GTRay

My experience tuning an NA with a microtech only netted very marginal gains in peak power but significantly improved the breadth of the power curve. The car did not have cats installed and was running a collected header, midpipe, and catback. the one thing i remember the customer noting was the how much odor had been eliminated from the exhaust. his girlfriend had refused to ride in the car because of the rotten egg smell. after the tune the odor was gone.

We experimented a bit with the intake operation. We ran it with the VDI operating and with it wired open. What we found was that the VDI was very critical to developing TQ at higher RPMs. Air flow speed and resonance tuning are super critical for generating TQ.

We also found that our gains didn't come from tuning the fuel side of the equation. The factory system does a great job at supplying fuel. Our gains were ALL in controlling the timing. The factory setup was incredibly conservative with the timing curve.

Timing was very critical for generating a solid TQ curve which translated to a very smooth power curve. I also suspect the changes to the timing are what helped clean up the exhaust odor.

Ray

rxtuner79

iTrader: (1)

If I remember correctly, and I may be mistaken, I remember reading a thread a few years back where someone made an extra 44 whp at 5k rpm using an Rtek 2.0.

j9fd3s

iTrader: (3)

i think it was more like 30, but again that was Mr ludwig. even I have found that leaning out the top end of the S5 fuel curve FEELS like 44hp.

C. Ludwig

iTrader: (27)

hahaha, that won't die.

That car did, in fact, pick up a huge amount of power. The problem was that it had a problem, that we never even attempted to diagnose, before we installed the ECU and went to work playing with the fuel. That particular car was used as a guinea pig for the Rtek development, and we weren't even trying to make power. Our only goal that day was to see if the beta version of the Rtek that DTI had supplied us even worked. I posted the results here and then DTI put them on their website (think they may have pulled it down). The car did pickup a huge amount of power. But, if it were running properly in the first place, there would not of been that much power to be had. DO NOT expect to pick up 40+ hp anywhere on an NA with any ECU. Your mileage may vary.

Casual_John

iTrader: (8)

I would say my car is running properly, for a 24 year old car. Sounds like adding a standalone may help it perform a little more efficiently, with a slight effect on fuel mapping and a bigger effect on timing. The bottom line sounds like it won't add much HP, but it might stretch the HP over a wider band.

Casual_John

iTrader: (8)

And talking about widebands...
Can you effectively tune a car using a standalone, if you don't have a wideband sensor/controller?

The standalone needs accessories, right? Without knowing the AFR from a wideband, you are tuning blind.

So when I budget for a Standalone, I need to include a wideband sensor and possibly a gauge, or some kind of data logging for the standalone to get AFR feedback.

Am i right?

Daviticus

You could possibly rely on a wideband sensor at the dyno you plan to tune on.

Every time I've set up a stand-alone, I've had the wideband in and operational for small on-the-fly tuning tweaks, but I've never dyno tuned any of my cars so it may be a moot point for you.

I do know that out here in Utah at least, there are tons of cars that have been flashed/tuned/running a stand-alone that have been dialed in on a dyno, and don't have a wideband.

Long of the short: Tuner/Owner Preference.

j9fd3s

iTrader: (3)

yeah you should, it really makes life a lot easier, and its much quicker too.

although if you do an Rtek, or safc, since you start with stock, you can get by without, or use the dyno's sensor.

AND all of the old school guys used to tune by ear, and well the butt dyno, it is a skill, and you have to learn it, but it can be done.

the only real problem with the wideband is that we fall into this trap, of "just tune it to xx afr" when really we should be tuning to the afr that the engine runs the best at. ive seen best power mixtures anywhere from mid 12's to about 14.

so you use the wideband as a tool to give the engine what it wants.

peejay

The problem with butt-dyno tuning a rotary is that they're really insensitive to air/fuel ratio. There is an optimal ratio, which will be dependent on many factors so you still need to find it by experimentation, but I've seen it where a 10% fuel change only made a 1-2% difference in power. 1-2% is just in the realm of noticable in the engine's torque curve, but you're not likely to feel that kind of difference on two different runs.

Heh... the way I tuned my first GSL-SE engine, with a narrowband, was to have a friend do WOT pulls uphill in 5th gear while dialing fuel down until the O2 sensor switched lean, then adding 10%. Didn't even really notice a difference then.

So for those of us who aren't looking for the last tiny bit of power, it's easiest to throw the air/fuel ratio to someplace we know is going to have safe EGTs. 13:1 works well enough, although I shoot a bit richer over 6000rpm for a little more in-chamber cooling at the expense of power and economy. Some engines make best power at 12.5:1, some make best at 14.2:1...

Even so, I've seen FCs pick up a lot of power over 4000rpm because the stock tune there is ABSURDLY rich in order to keep the catalysts from melting down. If the AFR is in the 10:1 range, there's almost guaranteed to be no free oxygen in the exhaust, so the catalysts won't have any O2 to react with the HCs and CO. Having to do a lot of work is what kills catalysts.

MadScience_7

Hmmm, slightly O/T. For those of us that still have cats, will we have to worry about burning them up when using a fuel controller to lean things out? Haven't seen any mention of that problem but I haven't looked much.

Thanks
Andy

Casual_John

iTrader: (8)

peejay says That's interesting. So each engine makes best power at a different magic AFR number? And the trick is finding that perfect number for each unique engine?

Then the cleanest burning AFR number, may not be the most powerful? And the AFR that makes the most power may not be the cleanest?

And because the setting that makes the most power may not be clean burning, it could stress out the catalytic converter? So if you want to protect your cats, don't expect to tune for best power, but rather aim for cleanest AFR.
However, if the cats are removed, you've got nothing to lose...go for power,eh?

peejay also says So once you discover this engine's unique AFR number, should you maintain that number through out the RPM band, keeping it fairly flat? Or do you have to go richer and richer as the RPMs gradually increase. Is there a specific ratio you want to hit, as you cross over 6000 rpm? Or do you just bump it up by 10% or something?

D Walker

iTrader: (1)

Not really an issue running cats very lean, its running them rich that kills them.

peejay

The amount of fuel that makes the most power will never be the cleanest. To greatly simplify things, combustion needs oxygen and fuel, it's easy to add fuel but hard to add oxygen, so best power means getting the most out of the amount of oxygen you have, by adding some extra fuel to ensure that ALL of the oxygen gets used.

Where it gets tricky is that adding fuel necessarily hurts power since it's deviating from complete combustion, so you need to add the minimum amount of extra fuel for best power... assuming that the engine can thermally handle it. And that amount of extra fuel will rely on a lot of factors, like fuel atomization and in-chamber mixture preparation.

Good engine guys find the engine's optimal air/fuel ratio. Great engine guys tweak the engine so best power occurs with a leaner air/fuel ratio...

The best power ratio can and will be different at different speeds.

I don't profess to be great or even good. I don't really care about power when I tune for fuel, I just care that it has a little more than enough. More fuel makes for cooler combustion, which should help engine life given how I use engines (multiple meanings of "use").

I look at the wideband for A/F, and I look at timeslips for ignition timing. I don't quite have the bucks to take time off of work and go spend a few hours at a dyno shop at $50-70 per hour.

peejay

Running converters rich doesn't hurt them one bit. They just "go to sleep".

What hurts converters is unburned air and fuel going right through the engine. That's why an OBD-II car that has a detected misfire will flash the MIL at you, misfires are a converter killing event.

Rotaries send a lot of air and fuel right out the exhaust ports, even when running as clean as they can. So Mazda makes the converters out of extremely high quality materials (they're not expensive for the hell of it) and sets the engine tune so that the converters only do anything during the emissions test loop. Under higher loads or speeds than are experienced in the test cycle, the air pump diverts to atmosphere and the fuel floodgates open.

D Walker

iTrader: (1)

AFR tuning is really secondary to tuning the timing. It is actually a balance between the two. Most N/A engine will make best power at about 12.9/13.1 AFR dependant mostly on timing allowed by the fuel, temperature, etc.
Engines esp rotaries, are FAR more sensitive to timing than AFR when it comes to power, even 1 or 2 degrees can make a huge difference in the power curve. Once again however, its not a straight answer as many things affect how much timing you can safely run at any given time. You can see the effect of timing on the dyno when knock control pulls timing, as the power will immediately dip, then recover if the computer advances the timing again.

j9fd3s

iTrader: (3)

this depends. on larger than stock ported engines, its common to tune it to a peak EGT number, the number varies, most people say 1650F. leaner makes more power, but reliability goes down.

the 89+ stock tune does this too, but instead of using the temp out of the engine, they use cat temp.

anyways, on a stock port, or ITS engine, we just tune for best power. when we put the haltech in the race car, we actually spent a couple afternoons on the dyno, and it made best power @13.1afr, so that's where we ran it. the engine went 2 seasons like that, with a 9400rpm redline, and its tired, but intact.

the cool thing about a stock port NA though, is that its a great place to learn to tune, as its hard to hurt it

peejay

Yes, as long as you're aware that the timing mark on your pulley is 25 degrees and not 20. Which I wasn't. Which is why I think I went through so many engines last year.

Unless bridge and large street port N/A engines are fine running 33 or so degrees at full throttle and no acceleration at high coolant/oil temps, that is. A whole lot of flat corner seal springs say otherwise.

That's what I get for not trusting gut feeling. It felt great at "18 degrees" but I was worried about high EGTs melting things (I already have glowy headers) so I bumped it up to "24".

Thing is, "18" degress was really probably about 22-23 in the first place.

j9fd3s

iTrader: (3)

we did that too! from the second we fired up the 2008 25 hours of thunderhill engine, it wasn't right, but we ignored it, and then it didn't dyno that great.

but we ignored it

and then the rocker arms started falling off

and then it started using coolant, 1 gallon an hour

and then it started using oil. (having done this 3 times, we know the factory rings only last like 12-14 hours before they check out)

it finished, but upon tear down we found 2 problems.

1. our tuner, who builds 9 second drag cars, advanced the timing like 5 degrees, saw no change and left it. which is fine, IF you're drag racing for 25 seconds, but it wasn't fine when we stepped on the gas for 25 HOURS. detonation killed um i think #4? it looked like someone had been hitting it with a hammer all night, which would have been more fun.

2. we got .020" over pistons, and a .030 over block, but once again, the drag race guys can get away with that. when the engines lifespan is under 7 MINUTES, you don't need to build a very good one.

so we've gotten more proactive about the gut feeling part!

Casual_John

iTrader: (8)

D Walker says So I should be looking at a standalone that offers the ability to adjust timing first, and fuel secondary. And I beleive I read that the SAFC can adjust fuel but not timing...is that right? Or are there different versions of the SAFC that can do both. Some people seem really critical of the SAFC for its limited functionality.

I'm hearing that people tend to recommend the RTEK over the SAFC because RTEK allows the adjustment of both timing and fuel, right? It may cost a little more than the SAFC, but you get what you pay for, eh?

But the RTEK still needs the AFM in the way for feedback. With a true standalone, the AFM can be eliminated. And this type of EMS has a higher price tag again, doesn't it.

So I should determine my objective before I buy anything. I don't think just tuning fuel is going to provide much bang for the buck, so I say the SAFC is out. The RTEK may be a viable option. Some say the AFM is not much of a bottleneck, so why should I go out of my way to eliminate it, since it won't make much of a difference. That's hard to quantify.

But if I spend a few extra bucks and get a megasquirt, would I be able to eliminate the AFM? Or am I just in a position to replace the clumsy AFM with installing another sensor along the intake, near the throttlebody, like an air temp sensor or air pressure sensor or something?

D Walker

iTrader: (1)

Yes, you will need a real standalone to really dial in an engine.

Casual_John

iTrader: (8)

So to get started with a real standalone, what else do I need to budget for and add to the package. A standalone unit also needs:
-Wideband oxygen sensor
-wideband afr controller
-AFR gauge
-EGT gauge

any more? anything else?

There's more to it than just a standalone, isn't there.

D Walker

iTrader: (1)

Well lessee-

Widebands are inexpensive, and what I normally recommend is an AEM UEGO which gives you the display as well as an output for the ECU.

EGT is not needed, and IMHO not a method for the tuning newcomer to mess around with

On a stock engine you will need the following if your building a harness, assuming you are replacing the MAF with a MAP Sensor and going Speed Density OR Alpha-N:

4 injector connectors
1 cooant temp sensor connector- usually can use the OEM sensor and its pigtail
1 TPS sensor connector- I cut off the OEM connector and use a Deutch DTM series connector, its just easier for me. You could also use a Weatherpack connector set whichis cheaper
1 CAS connector, again I use DTM connector set, use a weatherpack or the OEM if you have one
1 IAT sensor and its pigtail.
1 MAP sensor and its connector
1 Injector resistor pack if needed
Coil/Ignitors connectors for whichever ignition setup you are using. For re-using the stock stuff just use the OEM connectors harvested from a harness

Also you will need:
Relays for fuel pump and e-fan if your using it


And of course a lot depends on which ECU you use and how you choose to use it.

dj55b

iTrader: (2)

Hey John,

Why not get the Megasquirt? You'll have lots of local support which you'll find out will be a great thing. Between me, Aaron, and possibly Martin, we should be able to give you a hand and lead you in the right directions.

The MS2 which is prob the one to get for best support right now cost 250$
The innovate LC-1 wideband kit is 210$
GM Air temp and Coolant Temp Sensors 40$
12' DIYautotune wiring harness 70$
4 conductor dual shielded wire for CAS 30$
Heat shrink tubing and other connectors 20$

So that puts you at a total of about 620$ say 700$ to be on the safer side. That is all you really need to get up and going with. The EGT isn't all that needed and prob about 70% or more of people that have a standalone don't have EGT guages.

tasty danish

iTrader: (5)

Just to add, you don't need tuning gauges. You need to be datalogging. Using a gauge to tune with is a ridiculous idea.

dj55b

iTrader: (2)

The guage isn't there just for tuning, it is there as a monitoring system Incase anything happens. for example if you start reading lean mixtures, is your fuel pump up to par still ? is your fuel pressure regulator working properly, if your too rich, are your air filters clean ? are your spark plugs getting worn down?