Welcome! Log In Create A New Profile

Re: Maybe of interest only to me.... I have about 165 miles on my new motor

Own a Porsche? Join the Club.

Products for your Boxster, Cayman and Carrera.
So, long story short, i put a lot of work and money (parts, machining) in to a new 3.6 motor for my street-legal track car. Yesterday and today i began the critical task of breaking it in... properly i hope. Basic principles: vary the speed, gradually increase both load and rpms, and never lug or jerk (jerk = 2nd derivative of velocity, and is generally bad). So basically, when I have a new , powerful toy, its torture :-) Lots of miles, none on highway, and not the fun way.

The kid likes to pull and rev; not that I've pushed it. At idle i can barely feel it (good). The headers + stock exhaust give a nice rasp that's never annoying. Average economy is not good. seems to be running rich, both form mileage and faint odor. Any odor is a lot of fuel, IMO. 17 mpg on all back roads, going from 2.5k rpm top 4-4.5k rpm, which may in fact be the reason :-)

LSD seems tom make whining noises especially at low speed and high lock. Not sure if this is normal.
I need to speak with the tansmission guy. But its Easter and he's in Colorado. (GBOX).

The good news: lots of incredible back roads in NJ. Lots of friends to visit along the way. Truly "the long way home", both literally and figuratively.

So - to all here - Happy Easter and let's all think about important stuff, like how we can learn from the message of this holiday, regardless of our specific beliefs.


Grant gee-lenahan-at-vee-eff-email-dot-net
Lots of good stuff there, Grant. Agree with you 100% about breaking it in the right way. With a car like the Boxster, it's special hard to not start enjoying the power - specially in your case, where I imagine it's going to be a significant boost over what you had before. It's tempting to put your foot in it, but I'm a firm believer that if you break it in with varying speeds it will give you a longer lasting, better performing engine.

I've found that mileage does improve after the engine gets broken in, but the smell of exhaust fumes, suggests it may be running rich. I don't remember that from breaking in either of my Boxsters. 17 mpg also seems pretty low mileage if the engine is fully warmed up and running mostly on two lane back roads with few / no stops.

Glad you're enjoying those NJ back roads. It's a pretty incredible feeling this time of year after getting the car out, top down and the sun shining, enjoying the Symphony in Flat Six on the "long way home" smiling smiley

I had the pleasure of getting out and enjoying some above average, 70 degree temps here in Ontario as well and echo your message about this holiday.

Regarding the odor, did you change much--or anything-- with regards to the fuel system (injectors, TB MAF) or ECU?

Grant gee-lenahan-at-vee-eff-email-dot-net
Just wondering if you have a tank full of old (from Nov - Dec) fuel in the tank and / or had Stabil in there.

I know the first tank (of 4 month old) fuel I use in the spring, the exhaust, specially at start up, has a strange odor. Not sure if that's from old fuel or from the Stabil or a combo. I usually try to run that first tank pretty much to reserve if possible and then fill with fresh fuel. That could effect gas mileage too.

Grant gee-lenahan-at-vee-eff-email-dot-net
Too easy....
Gary in SoFL - 1 year ago
G-man...after four months of self inflicted Boxster hibernation, during your first excited drive, it may not be petrol or additive that is causing your gassy oder.

Just saying.

"A mile of highway will take you one mile. A mile of runway will take you anywhere."
Some raw fuel smell in the exhaust after a cold start is normal, of course. After the converters are warm I really can't recall smelling any fuel.

Have to mention that with a new engine (well, rebuilt) a fuel leak is possible. Some fitting didn't get tightened down or a seal/gasket/o-ring is bad.

The DME with the O2 sensors should keep the fueling correct. The converters like a bit over 14:1 air/fuel for this mixture -- in a healthy engine -- produces exhaust gases which the converters are best able to process.

Are both the intake and coolant temperatures correct? A DME that is led to believe the air is cold or the coolant is cold will enrichen the mixture. Are you running a low temp T-stat perhaps?

Are you going to do an "early" oil/filter service on the new engine?
Many good points.
grant - 1 year ago
I'll work backwards:

500 miles on the break-in specific oil that is in it (Driven/Gibbs, Dino, high ZDDP, break-in oil, specific from LNE).

Break in is mostly rolling onto the gas 2500 --> 4500 and engine breaking back, with of course a few more enthusiastic starts. No WOT yet. Nothing above 5k yet.

Smell is burned fuel, not raw.

Some of it may be that i found a power steering leak.

There is one exhaust related issue that may be affecting the performance of the O2 sensor feedback system.

The good news is that now with 230 mils on it, it runs GREAT. Idles almost imperceptibly. Wants to pull, but i wont yet let it off the leash.


Grant gee-lenahan-at-vee-eff-email-dot-net
Talk like that makws me want to go racing, Grant thumbs up

"A mile of highway will take you one mile. A mile of runway will take you anywhere."
Think the fuel economy is based on the higher RPMs for break-in. Think running 2500-4000 with a 3.6 liter engine is about right for 17 mpg on a new engine. Cruising on the highway in 7th gear in my 3.8 gets around 28 mpg. Tooling around town/commuting/long-way-home is easily in the upper teens, but I'm an aggressive driver. The LWH is usually mid-teens. thumbs up

Grant gee-lenahan-at-vee-eff-email-dot-net
Sorry, only registered users may post in this forum.

Click here to login