EPM + LQ9 coils trying to make big power

[NMccann]

Hey,

This might be a little vague at first...  My combo is in my sig.  I know there are many many pieces to this puzzle but maybe someones got an obvious fix for this. 

My combo consists of what's below, everything is new, I'm using the 1400 box with an EPM with eight LQ9 coils in wasted spark.  Tuning was going very well, sneaking up on the tune, power was ramping up well... we made 1000hp/1000tq on 91 octane pump gas @ 13lbs boost w/15deg timing.  We switched over to C16 and started to roll in some more timing and boost, AF was flat at 11:1 (4 WBs hooked up so AF was def. ok) but it's like the spark started blowing out around 1100hp.  I've never heard anything like this before... almost like a mechanical hammering sound, not nice at all especially with things turned way up.  The coil packs are rack mounted and are grounded diretly to the RS cyl. head, as well as back to the ecu.  This thing literally makes 1000hp like a timex run after run but that's it.  I even swapped out the coils for a set of LS7 coils my tuner recently made 1300hp with on a V6... same thing (he was using a BS3 though).  If anyone has any insight into this it would be greatly appreciated.  Anyone else try making big power with this type of setup?  At this point I'm thinking of getting a BS3 as I have a ton of money into this combo, $1800 wasted (as far as I'm concerned) in a dyno session and I have a set up I can't trust.  Besides that, I tried to call aem tech several times while at the dyno and couldn't get anyone which majorly ****ed me off...

Thanks

Nathan

[Blacksaleen95]

Are you sure it's blowing the spark out and it's not the valve springs? What springs are setup in those heads?  I know a lot of guys that have thought they had spark issues when it was just the valves floating, or not being able to handle the higher boost psi.

[NMccann]

good point, didn't even think of that.  But the shop that built the long block set up the heads, they're the springs that come with the CNC heads for a hyd roller, plus the guys added a couple of shims to up the seat pressure a bit.  The sounds this thing was making wern't like "hitting the wall" though more like random hammering.  If that makes any sense.  The motor is ok mechanically, cut oil filter apart - all good, compression check etc...  Have to explore that further I guess but getting to the dyno is such a pita...  I know there's a couple hundred more hp in this thing yet.

Thanks

[Blownstude]

What plugs are you running and what is the gap?  I had a similar problem on the dyno when I had them set to 0.032, changed them down to 0.24 and it went away.  But mine would kind of bog down briefly and then come back during spool up.  The mechanical hammering sound that you mention throws me off though. 

[NMccann]

Nope no bog down here.  That happened earlier in the day, I had a crappy old set of champion plugs in it.  Had them in for mockup/fab when I built the headers and just never changed em.  They weren't even gapped, straight out of the box, I think we made about 900hp with em lol.  I'm inclined to say detonation but it was running on C16 and not much more aggressively than on pump gas about an hour prior, so there's no way.  We knocked the gaps down to a little under .03" and it didn't seem to change anything.  BKR7EiX plugs btw.  Mechanicaly the engine is fine still - oil/filter compression etc...  have to keep digging I guess...  We didn't log timing errors, didn't even think of it.  But like I said 1000hp like a timex, every time. 

Thanks for the suggestions so far.

[Blownstude]

So the problem came once you switched to c16?  What heat range is that plug and what kind of plug?  I have always ran the NGK race plug R-5671-A9.  Try .020 for gap.  Is that a 7 heat range plug you are running?

[NMccann]

The guys at the dyno didn't feel comfortable going any further on pump gas, so yes, the problem only presented itself when on C16.  The plugs are a 7 heat range, we gapped them down to 0.25, we should have gone down to 0.020 just to see what would happen.  Before clueing things up at the dyno, we loaded up the pumpgas tune again and made a run on C16 fuel and things were ok...  This was just to check the tune, we didn't switch the fuel back to pump gas.  I really don't want to make another trip and risk things not working out, it's a major pita to get down to Edmonton with this thing, but at this point it doesn't look like I've got a choice.  I will def look into the plugs you're talking about tho. 

[Blownstude]

Also, sorry to get off topic with your thread but i have a quick question for you.  What type of cam are you running? Solid roller?  I am having an issue running my bronze distributor gear on the EPM i am in the process of installing.  Are you running the AEM epm on your car, and if so what did you do about the gear?

[NMccann]

I am running a comp cams hydraulic roller.  I'd have to check the cam card to figure out material though, seems to me one of the #s in the grind# indicate material...  I have an EPM, I'm running the gear that came on it.  I did purchase a comp cams polymer gear with the intent of running that, but it didn't fit, not even close.  The driven end of the epm is nothing like a 351W dist.  Since putting it in, I haven't checked it for wear, I should pull it out for a look at some point.  I sure hope that isn't my problem... would explain alot though.

[Blownstude]

OK, thanks for your input.  You shouldn't havae a problem with the hydraulic roller as their gear as it was designed to run on that.  From talking to the AEM tech line, the gear that comes on the epm is a cast iron gear.  It wouldn't be a bad idea to pull it out and take a look at it though. lmk thanks

[Blownstude]

Hey, did you ever get your car figured out?

[NMccann]

Hey,

Thanks for the interest, no it's not figured out yet   I've switched to an MSD crank trigger setup and I'm only using the EPM for cam sync.  I suspect timing drift may have had something to do with it as well, I'm really not 100% sure.  Btw, I checked the dist. gear, it's perfect.

Problem is, the little bit I've saved by going with the AEM I've lost BIG time on at the dyno.  Honestly after that experience, I feel I should have just ponied up the cash and bought a FAST or BS3 in the beginning.  Hate to be negative about the AEM, it's certainly full of features, but I just don't feel it's stable enough for what I'm doing.  I've switched to a FAST XFI setup with the XIM module, it's basically an LS1/2 setup I've repinned/rewired to work with an sbf.  I'll be hitting the dyno again sometime over the next few months.   

 

[Blackmagic94]

What cylinder heads are you running and those NGK plugs are projected tip plugs correct? 



I swapped from a projected tip BR plug to a R race plug that is non projected back in the day on single T66 setup on 6 psi of boost.


12.5@116 on the BK plug at .023"
11.8@122 on the R plug at .023"

no other changes.