The stock Greddy turbo is too small - no amount of fine tuning the pipework changes that .
In fact the way the pipework is designed is damned good for the intended power output of the kit .

 

Swoope, wassup man! Where you been?

 

Do you think there is a restriction when the intake is so much larger and then it reduces the small pipe all the way to the turbo?

 

the turbo is just compressing air anyway, there shouldnt be any restrictions

 

Yeah.... but I want my piping to be bigger than yours

 

gl cuz all my piping is black

 

oh well, I tried.

 

Not at the power levels the stock kit puts out .
That "small" pipe is 57mm ID - the turbo inlet is only 50mm .
Have a look at the exit of the turbo and that piece that bolts onto it if you are looking for restrictions .

 

Yeah I guess if it cannot pull enough air to exceed the limits of the pipe then it is probably a non issue.

 

/\ I have done a LOT of experimenting with this system and one thing that stood out to me was that up to a certain flow rate the system works very well . Which funnily enough is approx. at the power you are looking for .

Past that diminishing returns start to affect your results (IE the turbo has to work much harder than before to get the incremental increase in power) . It's when you see that happen that you know it's time to look at how restrictions are affecting performance .

 

Well, if I can get 280WHP reliably I'll be happy.

 

You say that now!

 

Yeah, well hopefully I can keep the nitrous around at a 25 shot or smaller for occasional fun but I'm not sure how the tune will fair with nitrous thrown in here and there.

 

Whoa---you are going to have nitrous on it too?
Are you going to be running a w/meth system?

One trouble with FI on the renesis is that this engine is not very tolerant.
You really have to stay on top of it. Race maintanence is indicated in some ways.
Adding nitrous--even a low 25 shot---can complicate things. You have to ask yourself if its worth it?
280 at the wheels is plenty to play with
Work on your gearing and reducing weight after that if you want more? Putting a 4:77 rear end and the 09 trans in it will change the car is ways that will bring a BIG smile to your face without asking more from the engine.
OD

 

Well the system is there and I think (right now anyway) that a super small shot can be tolerated. But I will see what the tuning experts say. The tranny and rear end are on my long list as well. I don't have any plans to run water/meth, I don't really think it is beneficial.

 

I'm in the exact same boat as you.
My old nitrous system is still basically all there .....

I've been considering these same things.....
A small shot around 2000 rpm .... would really help things spool up.
But then I think.... hell how often do I ever drive around 2500 rpm ... I typically engage the clutch around 3-4k rpm and never cruise under 3k rpm soooo what's the point. Would it be worth it, but it's there .... ahhhhhh


<grabbing popcorn and leaning back to watch the carnage>

 

except that those pesky fluid dynamics physics get in the way

it can only compress what it can pull in, trying to pull in 350+ g/s of mass airflow in through a 57mm ID pipe as long as the Greddy pipe is most likely a restriction of some sort. I don't claim to know how much the impact would be. Ideally you would put an airhorn on a turbo inlet for the best airflow and response, not a long, skinny pipe. The location of the Greddy turbo obviously limits what you can do. Minimizing the length of the required smaller diameter section makes sense to me. If 3" is the largest size you can get down to motor mount bracket opening and then drop it down to 60mm to the turbo inlet, then it still makes sense to do that IMO.

 

I tried looking but does anyone have a pic of the Greddy turbo/manifold installed with the intake tubes attached?

 

its very tight down there. It would be very difficult to increase the size of the tubing.

 

I am looking forward to seeing our builds come to fruition. In many ways we are doing the same things with many similar ideas. In other ways you and I have split more then I ever thought we would.

There was a point where I thought for sure we would both be turbo charged. So now I find us at a bit of a cross roads and I have a huge smile on my face in anticipation of builds for the both of us.

 

Why don't you just run it the way comes out of the box. Use some sort of Mazda Maniac tune and enjoy it. That way you know it will be reliable as an aftermarket turbo gets and you will not have to take everything apart all the time.
The increase you're going to get with tubing changes and the like will not be even noticable in everyday driving. I drove a car with one of the first kits out there and felt that for everyday driving it was right on. The cost of more is just past diminishing returns. Knowing that there have been x number of kits out there in the world makes you feel that sverything has already been broken that's going to get that way.
Unless you have a very complete shop small changes require a lot of running around and become expensive quickly. Then when they don't fit you start running again. And believe me they will not fit the first time or even the second. Leave the experementing to the guys with complete fabrication shops. Not to take anything away from a guy with good hands and working at home. But he'd be the first to tell you there's nothing like having all the tools.

 

I always stand behind a pioneer but I have to agree with the above post. The return on having bigger piping to the turbo isnt going to be worth the work. You have the knowledge to make this kit reliable and fun. I'd say, stick to the basics and enjoy the greddy kit for what it is.

 

Yes, I am excited, now if I can just get your damn coilovers sorted I can start on the fun stuff.

Yeah, I agree. I guess I'll have to see what I wanna do once all the little stuff is here and I am ready to wrench.

 

yeah, there's nothing like having all the tools ... but a lot of stuff is easier than you think if you know what to get where etc.

not to mention that's like saying "just get the AFE SS kit and be happy with the RX-8 as it is". Ain't gonna happen ...

 

Following on from the discussion of the last few days , this is how I would see the progression for hp using the base Greddy kit .


240-260whp - stock greddy turbo with the usual recommended upgrades

280-300 whp - Upgrade the compressor to BNR T04e 50 trim or equivalent . No other major changes required.

330-350 whp - Upgrade the compressor to BNR 60-1 , upgrade the suction piping to 21/2" min the compression piping to the I/C to 21/4" min , upgrade the I/C . Modify the turbo exit for better flow . Fit 3" exhaust . Upgrade fuel pump , injectors , ignition . Then pray it all hangs together .