Sapphonica

I've got a GReddy installed, bigger injectors, metal cat, and the XCEDE for EMS. Also, the engine was ported by Rick at Rick's Rotary.

We've got full control of fuel & timing, but haven't been able to make more than 240 WHP on California 91 Octane without pinging in the midrange after shifting on the street. Boost drops off to 5 psi up top with 100% duty cycle on the wastegate actuator, so I'm really not getting much benefit from the porting.

Timing is backed off a lot, and the AFRs are around 12, going up to about 12.5 at high RPMs.

I'll post my dyno after Shiv sends it to me.

I don't see any way to make more power without boosting the octane and/or putting in a bigger turbo to get more flow at high RPMs.

Any suggestions/advice are much appreciated. Also, if there are any rotary-specific tuners in the Bay area who think we can safely go for more power, please let me know.

Moostafa29

12 is way too much dude!

rkostolni

My car was tuned for 12.0 by PFS also. It ran fine, no pinging.

Your boost controller is not helping you hold boost becuase the wastegate is opening due to high exhaust gas pressure in the turbine housing and not from too high compressor outlet pressure. To remedy it, add more preload to your wastegate spring, or/and get a more freflowing exhuast.

Sapphonica

They're <= 11.5 in the mid-range where the shift-induced boost spikes happen.

Sapphonica

Is there a DYI w/pix for pre-loading the wastegate spring? With this & a freer exhaust, will it hold 7psi+ at higher RPMs?

guitarjunkie28

extra spring. this is a pretty common problem with the second gen rx7 turbos. on some of them, i weld on a 6mm bolt to give the spring an easy location to clamp to. fixes it right up, but i don't have pics.

sapph, 12's is way too lean for 10:1 compression.

rkostolni

Just pull off the wastegate actuator arm from the flap. Loosen the nut, and twist the end to extend the rod. Extend it till its slightly hard to get it onto the flap and then try it. Extend it more if need be.

I used a bicycle pump with a boost gauge to set myne. I extended the rod put it on the flap and pumped up the pressure. I kept extending it until the flap didn't budge till I hit 8psi. Probably overkill, but I hey, I have too much free time on my hands.

After doing this my base pressure was 6psi because when driving you have exhaust gas pushing on the flap to help open it. But I can hold 6psi till redline without the boost controller. With the boost controller I've held 9psi. I haven't tried going higher yet.

Moostafa29

I don't know how or why, but I've always been able to hold 7-8psi through the top end.

strokercharged95gt

Water/Methanol Injection! Helps cool your motor, bumps up your octane, and the methanol provides extra fuel!

http://store.summitracing.com/partde...part=sno-20010

MazdaManiac

iTrader: (3)

Water injection is just another thing to fail.

Try shooting for 10.5:1 on the shift. You are getting ping because of the ton of advance on the throttle lift.
Where are you measuring the A/F? (pre-CAT, pre-turbo?)

guitarjunkie28

but the most valuable benefit of the water injection for the renesis engine is it steam cleans your engine as you go. since the HC's get recycled, there is an enormous amount of carbon buildup on the rotors, compared to the older motors with peripheral exhaust ports. the carbon not only takes up volume and raises compression slightly, but it creates hot spots that lead to detonation.

i've been getting a lot of phone calls from guys who have had their turbo kits for ~10-20k miles and are blowing engines. if the motor lasts for 10k miles of abuse, it's more than likely not a tuning problem-rather the engine has been building up carbon.

WI (in my own opinion) is the way to go for a turbo renesis motor--even if you only inject a small amount (5-10%).

Sapphonica

Tailpipe, I think.

Too bad none of you heavy rotor-tuners are in the SF Bay area!

MazdaManiac

iTrader: (3)

Do you have a CAT? If so, your A/F numbers are useless.

EDIT: Oops! I see you have a metal CAT.
The A/F numbers you get at the tailpipe after a CAT are meaningless. They will usually be seemingly on the richside under load and on the lean side on light throttle, but this will be affected by temperature and time.

BigOLundh

iTrader: (1)

same here

guitarjunkie28

not always. some of the dynos sample all the gasses and calculate the afrs, instead of just measuring o2.

BigOLundh

iTrader: (1)

I hate to say this, and its not 100% - but before you mentioned Shiv was tuning your car, it sounded like his style. Its a long story... and more info can be found on WRX message boards, but just to make a long story short.. excessively retarding the timing is not always safe.

I'm not sure if this is what is causing the pinging... but i would suggest taking a look at getting it retuned by a rotary specialist.

-hS

MazdaManiac

iTrader: (3)

True, but most places just have a regular, 4-wire WBO2S.
At least having a water trap will fix some of the problems, but the main thing is that tailpipe measuring is slow and usually wrong.

Sapphonica

Is there a rotary tuning specialist in the SF Bay area?

Sapphonica

So, is more power to be found by going with a lower AFR (11ish?) and pulling less timing? What about boost? I'm running 7psi right now. Could it be bumped up to 8 safely with crummy CA gas provided the AFR is rich?

Has anyone posted an exhaustive explanation of turbo rotary tuning?

MazdaManiac

iTrader: (3)

I'll make a tuning FAQ next month on my WEB page.
I'm running the same 91 crap here in Arizona at 9 PSI, but I have bigger injectors.
I pull about -10° at the top of my MAP.

BigOLundh

iTrader: (1)

I'm not familiar of any in the area, but i know of a few that travel. Scott from Mazsport as well as Steve from Gotham Racing to tuning sessions across the country.

You can call them to see what it takes to bring them out your way. If you look on RX7Club.com you can see many threads on group tuning sessions and use that as a template to help set it up.

I'm sure there are many rotary owners in the Bay Area that would take advantage of this.

-hS

Sapphonica

I've got bigger injectors too...650cc I think.

rkostolni

They usually require a minimum of 4 cars to make their trip worth while.

rgonza

On rotary engine with turbo especialy renesis high compression rotors is best to runs 11.5 or 10.8 afr with 91 oct. gas and with timing of 10 deg. at 10 psig. at 7500 +.

Rgonza

MazdaManiac

iTrader: (3)

Those are probably good targets.
The OEM advance at 7500 RPM is around 25°, so a retard of -15° or more is needed for that much boost based on those assumptions.
I typically go for 1.5° per PSI overall.