# DTA for dummies



## cabzilla (Jan 3, 2000)

*This is for a 12v vr6 w/ 550cc injectors ar 3bar.*

First off we have general engine settings. For a vr, this is pretty close to what you want to see. One thing I have played around with is the coil on time. I had it at 2000 for a while, but I was getting breakup over about 15psi. Changing it to 3000 fixed things. Everything else is universal. 









Now we have the start fueling map. It's an arbitrary enrichment figure based on the mail fuel map, which I'll discuss next. You just need quite a bit of fuel to turn the motor over, and this reflects that. The figures in the columns and rows are % enrichment during startup. 








This is the main fuel map, with injector on-times in milliseconds. 








A few things of note about this map. It is oriented with throttle position as the horizontal axis and rpm as the vertical. Note the "pad" of extra fuel in the TP: 1 RPM: 501 position. This extra fuel softens the motor's return to idle. If it decels to 501 rpm, extra fuel (along with exta timing, discussed later) bumps it back up to ~1000 rpm. 
This map works in conjuction with a pressure compensation map that enriches by percentage based on manifold air pressure. 
TP columns 1-5 are light-throttle and are lean for cruising fuel economy. They are richer in low rpms to prevent bucking. 
Below is a graphical representation of the above fuel curve. Injector on-times match the torque curve of my motor, peaking around 4500 rpm. The axes are the same as the 2d fuel chart. Note the depression in the low rpm / throttle position areas for fuel econ. The large hump is in the peak torque area and decreases in direct proportion to torque. 








This is the timing map. It's very basic and manipulated entirely by the boost-dependent pressure compensation map. There is a "pad" of extra timing below idle just like in the fuel map to increase idle speed on decel. There is less timing at low rpms for driveability. 








This is the pressure compensation map, and the key to how your car performs. 








It's a simple map, with pressure in kpa, timing and fuel correction, based off of MAP sensor readings. kpa is a 10-base pressure measurement. 100kpa = atmospheric pressure. 200 kpa = 14.7 psi or 2 atms. Observe the increased timing advance (fuel econ and part throttle power) in zero to low (~120 kpa) boost. This is a 91 octane map and is conservative with timing. 
If you see fluctuations in boost via the data logging function of the DTA, this is where it is corrected for. If you have a 200kpa average (about 15psi) with spikes to 220 or so, you can achieve a flat A/F curve by bumping compensation at 220.
Also note the interaction between the base timing map and the pressure comp map. All timing figures are derived by the MAP sensor readings. Timing tapers in a linear fashion directly correlated to boost pressure. 
Below is the throttle pump effect map. This provides enrichment at the moment of throttle tip-in, which can prevent stuttering due to a momentary lean condition. 








Pedal speed is exactly that, how quickly you depress the pedal, and is an arbitrary number, higher figures here will not induce enrichment unless the pedal is pressed very quickly. Increase in fuel % is how much fuel is added if the above condition of pedal speed is met. Duration in turns determines the length in rpm of enrichment. 
Below is the water compensation map. Its primary function is to add needed fuel when the car is cold. It provides enrichment based on water temp, tapering to 0 once the car is up to normal operating temps. 








Below is the last map, air temp compensation. Physics dictates that each 10 degree celcius increase / decrease in temp causes a 3% change in oxygen molecule density in air. I have found that for a vr6, this is too extreme. The below chart has worked best for me. Following the 3% rule caused rich conditions in cold weather and lean ones in hot, as well as FUBARing hot restarts. If the car is up to operating temp and shut off, the IAT sensor heats up due to its location in the intake manifold. If you restart the car shortly thereafter, the heat-soaked IAT and the air temp correction makes the car run very lean until it cools back down. The below chart will provide consistent A/Fs in a wide variety of temperatures. I also have mild timing retard built in in the event of extremely high intake air temps. 










_Modified by cabzilla at 2:21 PM 2-3-2006_


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## Henric (Jan 2, 2003)

*Re: DTA for dummies (cabzilla)*

really nice whrite up! http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif 
even i understod a few things









/Henric


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## MarcoVR6SC (May 3, 2003)

*Re: DTA for dummies (Henric)*

Good info http://****************.com/smile/emthup.gif 
For what size injectors are the maps and at what fuel pressure?
That is for the 12v I guess.
For the sensor position, I had for the 12V also 78°, but I have just looked for the 24V and it is at the 14 tooth so should be 84° (6° x 14) BTDC. Now I am not sure the 24V and 12V are the same.



_Modified by MarcoVR6SC at 1:36 PM 2-3-2006_


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## JPLengineer (Jul 7, 2005)

*Re: DTA for dummies (cabzilla)*

THis is awsome!!
Great Thread . .
You're a daaaamn player ==> Pete


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## N_TENSETUNING (Dec 5, 2001)

*Re: DTA for dummies (JPLengineer)*

finally a worthwhile DTA thread!
http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif 
thanks Cabzilla!

dave


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## cabzilla (Jan 3, 2000)

*Re: DTA for dummies (MarcoVR6SC)*


_Quote, originally posted by *MarcoVR6SC* »_Good info http://****************.com/smile/emthup.gif 
For what size injectors are the maps and at what fuel pressure?
That is for the 12v I guess.
For the sensor position, I had for the 12V also 78°, but I have just looked for the 24V and it is at the 14 tooth so should be 84° (6° x 14) BTDC. Now I am not sure the 24V and 12V are the same.
_Modified by MarcoVR6SC at 1:36 PM 2-3-2006_

This is for a 12v vr6 w/ 550cc injectors ar 3bar.


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## MDTurborocco (Aug 24, 2003)

*Re: DTA for dummies (cabzilla)*

You feel like explaining some of the nonbasic functions like coil on time, ect....My buddy vr6chris had this standalone and I was pretty clueless on how to tune.....


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## cabzilla (Jan 3, 2000)

*Re: DTA for dummies (MDTurborocco)*

Coil on time determines how long the coilpack fires the plug for each cycle. If you're seeing stuttering or other signs of weak spark under boost, turn it up. 3000 microseconds is the practical limit, though.


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## lugnuts (Jul 26, 2001)

*Re: DTA for dummies (cabzilla)*

just to clarify, coil on time or dwell time is actually the length of time in which the coil itself is charged, after which time the spark energy is released.
When the signal is sent to the coil the current will rise for a specific period of time and then reach a peak, at which time it is no longer necessary to try to charge any more and after that an overcharge condition will occur which can reduce the life of the coil.


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## slappynuts (Feb 27, 2005)

*Re: DTA for dummies (lugnuts)*

What is the row that has 1-14?Its compared to the rpm colum.Is there a generic map calibration section?


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## MarcoVR6SC (May 3, 2003)

*Re: DTA for dummies (slappynuts)*

That are the throttle columns (TPS sensor as reference to load, not MAP sensor), you can calibrate them as you wish from 0 to 100% throttle. However, you can use the MAP sensor as reference to load, and fill in the rows (1-14) with Kpa values. In the new version of DTA (S60) you can use either metric or imperial values (plus a lot of other features such as VVT).


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## jazzpur (Dec 27, 2001)

*Re: DTA for dummies (MarcoVR6SC)*

http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## jazzpur (Dec 27, 2001)

*Re: DTA for dummies (jazzpur)*

pics are still down...
any word?


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## MKIII-JP (Dec 3, 2003)

*Re: DTA for dummies (jazzpur)*

How much can I find a NEW pro-8 for??? state side
and I see that there is a serial to USB conversion cable
DOES IT WORK, or is it glitchy??? I need USB.
and what needs to happen to run an 0BD1 VR for cam location?
some custom bracket-sensor set-up OR can I use the signal out from dizy??
looking for some info.
i have been searching.


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## cabzilla (Jan 3, 2000)

*Re: DTA for dummies (jazzpur)*


_Quote, originally posted by *jazzpur* »_pics are still down...
any word?

they are getting a new server. they'll be back, I promise.


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## cabzilla (Jan 3, 2000)

*Re: DTA for dummies (cabzilla)*

Someone wanted to see this, so I'm bumping it.


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## InspiringTech (Sep 9, 2002)

*Re: DTA for dummies (cabzilla)*

http://****************.com/smile/emthup.gif Customer service and a nice write up.


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## VWn00b (Mar 4, 2005)

Are you able to run the mk4 24v coils with DTA with the addition of an ignition harness, or would you reccomend just running a regular style coil setup?
btw, I ask because I'm going to be running DTA on my 2.slow build and thought it would make for something a bit different.


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## tyrone27 (Sep 7, 2001)

*Re: (VWn00b)*

bump interesting


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## vr6 nitrous (sweden) (Dec 18, 2002)

*Re: (tyrone27)*

got dta p8pro myself ,I hate that everything is in % ,that sucks


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## OhSnap (Jan 31, 2006)

*Re: (vr6 nitrous (sweden))*

hey can someone send me a map or 2 to get started im running p8 pro on my vr with 630's [email protected]


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## '95MullberryVR6 (May 31, 2002)

*Re: DTA for dummies (cabzilla)*

Can someone explain to me why the fuel map is based on the TPS and not manifold pressure esp. with forced induction or is that why there is a sererate fuel compensation map based on MAP? 
I think I'm finally starting to get this crap! 
How different would these maps be with a 4bar fpr and 42# injectors?


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## talx (Apr 4, 2003)

*Re: DTA for dummies ('95MullberryVR6)*

Well first of all I don’t see any reason one would want to tune a boosted engine using TPS as mane load except for the fact that it’s easier than tuning MAP as main loud 
But never the less tuning boostid engines by MAP is the best way to do it
Well if you increase fuel pressure the fuel map ms will decrease all along the map if you enlarge injector size same thing applies


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## Slayer (Aug 8, 2000)

*Re: DTA for dummies (talx)*

damn. quality post http://****************.com/smile/emthup.gif


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## '95MullberryVR6 (May 31, 2002)

*Re: DTA for dummies (talx)*


_Quote, originally posted by *talx* »_Well if you increase fuel pressure the fuel map ms will decrease all along the map if you enlarge injector size same thing applies 

"...fuel map ms..."? what's ms? milliseconds of duration?


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## Jefnes3 (Aug 17, 2001)

*Re: DTA for dummies ('95MullberryVR6)*

You can make MAP your MAIN load. (choose this option when start tuning)
Yep, fuel map is in milliseconds of inj. pulse.

Peronally: I don't like DTA. 
Crappy user interface. (anyone: IM me if you care for details)

-Jeff



_Modified by Jefnes3 at 9:17 AM 6-17-2006_


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## MarcoVR6SC (May 3, 2003)

*Re: (VWn00b)*


_Quote, originally posted by *VWn00b* »_Are you able to run the mk4 24v coils with DTA with the addition of an ignition harness, or would you reccomend just running a regular style coil setup?
btw, I ask because I'm going to be running DTA on my 2.slow build and thought it would make for something a bit different.

Yes you can, there's a check box to run amplified or non amplified coils. About the 24v coils, the early production coils (022 905 100A) had some failures, you need coils with at least ‘H’ or later version.


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## '95MullberryVR6 (May 31, 2002)

*Re: DTA for dummies (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_You can make MAP your MAIN load. (choose this option when start tuning)
Yep, fuel map is in milliseconds or inj. pulse.

Peronally: I don't like DTA. 
Crappy user interface. (anyone: IM me if you care for details)

-Jeff

Sent IM


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## xpalendocious (Nov 28, 2003)

mmm, DTA


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## tyrone27 (Sep 7, 2001)

*Re: (xpalendocious)*

Only system I want is the S60. it has everyone but one feature that will make it a ultimate stand alone. Thats knock sensor control. that the only feature it doesn't have. if it had that


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## VWn00b (Mar 4, 2005)

*Re: (MarcoVR6SC)*


_Quote, originally posted by *MarcoVR6SC* »_
Yes you can, there's a check box to run amplified or non amplified coils. About the 24v coils, the early production coils (022 905 100A) had some failures, you need coils with at least ‘H’ or later version.

Do you know how the 24v coils would be wired to the DTA ECU? Would I have to buy an ignition harness? If so, where would I buy this harness?


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## MarcoVR6SC (May 3, 2003)

*Re: (VWn00b)*

If you want to put DTA, you'll need a harness anyway, but you can splice it on the original wiring.
The amplified coils on the 24V have 4 connections, one +12V amplifier supply, one amplifier ground, one signal input and one ground from the secondary (spark) coil that you need to ground on the head.


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## talx (Apr 4, 2003)

*Re: (MarcoVR6SC)*

You can use them but you will need to use a pull up resistor 
Generally I would not advise to use these coils the DTA built in amplifier is good enough and on the P8 is protected so that if you burn a coil it will not burn the ECU
+ With some coils using an external amplifier people have experienced excess heat from the ECU
On the new S60 and other upcoming ECU’s they have solved this problem and added a built in pull up resistor that switches when you switch from amplified to unamplified coils http://****************.com/smile/emthup.gif


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## MarcoVR6SC (May 3, 2003)

*Re: (talx)*


_Quote, originally posted by *talx* »_You can use them but you will need to use a pull up resistor 
+ With some coils using an external amplifier people have experienced excess heat from the ECU
On the new S60 and other upcoming ECU’s they have solved this problem and added a built in pull up resistor that switches when you switch from amplified to unamplified coils http://****************.com/smile/emthup.gif 


I’ve had that heating problem also, but then I swapped to a non amplified Bosch coil and heating problems were over (with the 12 valve engine). I think you need to pull up then non used coil outputs to solve the heating problem.
I will try to use the original amplified coils (form R32) to run full sequential, plus if you want to use a wasted spark coil, you need special spark wires and they are not that cheap.


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