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Getting Started with tuning

12K views 71 replies 12 participants last post by  vetteoz 
#1 ·
So I thought it would be kinda neat to start a thread that maybe could benefit everyone that wants to tune.

If your gonna tune one of the first steps is to datalog.
A great site to start with for some free datalog software can be found here. You'll also find directions on that page to build your own OBD1 connector

http://winaldl.joby.se/

You can also find free tuning software at
tunerpro.net

trial software, they also carry datamaster
tunercat.com

Tunercat and datamaster is what is most often used when your getting a prom done by a mailorder company

If you prefer to tune yourself then you may need to look into burning your own proms.
Most common place for us guys to get the prom burning equipment and chips are through
moates.net

Hopefully this will get us all started on a thread that can end up with some good information and a place to discuss the early stages of tuning.
 
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#2 ·
Getting to know the parts

INPUTS
TPS- throttle position sensor
CTS- coolant temperature sensor
MAT/IAT- Air Inlet temperture
MAF- Mass Air Flow Sensor
MAP- Manifold Absolute Pressure
Crank/Cam Position Sensor
FRP - Less common Fuel Rail Pressure
Oxygen Sensor
Knock Sensor

OUTPUTS
Fuel Injectors
Fuel Pump
Ignition
IAC- idle Air Control
 
#3 ·
slrvette---This is very good info and a very good idea to start a thread like this. I just got my first Vette this past March 29th. A 2000 6 sp C5. I am interested in doing some mods in the future but for now I am just having fun and learning new things. I hear a lot of talk about doing mods and then "getting a tune" but no one ever elaborates on how to do this or what resources are available. This information helps a great deal. Please post more info if you got it. My ear is bent. :talk011:
 
#4 ·
Thanks for starting this thread Ed even though the ugrades for the Vette have been pushed back due to the new project. I will follow and bookmark this.
 
#5 ·
Very cool, Ed. I just got the EBL installed today and did about 10 VE learns, seems to run pretty good so far. I really don't know what kind of changes I need to make when it comes to the SA tables, but I'm researching and learning. My BLM's are starting to shape up and by golly I'm starting to feel more comfortable with tuning.
 
#6 · (Edited)
Cool, I'm glad you guys are into this. I thought maybe it could be something to help all of us.
And how could I forget to add dynamicefi's ebl/flash ecm.
The VE learns are nice for sure. I've found however that with a more modded engine they help but just don't get you where you want to be. One reason I thought this thread could help up all.I was thinking maybe the first thing we could discuss would be the function of each Input sensor. If were not certain of what the sensors do and there parameters then it will make looking at your datalog or making an adjustment to your tune that much more difficult
 
#7 ·
Is this a theoretical discussion on tuning? Are we talking stock ECUs or ALL ECUs?

There is commonality between all ECUs so perhaps we stick with that.

The Stock ecu is a great ECU. the issue is there is SO MUCH detail, it's hard to figure out sometimes.

Much more granular than any aftermarket ECU.

I am working to eliminate the stock ECU all together.

ON my car I am still controlling Speedo and TQ Converter lockup. I ordered a box from Dakota DIgital which will take care of the speedo and cruise control issues, and I will set the TQ Converter to lock up in OD every time as opposed to using a relay to do it at a certain speed.

Additionally, I used a fan thermostat in the driver's side head which goes ON at 200 and OFF at 180, bypassing the ECU. That was VERY easy, it works great, and still has a factory look.

There's a lot of things that can be done in a complete replacement for the ECU, a hybrid solution, or a complete stock situation.

Lots of ways to go. I think the FIRST place to start is to look at your combination and determine which route you want to take. I am going for complete replacement. When you start digging into it, there's really not much the stock ECU does outside of fuel/spark that can't be over come.
 
#8 ·
Is this a theoretical discussion on tuning? Are we talking stock ECUs or ALL ECUs?

There is commonality between all ECUs so perhaps we stick with that.
You got it!. There common ground between all tuning. VE,PE,AE,SA and tons more. Just thought maybe since were all doing it we'd get a good discussion going the help each other out. I'm gonna post about the sensor's later today so that should have good info as well. Or any of you other guys feel free as well.
 
#9 ·
TPS- tells the ecm exactly where the throttle blade is at all times. idle,cruise,acceleration,decelleration. So its pretty important.
Typical volt settings for the TPS
TBI- key on engine off is .525
TPI- key on engine off is .545

CTS- monitors the temperature of the engine

MAT/IAT- monitors typical air temperature coming into the engine.

MASS AIR FLOW- monitors the amount of air coming into the engine

MAP- monitors the pressure within the intake (manifold)

CRANK/CAM sensor- monitors engine speed and second indicates actual rotational position but is more critical to sequential systems.

FRP-not often used but is self explainitory. Monitors fuel rail pressure

O2 - corrects for errors between desired and delivered a/f ratios.

Knock sensor- detect the presence of detonation

WB02- like the O2 corrects for errors between desired and delivered A/F ratios... however is much more accurate than the 02.
 
#10 ·
#12 · (Edited)
SLVR, not to be a PIA but you left out the IAC....didn't see that in the mix...


OOPS never mind, saw it under outputs.

I think the place to start is:

1. What is the goal of tuning
2. What types of tuning. WHY? Dnyo vs. street tune.
 
#13 ·
Your always a PITA...LOL just kidding
I thought by giving brief explanations first of Inputs and outputs would be best. To many times all this is skipped. You get into the MAP and don't understand what your seeing, Then you try and research it on the net and it gets very frusterating for the DIY tuner... myself included.

I was hoping that maybe one of the injector vendors could jump in an explain the injector and the importance of it. Why lb/hr are important,BPC,BPW..etc.

Once the DIY tuner understands those items then we can move on to datalogging,goals, and some actual screenshots of some SA and VE MAPs. At that point the tuner will understand what they are looking at.

Just the type of thoughts I was having about it.
 
#15 · (Edited)
I was hoping that maybe one of the injector vendors could jump in an explain the injector and the importance of it. Why lb/hr are important,BPC,BPW..etc
First, there's two kinds of injectors, high impedance and low impedance.

The reason for this as flow rates increase and fuel pressures reach 5 bar on newer stock motors such as the Mopars, the high impedance injectors could not over come the pressure and volume necessary therefore, had to go low impedance, resulting in more current across the solinoid.

Most high impedance injectors end about 50-60 lbs, after that you will typically see low impedance. That being said, Injectors Plus is one of two vendors in the country that sell 160-200LB high impedance injectors.

SO...the impedance is typically dictated by the ECU you are running. If you are running an ECU that supports high impedance (like the OEM ones) you are limited to about 60 lbs. If you have a high impedance system and need low impedance injectors, we can supply drivers that you will have to add to accept low impedance injectors on that ECU.
 
#16 · (Edited)
Now sizing injectors is a bit of a science, and a bit of a skill. Sure anyone can pull a flow rate out of their *** and say make it fit XXXX application, however understanding WHY that flow rate is important is as important as getting it right.

I see a TON of misinformation flying around the internet about how to size an injector. I see too many people buying too small an injector for their application. Lots of bad recommendations out there.

We have a calculator on our site that addresses sizing injectors:

http://injectorsplus.com/calculation-tools.asp

This provides a basis of where to start looking

If you size the injectors too big, it will be hard to tune in your idle speed. If you size them too small, you will run lean at top and do thinks like melt pistons and stuff. Just got a set in from someone who did that.

One note I'd like to make here is that there's only a handful of manufacturers of injectors such as Bosch, Seimans, Delphi, Rochester, Lucas, Denso.....all other injectors are just a variation of these with a private label on them. Even if laser engraved.
 
#17 · (Edited)
Now the issue of correct sizing also addresses weather you have forced induction or naturally aspirated motor. That is where BSFC comes into play. But we'll stick with NA for now.

To explain WHY sizing is important as it relates to the size and HP of your motor requires you to understand the basic workings of the internal combustion engine and something called VE or VOLUMETRIC EFFICIENCY.

VE means when the piston comes down during the intake stroke, how much of that cyl is going to fill with air. Now most of the time if you get max 80% VE your doing well. This is reflected in the HP per CI argument we hear from time to time.

Competitions such as Engine Masters you may see VE as much as 110% but that is VERY hard to do and can only be done under very controlled circumstances... the major problem is port velocity required to get to that over 100% efficiency is not achievable. The ports "stall" or lock up at .6 MACH and typically requires air speed faster than that to get over 100%. That's why small port heads and big flow numbers don't work if your spinning it up to high RPMs and tend stop making power, falling on their face at lower RPMs than larger ports with equal or less flow, and therefore making less power. But I digress.......
 
#19 ·
Now think about what is happening, you have VE in filling a specific size cyl with a specific amount of air and fuel. This is called FUEL SUSPENSION. Again, this is more reliant to intake runner design which allows the droplets of fuel to remain a mist and not condense or consolidate within the fuel path.

So your question is, who gives a rat's butt....

It is important to understand those 10,000 foot theories in order to get a better grasp on what you are trying to accomplish with a tune.

The optimum most efficient use of fuel is called stoichiometric reaction which leaves a 14.7:1 ratio of oxegen to burned fuel. The goal when tuning is to try to keep with that number.

Now that rule is not hard and fast. In my car for example I idle lean, at 15-16 AFR. WHY? The cam likes that. Under acceleration or power requirements you should expect to see 11.6-12.3 for optimum power. at WOT it shouldn't drop below 11.

The lower the number is, the richer the mixture is.. So 17 is leaner than 13.
 
#27 ·
Something I wanted to comment on here. Fuel suspension is important because an intake/head that promotes better fuel suspension will require different tuning parameters than a head/intake where the QUALITY of the air flow sucks.

That is why I say it's not all about flow numbers for heads, but the quality of the air that is delivered.

The ability to suspend more fuel in the air will result in more power and different tuning nuances.

THIS IS IMPORTANT!!!!

The reason is because I see a lot of people ask "what size injectors do you have".....and responses that say....I have XXX on my motor.

Well, if their heads have BETTER QUALITY NOT QUANTITY of air flow, you will need to deliver LESS FUEL to get better results. It CAN effect both the tune, and the size of the injectors. That's why sizing isn't hard and fast. But the ECU allows you to tweak that, as does your fuel pressure.

Each combination is unique.
 
#20 ·
now, with all that out of the way, the question is......

WTF does this have to do with tuning?

Well, to understand what you are trying to achieve with the tune, you need to understand the circumstances that come to play when trying to tune. How the sensors work, and what relationship they have to the end goal.

So let's look at what the end goal is.

The end goal, in any tune, is to get the AFR correct so the car responds the way you want under particular conditions created. That's where the sensors come in, and all the sensors are related to each other.

So during the tune what you will be doing is considering the size of the motor, the VE. Try to figure out how much fuel is required at a particular VE, and tell the computer to give it that much. The variable that delivers fuel is called PULSE WIDTH or how long a particular injector stays open and continues to deliver fuel. Now, the motor requires a specific amount of fuel to maintain the correct AFR under given conditions. The smaller the injector, of course, the longer the pulse width. Of course, the PW is measured in MILLISECONDS. So a 20 lb injector will require twice the time as a 40LB injector. It's that simple.

Now, this is a GROSS over simplification of the process, and by no means do I expect a text book to be written based on my ramblings. HOWEVER, I think without a basic understanding of how fuel systems work, it's hard to even begin to discuss how to tune a car.

SO.....with this basic understanding, the next step is to understand what the sensors do and how they relate to each other when determining how much fuel to deliver and under what circumstance.
 
#21 · (Edited)
WHEW! Can someone read that over and tell me where I got lost?

I see too many "tuners" who don't understand what they are tuning or how the motor works tuning cars. It's not REQUIRED information but I believe if you understand the underlying theories about how this stuff comes together, the mystique of tuning kinda fits into place. It's not all black magic. It's not hard to do, but without experience and knowledge it's hard to do WELL. So our goal is to take the physics of delivering fuel into a combustion chamber and understand what that means to the ECU based on the sensors and conditions it is given, and ultimately, how much fuel needs to be deliered based on the feedback of those sensors.

All these sensors are, are indicators of engine conditions so the fuel can be put in or taken out. WHY do you put less fuel in a hot one vs. a cool one? WHY does the amount of vacuum change the amount of fuel you give. THOSE are the basis to understanding tuning, before you pick up a laptop.

thanks.
 
#23 ·
HA! In through the nose, out through the mouth!

Someone.....quick get me a bag.
 
#24 ·
I'll pause here instead of dumping too much info.

Next up, sensors, as SLVR talked about and how each is related to the other. Inputs first. Then outputs.
 
#25 ·
Exactly!
The only output that hasn't been explained yet is the IAC.
Anyone?

I think that this is coming out perfect. Very simple and basic for the beginner so you don't feel overwhelmed the first time you look at the datalog like I did!...lol
Almost ready to datalog?
 
#26 ·
IAC...as it says....IDLE AIR CONTROL

When you make a mixture more rich or lean it effects the idle. By opening the throttle plates, the idle can go up and down if you add more air in, or take air out of the mixture.

The car has to idle at a particular RPM under numerous conditions. The IAC does that.

For example, if your in neutral, the load on the engine is zero and the idle will be what it is.

What happens when you turn on the air conditioning? The computer know the idle should be say 1000 RPM. So it makes the idle 1000 RPM. When you go from Neutral to gear, the motor steps down again, so the IAC brings the idle back UP to where it's supposed to be.

How does it do that? Well picture a screw inside a pipe. The screw has a cone shaped head called a Pintle. The pintle fits inside the pipe which is also cone shaped on the inside. So the screw goes in and out of this cone shaped tapered recess in the pipe, depending on the idle.

So the ECU is looking at the INPUTS, sensors, and the RPM and saying......HMMM....the RPMs are high/low based on the input of the sensors I need to add/subtract air.

There is a hole in the throttle body which is opened or closed by the IAC moving in or out. When the IAC retracts the pintle the hole is opened, allowing more air into the system, raising the RPMS. When it is closed, the mixture is richer.

So it, the ECU, backs out, or runs in, the IAC until the idle meets the pre programmed designated idle. Once there, it stops.
 
#28 · (Edited)
I bought up another dynamic here in the last post. Fuel pressure.

Fuel pressure is important in tuning because it will effect how you tune as it will effect the flow of the injectors.

This is exactly why INJECTORS PLUS is more than injectors. All these elements come together to result in the correct FUEL DELIVERY SYSTEM. As I had said in the past injectors are like gum at the checkout line, the crap next to the mints and national enquirer while you stand behind someone with 25 items in the 10 item express lane. That's why you don't see Sea Foam or Injector Cleaner on my site, Autozone has it you can get it there, we stick to the meat and potatoes of how this stuff works.

There are serious considerations to the entire system when building a high performance motor, and they ALL effect the tune.

For example using a fuel pump that has -10 AN in and -10 AN out may have the tendency to run dry or experience cavitation. This will result in poor fuel pressure and effect the tune. The solution, use -12 in and -10 out a lot of times.

Which regulator you choose can determine the performance of the system. It has to be matched to the pump you're running. Just had a guy running a carb regulator on an EFI motor and wondering why it won't work. This again, WILL EFFECT THE TUNE.

Fuel pressure too will dictate what injectors you use. For example, I have sold Seimans injectors for very high performance applications, and very expensive motors. I have no problem with that. These are motors that run $50-70K just for the motor. Seimans are good injectors.

On the other hand I have a customer who has a forced air IMPALA he runs on the street not worth $15K. If I had my preference I'd put him into BOSCH. WHY? The Seimans are a great injector, but under FP of 60 pounds or so and up, the pintle vibrates and they fail. He melted a piston.

What we did was open his 60s to 80s when we rebuilt them to allow him to get the tune and lower his fuel pressure to ensure safety.

I think my point is, as evidenced by IP's tag line here "HIGH PERFORMANCE FUEL DELIVERY SYSTEMS" the tune is the LAST STEP in dealing with what you're going to require to get the car to run right, not the first.

Although injectors are that "gum" it's good to understand which product and which size is the right fit and the implications of choosing one injector over another for any given application. It's far more than "application and flow please".....that's where advice based on experience and knowledge can save you a lot of time and headaches in your tuning.
 
#29 · (Edited)
Flow matching...something else that effects a tune.

We hand match every set of injectors that leaves our shop. We buy a box of 300 injectors and the manufacturer says "flow matched" on the box. Don't believe it.

There is "flow matched" and "FLOW MATCHED". Some vendors will tell you a set of injectors is flow matched simply because it says so on the box. They reach in and grab a bunch and toss them in the bag and out the door we go.

Well, our experience tells us that whatever is printed on the box is not necessarily the truth. We hand pick every single injector we sell and flow match ever set on the bench before they leave the shop.

Why is this important? Well first, many of our customers have VERY expensive motors.

Second, if you don't have a truly flow matched set, it makes the car MUCH harder to tune. Inconsistencies in injectors can screw with the AFR the O2 sensor is picking up and you can wind up with some lean and some rich cylinders.

I can't afford to have customers blowing up motors, and the fact of the matter is the slight increase in cost for a truly flow matched set, will be off set by the time you save trying to tune, by a long shot. Professional tuners can save 2 hours on a tune between a flow matched set and not. Not MY numbers, theirs.

Think about what that means to the amateur.
 
#39 ·
I just left a shop that does hundreds of injectors with us a month. He deals mostly with imports, has a 20 car backup and six on the lifts. He's well known in this area and is well respected. NOT a rice guy, but a real performance guy who does imports.

Anyway, all the injectors we sell are FLOW MATCHED. Sure, we aren't going to be the cheapest, just the best. And the reason we do this is because it is far easier to tune.

The guy JR, who owns the shop, was telling me yesterday that he got a set of injectors before using us that weren't flow matched, he ripped them out because he couldn't get the car tuned, and this is a guy who does this on a daily basis, a real expert.

So as far as tuning is concerned, I thought this a validation story to spend a few extra bucks on flow matched sets. It will make life a lot easier for you down the line.
 
#30 · (Edited)
BTW, SLRV, all this is stream of consiousness. I am writing off the top of my head with no planing or fore thought.

If it's disjointed or needs re arranging, feel free.

I apologize for digging so far down the rabbit hole, but I think it's required to understand the SYSTEM before talking about how to tune it. Bottom line tuning is the last part in fuel system design and without a basic understanding of the elements that get you to that tuning, it's harder to understand.

if you think of tuning as simply trying to get the right AFR under certain loads, temps, timing conditions, it's not all that magical.
 
#32 ·
NOPE I couldn't.

Been up since 3AM!
 
#33 · (Edited)
What I didn't mention was the cam will effect a lot of this, for the sake of argument we can assume using a cam without a lot of overlap. We can keep this discussion to a fairly mild cam.

And one last comment before we get into how the inputs effect the outputs is that some of the theory we will discuss is general tuning. The stock ECU is very granular and incorporates parameters such as AC and speed. Aftermarket ECUs typically control spark and fuel only hence, being much simpler to tune. This is probably due to the advances in technology than shortcomings of aftermarket ECUs. GM designers had to build an ECU which would do particular things under every possible condition, from the heights of Colorado to the swamps of Florida. Typcially our cars stick in our general area, so this is less important. Not to mention GMs requirements to meet EPA laws. You won't see things like injector decay in an aftermarket system.
 
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