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i have a 2013 grandsport, 6 speed car. It is bone stock with the butterfly exhaust. I have 5100 miles it. We are getting ready to dyno the car to see what it makes as a baseline. I purchased some Granatelli wires for it and will swap them out on the dyno after we make 2 passes on the stock ls3 wires. If they do produce a 5-10hp gain I will be purchasing 2 more sets for my other lsx cars. I will be using a dynojet, the same dyno I have used on my old c5, trans am, and 03 cobra. Hopping they give me a 5-10 gain throughout the graph. Will post up results, graphs and video if I can. Should be done in about 2 hrs. I am going to dyno with the frc's off, and will try to keep the engine at about the same temp. It is 32 degrees out.
Ok.. My vette was reading a little high I believe as the car made 394rwhp corrected bone stock. It's the same dyno I have been using on all my past cars and my t/a made 448 on this dyno and trapped 120mph, and my c5 made 330rwhp and trapped 110 in the 1/4. So the first 2 passes were 393hp/393, and 394/393.. Wife the new wires, and the car warmed up the next 2 passes were 394/393, and 394/394 tq.. So pretty much 0 peak gain. Where I did gain was in the more important mid range. From 3000-4500RPMS I saw anywhere from a 1-5hp gain, and the same with the tq. The lines were also smoother and the car idles much better as well. I didn't get a 10rwhp gain as advertised, but compared to stock wires I got a smoother running car, and picked up in the mid range power. A 5 rwhp gain throughout the mid range for 130.00, isn't to shabby.
I will say that the wires were a pita to install as on a couple coil packs pushed the metal inside the wire up into the insulation. We had to push the wire back out enough so it would snap onto the coil pack. Very annoying and took more time to swap because of this.
Overall I am happy with the wires, and may purchase 2 more sets for my other LS cars.
Blue line is the stock wires, red is the new wires.
Last edited by 1998silverbird; Jan 30, 2015 at 10:04 AM.
[QUOTE=1998silverbird;18642089]Ok.. My vette was reading a little high I believe as the car made 394rwhp corrected bone stock.
With the Grandsport LS3 being hand-built, unlike the standard vette based LS3, I've seen Grandsport's dyno mid 390's consistently bone-stock. That $130 was well spent IMO for the slight mid-range gain!
Ok.. My vette was reading a little high I believe as the car made 394rwhp corrected bone stock.
With the Grandsport LS3 being hand-built, unlike the standard vette based LS3, I've seen Grandsport's dyno mid 390's consistently bone-stock. That $130 was well spent IMO for the slight mid-range gain!
Well That's good to know. I didn't even think about that.. I have had a couple people tell me that high 300's is typical for a stock ls3.. Yeah man 5rwhp gain for 130.00 is pretty decent. Most catbacks give you a 5-10 hp gain for 1000's of dollars.
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Granatelli spark plug wires dyno 
