If your tuned with some go fast goodies and you can't seem to get rid of that fall on it's face top end problem despite the dialed in tune I believe I have discovered a possible problem.

Most of us tuned regap our plugs tighter, I gap mine at .032 (pretty close to that at least). Yet I have experienced what I like to believe to be "incomplete burn" by observing my pyro, air load and stft. BRAND NEW replacement coil on plugs from GM when tested for KV netted me about 19,000 volts, or jumping about .124 inch at atmospheric pressure, the test isn't perfect but it's close. The coil from my car also scored 19,000, but I had the other two I tried get me about 21,000 volts.

Fords are notorious for weak coil on plugs, and so is GM, having had problems with vortec motors with 100K plus miles with a stumble or stutter at high rpms that couldn't be repeated driving normally.

I have taken it upon myself to contact the tech help line for MSD. I spoke to them about my findings, and knowing they recently came out with a replacement bolt on coil pack for the LSX motors and Vortec engines, I was hoping they'd be able to help us ECOTEC guys. I explained the circumstance, what my car is doing, what I'd be willing to pay (similar or a certain percent above GM replacement coils) The design of the coil, type of plug, boost pressure, relative compression ratio...etc. Then I spoke to an engineer named Steve, he explained that forced induction cars require a exponentially higher KV than NA, and also he believes the injection window (direct injection) is interfering with the spark, thus causing what feels like misfire (at that speed the computer cannot actually log individual misfire behaviors and may even log it as knock even though it isn't) Anyways, I don't want to get anyone's hopes up, but I explained the problem, which is similar to the problem LSX guys have experienced in the third gen blocks with individual coils that ended up being supercharged or turbocharged. So I basically expressed my personal request for a solution, from my calculations at 6500 rpm, 20-22 psi and with my plugs gapped to .032 I would need 29 KV to jump the gap. Factor in water/meth, injector window and cylinder turbulance and your looking more like 33-35 KV.

The only alternative is to look into what are called PRIMARY WINDING AMPLIFIERS which are in line plug in mini transformers that step up your primary voltage at the coil by a factor of 1.5 or 2. Here of course you will experience higher PCM amp loads and it may require each individual coil to have it's own chassis ground...I am only familiar with this system on modular ford engines.

I am REALLY curious to know what is wrong with BYT's car and a few others that seem to fall on their face at certain air loads and RPM.

 

Hey, I've been down at VIR for the past 2 days. I couldn't get rid of a -2.9 knock up top, even though the car had a pretty conservative 16 degree tune on it. I dialed it down to 15, and it still did it (edit: the amount of KR dropped though). It wasn't until I dumped in a few gallons of 100 that it went away. You know I don't have a pyro though, so it would hard for me to tell if it's an incomplete burn.

It was a hot event. Probably contributed to the knock up top. 250F oil temps. 90F ambient. Surprised a lot of folks in the balt, including the lead instructor (a racer), whom I let drive my car, and an old racer buddy of mine that I took for a ride. Both of them were completely astonished at what the car will do.

I think GM was smart to keep the GMS1 tune down to 10 degrees up top. You can't sustain 17-18 degree maps on track like you can on the street. I don't think folks realize how brutal road courses are to engines. I had plenty of clean 17 degree pulls on the street, but on track? By the time I got halfway down the back straight on the warmup lap, it was showing -2.9 KR. Mixed in about 1/2 100 octane, and the problem went away.

Would be interesting to see if it really is a spark issue. Let us know if they come up with new coil packs.

 

Wanger, I can only imagine what kind of heat you must produce on the track. It has got to be unreal.

 

ive been experiencing a similar problem since i put on my meth kit and got retuned...while tuning it was fine but then that night i did a pull on a high way on ramp and it "bucked" at higher rpms, id say around 5500-6000, im not sure if it was a spark blowout or a misfire, but it bucked pretty hard and then the rest of the way home it was bogging down under light acceleration/shifting, so i think there was some unburnt fuel/meth in the cylinder possibly, we tweeked with the boost activation switch for the meth to come in a little later because we thought it was possibly flooding the engine with meth at higher rpms...it pulled great at around 7pm that day, then the next night getting on the on ramp again it bucked hard at higher rpms again; tweeking with the setup again on sunday, but does this sound like what youre experiencing too? im still not sure if its a spark blowout or a misfire or what it exactly is, but i described it to my buddy and my tuner and my buddy thinks its a spark blowout and my tuner thinks its a misfire, to me it didnt feel like a misfire but ive never been in a car when its had a spark blowout so i couldnt say that its for sure a spark blowout either, but when i read this post it reminded me exactly of what problem im experiencing, and it only started doing this once we installed the meth and tuned for it

Just for reference, I have the NGK 4644 1 range colder plugs and right now theyre gapped at .035

I also have the LSJ not the LNF but it just seems all too similar to the problem im currently having

 

Sorry, but I doubt you don't have the same problem.

 

I never said it was the same problem, i said it seems similar. Hell, i hope its not the same problem because i dont want to have to **** with getting a whole new set of better coils

 

I'm starting to wonder if I should have ditched the cat on the downpipe. I have the MPx catted downpipe. Yeah, she runs HOT. GM did a great job with cooling though. I was very happy to see it only hit 250F oil temps on a 90F day. Honestly, I was expecting to see 300F.

This is another reason why I think moving to a BW turbo like the ZZP kit does is a terrible idea for anyone that does hard core track work. The BW is oil cooled only. I think the oil temps would go way up.

I don't know who C&D had driving when they did lightning lap in this car, but they were total ringer drivers. On the Grand course (my first time was today), with a student as a passenger, I got clocked at 3:14 by someone chasing me. Sure, I'm faster by a good clip without a passenger, but the thought that a bone stock SS was turning 3:13? That would have been one scary lap. As it is, I totally bomb the hell out of some sections, since I'm very familiar with them.

 

Yes you should ditch the cat on the DP.

 

Man, my wife is gonna be pissed if I have 3 downpipes sitting in the garage It's cheaper to get a catless than it is to weld in a vband kit on this downpipe. Decisions decisions.

I can't stand the way catless cars smell on a daily basis, so I don't really have any desire to run without one. I'd have to swap it once a year too for inspection.

 

Well, 14 hot laps Friday afternoon resulted in oil temps at 297 degrees, KR at 0 (I mix 93/100 1 for 1) first time with the w/m injection running on the track, my timing is STILL 17 degrees up top, the meth kept my EGTs down, the pyro had me around 1400 from the second lap to the last with a 200 degree differential in different sections. I also posted a new best this weekend on KDWs which are about totally scrubbed out now, and my front brakes need changing...so here I stand with a 1:20.9 @CGB. Ohh and they're redoing the WHOLE course layout I am excited to drive it next year. And because I hit the GT2 breakout time on several laps I now have to upgrade my safety gear including a crossbar, harness, catch can, purple k fire extinguisher and some other stuff, not to mention I'm in the market for a better helmet with a port I can run a hose from my a/c vent right into my head, it's unreal how hot it gets. (Yes I run my A/C, why not, it turns off when I need all the power anyways)

Next year I plan to come up to VIR and run the whole course, do they honor course licensure from another course? I get that I'd need a ride along to certify the run but I don't need to be thrown with the novices. At least not when I'm paying a good bit to get track time.

Also I'm getting ready to head to the next open track day they have at TWS. I haven't had the funds but now that I've got my tire situation squared up (sourced NT01s) I also plan to change my camber again, obviously. Remove the wing, strip out the interior since I won't be driving to and from. I'll trailer it to this event, last thing I want is to drive the car it and destroy a transmission or otherwise do something stupid like leave the course and hit something.

Anyways, I will keep you posted on what MSD says, they were pretty clear that if they go for R&D of a blaster 2 COP for our cars we won't see it for a year.

I actually plan to modify LSX MSD coils to the car if it comes down to that. I truly believe I am experiencing spark blowout, I mean what else could it be when it's air load related and happens regardless of timing.

 

297F, nice. I think you'll find that at VIR the temps will be lower because of the long straights. It's likely the slow sections that spike the temps.

For the NT01, run them with lots of camber and lots of pressure. I'm at -2.0 but I need more. These things have miserably soft sidewalls. Needs to be around 40-42 hot at my current camber. I'm going to try knocking it down to -2.5 for my next event.

Come to Trackdaze out at VIR. Good organization. Just let them know what your track experience is, and they will put you in the appropriate group. They might ask for a ride along as a check, but they are very good about moving folks around to the appropriate group. http://www.trackdaze.com Let me know which event! I'll try to make it for sure. In the black group, it's passing anywhere with a point. In the instructor group, it's passing anywhere, anytime. We're still pretty reasonable though, and most of us still point. You get some seriously expensive machinery showing up due to the pointing and passing rules. There were multiple World Challenge GT cars being test driven.

I haven't been on TWS for over a decade now. I think they changed some of the course since I've driven it. It's an alright course, but no match for some of the stuff you find on the east or west coast. The CGB map looks like it would be a fun track. Nice and flowing, and I could see it being hard on the brakes. VIR Full is definitely a power course. Total world class facilities though. Worth the trip!

 

I would love to do this for a living...seriously.

 

Instructing? I like doing it, but it's a bit of a mixed bag. If you have a poor student, it can be scary. If you have a really good student, it can be really scary :P

I will say that it's extremely rewarding to watch students progress. Unless they do it better than me. Then they're just young talented bastards that make me feel old and slow

 

I got alot of heat over chewing the behind of our resident Porsche lover and his V8 944, I followed him for 9 laps until he had a off track escapade from the pressure and I shot past him with a wave

My events list for 2011 include:

CGB Louisiana 400
NPR Quick 8s
Texas Mile (I'm going to attempt to break 180mph)
CGB Solo Sprint (Breast Cancer Awareness)
Road America
VIR Full Course
NPR 0-100-0 Raceway (I have that one in the bag, I've seen the resident SRT4s take 300 feet to stop from 100.

 

it seems like this is my problem i know im opening a oldish post, but damn, my car will somtimes misfire below 5k rpm if im in second and launch itll misfire like no other, same wiht third fourth never went fast enough for 5th. if im in third i usually dont misfire till like 5k as well but its fu**ing bad, very bad, my tune is dead on maf is not off at all ltft is are great. dals same, 0 kr, im tuned myself and im running 20lbs... Im s20g fully bolted hahn. It is wierd, it seems like blow by so i checked the gap on the plugs and theyre all .032 so thats good, compression test is great, i wonder if my coil is bad i switched them around so if i have a misfie the cylinder should change,i did write the numbers on the coil packs as well so i dont forget where they were. but yeah..

thanks

 

I still haven't completely solved it but at least I got the computer to stop picking out blowout as knock. What loads/rpms are you seeing the problem at, and what timing?

 

I wouldn't put MSD LSx coils on your ride. Coming from the LSX world previously, many people found that the HD 6.0 truck coils performed the best and had the best results. Even some of the F/I guys found success. They're cheap as hell too, can probably find them in a junk yard...

FWIW, best of luck man.

 

i misfired last nite when i did a NLS but it only did it the second time i attempted to do it not the first or the 3rd time so i figured i just messed up

 

if i slightly do the throttle to say 50% load and rpm of say 5k or above it does this, 100-200 load same, sometimes itll do it like 200% load and 6 k rpm instead of 50% and 5k rpm its just wierd, the tunes on, maf is great, maf corrections tuned in, dals are good mal is good, im running .87 lambda ive tried multiple afrs and same thing i checked plugs all look good. basically it does it when it wants but it will never let me go above k all it will do is spit and sputter, like its hitting a wall, spitts and sputters.I am running 16 degrees on top and sometimes i get kr and sometimes i dont. i ordered new plugs, the ones that are in it are the ngk two step colder and are at .032 gap

 

its not spark blowout at low airloads fyi.

 

yeah im confused, because everything is on but what gets me is my iat1s compared to my iat2s, my iat1s are speratic and jump to no end like one sec theyll be at like 32 degrees and then one second later itll say like 57 while iat2s are at ambient temps shown before 32 and so forths, so im thinking the maf is bad SINCE THE IAT1 is in the maf if im correct. and all this is at idle with temps ouside in the low 30s and high 20s.

no cel either, and no premature code or pending code

 

If your tune & stft's are spot on, can you unplug the MAF and see how it runs in open loop or does it limp out?

 

If you decide to get a catless one, Ill buy the catted one from you. Wouldnt mind swapping the stocker onto yours for inspection either if you dont have that one anymore.

 

When I first started having the misfiring issue above 6k I tried new plugs. I gapped them to .032 like I had been and saw no change. Someone traded me a set of new stockers for a set of 1 range colder AC Delco's and I threw them in without gapping them at all, and guess what, it didn't misfire. I do get it once in awhile still tho so Im wondering if I have an injector seal issue or dirty injector as well.

But I did notice what you are saying

 

First of all having expirenced these symptoms myself, I have always found it to be an injector issue. Your plugs should also be gapped to 0.030