Ignition Timing for 9 lbs??

[1DangerousV6]

Hey everyone. I just ordered my 9 lb pulley from asp racing. It's supposed to be here in about 1.5 weeks. I wanted to ask you guys that are running the powerdyne unit with 9 - 10 lbs of boost..do you have to retard the ignition timing at all? I'm currently running 6 lbs and as long as I fill it with premium fuel (like I did anyway) I don't have any problem at all. I don't even have the supplied ignition system installed. Just the unit itself, the FMU, and 1 step colder plugs. Should I still be alright with this setup? (although I'm still going to get a bypass valve) Thanks! [img]smile.gif[/img]

[John_D.]

I was getting about 5 degrees of knock retard running 10psi on 93 octane. So the kr should protect the engine.

But you could probably run only 2 degrees of timing retard and then not have any kr, instead of getting 5 degrees taken out by the pcm.

That puts you 3 degrees to the good...

If you have a way to monitor kr, that will tell you what your combo is doing for sure.

[1DangerousV6]

awesome...is knock retard the same thing as the ignition retard timing that im talking about?...i dont know much about the electronics i just bolt the **** in and go haha ...so are you saying the engine should take care of it itself..or that i should install the timing retard and set it to 2 degrees?...is it possible i could be getting some knock retard now and not even know it?...thanks!

[1DangerousV6]

by the way...i saw in the GM High Tech Performance article they ran 0 degrees ignition timing at the 8.5 psi level...maybe i could get away with just running higher octane?

[1DangerousV6]

hey John ...do you find that you need a bypass valve when running 10 lbs??

[John_D.]

Knock retard is timing that the pcm pulls, when the pcm detects spark knock (detonation) occuring.

Only it pulls more timing than necessary. Which saves your engine, but hurts performance. It's better to control how much is taken out, if you can.

I was content with letting the pcm take it out, but I knew I was doing an engine swap soon, so I wasn't trying to squeeze the last bit of power out of it through tuning.

I think I read somewhere that each degree of timing you can run is around 5 additional hp. So if the pcm takes out 5, that's 3 more degrees than necessary (maybe), or a 15hp loss.

I don't know what my knock retard was at 8 psi.

[1DangerousV6]

hmmmm...my problem is the boost timing module rksport sent to me retards the timing 2 degrees/lb of boost...minimum...then i can increase the amount of retard by turning the dial (i dont know how much because it isnt numbered like its supposed to be)...that was way too much...the supercharger wasnt doing anything...it was actually harming the engine by retarding the timing TOO much...i was actually going to sell it...so i started to uninstall things...as soon as i uninstlled the boost timing module it woke right up!! ...thats when i looked closer at the BTM and saw that it was doing this...so if i can get away with letting the engine take care of it itself i might just do that...thanks John!

[John_D.]

Originally posted by 1DangerousV6:
hey John ...do you find that you need a bypass valve when running 10 lbs??

I probably would have installed one eventually. Especially when I was spiking to 12psi at the top of 2nd. That would be a lot of load on the induction side if I ever suddenly let off the throttle at the top of 2nd.

I loosened the belt just a teeny bit, because I had too much boost for my setup. :eek: :D

But this meant I was loosing a little boost down low too. A better solution would have been keeping the boost up, on the low end, and letting it blow off on the top end.

[John_D.]

Originally posted by 1DangerousV6:
...retards the timing 2 degrees/lb of boost...minimum..

...so if i can get away with letting the engine take care of it itself i might just do that...thanks John!

Wow, that is a lot!!

The kr done by the pcm is probably going to cover you.

It would be good for you to get something (autotap for example) to monitor the kr, so you can tell if you're running too close to the edge or not. I'm not sure where the edge is, but I think 10 degrees of kr is getting pretty close to it.

[1DangerousV6]

wow...running almost twice as much boost as i'm running now is gonna ROCK haha...assuming i do it the right way...so for this amount of boost...would you recommend a blow off valve or a bypass valve?

[Arctc Wolf]

A MSD-DIS-4 will allow you to take out timing based on rpm. centrifugal sc's make more boost as rpm increases, so u could leave timing in at low rpm, and pull timing 1 degree at a time untill u have no more knock retard. basically, u'd pull a degree of timing out at the rpm that KR starts, and then see where it picks up again, and take a degree away at that rpm, ect. this way, u make as much power as possible based on boost, rpm, ect.

[1DangerousV6]

Wolf..thanks for the tip...i've been looking at a DIS-4 ...mostly for the nitrous...i don't know too much about them so i didn't know you could really use it that much for a supercharger too...sounds cool...i'll have to check that out

[John_D.]

Originally posted by 1DangerousV6:
wow...running almost twice as much boost as i'm running now is gonna ROCK haha...assuming i do it the right way...so for this amount of boost...would you recommend a blow off valve or a bypass valve?

Since you're going to be blowing through the maf, and putting the valve before the maf, you could use either. I'd probably go blow-off just because it's easier to install and you won't be recirculating hot air.

[John_D.]

Originally posted by 1DangerousV6:
i've been looking at a DIS-4

I ran one for a while. I didn't notice any difference when I took it off.

The timing retard was interesting, but there was something I didn't like about it. The rpm range was too blocky, or the timing retard amount was too chunky, or something...

The msd site has a copy of the instructions for setting the dipswitches. You could find that and review it, and see if it looks like it would work for you.

I might be thinking that I wanted it for nitrous, and only wanted retard when I was spraying, and didn't want it when I wasn't spraying. That might be why I didn't use it.

[1DangerousV6]

awesome...i'll probably just go with a blow off setup then...i just heard the bypass is supposed to smooth out the idle...i wouldnt say my idle is rough...but its not as smooth as it was before the supercharger...but for the power...i dont really care haha ...yeah i was looking at the DIS-4 just for the nitrous...but actually...i dont use the nitrous on the street at all...and for the couple times a year that i'll end up going to the track...i dont think im going to bother with retarding the ignition during spray...if its for #s ...i'll just squeeze out the extra horses...thanks!