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Discussion Starter #1
Is it ok to be going 3800 rpm in 6th gear at 100 mph before the break in period is done?
mine only has 200 miles so far and i keep the shifts under and at 4k but i was going 100 mph a few times at 4k while in 6th gear
let me know guys :roll: :roll: :roll:
 

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To ensure a good break-in, just make sure you vary the engine speed. Don't use cruise control or maintain steady speeds for prolonged periods of time.
 

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Omori gauges.

Speed is COMPLETELY irrelevant in terms of break in. Engine rpm and stress load is all that matters.

As far as your engine is concerned, going 3800 rpms in 3rd gear at 50 mph (or whatever speed you're going in 3rd @ 3800) is the same as going 100 in 6th gear @ 3800 rpms.

But Thunder is definately correct, you want to vary engine speed a lot. Keeping the same speed for a long time is bad for the break-in process.
 

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STi_Thunder said:
To ensure a good break-in, just make sure you vary the engine speed. Don't use cruise control or maintain steady speeds for prolonged periods of time.
Guys I don't want to make anyone mad or anything, but I have to disagree with that a little bit. Now I know this is the exact advice 100% of engine builders give out and I have to say it's the same technique I have used on my cars in the past, but here's a little something interesting.

I have had 2 friends so far that have broken their cars in on highway milage alone at constant speed. One was making trips here in the US and the other was driving to work and back super fast on the autoban in Germany. Both cars were Hondas (but that shouldn't matter). One was a GSR and the other an Si. With that being said those 2 cars alone where 2 of the fastest cars I have seen run at the track with a perfectly stock motor internally. And I don't mean just slightly faster... Both cars also had very nice acceleration throughout the RPM band as well.

On my next car I will try to mix in city and highway milage during breaking by using a 60 highway 40 city %. See how that does.

Just thought I'd share.
 

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JRSCCivic98, while the two cars you mentioned sound unharmed and perhaps positively affected, I'd stick with the engine builders and owners manual. I suspect their advice is built around scientific data that will hold up in the long run. I wouldn't want my STi to be the one to experiment on.
 

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JRSCCivic98 said:
I have had 2 friends so far that have broken their cars in on highway milage alone at constant speed. One was making trips here in the US and the other was driving to work and back super fast on the autoban in Germany. Both cars were Hondas (but that shouldn't matter). One was a GSR and the other an Si. With that being said those 2 cars alone where 2 of the fastest cars I have seen run at the track with a perfectly stock motor internally. And I don't mean just slightly faster... Both cars also had very nice acceleration throughout the RPM band as well.
I'd better follow the manufacturer's spec for break-in as well. Hondas are built different than Subarus. Either way, I'd still say that Honda will, in their manufacturer's manual, recommend varying the engine speed anyway...
 

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FS: 1995 Impreza LX

Well, you'll be varying the engine speed no matter what you do. Just because you drive on the highway or constant stop and go traffic you're still varying the RPM to a degree. After all you have to drive in the city to get to the highway. Besides, do you honestly think that those people that picked up their STis out of town drove them hundreds of miles back home constantly varying speed on the highway. (That would look kind of funny btw... hehe) In all actuallity the only way you'd do a poor job of seating the rings in an engine was if you flogged the hell out of the engine while it was cold and fairly low milage. Besides, boost is your enemy (somewhat... NA -> FI cars more then factory FI cars) when breaking in your engine. Since stop and go will cause boost to come into play I'd rather be on the highway where there isn't any being built up. You guys also have to remember that rings in an engine will seat withint the first few hours of engine usage. And besides ring seating you're really not doing anything else to the engine. Parts are build to such high tollarances today that you will find almost no machining metal specks in your first oil filter or oil. All we're actually doing in the breaking period is really more of a stress testing process anyway. You're just safely heat cycling the engine just like you would new breaks.

All in all, please don't think I'm telling you to do things differently. I'm just letting you know that engine break-in procedure per manufacturer is not always GOD's word.

BTW, have you ever watched the guys at the dock pull the cars off the boat and onto trucks for delivery. Total vialation of the break-in procedure. :roll:
 

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Break in periods are important and have been proven for mamy years now on various engine. The changing of rpms i more fro the cam than it is for the rings. I have ot do with inertial and rotaing forces cause by teh cams rotaion. hard to explain unless you all want a long drawn out explanation. But change the rpms, don't use the cruise control for more than 30 or so miles. And try to be nice to it.After about 1k miles or so... go have fun
 
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