What should the total timing be on a car at boost.

[virus77]

Lets say at 12 psi, 15 psi, 18 psi. What number should I look for under WOT. Currently im running 17 degrees on 12 psi and 15-16 degrees on 15 psi. Is there room for improvement with a few degrees of advance or is this about right.

[rn240sx]

What I was told is to retard the base timming 1/2 degree per lb of boost.So 12 psi would put u at 14 degree's at WOT.. ( 20 deg minus 6 deg for boost under wot )

What r u using to see timming under WOT..??

[virus77]

I have a palm datalogger than monitors timing, coolant temp, stuff like that. It resetes and reads codes too. 20 degrees is base timing, total timing on wot is different.

[Structure240sx]

total timing is 28 degrees onthe ka

for a built ka i would go by .5 degrees per psi

a stock ka i would go by .75 degrees per psi

[virus77]

28 degrees normally aspirated right?

[:: orion ::]

28 degrees is total timing from a stock ECU (That is...8 degrees total advance over the base, at the most).

And the subtract 'X' degrees per PSI is a good way to do it, but I wouldn't start pulling timing until 2psi.

So for 15psi, you'd pull 10 degrees based off of "Structure's" reccomendations (.75 degree per psi)...

15psi - 2 = 13

13 x .75 = 9.75, or -10 degrees.

So you'd want ~18 degrees of total timing for 15psi on pump gas, on a KA motor.

That's about right, from everything I've read.

- Brian

[sil80drifter]

How do you guys deal with part-throttle boost timing?

In fact how do you deal with part throttle timing when you have leaned things out with the SAFC while having bigger injectors, and you're OFF boost?

sil80

[:: orion ::]

Basically, from what I've read: The factory ECU looks at throttle position (TPS voltage) versus airflow (MAF voltage) to determine LOAD...then load vs RPM to determine timing advance/retard.

It drops timing to base (or so) with a crack of the throttle, then feeds timing advance back in based on load vs RPM.

With an AFC, this throws things off b/c the MAF voltage is altered by the AFC to read lower than it actually is...so it puts you in the wrong spot on the timing map.

So...what can you do to compensate...buy an AEM, or a Haltech.

Or, live by the constraints of the factory ECU, and just be aware what a change in base timing may effect.

- Brian

[ILikeMy240sx]

OR get a JWT or Enthalpy... I think its a cheap (relatively speaking to EMS or Haltech) alternative.

[Jookmasta]

what exactly is this wrong spot on the timing map? is it in an advanced or retarded spot on the timing map?

[sil80drifter]

advanced, which in turn causes ping.I wonder if filling up with 91/93 would make that go away.Or if retarding the base timing would make it go away on 87 gas. Strictly from the NA viewpoint.

sil80

[virus77]

28 degrees is total timing from a stock ECU (That is...8 degrees total advance over the base, at the most).

And the subtract 'X' degrees per PSI is a good way to do it, but I wouldn't start pulling timing until 2psi.

So for 15psi, you'd pull 10 degrees based off of "Structure's" reccomendations (.75 degree per psi)...

15psi - 2 = 13

13 x .75 = 9.75, or -10 degrees.

So you'd want ~18 degrees of total timing for 15psi on pump gas, on a KA motor.

That's about right, from everything I've read.

- Brian

Thats about sounds right to me. When you say pump gas, does 91 octance count (damn Cali). And is it safe to run 15-16 psi from a 50 trim t3/t4 on 91 octane, Ive only done it with toluene in my tank.

[Structure240sx]

virus i tried to AIM you early. i was wondering if you are running the msd knock alert? i jsut installed one today and had some questions.

using a device like this will really show how much boost/timing/octane/afr's you can get away with

[:: orion ::]

When you say pump gas, does 91 octance count (damn Cali). And is it safe to run 15-16 psi from a 50 trim t3/t4 on 91 octane, Ive only done it with toluene in my tank.

OOohhhhhh...that's cuttin' it close.

From what I've read of your Cali gas...it's no good. Sucks balls.

I'd think you'd want to be a little lower than 18 total timing for 91 octane and 16psi...I'd probably want to see a max of 16 or 17, with stock compression.

And again...in this field, I'm no expert...I only know the theory, and how all the timing adjustment affected my old hacked MAF setup (base at 17, for 9psi...gave about 22 degrees total timing according to a logger)...which lasted for a year until I upgraded to JWT/50lb/Cobra MAF. FWIW...

- Brian

[virus77]

its a built motor with 8.8 arias pistons.

[Red-KAT]

Got a question.

I have my e-manage set for 270 stock to 390 now...

With it pulling MAF voltage would this mess with the timing even when the TPS is unplugged? And does the ECU add or pull timing with the correction factor?

I guess a way to test this would be make my e-manage read 270 270 so it would do no correction and just run pig rich for a min.

That could be the cause of these base timing errors. (at least for me)

[:: orion ::]

its a built motor with 8.8 arias pistons.

Oh...that would've been good to know in the first post.

But taking that into consideration, I'd think you can use a couple more degrees across the board.

Up your base to ~22 degrees, I think it'll be FINE for a built bottom end with lower static compression.

(I run JWT with ~22 base at 12psi...works great, midrange TQ was much improved)

- Brian

[:: orion ::]

With it pulling MAF voltage would this mess with the timing even when the TPS is unplugged? And does the ECU add or pull timing with the correction factor?

...

That could be the cause of these base timing errors. (at least for me)

NOpe...the ECU DOES NOT mess with timing when the TPS is unplugged and the car is idling...that way you can set the base with no interference...and why it's so important to:

1) Unplug TPS2) Get the idle to ~750rpm3) Race the engine 3 times, then let it settle.

THEN set the base timing.

Sorry, no help for your issue.

- Brian

[Structure240sx]

or get a device that show the ecu timing and set that on the crank pulley. this way you only need to unplug the tps and not worry about the idle being a perfect rpm

[MarkEmark]

The thing that sucks about going by the ".5 deg retard per psi of boost" method of "controlling" timing is that you really sacrifice drivability, especially off boost and in the low end. The car will feel downright sluggish before boost and 3000-3500 rpm (depending on setup), and will even sometimes stumble or hesitate...thats how mine felt at 10 psi anyway, and I have a JWT ECU...I advanced the timing 2 degrees or so from what the JWT conservative maps were (I have the Blitz R-VIT II to measure timing) and it made a massive improvement in throttle response, driveability, etc....If you guys have the money for something to control timing dependent on boost/RPM (and not just retarding it an insane amount from idle), it will make a huge improvement, especially if you're already at 15 psi.

[sil80drifter]

Enter.... *drum roll*

MSD BTM!!!! for $160 (or cheaper if ebay) you can get yourself a nice timing retarder that is boost dependent, and will retard up to 3deg per psi!!! Yay.

sil80

[klattr1]

Lets say at 12 psi, 15 psi, 18 psi. What number should I look for under WOT. Currently im running 17 degrees on 12 psi and 15-16 degrees on 15 psi. Is there room for improvement with a few degrees of advance or is this about right.

i would say what you are running is pretty good for pump gas. the only way to truely how much timing is enough is by having a knock meter and noticing changes in the torque graph at dyno.with race gas, you'll be able to get away with a lil more timing (2-3 deg. more over the top of what you are currently running).

how are you currently controlling your timing?

[erollinc]

has anyone ran the msd btm???

[Titan]

Enter.... *drum roll*

MSD BTM!!!! for $160 (or cheaper if ebay) you can get yourself a nice timing retarder that is boost dependent, and will retard up to 3deg per psi!!! Yay.

sil80

You may want to fade that drum roll out, considering you also need a MSD ignition module to work with the BTM.

[WDRacing]

No you don't....I have the same one he listed and I don't have any problems at all. You may be thinking of the MSD 6 BTM, totally different ignition coil.

[Titan]

No you don't....I have the same one he listed and I don't have any problems at all. You may be thinking of the MSD 6 BTM, totally different ignition coil.

How did you wire it? I'm looking at the instructions and it mentions it must be used with a MSD ignition module. Maybe it's just this particular PN 8762 model?

Instructions here: http://www.msdignition.com/pdf/8762_frm22878.pdf

EDIT:

Nevermind, found it. Thanks.

Universal BTM: http://www.msdignition.com/pdf/frm23950.pdf

[WDRacing]

Bingo!!!!

[erollinc]

i must purchase one of these btms.... sounds great .... cusae i rode in a kat with just the timing retarded and man low end and idle sucks ... it would be nice if this smoooothed it all out

[Jookmasta]

well my kat has its timing retarded and i think my low end is just fine as is my idle. i think each engine may act differently.

[DRIFTEADOR]

what are the adjustment settings on msd's btm? can it retard in .25 increments? i've never used one before but from what i hear its basically to timing what a fmu is to fuel. i guess timing isnt as dependant to rpm vs load as fuel is, but it's not linear either...then again if youre using an afc what do you care for a good tune

if youre feeling ballsy you can get use a stethoscope to listen for knock on a dyno. i wouldn't recommend it don't stock ka's have knock sensors? i think i've read they do. why don't they control timing on boost? couldn't you log the voltage and measure for knock that way?