kbreese

Hi All - Looking at possibly purchasing a 2010-2013 S/C Grandsport. The ones I am seeing are in the 630-650rwhp range.

Few questions:

1.) I'd prefer an automatic (Only because I deal with such heavy traffic here on Long Island). How does the auto hold up to that amount of power, and how decent is the shifting (assuming it has a decent tune)

2.) How generally safe is the motor at that power level? Are there other things that need to be done as a safeguard? (For example when boosting the new 5.0's it's highly recommended to switch out the Oil Pump gears, etc.)

3.) How much does the extra weight on the front end affect the car's handling, etc.

Any other tips or comments are welcome. Thanks!

schpenxel

1. Depends on tune/how you drive it. They can hold up well and drive like stock or better when not on it. Major key is to keep them cool.. if you can do that and the tune is good then it should last a good while, even more so if you aren't drag racing it hard from a dead stop, etc.

2. Meth is a good addition. Power isn't what typically kills these motors, knock is. Meth will help prevent it.

kbreese

Thanks, so do you think one should definitely get a trans cooler then?

Yeah, Meth sounds like the way to go with the blower.

schpenxel

Might be fine with stock stall depending on ambient temps and how you drive it. With higher stall converter you'll need one for sure

neverstop

meth for sure

TRINIC5

I owned 2 supercharged vettes, if you're looking at any making that power, that means its already supercharged and is running for it to be up for sale, the most important things are to know what you're buying, I would recommend getting the complete knowledge of the car and what was done to it and by who, my friend bought a 2012 GS and did a Edelbrock supercharger, he drives that all over America making 630rwhp, he already put about 50k miles without any major problems.
If you're buying a stock car and wants to do a FI, then that's a different story, you will need to change a few things according to what kind of power and comfort you're trying to acquire, I would recommend ARH 1 3/4 Headers with performance cats, Melling oil pump, double timming chain, titanium retainers with double valve springs, Cam Swap is an option but its a bit costly according to your requirements. The auto can handle well if you're not racing it at the track very regular and don't have sticky tires at the track, if you intend to do the track, you will need a few adjustment to the trans, a stall is really recommended if you're drag racing at the track, for the street its not really required, the GS auto already has a trans oil cooler, it works fine from factory, no need to change it.
After all recommendation, get a set of tires and then the fun begins until someone blow your doors and then back to the shop to get more power and starts to drain the bank.

chpmnsws6

Why do you need to open the engine up? If you must, add some stiffer valve springs, but even that isn't needed. I fully agree with headers and no cats though

TRINIC5

Don't have to open engine to do valve springs

schpenxel

Leave the valve covers on, no issues changing springs with those on.

Turbo-Geist

JasonCzerak

Not "Exactly". You do need to remove the oil (or 710) filler cap. One can find a good quality set of bendable pliers from the local Harbor freight and go to town swapping the valve springs.

bmfvette

Wtf!

Just need Comps LS valve spring compressor tool and do it the easy way.
Last time I checked...you can't get to the springs with the valve covers on...

schpenxel

Sarcasm... you missed it

Tacticaladv

I currently run a 2010 A6 with an A&A V3SI kit with a 220/230 comp cam cut to A&A's specs. Running the stock convertor on drag radials.
Have a few thousand miles on it, kit was installed at 30K miles.
Car runs and drives like a stock car around town with just a little bit of cam surge at very low idle but nothing thats remotely annoying.
Play a little bit on the street and have done shift sector. Car ran great, controlled heat and had no issues.
My power level with cam and conservative tune through the auto is just above 600 RWHP with no meth. Car seems to love this HP level without any signs of kaboom, I've heard alot of people saying under 650 or so you have a pretty good chance of survival if your not constantly beating the car, over those numbers your rolling the dice on stock internals.

EvanZR1

LS3 is very reliable at 600-650RWHP level. I'm at 672RW on a manual GS with a bone stock motor and just LS7 exhaust manifolds (V3 Si currently running a 3.6" pulley at 11psi peak). Definitely do meth, I ran for a year without, and have had it for about a year now. If keeps the IATs very stable, and definitely helps with preventing knock. I've hammered on mine pretty hard including a full day last fall doing a 1/2 mile event, and two days at the Arkansas Mile this summer (19 passes, full throttle for a full mile with a best of 187MPH), including driving the car about 800 miles up and back for the event. I'm about to upgrade to a 3.4" pulley for about 13psi, and will be upgrading the valve springs and push rods as a precaution.