View Full Version : GMS coils (new design)


nineinchnail1024
05-03-2008, 09:23 PM
As many of you may have read in the forums, I had a not-so-positive experience with the last set of coils I bought from Granatelli Motorsports. I bought their original design a couple of years ago and had consistent failures from the coils. I eventually gave up on them and sold them. A few days ago, I was offered a great deal on a set of the updated design coils (thanks again, Dex), so I decided to give them a shot.

Some of you are probably wondering why I'd go back to granatelli after having problems with their first design. Well, I've bought many products from the company over the years, and the only one I ever had trouble with was their old design coils. Also, there are several other companies manufacturing coils for the S197 GT, but I could never get any real information from them in regards to the performance of their coils. All I could get out of them was that the coils were a "significant improvement over stock," which was not good enough for me. Granatelli actually has hard numbers in regards to the performance of their coils.

So, the review:

So far, so good. The install is extremely simple. If I didn't have the whipple supercharger, it would have taken 15 minutes, but I had to remove my intake and throttle body to get to the driver side coils, so it took about 40 minutes. I started the car immediately after installing them, and noticed an immediate improvement in the amount of time it took for the car to start. In fact, it took no time at all. I turned the key and the car was on. Usually it takes a half to a full second to start the car, but now it fires up immediately. I let the car warm up for a few minutes, and then slowly revved it up to about 4K RPMs. Revs were smooth and clean with no detectable spark blowout, despite the whipple. I gave it a quick rev to near the redline with the same result. Today I took it out on the road. I tried my hardest to punish the new coils and expose any weakness. I ran through the first three gears as hard and fast as possible. No problems. I shifted into fifth at 35 mph and floored it. Still no problems. I dropped into second at about 35 with the revs up. Still no problems. The car pulls smoothly and solidly and doesn't have that "rough around the edges" feel that I had become accustomed to with the stock coils.

As of now, everything is great. If there are any problems in the future, I will be sure to update this thread.

Fullsayl
05-03-2008, 09:49 PM
Thanks Nine, appreciate the input!

nineinchnail1024
05-04-2008, 10:05 PM
I put about 100 miles on my car today. Usually I don't put that many miles on her in two weeks, but the coils are running great. It appears that the issues with the previous generation Granatelli coils have been resolved. If I don't post anymore about them, it's safe to assume they are running well.

CataclysmGT
05-04-2008, 10:25 PM
They offer3 different coil packs, which ones did you get? Its something i am looking to upgrade as well.

blueherd02gt
05-04-2008, 11:02 PM
Bump*** I might be in the market too

nineinchnail1024
05-05-2008, 01:14 AM
I bought the 60,000 volt from Dex.

Texotic
05-05-2008, 03:12 AM
when i first read coils i was thinking coil-overs... i was like "i didn't know gms made coil overs... wtf?"

glad you like em

08Bullitt215
05-05-2008, 11:42 AM
BADASS! im looking into getting some pretty soon myself

aclass
05-05-2008, 11:50 AM
Hey Nine, How were you able to pinpoint "spark blow out" what exactly did it feel like? Sorry if I missed the explanation in a previous post but I was just wondering.

zkiller
05-05-2008, 12:22 PM
spark blow-out sounds like a popping or backfiring in your exhaust. It will appear at onset of boost, especially with a twin-screw, because you are at instant max boost.
If you have ever hit your rev limiter it sounds just like that.

MustangGT0405
05-05-2008, 12:31 PM
Are you going to put the car back on the Dyno? I am interested to see if you get any HP gain. I dont have spark blow out but I am only at 8psi currently.

Thanks,

Dex
05-05-2008, 12:33 PM
You can feel the car hesitate when there is a blow out too.


Glad the coils are working well for you! End of this month I will get a good dyno number on how much HP they add with FI

08Bullitt215
05-05-2008, 12:42 PM
what are they running for, cost? i knew that there was a sale on them a month or so ago but i didnt get them bc i was saving up for ARH's... the 60,000v

Dex
05-05-2008, 12:54 PM
Cost is like 4-500 bucks

08Bullitt215
05-05-2008, 01:06 PM
daaaamn! but they seem like there worth it...

Meangreen1200
05-05-2008, 05:45 PM
Who or what is Dex?

CataclysmGT
05-05-2008, 05:55 PM
Dex is the guy two posts above yours.
He spent lots of money...........due to some engine problems. :D

nineinchnail1024
05-06-2008, 12:18 AM
ORIGINAL: aclass

Hey Nine, How were you able to pinpoint "spark blow out" what exactly did it feel like? Sorry if I missed the explanation in a previous post but I was just wondering.


Minimal spark blowout feels like a slight hesitation or roughness at full boost. Bad spark blowout feels like your car is about to die. I only had minimal spark blowout, but I wasn't going to wait for it to get any worse.

nineinchnail1024
05-06-2008, 12:21 AM
ORIGINAL: Meangreen1200

Who or what is Dex?


He's a forum member who gave me a great deal on the coils. He's posted a couple of times in this thread.

Dex
05-06-2008, 03:40 PM
I am.....Dex *dun dun duuuuuunnnnn*


Spending more money on just engine problems :D