Think I figured out why my Motor Blew
 

I have been doing a bit of datalogging since I finished breaking my motor in.

I have recently discovered that my main problem was not fuel related but timing related.

I did a few 7-8 PSI runs (mind you this is with a streetport and T04b turbo). I was reviewing my timing map datalogs and discovered that at only 8 PSI I was at nearly 100% Load. The load was only 1 cell from the max load. I roughly calculated that my timing map will be maxed out at around 10 PSI. So if I boost any higher than 10PSI the timing will stay the same. This is bad because for every 1 PSI you should retard the timing approx. 1 degree.

So if I have the timing map set for 22 degrees BTDC at 8PSI
21 at 9PSI
20 at 10PSI

Then once I boost to 11PSI and up the Rtek timing map is still at 20 degrees BTDC.

Now when i was running 15-16 PSI this timing map issue (I believe) blew up my motor. The timing map was maxed out leading to the timing being way advanced and detonation occured.

Ed

The moral of the story is map your timing map at lower PSI before you turn up the boost. Make sure the timing map is how you want it and tha it is not maxing out on you.

Ed

Thanks for the update Edomund.

please show us a log of your timing when your done.

thanks

alright...so i have no idea about timing...the fuel side of tuning is pretty straight forward to me, but timing is something I've never understood. What is BTDC? From yur post it sounds almost as if it's a starting point or some sort? I guess I'm just trying to get you guys to give me a crash course in how to start tuning timing, and what I should be looking for on the 2.0 (I don't have the car now, it's at a local high school...and they're installing a FMIC as a class project). I plan on trying to do a very "safe" tune when I get the car back. I have a wideband and feel pretty safe on the fuel side and afr's...just no clue on how to even start with the timing.

Ed, that is great to know. I have just started to check this out myself.

are you looking at your Timmig Load Index Ed?

Mine reads 18 at 4.3psi and stays there all the way up till 10 psi. That was a hard pull.

BTDC = Before Top Dead Center. I would suggest you have someone who knows about timing tune your timing. At the very least help you. There are lots of threads on tuning timing read up a bit and it will help you out.

Yes I have been monotoring all the indexs. In particular the timing load index is what I was refering to in my previous post.

And now that I know the first cell= 0 I realize I was not in the second to highest load cell I was actually at 100% load (#18 cell).

I have the same thing, Wankler, now that I know 18=100% load I am maxing out the load at 7 PSI. This sucks because it seriously hinders the ability to acurately tune your timing above 7PSI in my case. Anything above 7PSI will have the same timing value.

you can just drop it down to a safe level like 12*BTDC but performance will be hindered. now what is it that is causing it to read full load? is it the AFM flapper maxing out?

I'm not sure how it measures load. I dont believe it is the AFM being maxed out because on my logs the AFM still has accurate readings even when the load index is maxed out the AFM is still reading values.

Yeah right now I have my timing tuned for 7 PSI and have my boost controller turned down to 7 PSI so the 100% load timing matches right now. But it's dumb to have all this potential in my motor and not be able to use it because of the timing issue.

Give me a rough guesstimate of what you think the power loss would be from setting the timing to 12* BTDC? I REALLY wish somebody around here knew how to tune. I don't know any shop within 100 miles of me that has a clue how to tune a rotary (or any turbo charged car for that matter)

A rough timing tuning rule is at 15 PSI you want 15* BTDC then advance 1 * for every PSI you drop.

IE. 15 PSI 15*
14 PSI 16*
13 PSI 17*
12 PSi 18*
and continue the same way until 2-3 PSI blend the stock map.

Problem is this is difficult to do with the rtek.

a few degrees of advance at 15PSI could probably mean the difference of 30HP, safety wise that 30HP doesn't seem like alot compared to a blown motor, just ask Ed... his motor was perfect when i tore it apart, it could have gone another 100k miles without any issue. :(

i have found it to be a rather concerning issue that many EMS manufacturers use similar to stock base timing maps, i ran into an issue with microtech base maps being far too aggressive also causing detonation at even 8PSI loads with 91 octane fuel. needless to say people have to be ery careful when tuning ignition, AFRs don't mean squat if the ignition curve is too steep.