How valid is the break-in period from the book?

The break in period is accurate - while modern engines require less break-in than older engines, the restriction on full throttle accelleration is more to condition the rear end than the engine.

"Told to me by a GM powertrain engineer"

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G8 GT 615

Thanks. I guess the hard part is the no greater then 68 mph for 3000 miles and the 5 mins max for using cruise.

Nice new car and everyone passing me is not fun!

Should not need more than 500 miles to break in the engine break it in like you will drive it. You don't need to wait 3000 miles to do more than 68 mph.

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2008 G8 GT Panther Black #366 of 888 2004 GTO Red on Red LS1 M6
1999 & 1996 Grand Prix GT / 1979 Trans AM 6.6 WS6 Auto

68 is idle for me. There is no way I could wait 3000 miles to do more than 68 mph. I'm 70+ just getting onto the interstate!

BTW, no one has passed me since I got my car and without the cruse, I'd have a ticket by now.

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08 Stealth Blue G8 GT - Fully Loaded Plus Some
http://i297.photobucket.com/albums/m...P8060079-1.jpg
NEP CAI with VMS HSRK, Mobil 1 0W-30 Advanced Fuel Economy
18% Tint, Blued Out: Reflectors, Badges, Gauges, & Center Stack
A Few GRRRR8 Mods, 12" RF Pro, Audio Control EQX, PPI PC 2300 WSE

In all honesty the rule of thumb is to break the vehicle in the way it will be driven on a daily basis. Most important is the proper warming and lubricating of the engine during the break-in period. Don't just jump in and drive it like you stole it untill the motor has aquired the 600 mile mark, at a minimum.

Sorry to be bumping an older post for my first contribution, but I have a unique situation regarding this topic. I'll be driving 1200 miles to SC to purchage my G8 GT and then driving the new vehicle back home (another 1200 miles). The route takes me through a wide range of climates that includes mountain passes. The trip would take well over 17 hours going back if I were to suffer at such a low speed (68). Does anyone have any suggestions on what kind of break-in period I should give for an extended cross-country trip for my new car's first drive?

Just drive it like you would drive the other vehicle. The long ride will do your g8 good, it'll set the rings and break everything else in. Don't be afraid to see what she can do.

have fun!

Don't drive it like you would a broken-in vehicle.

Given your situation, the important thing is to vary the RPM. Don't run for any length of time at one RPM. Run up through the gears, and run back down through the gears.

Changing the engine RPM changes the oil splash pattern inside the engine as well as the lubrication of the cylinder walls and rings. Acceleration tends to strip the oil off the cylinder walls (creating hot spots) and deceleration tends to flood them (cool and harden the hot spots).

If you are stuck on an interstate, run in 5th for a while and then run in 6th for a while. And then run in DOD for a while

No more than 75% throttle and keep it below 4800 RPM for the first 2 tanks of gas. But you can run up to 4800 at 75% throttle as many times as you like.

Then drive it like it wants to be driven

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G8 GT 615

And when you get to your destination, you'll be due for an oil change.

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G8 GT 615

I didn't get to read these responses before I left to drive the G8 back home, but oddly enough I followed pretty much the same procedure you have listed here so I think that I got a really good break in. I was averaging about 26 MPG on the drive up, which was actually comparable to my 2000 Grand AM GT. Now that I have the car back in Omaha, NE it appears that it's time to really work on the paint. Whoever did the buffing on it last left swirl marks over the entire car, including some of the lamp covers. Nothing some fine detailing won't fix, but it kind of disheartened me to have to work on it so much straight out of the box as it were.

The car drives like a dream and I am very satisfied with my person so count me in among the ranks of the new G8 enthusiasts. Now to figure out how to go about modding it up as this is the first car I've had that has been worth sinking money into for performance and other things. Do most people take their vehicles into a specialty store to get their work done or do most do it all themselves?

A slight hijack, but I'll just chalk it up to n00b status.

lol,
Ok, well i suppose that now you're past the break in process, the mods are easy and simple. it's about a 50/50 mix of DIy'ers and folks who take it in the shop.

I've been a mechanic now for 30 years, so i do the work myself.
The easiest mod is the CAI. Next step is the exhaust...if you can turn a wrench, you can do these mods relativilty easy. about 30 min for the CAI and 1-1.5 hrs for the exhaust. Those two mods will give you a healthy gain in hp. Once that is done, you can take it over to a tune shop where they will "tune" your vehicles computer to optimize it. total gains with tune....you should see around 50hp.

Thank you for the quick input. I appreciate the tips, I can certainly turn a wrench so I may give those mods a shot when I get some time to do them.

Ok, I'm a dope, what's CAI?

C old A ir I ntake

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G8 GT 615