miro_gt

just cant find a soliod answer about timing retarding under boost ... for some reason

OK, how much to retard the timing under boost ?

.. some say 0.35 deg/psi
.. some say 0.5 deg/psi
.. some say 0.75 deg/psi
.. some say 1 deg/psi
.. some say retard as little as possible without detonating ..
.. some say retard as little as possible up to peak torque, and then advance 0.2/500 RPM
.. some say retard by psi and by RPM .. but how much ?
.. others say only bullshit

so here we go, tell me your opinion about that !

BlueShadow

the reason you get so many diferent answers is because some people are more conservative and others are a little more aggressive. The conservative tuners tell you to pull back more timing per psi, and they might even tell you to pull out a lot of timing at really low boost. The more aggresive tuners out there would tell you that you can get away with a little more timing advance then the conservative tuners out there.

Are you looking to tune your own setup? If you wanna learn more You should check out the tuning forum on http://www.evans-tuning.com and start at pg 10 and read all the threads, especially the ones about tuning timing. There are a lot of threads on that subject over there. You can buy Jeff Hartman's how to tune book and if you read through it you'll learn a lot about how to tune your AFR timing, and a lot of other things about tuning and modifying with EMS's. You can also buy Ben Straders how to tune book, but Jeff Hartmans book is a lot more in depth ( I own both).

http://www.amazon.com/exec/obi...07846

miro_gt

thanks for the info ... nicely put

however, I wanna hear from people that are running boost retard at the moment, and specificly what engine, what boost, and what timing retard they have

BlueShadow

Are you gonna be tuning timing while on a dyno or did you just want to set a step retard and leave it at that?

If you are going to be going on a dyno, then set a conservative step retard then fine tune it on the dyno. From what I've read you advance timing until the torque curve on the dyno readout starts to plateau. Once the torque rise starts to levels off, then you retard timing 0.5* to 1*. By increasing and decreasing the load or resistance on the dyno you will be able to go through all your cells. I think for WOT, boosted cells you would want to do a pull and see what your torque numbers are. You adcanve timing a little and do another WOT pull and see where you gain and lose torque. If you gain torque you can try advancing timing at that load point to see if there is any more torque increase when you do your next WOT pull. If you lost torque or didn't gain any, then you would go back and retard the timing in those load cells and put them back to their previous value.


If you are just gonna set a step retard then not even worry about fine tuning on the dyno then it's just a matter of how much timing advnace you are comfirtable with. Also if you have a lower CR, wider bore and larger injectors you want to advance timing a little to improve driveability in the vacuum cells. For WOT and boosted cells, find out how much timng per psi you want to pull and then you pretty much leave it at that (unless something goes wrong).


I'm just a novice tuner, in fact I dont even have any dyno time under my belt, just a little street tuning and a lot of time palying with CromePRO on my laptop. But all the stuff I just posted was stuff I learned from Jeff Hartmans book and the Evans Tuning forum. You would think that I learned a lot of it from the 2 big tuning threads on H-T, but actually I learned just a little from those two threads. Trust me, if you buy Jeff Hartmans book and visit Evans Tuning, you'll learn a lot about how to tune your own stuff.

flip1199

are u tryin to be safe or trying to make power by adding timing? i know on the s300 it has it set at .75deg/lb for safety. just go with .75deg/lb unless your on a dyno and tryin make power.

miro_gt

I'm trying to make a reliable car .. not max power out of my engine ... since it's my only one ..lol .. I'm running a GReddy 15G kit on a stock D16Z6, at 5.5 psi with JRC intercooler, but out of what I've red the highest safe boost should be ~ 9 psi. This is only my opinion though. I've noticed that half of the people running 10 psi mess up with something, and end up with blown block, and about one out of 20 guys blow engine at 9 psi. At 8psi almost everybody run with no problems ... So I'll shoot for 9psi since it's gonna be my first boost increase

For the A/F ration - I'll shoot for 11.5 solid under boost ..
And for the timing - I'm a little confused. I'm having EManage, which is able to control timing by 1 deg with the timing harness installed. I've looked at the timing map, and the MAP sensor voltage starts from 2.0 V and goes to 5.0 V. Of what I'm understanding about it, the boost starts from 3.0 V and goes to 5.0 V in steps of 0.2 V ... Example: 3.2 V = ~1psi, 3.4 V = ~2 psi ... and so on until 5.0V = ~ 11 psi.
So, I can retard 1 deg per 0.2 V after 3.0 V mark ... or I can retard 1 deg per two cells, like 3.2V = -1 deg, 3,4 V = -1 deg, 3.6 V = -2 deg, 3.8 V = -2 deg, 4.0 V = -3 deg ... etc.
.. don't know which one is better, or I should make it RPM dependable as well, like retard more at the same voltage but higher RPM ..

thanks

hybrixt

Keep a/f at 11.5 and just do .70 retard per lbs of boost and you'll have a reliable tune unless your running different c/p ratio from stock.
If you wanna maximize your engine power go to a dyno and fine tune it.

Blaze45

Untill recentley I thought that you could just have a good AFR and pull a bunch of timming and crank the boost and be good to go. Not the case. I pulled TOO much timming. My EGT gauge began to max out @ 1600 degrees around 5k in 4th gear. Tunning timming isnt a walk in the park, but its not really rocket science eathier. If you have an EGT, its a good tool to have when playing with timming. O and BTW if you have the fuel and tunning tools for more boost, then tune it and run more boost!

good luck

Blaze

miro_gt

so 0.75 deg/psi retard is the final word for max. safety then ? ... for stock motor

and not RPM dependable ?