rob3379

I want to know why our 13B's have so many limitations in FI compared to the 13B in 3rd gens.

Is it our ECU's that are limiting us?

Is is b/c our compression is higher?

Is the motor built weaker compared to previous 13B?

Thanks,
Rob

ranger4277

What limitations?

ECU: ECUs are available to work around any limitations.

Compression: No.

Biggest limitation I've seen is the greddy kit itself. (crap computer/tune, tiny compressor)

In all respects the motor is stronger than the previous 13B. I don't know the numbers off hand, but it has been discussed.

What have the little birdies been saying? 25psi until stock seal failure?

brillo

One word ECU.

Now that we have options, this is a non issue.

Just don't do a half *** job tuning the ECU, and you'll be fine

zoom44

fuel system is a limitation to huge power. and im not too in love with the exhaust ports

Sapphonica

Ibid on the exhaust ports. Also, I think the compression ratio is a bit higher on the Renesis.

If you look at the old style exhaust ports (huge) vs the Renesis ports (tiny), you wonder how the engine can even breathe. There is also much funky-ness in the exhaust port shape, like a 90 degree bend.

I had my GReddy Renesis ported when it was rebuilt, along with 650cc injectors and a replacement for the crap eManage. Once its broken in, I'll tune it and we'll see if that helps.

zoom44

and i asked about your ports if there were pics and you didnt answer

rkostolni

I think the high compression ratio is going to be the main limitation for running high boost levels.

Sapphonica

Sorry, I've been so busy with work craziness that I forgot to ask Rick to take pix.

rob3379

I see!! If you say there are no limitations. Then why can't we use some of the 3rd gen technology and get 400 or 500 whp.

So is the fuel not up to 3rd gen specs or do the 3rd gen guys upgrade theres also?

I want to get to 400-500whp like alot of 3rd gens but I want to know what are the holdbacks?

Rob

guy321

I believe the answer is:

The FD's were built as boosted engines, where-as ours are built as NA engines.

We have a higher compression ratio and intake/exhaust to support the velocities of air needed to maintain driveability in NA form up to the performance specs that Mazda deemed appropriate for this vehicle.

If it were built as a boosted engine, the compression ratios/port sizes would have been tailored to building power with the turbo or supercharger.


We can add moderate boost, but beyond that the system would need more a more drastic re-design.

This is no different than needing to boost the internals or lower the compression ratio of a piston engine.

RotaryX.com

I agree. Also the fd has been out for over 11 years now. I think as time passes more and more will be learned about the rx8s limits.

rob3379

Does a 13B from a 3rd gen mount in the RX8?

guy321

If they can get a 3 rotor in there, I'm the 13b-rew will fir

rob3379

But what are the physical differences of the two?

Are the motor mounts in the same location?

Will all accessories bolt up?

Rob

zoom44

dude its not like it hasnt been done. the JIC drift car is running a rew. call them

fuel system is returnless. rea dthe puerto rican rx-8 threads to see what they did - also start searching and reading the threads that are already here. then if you have more questions when you read something ask in the thread you are reading

Synergy RX-8

yeah, some guy down there has a 20b engine in his RX-8, he gets 650 horsepaow with room to grow, all in an RX-8, there some work to be done but it will fit if you try hard enough.