How to SAFELY tune a piggyback setup

Discussion about ECU Tuning Products and Theories

How to SAFELY tune a piggyback setup

Postby JGSturbo » Sun Oct 29, 2006 10:20 pm

After all the discussion about piggybacks and AFCs in general I figured it was time to post my methods of tuning and setup when it comes to a piggyback setup.
Here's how I see based on my many hours and many different setups on my KA projects-

- Buy a wideband meter!! With an indash display.
I can not stress this enough, even if you take it to a dyno to have it tuned everyone should be monitoring their AFR on the street as well. Various factors can change AFR from the street to the dyno. Also if things go wrong you will know.
AEM wideband gauge, Innovative LC1 w/ the XD1 gauge, PLM300, etc. are all good units.

- A knock monitoring device is key. Listening for knock is pointless when by the time you can hear it on the outside, its too late.
The TXS Knocklite (included with the DTEC units or available separately) is a relatively new unit that can be programed for your particular engines noise profile via the stock knock sensor or any bosch knock sensor (the ford focus knock sensors are really affordable).
Alternatively a mic. pre-amp and headphones can be used (a knock sensor is just a microphone).

-Do not just whip-out a calculator to figure out some kind of base correction for larger injectors and think your finished. This hardly ever works correctly do to the various effects of MAF volts on actual injection time, -27% may drop dutycycle 50% which would cause the stock ECU to go crazy. This is WHY the WB meter is #1 . And its always better even at idle to start a little rich.
Based on my exp. if you want to figure out a number to start tuning from here's something that will get you in the range. The old method of trying to use % of injector increase will generally be too much. From my various tunes on various injector sizes this will put you a bit closer-
(old inj size) / (new injector size) = A
1-A = B
B*0.40*100 = % to take out (negative)
example-
270cc / 440cc = 0.613
1 - 0.613 = 0.387
0.387 * 0.40 = 0.1548 *100 = 15.48% which you would input as -15.5% into your low throttle correction fields.
This is pretty close to my settings on my 440cc /stock MAF tune.
Different injectors styles will have different response times (charge time for the coil) so settings will vary (Again do NOT just input estimations and expect it to be perfect).
Since the KAs are all factory setup for N/A AFRs it necessary to rich en up higher throttle areas that can see boost. Even on a .50 trim T3/T04E .63A/R boost can be had at around 25-30% throttle so those areas above that will need to be richened up. A decent starting number would be +10% from the idle setting (for ~8psi of boost). This should make for a rich starting point depending on the setup (AGAIN do NOT just input estimations and expect it to be perfect. Having the right tools to tune it in properly it what its all about).

-Timing
Timing is ALWAYS a concern with piggybacks. Some piggybacks have timing adjustment built in but most do not. For those that don't, MSD BTMs are nice for in cabin control and it will work at multiple boost levels (unlike dist. retarding). But basic retarding of the distributor is a decent low budget option, the only real differences would be not having different timing retard at different boost levels. But if your only aiming for one boost level and don't have any over boost conditions there's not a lot of difference.
Setting up timing is a matter of avoiding knock. The ECU will happily give you plenty of timing if knock isn't present. If knock is seen, timing goes bye-bye. There's been a lot of discussion of MAF signal reductions giving timing increases. Even with injectors as large as 630cc injectors I have not seen anything that a couple degrees of dist. retard wouldn't have fixed. If your just retarding the disty, your overall timing is going to be lower everywhere anyhow. Therefore fixing any possibility of increased timing.
Now that we have that out of the way, on to tuning timing.
This is where a knocklite comes in really handy because the ECU will retard timing before the knock is audible. Start out with significant timing retard and get a decent AFR tune (don't spend too much time for now, leave it a little bit rich). Then start making passes advancing a small amount each time (if your using a BTM, maybe a degree if your using a timing light). When you finally see a little knock, back up a notch and reset the factory computer. Its very important to reset the ECU when knock is seen because the ECU will start retarding. Unplug the 2 connectors at the battery or pull the battery ground for ~10 seconds then reconnect.
Once settled on a timing setting, the final AFRs can be tuned.
-Airflow meters
A meter swap isn't aways needed. If you have a nice flowing MAF like the S14 one you may actually leave it. The ECU will give maximum dutycycle before the MAF signal maxs out. And with large injectors you will always be taking away fuel until your injectors are tapped out. So basically even if the MAF is maxed out the ECU never sees that much voltage.
And the S14 MAF provides better signal than a larger MAF. Its actually kind of nice to have a stead MAF signal to adjust, makes it more predictable.
The only difficultly is if you wanted to run multiple boost settings on one map. Whatever maximum boost the car is tuned at is all the airflow its going to delivery for. There is nothing else to tell the ECU that airflow has increases after the MAF hits its limit. But there happens to be a work-around. Basically instead of using TPS signal to tell the piggyback what to do you install a suitable MAP sensor and wire its signal to the TPS input.
This actually does wonders for the response of the whole system.
Its really only functional for systems like the E-manage or DTEC-FCs that have multiple throttle ranges. Using a 2 bar map makes it very simple, at 0 psi it should show 1/2 throttle, 7psi 3/4 throttle, 15psi full throttle.
It gives air flow correction based on manifold pressure vs RPM, PERFECT!
The driveability of a normal N/A MAF and boost tunability of MAP.
-Air intake temp. sensor
To keep the ECU informed of the actual temp. entering the engine the AIT sensor needs to be in the cold pipe or in the cold side intercooler tank.
Ideally it should be located in the cold pipe, outside of the engine bay to avoid heat soak to the sensor. Just reading open air temps doesn't really tell the ECU much.
- Tune it properly!!!!! So many people botch the tuning and then blame the piggyback for various reasons when things go wrong. Then others (author included) take the time and care needed to do it right and it works. Either pay for the dyno time or datalog passes down a straight stretches of road. But don't just ask for somebody else's settings and figure your good to go. Paying for a "TUNED" ECU may take some labor out of the tuning, but all setups need to be custom tuned for good consistent results.
<12.0:1 / >11:1 under boost is the goal, don't be scared to take pass after pass to make a nice flat AFR line. 11:6-11.8:1 I veiw as the ideal goal. Also don't make huge jumps when tuning, start plenty rich and make smaller and smaller adjustments as you go. Sometimes as little as 0.2% can make quite the difference.

*work in progress
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Postby LigouriRd. » Mon Oct 30, 2006 7:10 am

Nice writeup just one note of comment:
The ECU will give maximum dutycycle before the MAF signal maxs out
-Not exactly true. With only 370cc injectors my S14 maf is maxed out at 11lbs of boost. Of course I can't see what the injector duty cycle is at right now but since I can run richer at 100% maf, I haven't reached the injector max duty cycle. Regardless, its a good idea to keep an eye on the maf voltage or the percentage.
Before I had my boost kreep issues under control the it would spike to 15lbs overcome the maf and then eventually overcome the injectors since no more fuel was being added. Luckily my wideband let me know that the A/F was starting to go lean and I got off the throttle.
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Postby bigo181979 » Mon Oct 30, 2006 7:35 am

This is gonna be of great help to some people like me, in the vary near future. :cheers:
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Postby JGSturbo » Mon Oct 30, 2006 9:56 am

LigouriRd. wrote:Nice writeup just one note of comment:
The ECU will give maximum dutycycle before the MAF signal maxs out
-Not exactly true. With only 370cc injectors my S14 maf is maxed out at 11lbs of boost. Of course I can't see what the injector duty cycle is at right now but since I can run richer at 100% maf, I haven't reached the injector max duty cycle. Regardless, its a good idea to keep an eye on the maf voltage or the percentage.
Before I had my boost kreep issues under control the it would spike to 15lbs overcome the maf and then eventually overcome the injectors since no more fuel was being added. .


I've done extensive logging of the dutycycles with my DTEC and I have gotten 89.9% duty before 5v MAF (5% correction = < 4.75V, and less considing the maf really didn't max until 12psi) which more % than should be used. Locked up injectors are a bad thing :(

With 630cc injectors @ 12psi I'm maxed on the MAF (4.995) and corrected down to 4.110v with a 65% dutycycle.

Luckily my wideband let me know that the A/F was starting to go lean and I got off the throttle

Thats the way it should be :D Behold the power of the indash wideband :)
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Postby joshds25 » Wed Nov 01, 2006 7:43 pm

Awsome write-up Lance :wink: Wish I had it when I first turboed :( Oh well others will have it for their first itme :)

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Postby silviaks2nr » Wed Nov 01, 2006 7:56 pm

thanks for the tips, I've been trying to tune my setup with an emanage/support tool etc with some setbacks. I was wondering what might be some good retarding values to use as a base low boost tune. If you have anything for the emanage blue specifically that would be awesome!
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Postby turbo2nr » Wed Nov 01, 2006 8:00 pm

sticky please!
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Postby veilside180sx » Wed Nov 01, 2006 9:33 pm

Ask and ye shall receive

turbo2nr wrote:sticky please!
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Postby babowc » Wed Nov 01, 2006 9:49 pm

yay stickied.

this post, however, intimidated me a bit.. i have to be honest :/
p00t wrote:. A turbo is basically changing the size of your motor depending on your mood 8)
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Postby JGSturbo » Wed Nov 01, 2006 10:47 pm

silviaks2nr wrote:thanks for the tips, I've been trying to tune my setup with an emanage/support tool etc with some setbacks. I was wondering what might be some good retarding values to use as a base low boost tune. If you have anything for the emanage blue specifically that would be awesome!


By my estimation I'm doing ~7 degs retard with my setup
( http://www.ka-t.org/forums/viewtopic.ph ... highlight= )
I'd start with 1/2- 3/4 deg. per psi timing retard.
You should get the pressure sensor for the E-manage, its will make tuning easier.
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Postby silviaks2nr » Wed Nov 01, 2006 10:54 pm

very true. do you know if there are other pressure sensors i could use to send the signal the the unit? I'd like to avoid paying $150 if possible
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Postby JGSturbo » Wed Nov 01, 2006 11:04 pm

Somebody was able to use the 25psi Motorola map sensor which is DIRT cheap. You could also use any old 2-3bar sensor as the throttle input like any other AFC computer. You just have to find out what throttle % = boost/vacuum.

IMO timng is just like tuning AFR with the right tools. Start safe then add a little bit every pass to find the threshold on a good knock monitoring system. You just have to watch AFR at the same time.
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Re: How to SAFELY tune a piggyback setup

Postby crashjust4kix » Sat Nov 04, 2006 12:10 am

JGSturbo wrote: But there happens to be a work-around. Basically instead of using TPS signal to tell the piggyback what to do you install a suitable MAP sensor and wire its signal to the TPS input.
This actually does wonders for the response of the whole system.
Its really only functional for systems like the E-manage or DTEC-FCs that have multiple throttle ranges. Using a 2 bar map makes it very simple, at 0 psi it should show 1/2 throttle, 7psi 3/4 throttle, 15psi full throttle.
It gives air flow correction based on manifold pressure vs RPM, PERFECT!
The driveability of a normal N/A MAF and boost tunability of MAP.



I was always curious as to whether this would work. one question, tho... where would one draw the ref. signal? isn't it supposed to be somewhere around 5 volts, and would jumpering off another 5 volt circuit interfere with anything?
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Re: How to SAFELY tune a piggyback setup

Postby JGSturbo » Sat Nov 04, 2006 9:29 am

crashjust4kix wrote:
JGSturbo wrote: But there happens to be a work-around. Basically instead of using TPS signal to tell the piggyback what to do you install a suitable MAP sensor and wire its signal to the TPS input.
This actually does wonders for the response of the whole system.
Its really only functional for systems like the E-manage or DTEC-FCs that have multiple throttle ranges. Using a 2 bar map makes it very simple, at 0 psi it should show 1/2 throttle, 7psi 3/4 throttle, 15psi full throttle.
It gives air flow correction based on manifold pressure vs RPM, PERFECT!
The driveability of a normal N/A MAF and boost tunability of MAP.



I was always curious as to whether this would work. one question, tho... where would one draw the ref. signal? isn't it supposed to be somewhere around 5 volts, and would jumpering off another 5 volt circuit interfere with anything?


On all cars (M/L) you can use the TPS power supply for a MAP.
I've never heard of anybody ever having any interferance problems sharing. Most ECUs have a good 5V power supply. You could also rigg your own 5V power supply. It really doesn't have to be exactly 5V so long as its regulated (like one inside an ECU would be).

Search "SAFC Hack".

I'll be converting my S14 to the method of AFC tps/load input in the near future in which I'll post a how to.
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Postby crashjust4kix » Sat Nov 04, 2006 8:01 pm

that's good to know, and keep us updated as to how it works out. btw, the turbo dodges from the 80's all use 2 bar maps, so they're everywhere. if I can find the vac/boost v. voltage chart, I'll pass it along to you or post it in case anyone is curious.
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Postby JGSturbo » Sat Nov 04, 2006 10:26 pm

crashjust4kix wrote:that's good to know, and keep us updated as to how it works out. btw, the turbo dodges from the 80's all use 2 bar maps, so they're everywhere. if I can find the vac/boost v. voltage chart, I'll pass it along to you or post it in case anyone is curious.


The most popular is the GM based sensor.
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Postby jwrose » Sun Dec 03, 2006 9:13 pm

can i get some more explanation on the mic pre amp and headphones as a knock sensor
how would i go about hooking that up
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Re: How to SAFELY tune a piggyback setup

Postby cdlong » Wed Dec 27, 2006 2:39 pm

JGSturbo wrote:- A knock monitoring device is key. Listening for knock is pointless when by the time you can hear it on the outside, its too late.
The TXS Knocklite (included with the DTEC units or available separately) is a relatively new unit that can be programed for your particular engines noise profile via the stock knock sensor or any bosch knock sensor (the ford focus knock sensors are really affordable).
Alternatively a mic. pre-amp and headphones can be used (a knock sensor is just a microphone).


doesn't the engine have a stock knock sensor? assuming you can read the signal with a data logger or Biki or something, wouldn't that be enough? or is it not accurate/sensitive enough?
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Re: How to SAFELY tune a piggyback setup

Postby JGSturbo » Mon Jan 15, 2007 11:18 pm

cdlong wrote:
JGSturbo wrote:- A knock monitoring device is key. Listening for knock is pointless when by the time you can hear it on the outside, its too late.
The TXS Knocklite (included with the DTEC units or available separately) is a relatively new unit that can be programed for your particular engines noise profile via the stock knock sensor or any bosch knock sensor (the ford focus knock sensors are really affordable).
Alternatively a mic. pre-amp and headphones can be used (a knock sensor is just a microphone).


doesn't the engine have a stock knock sensor? assuming you can read the signal with a data logger or Biki or something, wouldn't that be enough? or is it not accurate/sensitive enough?


Only if your datalogger has a fast scope function so you can see the wave form...
Basically your looking for spikes in the engine noise (abnormally jumps in voltage).
The TXS knocklite does this very well and is simple enough for about anybody to use.
With headphones or an audio recorder you can actually hear detonation very well, many expert tuners use the head phone method.

Yes, you read the stock knock sensor if you have one (SOHCs do not).
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Postby JGSturbo » Mon Jan 15, 2007 11:27 pm

jwrose wrote:can i get some more explanation on the mic pre amp and headphones as a knock sensor
how would i go about hooking that up


You need to hook a mic input to the knock sensor, simple as that. Any sound recorder with a mic jack will work as a datalogger.
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Postby champa » Fri Jan 26, 2007 11:23 am

(old inj size) / (new injector size) = A
1-A = B
B*0.40*100 = % to take out (negative)


where does the .40 number come from?
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Postby JGSturbo » Fri Jan 26, 2007 1:23 pm

It comes from the fact that if you put in -50% for 50% larger injectors, you will be OVER correcting like crazy. Then the ECU will fight the piggyback and run like CRAP.
That number is a rough estimate based on my S14 and the different injector sizes I have ran on it.
My 630cc S14 runs -23% correction.
270cc/630cc = 0.42857
0.42857-1= 0.571
0.5714*0.40*100= -22.84

I did the same cal. on my 440cc setup and 0.400 put me close ever time.
Now if your tossing in a large MAF, this won't work. You will actually need to subract much less. I still believe the usefulness of a larger MAF is lost when your current one isn't a restriction.
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Postby tvmendoza » Thu Aug 30, 2007 10:46 pm

does the TXS knocklight works with the stock sensor or do i have to get another knock sensor?

I saw that you recommend the focus knock sensor but which one are u talking about?
FORD FOCUS LE L4 2.0 P FI 2000
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FORD FOCUS SE L4 2.0 P FI 2000-2001
This ones all use the same is that the year that i need? or newer?
Thanks
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Postby JGSturbo » Fri Aug 31, 2007 11:07 am

Yes, you can tee in to the factory knock signal line (as shown in the KL instructions on turboxs.com ).
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Postby 98blackkat » Thu Feb 03, 2011 3:05 am

wow this is great. my big questions have been answered. first was the best way to wire in a map. 2 what bar. I havent even fully built the engine yet but im already working on the prelim tune and calcs. I have a emanage ultimate with a lc-1 wideband. would you recommend its auto tune as a base and refine from there. I have used it na just to get used to the tuning of it.
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Re: How to SAFELY tune a piggyback setup

Postby path s13 » Sat Mar 29, 2014 10:08 am

Can somebady help me! Im using a safc II n a dont know what to do with dmthe dense air setting! To be honest i have never mess around with it but would like to know.. im using 550cc inj aem fuelpump n60 maf and short block built!
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