Worst day At the Track :(

[asylum]

Eliminate the cause (no more oil @ the pickup point)
1) oil level always at maximum
2) baffle
3) bigger oil pan

Eliminate the consequences (no more oil injected in the motor)

4) accusump

Note that the accusump is your last rescue. It also adds (hot) oil lines, connections and a regulation system to get it running in an auto mode. Not always in par with the wish of simplification in a race car.

 

[skyline23]

This thread got kind of ugly, haha..Anyway, as I said before, I appreciate all the suggestions/feedback/condolences (makes it sound like someone died, which in the grand scheme of things I suppose I should be glad that the only thing that happened to me at the track is a blown engine).

Anyway, not taking any sides or anything, I don't know any of the history between anyone and don't know anyone here personally,but Ross did PM me to offer any help he can give, so thought that was nice.


As I mentioned in a previous post, Shad is picking the car up later in the week, so I should have a diagnosis on the extent of the damage the following week. If people are interested I can report back with what happens and what the next steps will be,who knows, maybe someone can learn from my experience and prevent this from happening to them.

 

[MetalSpikeRacing]

Eliminate the cause (no more oil @ the pickup point)
1) oil level always at maximum
2) baffle
3) bigger oil pan

Eliminate the consequences (no more oil injected in the motor)

4) accusump

Note that the accusump is your last rescue. It also adds (hot) oil lines, connections and a regulation system to get it running in an auto mode. Not always in par with the wish of simplification in a race car.

I am with you in this one 100%, I don't like the idea of those extra lines with hot oil, but those could be taken care of with braided lines.

On the other side how reliable is the switch/system that triggers it? You know my theory...MLMA lol.

A bigger oil pan should take care of bussisnes, shouldnt it?
Also if the oil pick up is the problem, wouldnt a longer pick up line solve the problem?

I am always checking my oil level and keep it at max(paranoia) .
Rob bafled the pan for me, I was thinking on getting a accusump but maybe a bigger pan would just do.

The idea of a blown engine is always in the back of our heads when tracking our car, and at around 6000 a pop....I should of just stick with soccer.

-MSR

 

[stuntman]

I would highly recommend a good baffle for anyone who seriously tracks their cars. Most people who just enjoy a track day probably won't have to worry any more than they would on a canyon run but it's cheap insurance.

Accusumps are more work but if you don't even change your own oil (or have a race shop do it for you) I probably wouldn't suggest one. They are good for a few more seconds of safety over a baffled pan (which better targets the problem) but in a long duration corner, they will only delay the inevitable if their is a fundamental problem.

 

[Coz]

X1

Eliminate the cause (no more oil @ the pickup point)
1) oil level always at maximum
2) baffle
3) bigger oil pan

Eliminate the consequences (no more oil injected in the motor)

4) accusump

 

[Honcho]

Can part of this issue be slow oil drain-back from the heads? As I understand it, under periods of sustained VTEC (especially on the early cars), the heads tend to fill with oil. Based on some searching on Prime, DAL and other early Prime trackers (circa 2001-2003) hypothesized that inadequate crankcase ventilation may be the culprit. Basically, they surmized that oil was being trapped in the heads and unable to drain back down to the pan due to too much crankcase pressure. By holding all the oil in the head, it's essentially creating a low-oil situation in the pan, which could lead to a starvation event. In the 9 years since this post, has anyone figured out (1) if this is a real problem and (2) a way to get the oil to freely drain back down into the pan under sustained VTEC?

http://www.nsxprime.com/forums/showthread.php?t=65872&highlight=vapor+valve+cover

 

[rossii]

Just curious as to why this would even be an issue on the NSX? I mean the car was designed to be taken on the track and based on the OP's post it doesnt seem he was taking corners at high enough speeds. Can someone explain this to me?

 

[stuntman]

Just curious as to why this would even be an issue on the NSX? I mean the car was designed to be taken on the track and based on the OP's post it doesnt seem he was taking corners at high enough speeds. Can someone explain this to me?

The car was designed in the late 80's with tiny 205/225 tires which cannot generate anywhere near the modern 215-235 front 245-275 rear street and R-compound tires. The oil pan design is also not very good with zero baffling from the factory.

For the OP there's likely some other contributing factor like low oil level or something else. Failures do happen. I had a crank SNAP in HALF on a bone-stock NA application (my street car).

 

[Ponyboy]

Just curious as to why this would even be an issue on the NSX? I mean the car was designed to be taken on the track and based on the OP's post it doesnt seem he was taking corners at high enough speeds. Can someone explain this to me?

It's a mechanical object. Stuff breaks even on well designed vehicles. I can't begin to count how many turbo 911s/944s I've seen blow turbos/engines on track and, IMHO, those are just about the epitomy of a good track cars.

I can't help but wonder if this would be a non-issue if Honda employed a dry-sump system (fat chance) or if they designed some kind of oil pan baffle. Maybe Honda thought that if Senna or their extensive Nurburgring testing didn't bring out a mechanical break, then they were home free?

 

[Honcho]

Billy is right. This is directly from the 1990 Honda literature:

"The NSX can maintain a sustained 0.8 g lateral load and can spike up to 1.2 g without oil starvation."

Therefore, if you mod your NSX where you are going above these numbers, you are going beyond the design spec of the oil system. The AO22 Yokos were sticky tires, but that was 20 years ago. Even todays mid-level sport tires outperform them in terms of grip, due to advances in tire technology. Tires like the RE-11, AD08, Star Spec, etc. push it way out there. Combine that with wider tires and you get sustained cornering loads well over 0.8 g.

This tells me first that a pan baffle is pretty much mandatory for any modded NSX that is tracked. Second, it tells me that perhaps the extra g's are interfering with oil drainback from the heads under VTEC, as suggested in my linked post from 2002. In any event, I think this is a very serious issue and I am surprised that it has not been more comprehensively addressed in the past 9 years. Since a lot of the old track guys who started those threads are long gone, I would love to hear what Shad, LarryB, SOS, etc think about it.

 

[Ponyboy]

I mean the car was designed to be taken on the track and based on the OP's post it doesnt seem he was taking corners at high enough speeds. Can someone explain this to me?

What's the typical max g loading on the Corkscrew?

 

[EdinKali]

For the OP there's likely some other contributing factor like low oil level or something else. Failures do happen. I had a crank SNAP in HALF on a bone-stock NA application (my street car).

Yeah, the OP stated that his oil level was not at the full mark. I have always run my oil level a little past the full mark for competition/track events and Shad said he does the same.

 

[CL65 Captain]

yes, but you have to be careful that you don't run it too full otherwise you will end up with the oil foaming due to the crank "whipping" it up.

 

[Honcho]

I would characterize the corkscrew as a "spike" and since it is fairly low speed, the g's probably aren't that high.

 

[e.pie]

Billy is right. This is directly from the 1990 Honda literature:

"The NSX can maintain a sustained 0.8 g lateral load and can spike up to 1.2 g without oil starvation."

Therefore, if you mod your NSX where you are going above these numbers, you are going beyond the design spec of the oil system. The AO22 Yokos were sticky tires, but that was 20 years ago. Even todays mid-level sport tires outperform them in terms of grip, due to advances in tire technology. Tires like the RE-11, AD08, Star Spec, etc. push it way out there. Combine that with wider tires and you get sustained cornering loads well over 0.8 g.

This tells me first that a pan baffle is pretty much mandatory for any modded NSX that is tracked. Second, it tells me that perhaps the extra g's are interfering with oil drainback from the heads under VTEC, as suggested in my linked post from 2002. In any event, I think this is a very serious issue and I am surprised that it has not been more comprehensively addressed in the past 9 years. Since a lot of the old track guys who started those threads are long gone, I would love to hear what Shad, LarryB, SOS, etc think about it.

I am pulling well over 1g on Kumho XS and spiking around 1.25, No issues but I've got an STMPO baffle and 3qt accusump though, better safe than sorry.

 

[skyline23]

I have been wondering the same thing. Does anyone have any explanation as to why The NSX didn't have a Dry Sump system to begin with? From my understanding Dry Sump systems are typically more complex and expensive, but as we all know, minimizing cost was not really a goal for Honda when developing this car.

Just curious as to why this would even be an issue on the NSX? I mean the car was designed to be taken on the track and based on the OP's post it doesnt seem he was taking corners at high enough speeds. Can someone explain this to me?

 

[stuntman]

What's the typical max g loading on the Corkscrew?

The corkscrew is more of a brief spike. It also has a lot of vertical load. Long duration flat sweeping right-hand corners is more of an issue.

yes, but you have to be careful that you don't run it too full otherwise you will end up with the oil foaming due to the crank "whipping" it up.

You haveto submerge the oil galley and start to submerge the main caps before you get to that issue. Since the 'max' line on the dipstick is not near this height, I don't think another quart or so is a big issue. You'd probably have to add a lot of oil for the crank to touch it.

I have been wondering the same thing. Does anyone have any explanation as to why The NSX didn't have a Dry Sump system to begin with? From my understanding Dry Sump systems are typically more complex and expensive, but as we all know, minimizing cost was not really a goal for Honda when developing this car.

It was designed in the late 80s and its a street car, not a racecar. Everything is a compromise and a dry sump was probably not worth the substantial increase in cost for an issue that would probably not occur atall with the tire size, technology, grip, and G levels at the time.

0.02

 

[Ponyboy]

I have been wondering the same thing. Does anyone have any explanation as to why The NSX didn't have a Dry Sump system to begin with? From my understanding Dry Sump systems are typically more complex and expensive, but as we all know, minimizing cost was not really a goal for Honda when developing this car.

Increasing displacement from 2.7 to 3 liters was done at the last minute and at great engineering expense. Since both engines were Legend derived, Honda never having dry-sumped previously in a road car, and the added expense of designing a system, I'm sure it was deemed too costly an add-on if it was even thought of at all.

I think it'd be a great question for Ueharasan at this year's NSXPO.