after peak torque, do you guys start to add more timing? if so what kinda numbers are we talking and when to stop advancing timing? if possible....posting some timing maps would be sweet!


this is my dyno sheet, 10psi on a t3/t4b on stock F23, any ideas on what u guys would do with timing on this?

 

^^^^BUMP^^^^

 

not an expert as u know, but wouldn't you want to possibly retard the timing a little bit.

I mean, normal to possibly a little advanced timing while building tq, then backing it off a little bit after peak? Also, if there isn't any knock or det, with a cooler than normal intake charge, maybe u could add a little instead of backing it off.

My shot at it, take it for what it's worth.

 

that dyno run was done on this timing map. come on gang, there not many boosted accord out there, so i need some advice. us accords dont roam the streets in the numbers as u tegs and civics, so theres not much info to go on.

 

Why are you wanting to add timing back into it after you've already pulled it out?
If you did this you would be at a higher RPM range and could possible start to detonate. What is your fuel set up? Those numbers aren't that far off of what they should be. Also is this a 5spd or auto?

 

here are some notes i have gather from mr Boosted hybrid

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boosted-Hybrid &raquo;</TD></TR><TR><TD CLASS="quote">The best way to monitor knock is using your ears. I have the luxury of pulling the plugs under wot load, and shutting the engine down in a controlled environment...which is not practical on the street (although I used to do this all the time on back roads). Your ears can hear knock extremely well, and that is honestly what i have come to conclude to determine knock. I have a knocklink knock monitor that I have adapted to the OEM knock sensor, it works well, but its hard to set it up when you need to determine the actual knock and background noise from the engine. Since its a piezoelectric type sensor, that transmits frequency to voltage (small scale), it picks up alot of noise if you dont have it calibrated properly. I used my ears to calibrate the set-up with a stephoscope, that works the best as far as determening knock that i have found. I wish that someone would build and implement a knock board onto the OEM ecu that could actually process the knock signal into a useful tuning tool.

Setting aside the ability to determine if the engine is knocking, the timing values that occur right before knock are what is known as the maximum brake torque timing (MBTT) values. These ignition advance values represent the point at which the threshold of knock is able to occur. You want to be below this value, the only true way of determining the MBTT is through a dyno. You increase the timing values until gains are not found, by pulling the plugs and confirming the lack of knock you know that you are at the MBTT point. At this point the cylinder pressures are at the highest level that are controllable, but this is also were you are putting the highest amount of stress (short of actual knock) on the bearings/rods/pistons/etc. You want to be under the limit of knock, so you back off the timing 0.5-1 degrees from the MBTT point. This will unload the internals, and save the engine alot of abuse.

</TD></TR></TABLE>

 

this is a 5spd. the reason i post is because my powerband shouldn't fall off untill a lil after 6,000rpms. at least that is how it is on a stock F23 motor.

this is a stock F23 w/ a intake


this is a boosted accord on a FMU setup


also there also a 280whp/280wtq accord.....6genaccord i think it is, and the power curves are almost all the same, horse power doesn't fall untill 6,000rpms. my power curve IMO should be tuned to that power curve, but my horse power and torque fall off before 6,000rpms

 

what kind of fuel/timing management are you using.

 

Because of the turbo spooling power is going to come on at a differrent point then with a NA set up. If your trying to strech the power curve with your turbo car to be the same as a NA car you may want a bigger turbo to get more top end. This would in theory push the power curve closer to the 6000rpm mark your looking for. If you just up the boost the turbo ma run out of room and start to fall on its face and your curve could start to move the other direction.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Turbowa &raquo;</TD></TR><TR><TD CLASS="quote">Because of the turbo spooling power is going to come on at a differrent point then with a NA set up. If your trying to strech the power curve with your turbo car to be the same as a NA car you may want a bigger turbo to get more top end. This would in theory push the power curve closer to the 6000rpm mark your looking for. If you just up the boost the turbo ma run out of room and start to fall on its face and your curve could start to move the other direction.</TD></TR></TABLE>

I got a question. How do you determine if a turbo is "running out of gas" on a particular setup? Is there some sort of test to confirm this, or is it just from experience or something.

 

Fuel should follow your torque curve...as it starts to drop, you need to decrease fuel.

Generaly timing should be pulled after peak torque as well.

 

i'm on AEM EMS

IMO this turbo has plenty or room still, this was only at barely 9psi, boost fell to 8.5psi cuz i installed a bad MBC spring, orignal one got lost, but now that problem is fixed. i hold a solid 10.5psi across the whole rpm range.

i also know timing should be pulled after peak torque, but again, this is a 2.3 SOHC VTEC, my timing maps are gonna look different compared to u B-series. i tried running about 20 degrees of timing like many of u B series @10psi and according to my datalogs, there was crazy spikes all over from my knock sensor, that=very bad things. i'm back to my timing map above. that map gave me the best knock data, i guess i'll just stay with it.

i was hoping there was more boosted
F-series around here that know their timing maps or have street tuned or had it tuned by a pro. i guess theres not many. one EMS tuner from the AEM EMS Fourms said the F eries dont like or dont need much timing. i guess he was right, but he never got back to me on how many F series engines he has tuned.

 

btw......this is my timing map looks like


and this is what my fuel map looks like


and again, look back at my dyno pull.....look at my air:fuel, i street tuned to a 11.5:1 across the whole rpm range. keep the info coming!

 

this is my datalog of the second dyno pull, nevermind the o2 readings, my wideband is tripping out when under heavy acceleration.


dark green is vehicle speed
red is engine speed
yellow is timing
blue is knock data or knock volts
light green is boost
voilet is o2 or air:fuel
greenish blue is throttle

 

general rule tha I use, is that I retard 1 or 2 deg. of timing for every psi boost. But if the car makes power and it does not knock then I keep advancing untill it stops making power/torque.

On my gsr eng, I boost about 10 psi and my timing map at that boost is about 26 to 28 deg. BTDC.

 

well its very obvious to me that F23 doesn't like much timing then. i have tried 20 degrees at 10psi what many of u b-series run, and it didn't like it at all.

 

what fuel/timing management do you have?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98ctr &raquo;</TD></TR><TR><TD CLASS="quote">what fuel/timing management do you have?
</TD></TR></TABLE> look at the pics. he's running an AEM EMS.

 

yeah it is hard to find many f series. Sorry no help on the timing, but I would say you have more power in that setup if you bring it a bit closer to 12:1 on the a/f. I am no expert though, bear in mind.