Slowcrash_101

On a hot day sitting in traffic oil can get up to 230-240, depending on the oil, an oil that is 10cst aka 30 weight at 212 can go down to a 10 weight at higher temps since viscosity doesn't track linearly with temperature.

12 psi is an average, it's usually around 10, but can be as high as 15 depending on mileage, condition of the oil squirters, and a host of other things associated with oil pressure. Oil pressure is probably fine to engage VTEC at 3500, but that's not likely why the OP's engine blew. Cracked top lands are characteristic LSPI.

Chuck S

As long as we're posting worthless opinions I'm convinced the reason for the 6000rpm VTEC engagement in the S2000 is to create an illusion of power (VTEC YO!) as there is a big area between the power curves of the high and low power cams at 6000. Engine changes cams: BAM! An instant additional 50 horsepower! VTEC YO! At 3600rpm VTEC the power curves are pretty much touching although the VTEC power rolls on rapidly after that point on WOT gaining a lot of mid range power. The power gain is between 3600 and 6000rpm. My Gerby tuned engine has 3600 VTEC engagement -- transformed the car.

-- Chuck

Car Analogy

Your Gernby tuned engine doesn't have a stock cat. The two choices Honda had were vtec yo with vtec@6k, or power dip if they tried to set it much lower.

Even if they thought vtec yo was a benefit, they didn't really have any other choice.

engifineer

I think more of the reason lies in the actual intent of VTEC. VTEC allows higher performance at high rpm and better economy at low RPM. Making the car a bit more efficient when you are not beating on it. Easy to keep the car below 6k if you really want to and this gives the best of both worlds. Shifting at 3600 to stay out of VTEC would make the car a tad harder to drive in the "Economy" mode. Most of us drive the piss out of the car and thus are less concerned with that, and the improvement in low end pull and some high end power of tuning for a lower engagement is beneficial from a pure performance standpoint.

I have a Karcepts tune on my AP1. Buddy had a Gernby. His engagement was lower (mine is 4k). I had about 5 more HP at peak with similar tq curves on the dyno. I really do not think that on a non boosted car, an engagement below about 4k is doing a lot in terms of performance. However, this was a test of one dyno pull between two cars so sample size is very small here. Actually driving the two cars on an autox course back to back, we both felt there were very very similar and the differences were really not noticeable between the cars. We had almost identical setups otherwise and I was able to put the same times down in each car as was he.

Both of us though did have Berk cats (mine is 63mm as is his if I recall correctly). He had a different exhaust from the cat back, I run the stock exhaust from the cat back. Both had a PLM header. I think he had the K&N intake on and mine was stock at the time. I do have a K&N now but honestly, it just frees up room in the engine bay and makes nice noises lol.

Car Analogy

But vtec doesn't engage unless wot or close to it. If you are driving in economy mode, you aren't flooring it. If you are trying to be in economy, but suddenly need to floor it, danger, etc, you are probably ok with briefly tossing all economy aside. Because death.

Regardless if vtec is 4k or 6k, its still not happening unless you floor it. So you can still rev to 6k and beyond, and never engage vtec, despite vtec at 4k or 6k, if you aren't flooring it.

Admittedly, going past 4k just driving around way more plausible than going past 6k without flooring it. Still happens, just less common.

I think any concessions Honda made to balance of economy vs performance are entirely encapsulated in vtec only if you floor it. Actual vtec rpm wouldn't need to be part of that equation.

Chuck S

Not sure the lower floor for VTEC activation but WOT is not required. It's not going on the high power cam, though, just cruising at the speed limit but is there under my right foot at highway cruise speeds. I suspect the ECU can be programmed for this. Pedal position, rpm, load.

-- Chuck

FastUnicorn

My top lands were not cracked, the top rings were cracked. And there is erosion on the intake side of every piston. I did numerous logs in normal driving dialing in part-throttle fueling and never picked up any knock. Like, 6+ 30-minute datalogs trying to hit as many cells as possible. I did somewhere north of 70 WOT runs, generally starting from 2k RPM, and I never detected knock. This all leads me to believe that something changed that caused my issue. I did a good bit of research to brush up on LSPI, and it appears to be much more associated with small, direct injection, turbocharged motors making boost at low RPM. I really couldn't find any discussion of it happening in NA motors or port injected motors, and as mentioned, my car makes VERY little boost down low, where LSPI typically occurs. 3 PSI @ 4000 RPM. It also occurs randomly throughout the combustion chamber, and all of my damage was limited to the intake side of every piston.

I realize that *I* was the one asking for help here, and just disagreeing with everyone that tries to help is not very productive, but I have serious doubts about this destruction being caused by LSPI.

It looks like I don't need to say any more on the VTEC changeover, 3500 RPM is fine.

Additionally, this weekend I attended Gridlife Midwest Festival and showed my pistons to a number of people that are a good deal smarter than me. Several of them remarked that the failed catalytic converter could have been the cause of the damage, primarily by causing a lot of heat buildup in the cylinders by restricting exhaust flow. I am going to reach out to the local expert Honda tuner to ask about a consult - have him look over my logs, my tune, and the pistons just to get his opinion on what happened. I am so afraid of blowing this new motor, I am scared to drive the car with any aggression at all, and that is just a waste.

noodels

Agree as your post 4 referred to HFC failure issue.There a few topics regarding HFC failures with FI.The TP is needed for FI applications .