GurgenPB

iTrader: (2)

Hey Guys

A lot of the SoCal G35 brethren and my dear 350z friends 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

tig488

iTrader: (18)

hold on,

you blew your engine a whille back right? and had it built...

then, you blew your built engine?!?!

damn dude, slow the fock down!!!

slay2k

lol,

I love you Gurgen, you're my god damn hero!!!!

-slay

Zcool

I'm sorry to hear about your blown engine (again) but very grateful for the research you're doing. You might want to set up a fund to collect donations for your efforts.

Sharif@Forged

iTrader: (92)

we've already talked..so there is nothing more I can say...other than sorry. This stuff sucks. Thanks for sharing and keeping us posted Gurgen...you'll be back soon enough!

zero2prove

"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...."

You'll get less resolution with a bigger Maf housing. Any real tuner would have known that using a larger Maf housing would cause your motor to run way to lean and if timing is still being controlled by your stock ecu than you'll run to much timing as well. Running a larger maf tricks the ecu into thinking its running less load therefore advancing timing quite a bit. On a FI car ( I assume that's what you have) that spells danger. You'll have to install a honey comb screen of some sort in front of the Maf sensor in order to get laminar flow and better resolution.
Sorry to say this but your car should have never left the shop unless for sure it was running right. What type of R&D were you conducting that you couldn't do on a dyno?

Good luck on the next motor.

Sharif@Forged

iTrader: (92)

Hey Zero....go easy on Gurgen. He is obvisouly admitting his error and doesnt need you rubbing it in...sheesh.
We should be thankful that people choose to share their experiences with his...even the negative ones.


I think by resolution, Gurgen was refering to the max volume of air that the MAF can read. If my memory serves me correctly, the stock MAF can only read 33lb/min of air. A larger MAF could read more. TS reflashed his ECU to compensate for the leaness....he didnt just drop it in and go.

If Gurgen can get this working correctly, you will have the ulimate tuning device. Becuase no matter what, hotwire MAF is the BEST way to tune our car..not pressure as some people tend to think.

As long as the MAF can read the full volume of air and the turbo's peak...we'll be golden.

g356gear

iTrader: (12)

That's a pretty bold statement to make about MAF for tuning.....especially with the success of the HKS Fcon V-pro by a few members of this board...but I guess everyone has an opinion

Sharif@Forged

iTrader: (92)

The reason that MAF is better than pressure or speed density, is becuase the MAF factors in ambient temp and humidity as well. Speed density system does not, unless you have a seperate baro sensor.

Dont get me wrong, the HKS FCON is a terrific standalone, and it is still much easier than reflashing. But I am just saying that a quality MAF based system is more accurate than pressure....as long as the MAF can measure the actual volume of air coming through.

Personally, I would still want the standlone, for all the other functionality and control it provides.

georgec

Sorry to hear this gurgen.

Best you speak with your friend from downunder.......and please next time get to a competent dyno shop quickly with a true load base dyno for some serious mapping work, it's much cheaper than breaking a good built engine.

Hope you have a much better year in 05................if you do this again I will fly over and sort this problem for you once and for all.

Good luck mate and email/pm me if you need any help.

Georgec

going deep

Sorry to hear about your second loss. Are you certain that the largrer MAF is what caused you to go lean? Are there any other possibilities you're looking at?

Good luck with the next build. I am in the middle of my build right now after I broke a rod and it put a hole in my block. I actually have an extra set of Ross pistons coming in next week if you're interested. I ended up buying some Arias pistons after I found out there was a delay in my original order with Ross. They're 9:1, with .02 overbore.

joenismo

I am sorry to hear this news at least it seems as though you are in good spirits about it.

damen

sorry to hear of your loses again. good luck with your next build up and thanks for sharing your experiences. someone will learn from it.

accordfreak

iTrader: (15)

wow pretty crazy.. goodluck with your 2nd build!

phunk

iTrader: (21)

i could argue forever on the MAP system vs MAF system... however just keep in mind that some of the best running cars in the world come straight out of the factory with a Speed Density system. GQ: Speed Density cars are not ONLY tuned via MAP vs RPM. There are several correction maps as well, such as the ones you list.

I would prefer MAF over MAP if it was possibly to do it right in the 350z... but its not going to be easy. If you want to do it right then your first step is to take the thing out of the damn charge pipe and put it where it was intended to be.

spazpilot

iTrader: (2)

Damn dude !!!!!!! My heart is just breaking for you gurgenpb01 . I am just glad to see that you have not given up on your goals. Wish you the best on your next build

kjbalto

Like everybody else said, I'm sorry you're going through all these headaches and money. I think a lot of people would've given up by now and put the car back to stock but you're still determined to get the car done right. Good luck on your mission.

t32gzz

iTrader: (1)

Gurgen... I cannot believe your luck. I am sorry to hear about the 2nd loss, but it is guys like you who help everyone else on this board.

Thanks for your continued efforts and shared knowledge on the VQ. I wish you the best of luck and I can see the thread now...

"Back Again & Better Than Ever!"

turbo-maxima

slow down and do things right. You spent all that money to throw it away.

going deep

What a helpful post!!!

Like if he intended things to come out this way.