djtimodj

Picking my car up tomorrow to break the motor in. The tuner has given me a base break in map of 0.35 bar (5psi) boost and a rev limit of 4750 RPM.

The AFR he said is around 14 while the car is cruising and in vacuum. The AFR then drops down to 12 as boost come in (4750rpm is around peak torque to).

The timing is conservative as well 16 degrees dropping to 9-10 degrees.

To me the AFR seams a little lean? He said for my final tune he will target 11.8 -12 afr at red line, I asked why not a little richer say target 11.5-11.8 afr but he said that there is no need for extra fuel and the car does not need the fuel to absorb much heat at the final boost level of around 1 bar?

You guys who no a bit more about tuning think this sound's ok??

I really would like the car a bit richer but don't want to be a dick telling my mapper how to do his job! He has 20 years of tuning skylines and now a few years of doing VQ motors too.

Any help would be great.

Vas_Z33

iTrader: (39)

a lot of people say 10.9-11.1 is great , however from my POV i think its not thattt great,.. yes safe, but it ****s up your cylinder walls for being too rich. I think around 11.8 would be best.

ttg35fort

iTrader: (2)

I did some research on this a while back. Washing of the cylindar walls generally becomes an issue of concern when the AFR drops below about 9 or so.

That said, for 5 psi of boost I think the AFR selected by the tuner should be fine for the break in period. (I'm assuming it is a low compression motor since it was built for FI).

Now, if after your break-in period you are going to be shooting for some very high torque number, like close to 600 ft-lb, 11.8-12 might be a little on the lean side. But that, of course, would take more than 1 bar of boost. It's when you are really pushing the motor at high boost that you may want a little lower AFR. The added fuel in the air/fuel mixture helps cool the air/fuel mixture a bit to help stave off detonation.

On my last build, we dropped the AFR to below 11 at peak torque, which was around 600 ft-lb in the low 4k rpm range. We pulled the AFR back up a bit for the higher rpm ranges as the torque dropped down. Up close to red line we were probably somewhere around 11.5 or so and got just north of 600 whp. We were at around 17.5 psi of boost. My motor had a 8.8:1 compression ratio and we were running 93 octane. I'll see if I have a chart with the torque/hp and AFR.

In sum, OP, trust your tuner. If you have some reason to doubt him, then you might look for another tuner. Based on the information that you have provided, IMO, it seems that he knows what he is talking about.

EDIT: I do not have a chart showing my AFR vs boost/rpm.

One note, when we were tuning the motor, Roger (Japtrix) had headphones plugged into my knock amp and was listening for signs of detonation. We had moderate temperatures that evening, maybe low 70s. He did add a bit more fuel to provide a margin of safety. A little extra fuel won't hurt unless you get so rich that you start washing the cylinders.

One other note, I have a Cosworth intake plenum, so I was getting a little more air flow than a stock plenum. This is a mere guess on my part, but I would speculate that 17.5 psi of boost with the Cosworth is probably equivalent to 18.5 of boost with a stock plenum/plenum spacer.

rcdash

iTrader: (18)

I concur. I don't see anything alarming in what you posted. You could always break in the motor at a lower PSI - like 1 - if you have any concern about knock at peak torque! NA engines (0 psi WOT) are tuned to 12.6 to 13 at peak torque to redline, stock compression.

djtimodj

Thanks for the quick replys. Makes me feel a little better that the AFR's dont sound too lean for the break in. Bore wash is somthink i want to avoid at all cost really. When i go back for my full tune i really am aiming for 500whp and 500lb/ft so a target AFR of 11.5 to 11.8 is where id like to see it. Does that sound like the right move?

thom000001

My break in was on a max of 9psi (wastegate pressure) although i never pushed it to see 9psi early, and max of 11-12 degrees timing, A/F was in the mid 11's (as per the gauge)........

short break in for mine too, like 250miles.....motor turned something like 500miles when it made the 769rwhp

Tom

ttg35fort

iTrader: (2)

I think the above should be fine for that level of torque/hp, again assuming that you have a low compression motor and use high octane gas. I would probably aim toward the lower side of your target AFR at peak torque. Just make sure there is no knocking and that you have some safety margin built in. Running a little rich you will lose a bit of HP, but it won't hurt the motor. It just makes things run a little cooler, which is good. Like I said, at peak torque my AFR was below 11 (somewhere between 10.5 and 10.8, but I don't remember exactly). But I was pushing the motor to the edge and really reaching the limits of 93 octane. At 500 ft-lb and hp, I would be comfortable with 11.5 AFR at peak torque and slowly rising to 11.8 or so at peak rpm, with the appropriate timing.

It would not be a bad idea to use a suitable knock detector. I don't know what EMS you are running, but I have an HKS F-CON V Pro and use an HKS knock amplifier. It works with the EMS to pull back the timing if knock is detected. Getting bad gas is a rare occurance, but it still does happen from time to time.

midz350

iTrader: (4)

I thought you shouldn't get into boost while breaking in the engine!!!

Jay'Z

iTrader: (118)

ttg35fort

iTrader: (2)

I researched this subject like crazy before round 1 of my build. There are a lot of different opinions as to the proper breakin procedure. That is one of them. Others say you can run low boost during break in, while others say drive it like you stole it.

I found only one thread (in a motorcycle forum I think, but I'm going back nearly two years) that actually backed up their recommendation with an actual tear down and inspection some time after the breakin period. If I remember correctly, it was a turbocharged motorcyle engine and they broke the motor in on the dyno, getting to high power fairly early on. When they later broke down the motor and inspected it, their conclusion was that the rings seated well and everything was in great shape.

I'm not suggesting that a motorcycle motor is the same as a VQ, but it was the only recommended breakin procedure that I found which was backed up by an actual teardown and inspection of the motor. Perhaps since then someone has done the same for a turbocharged aluminum block car motor, I don't know.

JetPilot had Japtrix breakin his motor on the dyno. I think he had them following a recommended breakin procedure that he found somewhere. Perhaps he can chime in and point us to where he found that particular procedure.

midz350

iTrader: (4)

I'm waiting for my built short block to arrive really soon and was wondering about that

ttg35fort

iTrader: (2)

Here is the break-in procedure recommended by Cobb Tuning:

http://www.cobbtuning.com/info/?ID=3475

In short, they recommend no more than 1-2 psi of boost and 3500 rpm for the first 100 miles. They recommend no more than 3-5 psi of boost and 4500 rpm for 100-500 miles. Then they recommend no more than 6-8 psi of boost and 5000 rpm for 500 - 1000 miles.

Throughout the break-in period, they recommend varying the engine rpms, and provide a lot of other good pointers.

I PM'd JetPilot for a link to the break-in procedure that he used. When I get it, I'll post it.

r0mey

iTrader: (35)

On my first motor I drove it for about 1500-2k miles under light boost 5psi fuel cut. My rings were perfect. This is what most of the cars did that came out of "mrc" and there were no break-in issues

ttg35fort

iTrader: (2)

One more note...

I originally leased my G35. Since I was planning on turning it back in at the end of the lease, I did not bother with any easy type of break-in. I was hammering the motor very hard, taking it to red line at full throttle multiple times the first day.

When I sent the motor to IPP in lieu of incurring a core charge when I got my first motor, Kyle said everything looked very good. By that time the motor had around 40k mi. Now, that motor was N/A, so my experience with that motor should be taken with a grain of salt.

midz350

iTrader: (4)

Thanks guy's.

ttg35fort

iTrader: (2)

Here is a link that provides a dyno break-in procedure:

http://www.mototuneusa.com/break_in_secrets.htm

I don't think this is the one JetPilot used, but it is just more information to confuse things.

EDIT: This may have been the dyno break-in procedure that I referred to above. They provide a comparison between a motorcycle piston broken-in with their procedure and one broken-in in accordance with the owner's manual instructions. They do not indicate, however, that this was a turbocharged motor, contrary to what I thought I remembered. Like I said, it was nearly two years ago, and I guess my memory is not as good as it used to be.

thom000001

/\/\/\/\
Terry, I am of the opinion that the rings seat pretty quick (weather they seat right or not)...and I do not want to wait 1000miles to find a problem lol..

So we did normal driving with minimal boost for first few hundred miles and did a oil change....check for things in oil and change plugs (inspect plugs as well).....then make some noise!!!!!!

lol.....

You know the ole adige with engine break-ins....as 100 mechanics how to break in a motor and you will get AT LEAST 100 different answers!

Tom

djtimodj

So far guys im 400 miles into my break in now. Car runs well boost's up to 0.38 bar in 5-6th gear on the motorway. Ive not rev'ed it past 4K rpm yet. My break in will be 1k to 1.5K and then a fluid change and some more boost.

Fingers crossed..

ttg35fort

iTrader: (2)

I see that you have an oil change planned at 1k to 1.5k. Have you done any oil changes yet? If not, you may want to do so now, and change the oil filter. Cobb Tuning's break-in procedure actually recommends the first oil and filter change at 50-100 mi. They explain why in the link I posted.

It may be a little over cautious, but I figure it can't hurt.

djtimodj

I asked the tuner about doing a oil and filter change while half way through thebreak in (im using joe gibbs break in oil) they have allways just run the car in with the same oil and then change to good stuff (im using motul 300v 15w50) for the final map. I understand that the oil may contain bits of crap as the motor wears in but the filter should catch it if there were any??