Has anyone else considered that, because the GReddy turbo has a manifold for Mitsubishi Series turbos (the turbo it comes with is an 18g in a TD06 housing), that you could swap in perhaps a SlowBoyRacing SBR-GT35R or a Forced Performance FP3052 or FP3065, run it at low boost like GReddy (max 8 psi) and get RIDICULOUS flow (as long as you upgraded the fuel system) ?

I'm talking the Mitsu-flanged equivalents of the Garrett bad boys like the GT35R or GT42R (I had a GT3540R on my RX-7 and that turbo was ridiculous, full spool at 3000 rpm and it pulled like a raped ape to redline).

These would actually be HOLYSHIT turbos, just look at this dyno



We'd have no way to hold traction with that (and remember, that's spool up on a 2.0L I4 - rotaries spool up 3 times faster than a normal piston engine due to the heat!), but I'm just throwing out ideas. We could easily mount an FP Green or Red or whatever.

I'm thinking about this because I'm seeing the other turbo kits out there running big turbos. The advantage of the GReddy kit is reliability and a super-cheap price. You could get the GReddy, install the plumbing, and upgrade the turbo later once you've got the fuel system down to run 8 psi with a huge honkin turbo and blow those other kits out of the water.

 

Upgrading the greddy turbo would mean a BIGGER turbo. As philodox has said before, it is a really tight fit down where the turbo is located.
Here's the picute he took.

 

My mechanic commented the same thing. The space where they put the turbo is very tight. Also the intercooler while a good size for this turbo might be on the small size for a larger size turbo. The upgrade kit would have to include : larger turbo, upgraded fuel system, & bigger IC.

 

In reading the GReddy literature one will find that their bolt-on turbo kits are specifically designed as a kit whereby one can perform gradual upgrades and increases in power as they become more comfortable with the notion of turbocharging. As such, the intercooler is designed for this particular application but to increase the boost would, most likely, require a better unit. The turbo, itself, specs out somewhere in the 425 h.p. range if I understand that part correctly. So they supply us with the parts to get a modest level of boost for a fair price in the hopes that we will return to them for the larger cooler, a BOV, the aluminum oil pan, and other stuff we will need when we get serious about our boost levels.

CRH

 

But I'm considering keeping similar boost levels . . . though your point is taken.

As far as size, the FP3052 isn't really that much bigger, its just got a whole lot more advanced compressor wheel that churns out TONS more power (compare an 18g turbo to a GT35R compressor map and you'll see what I mean - flows about twice as much) at the same boost levels, which is why I was considering it - our engines won't be able to safely hold more than 12 psi (based on the stock 10:1 compression ratio), so I was figuring, add more fuel, better cooling, and a more advanced turbo and you'd see a lot more power.

 

Either way, you are taking an active involvement in the modification of the GReddy turbo kit, and that is their intention. They can only hope you return to GReddy for future needs. I wouldn't be too concerned with the maximum potential for boost at this point. Although it seems that a 10:1 compression ratio doesn't allow for much I would like to point out that current technology and understanding of physics is experiencing some major changes. These changes are allowing us to do more than we previously thought possible. I look at it this way; we can run the boost up to the point that either one, or both, of two things occur. Either mechanical failure from housing pressures being too high, or uncontrolled ignition. My experience with the nitrous system shows that the Renesis can handle occasional detonation and other abusive situations so that gives us a bit more "headroom" with the development end of things. Once we discover the threshholds of both pressure and ignition control we will have a much better understanding of the limits of the Renesis. My only point is that I am not establishing any pre-conceived limits because even Acosta Motorsports didn't think 300 h.p. was possible and several of us will be knocking on that door(no pun intended) in the next few weeks.

CRH

 

Charles - good points.

My main concern is, as you've stated, both serious detonation, and the ability of the rotors and seals to take increased pressure - never mind both of those happening together. With my RX-7 the threshold for turning was NOT large, you had to tune rich, safe, and accurate or else you were dealing with a world of **** - even with my fully built engine.

Aside from better fuel and a bigger turbo, I'm really curious about porting results. KD Rotary got their hands on a few Renesis engines and should start playing around soon.

 

You would need to modify the manifold so that the turbo sits at a different angle to accomodate the larger compressor scroll.

I looked at the GT series turbos - the GT28 would be perfect at low boost. Too rich for my blood.

 

Due to this discussion I have already informed my buddy to get ready to use his plasma cutter to replace a portion of the floorpan and make clearance for a better turbo after I get used to the GReddy.

Cretinx, When I was tuning the nitrous kit and discovering which jets work best with which on the RX-8 I was pleasantly surprised to find that the Renesis has much higher tolerance levels for abuse than what I had heard about regarding the previous rotaries. Mr. Abrams has also commented in the past about how lean he was able to run his A/F ratio when tuning his turbo and still not experience detonation. I would say that the Renesis will prove to be much more forgiving in terms of tuning so we will have a larger window to work with. Of course, the higher we go in our output levels the narrower that window becomes. My point is that it was originally thought the Renny was not amenable to much tuning and that the seals would fail. Jeff and I have discoverd that to NOT be the case. That's why I am looking forward to 7 psi and a 100 shot. Then again, I am just reckless anyway.

CRH

 

Do you think the increased tolerance is because the car actually detunes itself to save the cat? Kind of like a built in knock sensor?

 

GT28 isn't in its efficiency curve until higher boost than we're gonna wanna run, and its only rated for 280 hp, 350 if you get the GT28RS (disco potatoe) - which is still less than the GReddy which should be good for 400+

My goal here is to get more power, not better response - in fact if I've learned anything about RWD cars, its better to have a steady, smoothe power curve rather than a whiizzzzzzzzz SLAM (which is what we always went for on our GSXs)

 

No. That would show up in the throttle, fuel delivery or ignition timing. Those are the only three components of power and the only three things the PCM can control.
None of those indicate and variation beyond what is expected when under boost.

I datalog all of those components when on the dyno and they are smooth and optimal.

 

So you mean to say Ford actually made Mazda build a tough, durable, reliable rotary!?

SWEET! Now I don't have to spend $5000 to rebuild the Renesis like I did with my 13b-REW.

 

Ford didn't do a damn thing, credit the effort to the love of the rotary by the engineers.

 

Ford helped by staying out of the picture.
The RX-8 was developed in semi-secrecy to some degree and under the budget radar.
Had Ford known that Mazda was experimenting with the rotary, they would have shut it down. The RX-8 was developed in a time when Mazda was bleeding red ink.

 

As a Ford employee I can vouch for what Jeff is saying. Ford has been making some very strange decisions, lately.

As far as the ECU responding to mods, even though I haven't datalogged any of my mods, I think if the proposition were true that the ECU detunes the engine to save the cat none of these mods would show sizeable gains. Since the contrary is happening I'll move forward until I break something. Then I'll fix it and move even further forward.

CRH