Newly Built SHO motors and boost

[RJ-92]

When building a new low CR motor for boost should the engine be broken in prior to it being boosted. I know Fred and a few others have done this, and I would assume it to be easier on the motor than breaking it in under boost but is it necessary?

 

[sho_sc]

Absolutely! I would keep a check on compression or even better leak down test and not boost until the rings have seated.

 

[wicked93gs]

no, this is false, any engine built for boost should be broken in under boost as well(they dont take the turbo off on an SRT4 to break them in) but boost is not the important part of the break in equation...engine load is, you MUST get on your car a few times (quickly accelerating and decelerating under load about 5 or 6 times, high RPM is preferrable, this is the reason that new cars aleways have a few miles on them) this is to properly seat the rings against the cylinder wall, the reason in has to be in the first 20 miles though is that the rings quickly wear down against the cylinder hone and if you break it in gently....you'll get a gentle car because the ring seal against the cylinder wall, now thats just general engine break in procedure, for boost. try to break it in under boost...but use an OLD TURBO or blower, the break in causes metal shavings from those same rings to go into the ehuast and you dont want that crap in your turbo or blower, thats a good way to significantly shorten its life, I'm not the best at explaining it, but this is the theory

 

[F-22 Raptor SHO]

(quickly accelerating and decelerating under load about 5 or 6 times, high RPM is preferrable, this is the reason that new cars aleways have a few miles on them)

I do not believe this statement is accurate. Car Manufacturers do not do this. The logic of this step would cost car companies tons of money. 2 million cars made per year x 2 miles of break in is 4 million miles. This just doesnt make sense.

Any miles that are on your brand new car (I've seen em with less than 1 on them. Is from the transport off the line into the mfg lot, onto the transport trailer and back off to the dealers lot.

 

[Toolman]

Especially would you not want to do a lot of high RPM driving right away. Stay away from the drag strip and road course.

 

[SHOMurph]

no, this is false, any engine built for boost should be broken in under boost as well(they dont take the turbo off on an SRT4 to break them in) but boost is not the important part of the break in equation...engine load is, you MUST get on your car a few times (quickly accelerating and decelerating under load about 5 or 6 times, high RPM is preferrable, this is the reason that new cars aleways have a few miles on them) this is to properly seat the rings against the cylinder wall, the reason in has to be in the first 20 miles though is that the rings quickly wear down against the cylinder hone and if you break it in gently....you'll get a gentle car because the ring seal against the cylinder wall, now thats just general engine break in procedure, for boost. try to break it in under boost...but use an OLD TURBO or blower, the break in causes metal shavings from those same rings to go into the ehuast and you dont want that crap in your turbo or blower, thats a good way to significantly shorten its life, I'm not the best at explaining it, but this is the theory

Are you trying to buy a supercharger cheap when someone blows their motor??! just kidding.

You want the motor to heat up and cool down many times. That is proper breakin' (use Texas accent here.)

There are those who believe you should flog a car as soon as you get it. I'm not one of those people.

Put on about 500 miles without boost and thats the safe bet.

 

[AutoSHO]

Actually, running an engine fairly hard is the perfect way to break it in. The first 50 miles of engine running after a new engine is built are the most critical to getting the rings to seat. The higher pressures of higher RPM/load allow the rings a much better chance to seat and seal well against the cylinder walls than if you baby the engine and try to be gentle.

 

[Toolman]

So I guess the general concensus is, there is no concensus.

 

[Off Road SHO]

So I guess the general concensus is, there is no concensus.

Then we all can agree on one thing; that we're not going to agree on this one.

Cast iron rings will seat in almost immediately after running the motor for 8-12 hours. Anything with chromium in it will take much longer. What you DON'T want to do to a new motor is operate it at a steady state for long periods of time; always use low, medium and high rpms the first 500 miles.

Why, because as rings bed in (seat) they are scraping the the highest points off of the cross hatching and carrying it to the top of the pistons stroke and leaving it there. This crud along with all the other misc manufacturing debris forms a ring. The higher the rpms, the farther the rod stretches and the higher the ring. If you run at 2,500 rpm for 500 miles, all the crud will be at a lower level, just waiting for you to romp on it so the rod can drive the piston through that barrier.

Now granted, engine block machining has come a long way and the material are so much better nowadays, but I would still exercise that baby.

Tom

 

[SleeperStyle]

It just makes sense to break the motor in without the extra heat of forced induction.

 

[SHOMurph]

Another issue with new boosted SHO motors is to make sure that everything is working properly.

I wouldn't take a new motor with x amount of boost and immediately haul ***.

Unless you have a wideband your Air/Fuel could be off. Gotta make sure the tuning is in the ballpark. Tuning is tricky with these motors.

Make sure belts aren't slipping (SC guys.)

I like to run a new motor easy with new rod bearings also for a little bit.

If you installed a new clutch with your motor its a good idea to drive it for a little bit to break clutch/pressure plate in.

Just with instaling a N/A new SHO motor there could be many possiblities of little stuff that could not be right (hoses not tight enough, cam seal/front main didn't seat right etc.) Add boost and multiply the potential problems that could go wrong.

 

[AutoSHO]

I, personally, would do without the boost for the inital break-in, unless you are certain the tune is good and the spark advance is *very* safe. The pressures from normal combustion are enough to get the rings to seat, so as long as you are in good tune and can safely run N/A it is probably a better idea to run that way. If you are certain the tune is safe, there's no reason not to run the boost as well.

Like Tom said... Exercise that baby!

 

[SHOMurph]

Every motor responds to tuning different. The problem with our SHO motors is that there is no certain way to tell the tune is safe until a/f/dyno under boost. There isn't a proven formula on what is a safe tune. Unless you have a tweecer with lotsa knowledge on how to tune these cars its better to break it in slowly. If you dump alot of fuel in then you can dump too much in and kaboom like what happen to my motor.

Running without boost and running the engine hard is like trying to use the bathroom with your pants still on.

 

[Off Road SHO]

Running without boost and running the engine hard is like trying to use the bathroom with your pants still on.

:laugh_ti: :laugh_ti: :laugh_ti: :laugh_ti:

And how do you know this?


Tom

 

[Revere sho]

where can you buy brand new sho motors and how much are they?

o ya and for what was said before about a new car only having 1 mile on it is not always true.

i know with chrysler, jeep, dodge, part of the new car prep is that it is manditory to drive at least 3 miles. the average car that ive seen once it was done with comeing off of the truck and going through the pdi, predelivery inspection would have between 5-7 miles on it.

 

[SHOMurph]

TexanTony will build you one to custom specs.

 

[wicked93gs]

I wasnt saying to romp on the motor 9 or 10 times quickly accelerating a deccelerating is not romping, its ring seating, even a haynes manual will tell you to do this, I do not under any circumstances suggest staying at high RPM any length of time, the reason I reccomend boost though is that it creates more load on the piston for better sealing immediatley, not to mention, as off road SHO points out is to get the most of the metal shavings(crud) as high as possible in the hopes of ejecting as much as possible out the exhaust ports and like he said to make sure what ridge there is will be as high up the wall as possible so it does not provide an obstacle later when you DO want to rev, with my neon I didnt rev much past 5k or so on the break in, but if given another chance, I would have redlined it once or twice(not for long, but long enough) and my SHO motor I will be breaking in this way

 

[sho_sc]

they dont take the turbo off on an SRT4 to break them in)

cause they are "engineered" to run boosted.

Looks like we all have different opinions; and so does every other major car performance group ... here is what I do; Mr. Brock says it better Brock Break-in Procedures just remember that the "RPM range is higher on the bikes than our SHOs".

 

[SHOMurph]

cause they are "engineered" to run boosted.

Looks like we all have different opinions; and so does every other major car performance group ... here is what I do; Mr. Brock says it better Brock Break-in Procedures just remember that the "RPM range is higher on the bikes than our SHOs".

Last time I bought a new car the owner's manual said to change the oil every 7k miles. Yeahhhhh right!! Dodge probably doesn' want the SRT to last 300k do they?

I agree with Brock....get the motor hot and let it cool many times before romping.

I change the oil every 500 miles for the first 1500 miles....but I'm **** about oil changes.

:hpoop:

 

[wicked93gs]

a "newly built SHO motor" is engineered for boost too...whats your point? and besides...other than low compression pistons and oil squirters the SRT4 motor is exactly the same as the NA PT cruiser motor so its not any more "engineered" for boost than my foot is or any other NA motor, my point though is simply that boost help creates load so break it in under boost(unless your have a $3000 S/C, then its not worth the risk of getting metal shavings in it