Hey Guys

A lot of the SoCal G brethren already know this, but this happened at the California Speedway a couple of weeks ago... The car was just not ready for the track after the initial tune, and I should never have taken it out that day. I was not going hard at all.... in fact it happened the very first time the throttle went to ~70%... the mixture went lean (~16:1) and it was all over. Stupid me... What was I thinking even driving an R&D car... The mixture was fine at ~20, 30, 40%, and at 100%, but NOT at 71% !!!!!!! You live... you learn!

Now there is a hole on the side of the piston and its three rings...

My plan: The block was badly damaged and I was already at the .020" over bore size. Hence, there was nothing I could do with that block aside from sleeving it. Well.... let's just wait for "Back With a Vengeance: Part 2". So, I dropped it off at AEBS monday. The custom Arias pistons (9.3:1) will be ready in a couple of weeks as well...

Thanks to the forged internals, the piston melted and not disintegrated and blown everythign else in sight. Everything aside from the pistons stays.. Pouter rods, ARP studs, the block....

Bad luck.... I really sucked the bad luck out of this place... so all you FIers are all clear to go on with your projects... it'll be smooth sailing.

As far as why the mixture went lean.... we placed the MAF sensor into a 3.95" ID housing instead of hte stock plastic 2.57" ID housing, which will afford exactly 2.0x times the area and hopefully more resolution... It seems as though the ECU reacted to this REALLY badly!!! More R&D to come... I don't think this idea is dead, however....

Cheers, pics to come soon.

Gurgen

 

Damn gurgen, hate to hear this. Hope the new engine is ready soon and you're back up and running.

 

That's a bummer, sorry to hear it.

 

Yea man, i was so excited to see everythign finished and working well, and now this? Man im abotu to cry Good luck with it, keep us updated!

 

sorry to hear about that. I was told at JGTC by a friend that a G35 sedan blew the engine the day before and I was praying it wasn't yours. Maybe you should consider gutting the electronics and go with the RB28DETT or VG30DETT transplant.

 

Gurgen--

I just read your post and now have a sick feeling in my stomach.... I'm sorry to hear about it....don't know what else to say.

W

 

Wow, sorry to hear about this lattest event. I noticed your 2.57 ID measurement for the oem MAF housing. I ran out to mine since it's off the car and I get 2.83" as a ID tapering to 2.79" off a dial caliper. And I just knew it was 3" ID, he he.

 

WOW. that's all i can say.chin up man,will get it right.

 

Hey Guys

thanks for all your comments. I had jut a couple of minutes to post yesterday, so allow me to elaborate what the problem was.

This time around, I was logging everything (AFR, RPM, IAT, Injector Duty Cycle, MAF, Throttle position) and that is how I know exactly what happened (failure at 71% throttle). The new tuning approach that we were trying was to place the MAF into a bigger housing .... this turned out to be a much bigger ordeal than we first anticipated. Right after we flashed the ECU (next couple of hours), the A/F was very stable at 12:1 (and lower at lower at different laods) with idle/closed loop A/f at around 14.7. Several hours later (the next morning), the A/F started to do some peculiar things, like going to high 18's at idle. Given that our new MAF housing was only about 4" long, and that the MAF voltage logs had a lot of noise, it was obvious that there was a lot of turbulence in that housing. This, it seems, contributed to the demise. At this point, I am thinking of extending the MAF housing another 4" or so to smooth out the air, and put in a 350z MAF (I ahve the gimped early 5AT G35 MAF that maxes out much earlier, not ot mention why it is only 2.57" ID...) . When/if I get a chance, I will post the screenshot of the A/F log, so you can see for yourself. The ECU was hunting around the entire time for the "right" a/f; this is certainly consistent with turbulence in the housing, or just that the changed MAF characteristic not mating well with the stock ECU maps.... R&D will continue when i get my engine back.... should be a lot sooner this time around...

 

Damn Gurgen, I guess you have the lead.

Gurgen 2

KPierson 1

I guess its time to play some catch up!

Good luck with the next build,
Third times the charm!

 

Hey Guys

Finally got a little time to respond...

Sukarain.... We, fortunately, know exactly what happened this time around. After this engine is sleeved and rebuilt, it will be very capable. The weak links, I reckon, at that point will be the forged pistons, which will be able to take about 20-25psi consistently but not much more than that (high silicon material), and/or the crank, which by several estimates can take 600-800 whp. Some say that the crank is much better than that and will be able to take 1200 hp... I don't personally think so, but hey, Tom is pushiing ~940 chp on an engine dyno with a stock crank...we'll see how long that lasts. Either way, I will be able to get about 550 whp out of my setup (the 1420 turbos and the PE 510 cc injectors), and these will be SAFE 550 hp... So, a transplant just would not make sense for a streetable/sleeper car...

The biggest onstacle at this point is engine management.... I am not giving up on a custom reflash idea just yet... I think it can be a very good solution once we straighten out the MAF situation...

Chicago.... Thanks for your comments.. Unfortunately over the course of redefining the boundaries of Murphy's Law, I have grown quite desensitized to these pitfalls... What the heck are you gonna do... you just have to getthe car fixed and move on to the next step... The only comfort: "it will be great when it is DONE". Because there is no abundance of tuning methods for our cars at higher boost levels (aside from the HKS F-Con), the date of the car's completion is completely undetermined...

 

Kev, this is one leadership list that i certainly did NOT want to top.... I hope things are progressing with your car (the colision repair), so you can move on to building up the beast....

 

Hey Gurgen, I heard from a few of the so cal. G35 members about this and I'm really sorry to hear this. The 350z maf is bigger than the 5AT G35 maf for sure, I think swapping it would be a good idea.

Also there is someone here in Fremont (I think his name is andrew, my friends at Weapon-R know him) working on a chip upgrade for the 350z because the ECU flashes aren't permenant. I can grab his contact info if you'd like.

 

Thanks...

But, whoever told you that the ECU flashes were not permanent was simply wrong.... they ARE.... you replace the firmware and all the maps withing the ecu by reflashing it...

 

ok, I initially thought they were permanent, then someone told me that since the ecu learns it would "overwrite itself" over time, which I thought sounded strange.

Anyway, good luck rebuilding your car (again)... I hope you don't dig too big of a $$$ hole for yourself!