything you’d want on a street car if you have a competent tuner mapping it. Said competent tuner is harder to find than you’d think but that’s going to be true no matter the ECU choice...
 

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Not fully bolt on, needs some work. You need 0.8mm restrictors and modification for the from oil drain, ie a 10mm alloy plate or heat and bend to clear compressor housing. You also need to elongate both front and rear drain flange holes.
 

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GT2860R-7 is equivalent to R34 N1 turbos. I believe that they're actually fairly comparable to the stock R34 ceramic turbos but can run more boost without falling apart. GT2859R-9 will give you a little more power at the top end as the compressor efficiency remains near max even if you run 1.4 bar whereas the -7s mostly start making heat around ~1.2 bar.

The downside of the -9s is that you will lose ~100-200 RPM in boost threshold at the low end relative to -7s. Hard to say exactly how much because I've never really seen anyone do back to back runs.

Both turbos will bolt on without issues.

I would also say put the air filters back to stock, paper filters are there because they protect your engine. Going with anything else usually reduces the life of your engine due to increased silica content in the oil.

If you want to run the -7s I'm pretty sure the stock actuators are fine, 14.7 PSI means your wastegate boost pressure is 1 bar, if it comes with a 6-7 psi spring you'll want to upgrade to anywhere between 10 to 14 psi rated springs as the wastegate will only hold up to about 2x the rating unless you use CO2 boost control at which point a 5 psi spring is more than enough.

If you plan on running ~1 bar of boost then you can probably get away with just buying a Haltech Elite 2500 + plug-in harness and nothing else, as long as injector duty cycle stays below ~90% the fuel system should be ok. However, if you plan on running more boost than that you need more injector, more MAF, and more fuel pump. R35 injectors are cheap in most places as are R35 MAFs. Tomei and Nismo both make drop-in fuel pumps, probably a few more out there like Walbro and other common names.
Agree with you. Anything beyond 1.3 bar on Garrett actuators and the spring tension is not strong enough. We advise HKS actuators. Those old school fuel pumps are not worth spending money on they are double the price of a Walbro 450/460 and has less flow.

As for Haltech Elite 2500 great ecu I’ve had mine since 2015 and works flawlessly with so many options and features. But here everyone likes Link....
 

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Last I checked Link doesn't support the dual MAF setup, if you care about part load fueling MAF should be a baseline requirement for the RB26, you can make alpha-N/speed density blending work kind of decently but closed-loop O2 control isn't something you want to make a habit of relying on.

Edit: Are there brushless fuel pumps out there? That's an upgrade worth springing for if only to help ensure reliability, cooler fuel, less alternator load, etc...
 

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Can run both map and maf so you can have the best of both worlds. Also using the WBC2 can be fitted to factory location one per bank.
 

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Not fully bolt on, needs some work. You need 0.8mm restrictors and modification for the from oil drain, ie a 10mm alloy plate or heat and bend to clear compressor housing. You also need to elongate both front and rear drain flange holes.
I***8217;ve just fitted some brand new -7***8217;s to my 32 and the drain flange holes lined up spot on, luckily I had another front oil drain from some other turbos I had :D
 

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Can run both map and maf so you can have the best of both worlds. Also using the WBC2 can be fitted to factory location one per bank.
Is there anything in particular that the MAP can give? I know with stuff like the Evo it's used to help bias the load estimates in transients but with ITBs the range between like 15-20% throttle and 100% throttle is basically lost on a MAP.
 

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