I've been pondering this since my dyno run and want to be prepared next time I go.

Say I do my first couple pulls and everythign looks good. 8psi and 12psi pulls go great with 11.3 AFRs, timing around 12/0 up top. For my third pull I want to sqeeze more power out of it.

Which would you do? Lean it out to 11.8, give it 4-5 degrees more timing or just leave it alone and turn it up to 15-16psi? which do you think is safer and why?

Once I finish fine tuning I'd like to have several variations already programmed into my cobb and ready to flash once its strapped to the dyno.

Thanks in advance for any advice

 

I like to get the tuning done before i get to the dyno and just do pulls based on what I already know works on the road by analysing MAF logs .

That way the dyno runs are pretty drama free and I can analyse what happened in my own time afterwards .

 

The real question for yourself is, how much am I willing to risk for pop goes the Renesis weasel?

 

/\ good point

 

Fill it with race gas, leave the AFRs alone and move the timing around to see which delivers more power. If adding 2° timing makes no more power, up the boost and them play with timing again.
I'd actually do all this at 10.5:1 if your ignition can handle it.
You also might be surprised what happens when you pull timing.

Until you have moved the timing 2° - 3° in both directions, you don't really know where you are in relationship to detonation, and you can find out waaaay before it breaks something by the way it affects power and EGTs with high octane fuel.

That said, unless you have a ton of money, do it on the street first and then bring the results to the dyno for verification.

 

Very good info, thanks MM I really wasnt sure which direction to approach it to try squeeze more out of it.

I intend to do all I can on the street. But the more 3rd(and 4th) gear pulls I do the greater my risk of a ticket :P

 

I would also add that it is best to have two boosted profiles set up and tested going in.

Since the AP and flashing all that jazz can take a while - try to get one good map with say a 10 and a 12 PSI boost setting. THen you can do both those pulls back to back and see what your power curves look like.

One last note - make a map with no knock retard in case that jumps into the mix. When CW was dynoing his, while troubleshooting we noticed he was running like 8 degrees of advance at 5000 RPM, we zeroed out his knock maps and get got back to his normal timing - EVEN though the Knock was reading zero... I don't know why - I wasn't there I was on the phone. But something to consider. And our Knock sensor is junk anyway.

 

Just for fun...since I dynoing my car next week.

I'll post my dyno plan so far - I still need to finish it.

1) MAF and VE% done - scale the maf in those high areas that you can't hit normally on the road for very long.
2) Just WG
3) BC Low @ 10 PSI
4) BC High @ 12 PSI

Those are my first four pulls...

 

Its not the knock profile that is retarding timing. Its the timing/RPM delta maps.

 

Interesting, I have never adjusted those.

Why would taking the KR out give CW his timing back then?

 

Well, get on it, because that is where are your timing calculations are done.
The base ignition maps are just that - a base.

Did you actually see him do it? (Understand what I am asking you? )
There is a lot of interaction, BTW. If the KS tables have base values that affect "0" range, you can get some weird stuff.
I actually never touch the KS tables. My knock sensor is removed from the block, wrapped in foam and wire-tied to the oil filter stand-off.

 

I didn't see anything, I got a phone call while in Dive School and was trying to walk him through some of his low power issues. Yes I understand what you are driving at... that is why I am trying to be forthright on my experiences.

I agree removing the KS is not a bad idea....

With my base timing tables only - and leaving the RPM Delta ones alone, I am getting timing where I want it to date (within 2 degrees).... then again - I had to go on a small break until I get my Cobb Tuner software link emailed to me, so now I'll have to see what is up.

 

Thanks for all the input guys

That is exactly where my train of thought was. If I switch to my other spring and valve seat(8PSI) Then use my 3 BC settings off, A and B for the other runs. Or I could even use A, B and "Scramble boost"
something like:

1. WG 8PSI
2. BC "A" 12PSI
3 omgwtf BC "B" 15PSI(but ramping up from 10 or 12 spring setting)

Um, I wouldnt be the guy boosting his engine with a homemade turbo kit if I was the squeamish type. I would look at it as a good excuse to try some porting and upgraded seals Now I"m not trying to blow it up, but I"m not afraid to push it a bit either.

 

U got meth?

I thought about doing a 16PSI OMGWTFBBQQQQQ pull, but technically I really should have charge cooling to do something like that.... ego is a bitch sometimes.

 

Depending on what your 16 PSI means in the flow department, there is a pretty good chance it won't make any more power.
I found very little (without doing other stuff) going from 14 to 16 on my setup.

 

Based on my 12 PSI flow... I figured 16 would be the max this 3071 can run on this engine.

I pull 400 on factory WG, and I am looking for 430 at 12 psi. I was hoping for 450 at 16.... but then again, I have never run it higher than 12 so.....

 

Couldnt I just like..pee on the intercooler or something?

 

You can come to VA, it's been like 27 the last few days..... which doesn't hurt.

 

LOL actually my buddy who went to the dyno with me last week texted me today "Dyno again today?". I'm not ready yet. Too bad too since its been in the 40s all day

 

I can tell you on the BNR 60-1 at 14 PSI... it's going to make some serious power. Jcab almost broke 300WHP at 9PSI with a huuuge boost leak.

 

is that because you are already soooooo far outside your efficiency island or is your hotside too much of a restriction ?

 

^ lol I was waiting for that!

 

Mostly the former.
At 14 PSI, I'm already moving over 55 pounds of air.
Remember, this turbo is designed for about 54 pounds of air at most (which is a f*ck-load of air and about what the BNR is capable of as well). You do the math.

As far as the hot side, the wastegate is open at the HP peak so the total flow area after the ports is already bigger than the exhaust ports themselves.
Once again, you do the math.

 

any idea what the efficiecy looks like or what rpm it would be spinnig at ?

 

Yes. Wanna go digging through my 5-year-old thread on the matter or are you gonna ask me to post a chart?