Hey all...

I wanted to start a list of facts for everyone who is going to tune their rx7. The range of knowledge should go from the most basic level up through the highest experience. Of course I am counting on all of you to help share the knowledge you have in this regard.

Please contribute a line or two..or ten...share some thoughts and experiences on tuning..general how to's and anything else. If you do so..it will help others who want to do it and hopefully you too.

here are some very basic things...like i said...please contribute some ideas to this list.


1 the safe afr for rx7's is somewhere between 11.0-11.5:1. It is important to keep safe afr's throughout the power band.

2 the fuel curve should be very even and smooth...not erratic and jagged.

3 its better to be rich than lean..simple as it sounds.

4 no negative split...negative split will happen when the leading plugs fire after the trailing plugs causing poetential damage to your motor.

5 when tuning start rich and bring the fuel down to the appropriate levels



what other common knowledge can you guys think of?

what other basic things could be added to this list?

thanks


j

 

Best done on a dyno with a Wideband O2 sensor.

 

the dyno is not accurate to actual on the street driving to my understanding.

am I wrong?

6. beware heat...heat soak and pay attention to your temperatures...let the car cool down between runs.

7 beware holding the rpms at a particular level for extended periods of time in order to get the readings you are looking for

8 patience

9 when in doubt...ask questions...if its an important question ask more than one person...second opinions can be key. Each high profile tuner i have spoken with has different beliefs and suggestions...sometimes conflicting info is presented.

10 tuning by mail can be risky and may result in detonation as all cars are different and perform in unique ways...use services like this with caution

11 ....

your turn...come on guys...lets hear the facts...

Im a noob at tuning but am determined to learn as I have come to the point where I do not trust my car in another tuners hands.

share the wealth

thanks guys...


j

 

I will add a few things.

First thing is 11.0-11.5:1 is not always the best ratio. It is dependant on fuel. If you are referring to pump fuel which is oxygenated/unleaded, then yes. If you are referring to race gas that is not oxygenated and leaded, no. With race gas you can bring the levels up to around 12.0:1.

When cranking you want 20* of timing (which most people seem to miss). This allows the motor to turn over faster.

Do not make any major changes to maps.

Be careful who you get your tuning advice from. There is a lot of bad advice out there that flies around.

 

Couple things..


11.5 on 93 octane fuel is good for a turbo car. But NAs are different and should be tuned different


WB is great for setting A/F ratios, but you also NEED a EGT probe for timming.


A dyno is pretty much worthless as far as i can tell, unless you want a # to brag about. Course it does give you a place you can make a complete 4th gear run safe.



Running 0 split usually increases power. But most recomend running 3-5* split to be safe.

MAKE SURE YOU HAVE THE RIGHT HEAT RANGE OF PLUG! Most people run the stock plugs. but when you are pushing ~400RWHP you need to go with a colder plug. I think a 10 would be good.


-Zach

 

You should not try to get 11.x:1 at all places on the map, only in the boost/load regions. Put that kind of AFR in the < 3K / < O PSI cells and you will never pass emissions and carbon things up when just driving around. When you are not on boost you are for all practical purposes NA.

 

so what should the afr's be when you are in vacuum??

what other places should be different?

j

 

How do you start to tune? I am about to get the PFC but have no clue as to what I should be looking for, changing first, comparing to.... I am sure I will figure it out but some tips would be great

 

get the datalogit and a wideband...its not worth your time to do anything til you have the tools to do it.

you need wideband readings...and the ability to get to the maps on the pfc...

 

Watch this thread:
https://www.rx7club.com/forum/showth...hreadid=110481

 

double post

 

Read the Manual as if you were to be tested at the end.

Check your timing, make sure your timing marks line up before doing any major tuning with load.


-wayne

 

you need wideband readings...and the ability to get to the maps on the pfc...

do they sell accurate wideband gauges

 

How does a wideband help when tuning exactly. Does it help with your air/fuel. A more accurate reading or somthing? I am pretty sure the wideband is for o2 right?

 

One more thing how does the datalogic help better than just the commander?

 

Wideband O2 sensor is a more accurate oxygen sensor and has a better range of detection.

A narrowband O2 sensor is typically what the sell in factory vehiles due to lower cost per part. It will give you (or ECU) an indication if you're rich or not. It's range is very limited (hence, narrow) so when you are a little rich, the accuracy may be off (same if you're lean).

You can run A/F on vacuum as high as 14.7 if you want. I tend to tune for fairly lean vacuum or cruising rpm/throttle ranges since I don't want my car nor my friend's to smog up the neighborhood or eat up miles from the tank.

With pump gas, I would aim for 10.8 A/F ratios (assuming about 100 C air temp located on throttle body and coolant around 190 C in Texas land). It allows for margin with various gas and environmental conditions.

Start real rich on the fuel and progressively lean out the fuel for boost runs and cruising. Listen to the engine to hear any erractic noises (or pings).

On idle, I will add/subtract fuel based on idle smoothness and rpm. The higher was better for my FC. Once it was at it's highest and running smooth and stable (no erratic pulses), I would set my idle adjust screw to the desired rpm (850rpm). On my street port FC, I had a higher rpm (1000rpm).

J

 

the datalogit gives you access to the base inj map...and many other features you cannot reach on the commander (fan temp adjustments etc..).

it also has a new feature called mapwatcher...GOD BLESS MAPWATCHER!...which allows you to drive around and fill up your map with an afr reading for each cel...this allows for quick adjusting and for easy analysis.

it reads everything...inj readings...fuel readings...temps...you name it.

the difference between a commander and the datalogit is like the difference between a fisher price doctors kit and one at the may clinic.

the datalogit is a MUST have if you own the pfc...you cant trust the tuners nowadays in my experience and the datalogit gives you the power to do it yourself. ..or check their work...it is the necessary factor in having a well tuned machine and not.

IMHO...

j

 

Since I have I have installed a wideband in my car, I can shed some light on wideband readings versus standard 02 readings. If you are at point x, at a given load, and you make an abrupt large shift to rich, the wideband will show it right away, however a standard o2 will show LEANER due to lowered combustion temps, if you followed a standard 02 for tuning, you would probably end up drowning the motor in fuel trying to get a safe a/f ratio. Also on datalogs, even a heated 4 wire o2 sensors is 2 rows behind in its reaction compared to the wideband which is always right there with the duty cycle changes.
An autometer a/f guage seems to have a range of 15:1-13.4:1 or there abouts depending on what 02 you use with it, my idle on the wideband is reading at 13.5 average, but the autometer shows completly rich..Max

 

great info guys...keep it coming!

 

What we should so is find some of the REALLY good tuning threads about timing, a/f ratios, proper egt's, plugs and ignition info. Then link threads like that to here. It would basically put everything in one place.

Here is a AWSOME thread on timing, also if you take notice of the people who are talking in this thread there should be no doubt that its right. There is enough info on this thread that no one sould have questions about timing.

https://www.rx7club.com/forum/showth...5&pagenumber=1

STEPHEN

 

Thanks alot everyone I just want to be prepared for when I get my pfc. I am in the process of looking for a laptop to get the datalogic. I found the datalogic on rx7.com is that the best place to get it?