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-   -   Timing - retard or not? (https://www.homemadeturbo.com/engine-management-10/timing-retard-not-14377/)

Nick7 01-15-2004 08:36 AM

Timing - retard or not?
 
Hopefully day after tomorrow I'll finally be able to make charge pipes.
I have D14A4 engine, compression ratio is 9.1. I plan to boost to 6-7psi, not more, also use FMU for fuel.

From experience.. do you guys think I'll need to retard timing? How much?

I know I'll have to test and see if there is any knocking or not, adjust appropriate to this... but wondering from others experience - is it possible it'll run OK without retarding - and without danger to engine?

surfer 01-15-2004 09:11 AM

Re:Timing - retard or not?
 
It wont boost without retarding the timing, it'll just knock like ----, msd btm's are good to use, so i hear

blundar 01-15-2004 10:10 AM

Re:Timing - retard or not?
 
I beg to disagree.

You're playing with fire to some degree using a FMU and nothing to retard timing, but it can be done.

My rule of thumb is 0.25 degrees/psi until 5psi. That's a degree and a half of retard at 7psi. That's nothing. Set your timing on the distributor conservatively - i.e. retard the distributor a little and you'll be fine.

surfer 01-15-2004 01:26 PM

Re:Timing - retard or not?
 
Not the best way to eek out the power though

Nick7 01-15-2004 03:54 PM

Re:Timing - retard or not?
 

Originally Posted by blundar
I beg to disagree.

You're playing with fire to some degree using a FMU and nothing to retard timing, but it can be done.

My rule of thumb is 0.25 degrees/psi until 5psi. That's a degree and a half of retard at 7psi. That's nothing. Set your timing on the distributor conservatively - i.e. retard the distributor a little and you'll be fine.

Umm.... but - using AFC hack with same PSI seems much more dangerous to me than FMU.
As 1st, FMU tends to run rich, and 2nd - AFC hack with larger injectors fools ECU that it sends lower MAP reading - but sidefect is that due to this ECU also advances timing. With FMU there is no timing advance.
I've read on TurboD16 forums that some people even managed 10psi with AFC and no timing retard. I personally would never run 10psi without any time retard, but it seems it could be done.

This is why I asked here if someone had experience running low boost without any time retard - AFAIK greddy and some other kits that run 5 - 5.5psi also dont use any time retard - please correct me if I'm wrong - this is at least what I've heard.

On that note I asked if I could maybe go by without any time retard. Anyway, very soon charge pipes will be on, and I'll see if I'll get any pinging....

blundar 01-15-2004 04:11 PM

Re:Timing - retard or not?
 
Motors don't need that much retard for low boost. From what I've seen, gradually increasing the retard as boost increases generally produces a lot more power.

0.25deg/psi from 0-5psi
0.5deg/psi from 5-7.5psi
0.75deg/psi from 7.5-11psi

Using decent NA maps and my rules, at 11psi you should be between 16-20 degrees timing at WOT. Right where you want to be. Too many turbo tunes go conservative on the retard leading to wack EGTs.

Not havign any retard for low boost isn't great but I wouldn't worry about breaking anything from timing at 7psi.

just my 2 cents


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