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. Author: blundar Date: 08-12-03 14:12

EGT (or Exhaust Gas Temp Sensor) and Wide Band O2 used in combination with Data Logging can be a really powerful tool. Timing changes produce more effects in EGT and fuel changes produce more effects on wideband. Deluded explained some basics to me but most of it flew over my head. :)

Author: Deluded Date: 08-12-03 22:25

Blundar nailed it WBO2, datalogging, EGT , and RTP helps loads too. you are just guessing without at least the first two tools. if more timing advance is needed, it will result in a leaner O2 by detonation. We break very few street engines with these tuning parameters:

  • less than 10psi: 12:1 Air Fuel Ratio
  • up to 16psi: 11:1 Air Fuel Ratio
  • 9.5:1 compression or less: 1 degree retard/#boost
  • above 9.5:1 compression at least 1.25 degrees per psi

A little knowledge can be a dangerous thing.

You can find a howto for tuning to pass a smog test by checking out Tuning For Smog -- markolson - 19 Feb 2005

Here is a log from MSN conversation between Synoptic and Blundar. An how-to for tunning the maps of the ECU for WOT operation. It is very basic, but it gives a good idea of how it works.


11:54:14 AM Dave B. you have a wideband, I presume?

11:54:18 AM Synoptic. hmm

11:54:21 AM Synoptic. no

11:54:23 AM Synoptic. :P

11:54:24 AM Blundar if not, forget it

11:54:28 AM Synoptic. i need to fix civic1990si one's

11:54:31 AM Synoptic. we do that today

11:54:40 AM Synoptic. its the DIY one

11:54:54 AM Synoptic. lets say i'm gonna have one this afternboon

11:55:05 AM Blundar then put it on the car

11:55:07 AM Blundar wait

11:55:13 AM Blundar do you have a narrowband out or not?

11:55:35 AM Blundar the ECU will get pissed off about not having a narrowband

11:55:36 AM Synoptic. i have 2 o2 input on my header

11:55:43 AM Synoptic. so i'll simply add the wb

11:55:44 AM Blundar ok then you're set

11:55:52 AM Blundar drive around with the WB

11:56:04 AM Blundar you'll see what afrs you're at

11:56:18 AM Synoptic. k

11:56:28 AM Synoptic. will AFr change a lot while dringin ?

11:56:33 AM Synoptic. or it will stabilize ?

11:56:48 AM Blundar change a LOT

11:56:56 AM Synoptic. and how to i modify my afr, using te, timing, fuel? how does it ork?

11:56:58 AM Synoptic. okok

11:57:06 AM Synoptic. so how do i tune my car then..

11:57:08 AM Blundar afr is mostly fuel 11:57:08 AM Synoptic. i'm a morron

11:57:09 AM Synoptic. help me

11:57:13 AM Blundar heheheh

11:57:14 AM Synoptic. ok

11:57:24 AM Blundar nick, I honestly don't have time to hold your hand on this

11:57:58 AM Blundar I'm trying to recover a crashed reiserfs in another window :)

11:58:03 AM Synoptic. basically, do I run at steady RPM to see what AFR it is ? average),

i do that for all RPMS, tak enote, enrich, then try again ?

11:58:13 AM Synoptic. i love linux

11:58:18 AM Blundar its much more difficult than that

11:58:32 AM Blundar because you won't be able to hold a steady RPM @WOT without a dyno

11:58:37 AM Blundar you'll be able to do a pull

11:58:49 AM Blundar start at low RPM in e=3rd or 4th geat

11:58:53 AM Blundar floor it

11:59:01 AM Blundar watch the AFRs as you gradually accelerate

11:59:04 AM Blundar watch tach

11:59:13 AM Blundar you'll see it change wtih RPM

11:59:21 AM Blundar make some changes to fuel, observe changes in AFR

11:59:24 AM Blundar repeat

11:59:36 AM Synoptic. k

11:59:38 AM Synoptic. ok

11:59:39 AM Synoptic. i get it

11:59:41 AM Blundar you'll quickly learn how much to change fuel to get disred afr

11:59:49 AM Blundar start relatively small

11:59:52 AM Synoptic. then engine need to have force applyed..

11:59:58 AM Blundar you';d be amazed what 3-5% will do

12:00:03 PM Synoptic. kk

12:00:09 PM Synoptic. keep stock timing

12:00:15 PM Synoptic. then adjust if i hear detonation

12:00:23 PM Synoptic. but if i put more fuel, i should advance it

12:00:25 PM Synoptic. i know that

12:00:34 PM Synoptic. timing will only change the powerband curve, right ?

12:00:45 PM Blundar timing will change everything

12:00:48 PM Blundar nail your fuel first

12:00:52 PM Synoptic. ok

12:00:53 PM Blundar then go back and play with timing

12:00:54 PM Synoptic. stock timing

12:00:56 PM Synoptic. stock pressure

12:01:00 PM Synoptic. go for fuel

12:01:01 PM Synoptic. then

12:01:03 PM Synoptic. timing

12:01:05 PM Synoptic. then

12:01:08 PM Synoptic. pressure

12:01:14 PM Blundar yessssssss

12:01:15 PM Synoptic. kk

12:01:18 PM Blundar pretty much

12:01:19 PM Synoptic. k

12:01:38 PM Synoptic. and floor it on 4th or 3rd so rpm doesnt go up super fast and ngine

stil have a load.

12:01:50 PM Synoptic. that will do a base tune..

12:01:59 PM Synoptic. and with that i could go on a dyno.

12:02:00 PM Blundar yeah

12:02:02 PM Synoptic. kk

12:02:03 PM Synoptic. i get it

12:02:04 PM Blundar that will do WOT

12:02:07 PM Synoptic. okoko

12:02:10 PM Synoptic. yes yes

12:02:12 PM Synoptic. WOT

12:02:14 PM Blundar part throttle is much tougher

12:02:21 PM Synoptic. meaning, the less vaccum in the table

12:02:33 PM Blundar you kinda have to infer things from WOT changes

12:02:39 PM Synoptic. so I should be playing in the last colums of the table

12:02:44 PM Blundar you want part throttle much leaner than WOT

12:02:59 PM Blundar rightmost 3-4 columns is all you should really touch

12:03:06 PM Synoptic. kk

12:03:09 PM Synoptic. cool

12:03:15 PM Synoptic. I feel 0.5% less morron

12:03:17 PM Synoptic. :)

12:03:30 PM Synoptic. we should write this howto on the wiki

12:03:33 PM Blundar :)


Revision: r1.2 - 19 Feb 2005 - 21:45 GMT - markolson { Edit | Attach | History | More }
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