What's the best AFR for people who use VP C16. This question is directed to people making big power.

Thanks.

 

I see that Erniet's car was tuned at 12.0 AFR. Here is the link:https://www.rx7club.com/showpost.php...1&postcount=64

Is this about the best AFR when using C16 and wanting big hp?

 

That's up to your tuner!

 

leaner is meaner if you want big power

But as Crispeed said, its up to your tuner('s *****, hehehe)

Howard Coleman will be tuning up to 13.5:1 or so on pump gas...he wants big power and lower duty cycles.

 

I'm just curious to see what other people tune to (Their limits for big power). How about yours?

 

I don't think chrispeed is running gas.

 

I'm sure he used to and I'm sure he's tuned plenty of C16 cars.

 

Don't worry about it. Thats your tuners job! Im sure Steve is plenty capable. He's made big power with his car. Its not his first rodeo.....

 

I'm not worried, just curious to what the competition..........eh I mean other people are running

 

Every application is different and there are no set standards in doing so. What might work with one setup is not going to work with another. That's why conservative tuning would come into play most of the times. Honestly if your application requires you to to be on the edge to make decent power then there are bottle necks left in there somewhere.

 

Alright, well that's not the answer I was expecting but ohwell........

 

I only gained about 10 horsepower going from 11.5 to 12.0 A/F. So I sacrificed the 10hp for the safety margin.

 

Steve Kan emailed me and let me know he wants to tune my car at 11.6

 

WHat's changed under the hood since the last time he tuned you? What are your a/fs @ 530whp? You got new porting or fuel delivery or ignition or something? You decided not to change turbo, right?

 

Are you still doing the auto conversion?

 

Yeah, I'm going to do a C4. What stall do you reccomend or does that depend on what rpm my peak torque is?

 

These are some of the things I've changed since my last tune in october.

More injector, 24-29 psi wastegate spring, better boost controller, race plugs, tial 50mm bov and my exhaust is now open from the downpipe. Might be some other things besides that but I can't remember.


We stopped last time because my wastegate spring was too small.

 

Before you tune?

 

No, it's getting tuned this saturday and I still have my stock 5 speed in the car.

I won't be doing the C4 until spring. I still need to buy the converter but not sure which one to get. Thinking 6500???

 

0 to 15psi - 12.0

15 to 22 - 11.5

22 - 30 - 11.0

over 30 - 10.5

That's basically how I have my A/F table set in the Tec 3.

Anthony

 

Anthony your leaving alot of power on the table with afr's in the 10.5 range with C16

 

On pure C16 12.0 A/F's wouldn't scare me.... at 35 psi.

 

Since you drive a supra, I'm sure that wouldn't scare you.

 

What would you say was "safe" or what would you recommend for those boost levels I noted.

It's just that I see some rotaries make a million passes on the dyno on high boost and never blow up because they are running a lot richer on top.

Anthony

 

Some tune for power and some for reliability. Then there are dyno queens and track queens.
Most of the high horsepower rotaries that I've tuned is not worth the extra 20 whp for tuning them lean in my opinion, especialy if it's a street application and if power is going to be sustained for any length of time.
Power cannot be detremined only by A/F measurement. You got to have a right balance of A/F, Ign. timing and Egt's just to name a few. Just for example let's say you tune to 12.0 A/F on the dyno and made good power with safe egt's. Now you go out on the street and hold that sucker in high gear for any length of time and that same 12.0 A/f is resulting in turbine melting, apex seal growing, warping, breaking and spring flattenning egt's what will you do then? Sacrifice reliabilty for a little power.