Granatelli Motorsports coil packs

[Five Oh Brian]

holy old thread batman! lol

Yes, old thread, but I've learned the hard way around here to use the "search" feature and to not start my own new threads.

 

[Five Oh Brian]

Stock has been doing hell of a good job for me since I made this thread o so long ago

Stock wasn't cutting it for me with the blower. Spark blowout was a real issue with the blower. Not only does my car run silky smooth now, but initial tip in feels noticably more powerful (almost like the feeling when you add several degrees of timing) and the stumble/hesitation always drove me crazy so I'm so glad the hotter coils cured that!

I trust you can get away with the stock coils since you're still NA.

 

[05stroker]

Stock wasn't cutting it for me with the blower. Spark blowout was a real issue with the blower. Not only does my car run silky smooth now, but initial tip in feels noticably more powerful (almost like the feeling when you add several degrees of timing) and the stumble/hesitation always drove me crazy so I'm so glad the hotter coils cured that!

I trust you can get away with the stock coils since you're still NA.

Im glad these helped you . I added the MSD coils for the same issue . Whatever the real issue was at the time the MSD COPs solved it , but I would assume now that they were just making up for some tuning issues at the time . Many have gone allot further then you and I on the stock COPs. Whatever works I guess .

 

[HOLYWD]

I like my granatelli's , np's so far .

 

[cycosarge]

I had spark blow-out when I added my Kenne Bell Stage 2 and I switched to the GMS 60K volt coils. They were very expensive, but I have never had blow-out since. It's been about 5000 miles with no issues.

 

[MikeVistaBlue06]

I had serious spark blowout when I installed my Vortech blower a few years ago. Switching from the factory spark plugs to copper/colder FRPP 3V0's really helped, but there was always a hint of spark blowout in extreme situations and the car was never silky smooth. Still enough to run an 11.85 @ 113+, but not factory, silky smooth.

Fast forward to now. I decided to try hotter coils and just installed the GMS "hot street" coils. They aren't terribly expensive ($250), so I figured it couldn't hurt to try and I have the stock coils just in case. They are rated to produce 45K volts vs the stock coils rating of 20K volts.

I gotta tell you that the car runs silky smooth now! Excellent tip in with no hesitation like I always had with the blower & factory coils. I've gotta get to our local dyno and dragstrip to see if there's any more power being made, but just having the car run smoother (and a noticable improvement in fuel economy) is enough of a plus for the minimal money spent.

If GMS had problems in the past, I believe they may have fixed them. So far, color me happy with this mod.

Not to bust your bubble, but unless the aftermarket COPs show lower resistance AND more inductance, they ain't better. Fatter wires on both the primary and secondary, and more windings on the secondary are what you want.

I am glad it is running better for you.

Increased voltage does nothing for spark energy. Increased current flow, does since the energy in a coil directly related to the current squared!

http://www.s197forum.com/forum/showpost.php?p=182890&postcount=23

http://www.s197forum.com/forum/showthread.php?t=11534&highlight=coils

http://www.s197forum.com/forum/search.php?searchid=1828231

HTH

Mike

 

[Five Oh Brian]

Not to bust your bubble, but unless the aftermarket COPs show lower resistance AND more inductance, they ain't better. Fatter wires on both the primary and secondary, and more windings on the secondary are what you want.

I am glad it is running better for you.

Increased voltage does nothing for spark energy. Increased current flow, does since the energy in a coil directly related to the current squared!

HTH

Mike

I don't care one bit about the science of it all. The GMS COP's have my car finally running silky smooth with much better tip in. The car is much, much more enjoyable to drive now.

As soon as I get to the track again, I'll post up timeslips to see if there was any tangible gains. But, even if there's no more power, just having the car run so smooth was worth it for me.

 

[MikeVistaBlue06]

I don't care one bit about the science of it all.

Well this is certainly the wrong forum for you.

Mike

 

[Five Oh Brian]

Well this is certainly the wrong forum for you.

Mike

Allow me to rephrase it then. I studied a lot of physics in high school and college way back when. I've created a lot of equations to explain a lot of what happens at the dragstrip (for my own use). I understand the science behind what you're saying. However, I don't care about the "how" as much as the results in this particular issue.

 

[Five Oh Brian]

So, the GMS COP's definitely helped my car, but I had to use factory platinum plugs with them initially while I waited for new FRPP 3V0's to show up. Well, I finally got the colder/copper plugs in and went for a spin at long last with the right plugs and the new GMS COP's. All I can say is 'holy crap'!!!! The car run so incredibly smooth now, but more importantly, there is a very noticable increase in low end oomph. The buttometer says there's gotta be an extra 20-25 hp and/or tq, but I won't know for sure until I get back to the dyno in a few weeks. Next drag day is September 17th, so I'm expecting trap speeds to go up some.

 

[TurboPete]

My problem with the a/m COP was that they miss at low speeds under load . Never really tried to see if it was working at high boost up top. The fact that they were missing at part throttle at low speeds was enough for me to go back to Stock COP .
Now Im having a little bit of an issue with blowout at 840 rwhp . Cylinder pressure is high especially with stock heads and cam . My only solution was either go with ported heads , or better spark by either A/M COP or a KB BAS.
I installed a BAS but really haven't done any real testing b/c the weather has been crap. Hopefully Ill have some data for everyone this week . If no more blowout expect Me to turn up the boost to 27 psi's .


Pete

 

[viciousride]

Gents,

Excuse my ignorance on the subject, but when datalogging a run what indicators/parameters do you look for to determine spark blowout?

 

[s8v4o]

Gents,

Excuse my ignorance on the subject, but when datalogging a run what indicators/parameters do you look for to determine spark blowout?

Spark "blowout" would actually show up as lean condition if you are using a wideband. It shows a lean condition because you have an unburnt mixture/oxygen passing right by the O2 sensor. The O2 doesn't rteally care about the unburnt fuel though, as it only reads the amount of oxygen in the exhaust. Maybe someone with more experience than I can tell you others parameters to datalog.

 

[Five Oh Brian]

My problem with the a/m COP was that they miss at low speeds under load . Never really tried to see if it was working at high boost up top. The fact that they were missing at part throttle at low speeds was enough for me to go back to Stock COP .
Now Im having a little bit of an issue with blowout at 840 rwhp . Cylinder pressure is high especially with stock heads and cam . My only solution was either go with ported heads , or better spark by either A/M COP or a KB BAS.
I installed a BAS but really haven't done any real testing b/c the weather has been crap. Hopefully Ill have some data for everyone this week . If no more blowout expect Me to turn up the boost to 27 psi's .


Pete

My stock COP's were actually missing at low speeds under load, whereas the GMC COP's have cured that. I am really amazed at how much better/stronger the car feels now, especially given that I was skeptical of seeing any gains with them in the first place.

 

[Five Oh Brian]

I posted this in another thread, but thought it would be a nice recap here of my experience with Granatelli (GMS) Coil on Plugs....


So, here is a summary of this year's racing data from my timeslips with the only power variables being spark plug gap and coils...

• .045 gap and stock 20K volt coils. Average trap speeds of 112 to 113 mph.
• .028 gap and stock 20K volt coils. Average trap speeds of 107 to 109 mph. So, with stock coils, just gapping down from .045 to .028 (absolutely no other changes) cost me 4-5 mph through the traps (ouch!).
• .028 gap and GMS 42K volt coils. Average trap speeds of 111 to 112 mph. The GMS coils got back 3-4 mph of the loss from the tighter gap (nice!).
• .045 gap and GMS 42K volt coils. Average trap speeds of 113.5 to 114 mph. Widening the gap netted me another 2 mph roughly.

In summary, I am 100% certain that a .045 gap with aftermarket coils is worth about 20-30 rwhp (maybe more) in my car vs .028 gap with stock coils. Looking at my recap above, we're talking about a 5-6 mph improvement in trap speeds between those 2 scenarios. That's very significant no matter how you disect it. And for those who hate GMS for whatever reason, please note that my car went faster through the traps with the GMS coils regardless of which gap you compare. As always, your results may vary, but I feel the GMS coils were money very well spent ($249).​

 

[Greg Hazlett]

You are at .45 gap on a s/c car? WOW!

 

[Five Oh Brian]

You are at .45 gap on a s/c car? WOW!

Yeah, I know, more gap than most recommend. However, I ran at .045 not knowing any better for 2 years with the blower w/o incident. Always had a bit of misfire/blowout, though. The hotter coils have allowed me to run smoothly at .045 and make more power.

My car has never felt better in all driving scenarios and I set a personal best at the dragstrip over the weekend (best 60', best 1/8 mile, best 1/4 mile, best trap speed, etc.), so it's definitely making more power than when it was gapped down to .028 for the past few months.

 

[white05gt]

For what it's worth, I believe mine were never gapped when they were installed and I didn't install them.

 

[Chilliwack 42]

Brian what was your ET stock vs gms and the different gapping.

 

[Five Oh Brian]

Brian what was your ET stock vs gms and the different gapping.

Spark gap and voltage speak more to power production, which translates to trap speed. ET is more a function or traction/launch at a given power level.


That said, my average ET's per my timeslip spreadsheet for this season were....

• .045 gap and stock 20K volt coils. Average ET 12.35
• .028 gap and stock 20K volt coils. Average ET 12.60
• .028 gap and GMS 42K volt coils. Average ET 12.34
• .045 gap and GMS 42K volt coils. Average ET 11.88

My car obviously likes a wider gap or more voltage, but absolutely rocks with the combination of both a wider gap and more voltage. My car feels like it's making 20-30 more lb ft torque as it launches much harder and pulls hard down low like it never has before!

Worth noting, our two local tracks are both near sea level and the weather is fairly calm & mild here near Seattle. I avoid super hot mid-summer days at the track, so the air (DA) was fairly consistent for all of my track days this year. I guess what I'm trying to say is that the DA corrections don't amount to much for any of my runs this season since I only raced in fair weather, so the raw timeslip numbers above are very comparable.