Sputter in WOT high gears

[HisandHerTurbo]

Well, For the first 3 runs the car felt great! I got to do 4 runs 2 of them I bogged really bad and the other 2 I spun the tires really bad, no happy medium. I trapped really good though, between 124.76 and 126.35 all 4 runs.
The 4th run brought me back to a problem I had up until I did the first 3 runs today. Had this problem ever since I got the car running again. The problem is that in 3rd and 4th gear I get a sputter/hesitation. First I blamed it on the 11 month old fuel (long been replaced), Then I assumed it was fouled mis-gapped spark-plugs (replaced last night, one was at .032 the others were correct at .028). Then on the way down there when it did it to me again, I thought maybe since I tightened up the internal waste-gate actuator arm (adjustable) while I was putting the car back together, that might be it (too much for the turbo to do). So, when I got to PMP I loosened up the manual boost controller only to find the spring was pressed down, moved it back into place and then went not as tight on it. Then the first 3 runs went great (temp was kind of cool outside). 4th and final run the hesitation came back. so I took a log of it on the way home in 4th gear.
Just wondering if anyone else has some thoughts on this, I am just assuming when it got hotter out, I pushed the turbo to it's limits again. I don't know, but what's wierd is that when it "sputters" you notice it on everything, inj duty, air, fuel, and rpm's.
I also did a leak test when I replaced the plugs and fixed what little leaks I had.
Also, I believe I hear my TAiL BOV when the sputter hits.

What are your thoughts
TY
JOE


MODS

Buschur Stage II head w/ FP 2x cams and FP dual springs
Buschur Stage I Block w/ Eagle rods, Wiseco Pistons, & Knife edged crank
Magnus intake Manifold w/ Hal special 64mm 1G TB
Tial BOV
AGP RS60 Turbo
DV/DT Fab Race FMIC (3” piping short route)
MSD Dis-2
MAF-T w/ 3 ½” MAF
TRE Race Tranny (4 Spider)
-6an fuel lines feed and return
950cc FIC (Delphi’s)
Aeromotive AFPR
Battery relocated to trunk
Gram Lights 57F 17x7.5
Buschur Coil on Plug ignition
Unorthodox Racing pulley kit - crank
PTT Twin Disk
Re-wired Walbro 255 pump
DSMLink
3” Turbo to Tip exhaust (RS*R DP, custom cat-back, Thermal Muffler)
Ported EVO III Exhaust Manifold
Ported 2G O2
BR Manual boost controller
Eibach Pro-kit springs
B&M Short Throw Shifter @ 50%
Autometer Boost, EGT, Oil pressure and fuel pressure gauges
AEM 6-1 WB gauge


TY
JOE

[thiazole]

Does it happen at a specific rpm in 3rd and 4th gear? Is it the point that you hit full boost? Is it around the peak g/rev in your log?

[XakEp]

Replace plugs and wires.

[HisandHerTurbo]

Thought I posted my logs.......... And it doesn't always do it in 3rd, just does it when it wants.

And I did replace the plugs, and I don't have wires

[XakEp]

Thought I posted my logs.......... And it doesn't always do it in 3rd, just does it when it wants.

And I did replace the plugs, and I don't have wires

Do you have COP? If not, replace your spark plug wires. If you do, then you're seeing spark blowout.

[Toybreaker]

^^^What he said.

Joe, I've been seeing some issues with the spark plug booties on some of the cop set-ups. They get little tears in them, and then the spark leaks down the side, or out the top or bottom.

Yet another reason a little di-electric grease on the boots is a good idea. ;)

The boots will come on and off the plugs easier, and there's less chance of tearing them during midnight plug swaps.

[Wazzelby]

And if that doesn't solve the problem take another look at two things:
1 - what are you using to drive the COP? do you have a mSD or anything installed? I see you have the "Buschur Coil on Plug ignition" but I'm not sure what that includes. If you are just using the COP with no ignition it could be the culprit. For some it works great, others not so much.
2 - have you tried swapping your GM Maf? I went through two before I found one that didn't sputter no matter how much I tuned it.

Another thing I noticed on your logs is that the wideband seems to stay right at 14.6-14.7 no matter what. Is it not working correctly or are you actually tuned to 14.6 even under full boost. It just doesn't seem to fluctuate.

[HisandHerTurbo]

Yes I have a COP (I will try a known good coils with 8.5mm wires and see if it changes)

Yes I have the MSD Dis-2 with the COP

Yeah sorry, forgot to mention the AEM WB is currently stuck at 14.6

Spark blow-out.......... is that the same thing as saying a small tear in the booties? or is that something different?

MAF, same one has had no issues in the past....... not to say it didn't go out, but it was good

Di-electric grease......... all down the outsides? all over the whole thing?

TY
JOE

Keep them coming, today I will try the coil and wires

[XakEp]

Spark blowout is when your spark isnt strong enough to fully ignite the fuel mixture in the cylinder and suddenly you're down a cylinder for the power stroke.

When the spark blows out, you'll have a sudden gap in accurate logging data. I've had it happen to me, much much worse than this.

[HisandHerTurbo]

TY, K, what causes it? what's the fix?

[thiazole]

That is where I was going too. If you are gapping at .028", then .026" will probably solve your problem. I don't think people with COPs usually have to gap their plugs very tight, but you are also making a lot of power, so I'm not sure. Anyone one else here with a similar COP setup flowing 50-55lbs/min that can chime in?

[XakEp]

Make sure your plugs are gapped properly and your ignition is putting out enough power. Examine your COP plugs and see if they're in spec for output and make sure the boots are intact.

[thiazole]

TY, K, what causes it? what's the fix?

Although the name "spark blow-out" implies the spark is lost due to a turbulent environment, I think the underlying cause is due to the fact that 1) the more cylinder pressure you have, the more resistant the a/f mixture is to igniting, and 2) the more cylinder pressure you have the more energy it takes for the spark to jump the gap. Any minor problem in your ignition system could be the ultimate reason your ignition system is slightly inadequate as other have noted - I even had a pretty bad blow-out problem last year that was mostly caused from using a 5 or 6 year old battery.

[HisandHerTurbo]

Well....... I wonder if a smaller gap (other then .028) would help.
Also, I thought maybe today switching to my coil pack and Magnacore's fixed it. But of course it didn't.

[thiazole]

I think that is a good solution for now. Nothing wrong with being at 0.026". I would think you'd be able to handle 0.028" with your ignition setup, but I'm still on the stock ignition, so I just don't know your ingition's limitations. I know a lot of people go as low as 0.022 - 0.024" to remedy this problem. I was actually at 0.018" last year before replacing my battery.

I've also found that leaning it out a little reduces blow-out as well. I'm not sure if you are running a little rich or not (since your WB is broke), but that can definitely contribute to the problem.

[D Walker]

What fuel are you running?

[D Walker]

I think that is a good solution for now. Nothing wrong with being at 0.026". I would think you'd be able to handle 0.028" with your ignition setup, but I'm still on the stock ignition, so I just don't know your ingition's limitations. I know a lot of people go as low as 0.022 - 0.024" to remedy this problem. I was actually at 0.018" last year before replacing my battery.

I've also found that leaning it out a little reduces blow-out as well. I'm not sure if you are running a little rich or not (since your WB is broke), but that can definitely contribute to the problem.


The 300M coils are not designed to fire under high cylinder pressure/RPM, and even using them with an MSD will not always cure the issue, especially if your running E-85, so the only solution is to lower the gap or change your setup. Even lowering the gap is not the perfect answer, as that can cause other issues.

[HisandHerTurbo]

I keep T111 (Phillips 66 111 Octane Leaded Race Fuel) in the car at all times.
I will try to run a little more lean and see if that helps out.
If that doesn't help, I will go with .025 for my gap (that's the next lowest I have on my feeler guages).

[HisandHerTurbo]

Still have this issue, would love to have it fixed before saturday and bandimere. Expecially since I goto NTC on Sunday. I even lowered my gap to .025, not only did it not help I had a stutter in 2nd this time, top of the gear.
Switched my COP for a known good set of coils and magnacores.

Here is an updated log where it did it a little bit in 2nd

THX
JOE