Sapphonica

Are there bigger injectors and a higher-capacity fuel pump available for the RX-8?

I'm not up on rotary engineering enough to know which injectors (or all) need to be upgraded to support hi-rpm/hi-boost.

If these parts are available, please let me which vendor(s) sells them & approximately how much I should expect to spend. If this info is already posted somewhere (I did look), please point me to the correct thread(s).

Just so ya'll know, depending on cost, I might try to find the upper HP capacity of the GReddy. We've already seen the fuel start to go a bit lean at higher boost/higher RPM (8 psi 7k+ rpm), so pushing it higher might require more capacity. Either that or the ECU is pulling fuel?

rotarygod

The upper horespower capacity of the Greddy is right around 300 hp. It's not fuel limited. It's airflow limited. The turbo is getting maxed out.

Moostafa29

Send the turbo to Mazsport to get upgraded.

Sapphonica

Is there another turbo that will fit in the GReddy housing?

Sapphonica

Has the 300 HP airflow limit been proven empirically, or does it have some other basis?

rotarygod

It's been more than proven. It is now a very well known fact. Many people have shown that boost rapidly falls off at higher rpm's due to inability to flow more air. The turbo is just plain and simply, too small.

Sapphonica

Oh, it's a size thing...my poor GReddy!

rotarygod

It was designed to do a certain job and do it well. That is to be a nice power upgrade over stock and have quick spool. It does that quite well. You can't have this and still have the efficiency to make big power though. There is always a tradeoff. Greddy designed a kit around street performance with a modest gain. It's a nice turbo but don't expect miracles out of the little guy. You will need a bigger turbo for that. Fortunately Mazsport is working on a compressor wheel upgrade for that turbo which should be able to take you over 300 hp. This doesn't mean it will do 400 or 500 hp though. You'd be surprised just how fun your Greddy turbo can be with proper tuning at around the 300 hp level. Don't get so much hooked up on power numbers. Results are more important on the street than on a piece of paper. You've still got more potential left in your system if you are still using the eManage. get it tuned and see how well you like it. You might be surprised just how fast that car can really be with that turbo.

Moostafa29

Call Scott at Mazsport. You may get led in the right path.

Sapphonica

Thanks for the tip, M. Scott confirmed they will have a killer product available for GReddy owners very soon (I also don't want to steal his thunder...I'll let him post the juicy details).

I'm stoked!!!

Moostafa29

Told you. I should be sending mine in later this week or next, just need to talk to him again and work out some more details.