Karnx

Hello all!

I've had my 2012 centennial edition grand sport (MN6) for about a month and I am loving the heck out of it! However, I am looking to add more horsepower..around 500-550rwhp
Pros of keeping my grand sport
-only 6k miles
-magnetic suspension
-dual NPP exhaust
-$6500 for supercharger installed and $2k for headers/cai/x-pipe (not sure how much installation will cost) but lets say 9k for all parts and labor for the mods for grand sport.
Also, If I supercharge and do headers...should I keep stock h? x? pipe and 2.5" NPP or swap to 3" ZR1 whole exhaust system?

Trade in for 2012+ Z06 will cost roughly 10-15k depending the trade in value.

So as you can tell, both of these will roughly cost the same and my current grand sport is very nicely packaged (78k MSRP) so it has all the bells and whistles.What makes more sense in the long run.... keeping the car for at least 3-4years.

1Sikstik

The LS3 is a little more supercharger friendly than the LS7. Its a hard choice and probably comes down to how you will use it. The Z top isnt removable, but you do get the aluminum frame and the carbon fiber goodies with the Z, and it weighs less. Im not sure there is a wrong decision

I have a supercharged Z and I love it.

I did the x pipe, go with 3"

roscoe118

Unless you are a track rat, keep the GS and supercharge it!

wayback

This is what I would do. LS3 is a better platform for supercharging. If you go to a Z you might want more power anyway.

Phillip123

SuperCharge it! Won't regret it.

WA 2 FST

If you install long tube headers, you will have to get a new H/X-pipe, but you can keep your stock NPP exhaust. That's what I did, and I don't think the difference in 2.5" and 3" at my power level is significant enough to warrant a complete swap of the axle-back exhaust setup.

As others have said, you really cannot go wrong with either choice. If you really like your car, I'd mod it and be done...you'll enjoy it immensely.

If you can find a Z06 with super low miles that has been as well-kept as your current car... then I could understand the desire to move to one of those, as they are absolutely terrific cars.

jrose7004

Trade it!

LFZ

Just going to sit here and wait for all the comments from the Z06/LS7 experts here.....

Nosferatu

Figure an extra $1000 in your budget for methanol. After driving my boosted LS3 both with and without I would never recommend without it.

Anyways, if this doesn't convince you to boost the LS3, I dunno...here's my current pulling power on a 3rd gear hit in a non-GS (taller gearing)...

No number of bolt-ons on a Z06 is going to keep up with a boosted LS3 unless it sprays or goes boosted itself.

EvanZR1

Supercharge it. Mine with just Z06 exhaust manifolds and A&A V3 Si is at 600RWHP. Drives like stock until I hammer it, and is very reliable.

The other option would be go for a C6 ZR1. Prices on those is dropping and becoming attractive.

Dano523

Depends on the end game,

427 with tune will have you close to 500rwhp, but it's all the extra upgrades that come on the Z06 that justifies the extra money for it.

Yes, ls-3 supercharged will have more power than a N/A ls-7 tuned, but then is comes down to putting the power to use. If all your going to do is strip and roll race, then Z06 may be a waste in your hands.

On the other hand, if you are going to high speed road course the car, then the the Z06 will shine over the supercharged GS in the technical sections and most of the track instead.


Lastly is resale time, and unless you can find someone that want what mods you have done to the GS, then it going to take a hit on resale value. As for getting to back to stock at that time, then you need to add the price of labor to the mods now as well.

Bluntly, if the car is going to see any high speed road course work, then you will be better off selling the GS, and picking up a Z06 instead. Come resale time, lot less work just flashing the tune back to OEM to sell the Z06, and in the mean time, most that want more HP, don't realize what the car already has in power since GM had hobbled the hell out of the car to make it street drivable in a novices hands to start with.

Trust me, I could put most novices in my LS-2 that has just been ECM remapped/retuned, and most would just end up breaking the tires loose/back end sideways most of the test drive instead (yes, GM really de-hobbles the ***** out the Vets with the factory ECM tuning to make the car street civilized).

Karnx

Thank for you all for the thoughtful insights! One thing is for sure that I will not be adding methanol. It's out of the question.

Since I won't track the car i will keep the grand sport and slowly start modding it!

First mods will be:
Headers, X-pipe and CAI!
Should I take off the NPPs and put 3 inch corsa since I am planning to supercharge it or keep the stock 2.5 NPPs. Not sure if 2.5" will build up too much back pressure... Also any recommendations for a mild steetable cam?

KnightmareCS

Low/safe boost, bolt-ons, GS... can't go wrong!
A Centennial edition on top of that!?
No question: keep it and mod it!

Nosferatu

Umm...I'm trying to understand your logic?

You want inconsistent power by going supercharged and then no methanol. Enjoy your one full throttle hit and then be down 50 RWHP...

What's your big fear of methanol? Doing a cam is way more aggressive in terms of modification and also in the drivability department as well. A 5 gallon jug for methanol for $35 lasted me 6 months and I drive the car hard on a daily basis.

Karnx

It's not the price of methanol I'm worried about... I have read it eats up coating on rotors and also if it were to fail then the tune will be messed up... From my understanding a streetable cam only needs maintenance every 40-50k miles of the springs are done right
...someone more experienced can chime in!

Also how will a supercharger be inconsistent? i have nothing but good things about the ECS 1500 supercharger.

P.s I will do some more research on methanol since atm I don't know too much about it. Maybe I can run it for its safety just to cool the engine..

Dano523

Winter blend windshield washer fluid is about 25% meth ,and 75% water. Standard windshield wiper fluid is about 20% meth, and 80% water instead. So you are are already using meth in the car to start with!!!!!

With a supercharger, you end up with a 50/50 mix instead that is sprayed into the intake. This keeps the octane rating up above the tune levels so you don't run into a detonation problem, and since the meth being sprayed in will cool the air as well, your not running into timing pull problems from heat soak. Lastly, since as the 50% water is turning into steam in the engine as the cylinders fire, your gaining more power on the down stroke from the steam, while at the same time, the steam is keeping the inside of the cylinder parts clean as well (oil build up in the cylinders causes a reduction in octane rating of the fuel).


As for meth, you can pick it up at any local chemical supply store for around $6 a gallon, and you mix it with 1 to 1 with distilled water to make meth 50/50 mix for the car (around $4 a gallon for meth).

As for either an extra meth tank, or just using the windshield wiper fluid tank for both the motor and the windshields, it's really your call.

To use up a gallon of meth in say a hour, you would need to be pounding on the motor hard for that hour on a high speed road course. With a full windshield wiper fluid tank full of meth, it will last weeks of road driving. Plus, when the tank does get low, the dash light will come on to tell you to fill the tank up long before you run out. With the extra tank system instead, it too has a low level light to tell you if the tank is low.


So bluntly, your getting all the positive effects of Running E85, with some engine cleaning thrown in. But since your not going to be pounding on the motor all the time, the Meth kit is less expensive over all for street use than E85, since it just going to be injecting the meth mix into the motor when you get on the motor and into the boost.

BadAV

Supercharge the GS. Add the 3" h-pipe; you could probably pick up a Z06 exhaust pretty cheap if you watch the forum and Craigslist for a while.

Meth isn't necessary with a good tune, but it adds a safety factor and can allow you to increase timing due to the increased octane effect. Personally, I feel with an intercooled supercharger and a good tune, you don't need meth for the street.

I've had an MP112 Magnacharger on my Avalanche for 65k miles now. It's pullied down, cammed, stalled, and has headers. I don't run meth and have never felt the need to. I do run water wetter in the radiator and the intercooler reservoir because the MP112 intercooler is on the small side and heat soak can be an issue. It still makes plenty of power on the street; if I was tracking it, I would probably run meth. I bought the Magnacharger to help a 6k pound pig of a truck get off the line better and to have some fun with unsuspecting pony cars at stop lights. The Magnacharger has been 100% reliable; I haven't touched it since it was bolted on in 2004. The Avalanche feels faster than my '12 GS Centennial, even though I know it isn't. Full torque, right off the line, goes a long way to making it feel faster than it is.

Seadawg

I have a 2011 with the same setup, and do plan to supercharge later. I've so far went with a tune the LG Super Pro 1 7/8 inch headers, high flow cat, and 3" exhaust (stayed with OEM NPP mufflers) and it bumped me to approx. 425 rwhp/ 425 rwtq. Explosive Performance here in FL in about a half a day for less than $2k.

Having said that, just a supercharger setup (any brand or style) will easily bump you to the mid 500 rwhp range, WITHOUT headers.

Nosferatu

Read what Dano said just below your comment. I'll elaborate on my comments...

Any sort of forced induction setup generates substantially more heat (byproduct of compressing air). This increase in heat will reduce your power. I've driven both PD and centrifugal based supercharging setups on the LS3 and after 1 or 2 full throttle hits there was a noticeable loss in power and noticeable the car would be pulling power down (e.g. reducing timing). It's much worse on a PD setup (I drove an E-Force never a heartbeat so my comparison is based on the E-Force).

Methanol is a chemical intercooler, keeps the intake charges cooler, allows the timing to stay advanced, cleans up the cylinder walls, and keeps the power consistent. There's never any power loss that you can feel. I ran the car back to back to back at the track and hit the same ET/MPH with methanol.

If it fails, tunes have built in safety mechanisms. I recently found out I had a weak fuel pump on my setup and when the engine didn't receive the fuel it commanded it fell on it's face up top. Find a good tuner, they'll try their best to keep the engine running safely if certain areas were to fail.

EvanZR1

I don't agree with this. I'm in Texas, and have validated that the loss is nowhere close to that, it's actually only about 25RWHP worst case. When we were first tuning my car, it was the middle of summer 100 degrees) and humid, and we didn't finish the tuning until after 5 dyno runs. The 6th run was 575RWHP. I went back and had the car dynoed during the winter (probably 50 degrees cooler ambient, with low humidity), and on it's 1st pull it made 593RWHP and on it's 2nd it made 600RWHP. So let's see, after one full throttle hit, I actually gained 7RWHP, and only lost 25RWHP over 6 pulls and a lot hotter ambient temps with high humidity.

Do I think meth is worthwhile? Absolutely. Do I think you must have it? No. If all you want is 550-600RWHP, you really don't need it and it adds extra complexity and one more thing to worry about. Having said that, it's an easy way to gain 50+HP, I've had two local buddies with similar setups to mine add 50/50 meth/water and pick up nice gains with no other changes.