I've been trying to find something official explaining the lowered boost pressures during break-in and can't find anything. I've seen intervals of 500, 1000, and 2000 miles mentioned in different threads. Has anyone seen an official GM coorespondance on the issue.

My boost is everywhere right now (although I just hit it every once and a while). I've seen 10, 12 and 15 but temps were in the teens when I hit 15. What is the official boost that the SS should produce when fully broken-in?

 

Sorry, there is not any reduced boost during breakin on these cars. I have
a SS and had a GXP for over a year and they both act the same. The LNF
engine in the HHR SS and GXP is run a a new type of Bosch ecm that
actively controls boost as one way to monitor torque and keep it within
a specified level. You WILL see boost vary. I see 15 some days and 19-20
on others. It depends mainly on temp cause on a hot day it takes more
boost to make the same torque than when the air is nice and cold.
There are ways to increase boost including a IAT2 mod and a ecm flash
using a PPC controller from Hahn racecraft. The 1st is cheap, the second
not so cheap very the stock ecm can re returned to cars ecm at any time.

turbofreak
retired engineer on factory GM racing team

 

so they didn't limit boost like they did on the LSJ? weird, that's different then what I heard from my guys @ gm powertrain.

 

That's what I figured. Man how the rumor mill turns on new cars I was trying to get a look at the turbo and it appears it may have an electronically controlled wastegate.

 

20 PSI on a stock engine? WOW!

 

I did not mention it since I thought that "limited boost during break-in" misinformation would fade away on its own, but you added some very interesting info about the variable boost vs torque. Max I have seen is about 15 psi, but we have had very wet and cool weather, and elevation here is about 800 ft.

 

Put some more miles on HHR SS today and I will now modify my comment
about limited boost especially vs the GXP I owned. On the GXP I can raise
rpm and launch and get full 15 psi boost almost immediately in 1st gear.
It seemed like with the SS it was taking more throttle to get into boost
in 1st gear but I had not really gone heavy wot in 1st gear yet. So I did a hard run and I can see the ecm limiting boost to about 10 psi in 1st gear.
It goes to 15+ psi in 2nd and 3rd- pulling pretty hard- I can feel some
torque steer it is pulling so hard.
It is possible that some of what I am seeing is the ecm reducing boost in
1st when it sees wheelspin cause I am getting some. Will do some
more tests including turning off TC and ESC completely and see if I see
same lower boost in 1st gear or whether it allows the full 15 psi.

turbofreak

 

Are the SS's really boost limited for the first 500 or so miles, or is that an urban legend? I have not seen that done on any other car, although its not out of the realm of possibility. SO: Had anyone driven enough miles to prove it, because I'm thinking that the auto cars are running less boost to keep HP at 235?
PS: If you guys ever have been on an assembly line, and see how they drive them full throttle on the test dyno (every car is dynoed at speed, thats how they know the engine is close to good, I've seen them smoking like a fiend), then you wouldn't worry about a short burst of boosted speed.

 

Mazdaspeed 3 is limited in 1st & 2nd gear.

 

I haven't found anything in the owners manual or the repair manual about a 500 mile break in period, except the normal jargon below. Another possible urban legend. I have also seen the dyno tests at the factories and they are ruthless with these vehicles. Looks to be one of the better jobs!!

New Vehicle Break-In
Notice: Your vehicle does not need an elaborate break-in. But it will perform better in the long run if you follow these guidelines:

• Do not drive at any one constant speed, fast or slow, for the first 500 miles (805 km). Do not make full-throttle starts. Avoid downshifting to brake or slow the vehicle.

• Avoid making hard stops for the first 200 miles (322 km) or so. During this time the new brake linings are not yet broken in. Hard stops with new linings can mean premature wear and earlier replacement. Follow this breaking-in guideline every time you get new brake linings.

• Do not tow a trailer during break-in. See Towing a Trailer for the trailer towing capabilities of your vehicle and more information.

Following break-in, engine speed and load can be gradually increased.