They always say~ " Third times a Charm ". I have to agree with whats already been mentioned. As much as I hate to hear about anyone blowing their engine.... it takes people who "lead the way" for what we are aiming to do with our cars. You can learn a lot from setbacks as well as a people's success. I'm glad some people have the budget to make these mistakes. I myself will probably get one chance and one chance alone to get it right! lol
I will be pateintly saving for my APS install, engine build up and conservative tune that nets 450 whp My goals for my car are FUN and as much reliability and longevity as possible. None of my goals would be conceivable with out peoples experience on this forum ( it would be impossible for me to trust a shop alone w/out my own F.I. knowlege that I happened to gain here ). So thanks Jurgen for your contribution...I'm sure your next will have all to do with success!

 

gurgen:

so sorry..u must be really patient to be able to cope with all this without producing any fatalities...good luck, hope everything goes smooth for you!!

-TODD

 

gurgen....sorry to hear this....do you recall your RPMs(when you realized it was "hitting the fan")....and the temperature at the track that day?

 

gurgen were you running the J&S as well when this happened?
of course if you really ran that lean at 70% timing retard alone prolly wouldn't have saved ya.

 

8...(

Id have gone into denial.

 

Hey Guys.


Wow .... many replies in just about a day... allow me to calrify a few things and respond to your posts...

First of all... YES, the car was not ready to be tracked... and i was not "tracking" it in the conventional sense. I was not able to geta refund for the track event, and thought that I would go out there andjsutdrive at partial throttle ata low boost setting (which unfortunately is 8.5 ps or so). I was just limping around the track just to get a sense of how my car handled, that's all. My mistake was to to think that pulling 14 or so degrees with the J&S and riding at partial throttle would not damage anything. 95% of the time I was under 30-40% throttle. Everything (A/F, RPM, Throttle position sensor, Inj. duty cycle, MAF voltage, and intake air temp) was being logged, so I know exactly what happened: 16:1 A/F spike at ~71% throttle. So, that caused the car to smoke and, upon later analysis, a whole on the side of the #3 piston... everything else is intact....

As far as what we were doing with the MAF.. allow me to explain. I did not just slap on a bigger MAF and call it a day... I am not stupid. The Nissan Titan has the exact same MAF as the 350z only in a bigger housing... So, in fact I will be using a nissan titan Maf next...

This time around, I used my stock g35 maf and we fabricated a 3.96" ID (instead of my ~2.7" ID => 2x the corss sectional area) maf housing but kept it very short to not cut the PE pre-TB intake pipe (as an initial trial). We did not have a pre-maf transition or a mesh of any kind. This caused the voltage to have a lot more noise than before (at idle as well as under load), but DID still succeed in lowering the voltage of a full-load run to around 4.6 (insteadof the peaking 4.8-4.9). At first, we started out with a stock fuel table and the car ran VERY lean (14-15:1). We then richened up the table and got a good a/f (mid-11's). Several hours later (the next morning), the A/F started to do some peculiar things, like going to high 18's at idle. Giving it a touch of throttle, brought the A/f to a stable 14.7. 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 rocky idle, as well as my eventual demise. At this point, we were, and ARE, planning on extending the MAF housing (with a mesh) 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, more research is needed 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...

This will be a temporary solution at worst (and I WILL be running at low boost) until we find a good engine management route (if this does not work out).

Zero2prove...
As described above, I am well aware of the consequences of a bigger maf housing. Obviouosly we were going to compensate the maps for it in the ECu. Also, it is increasing the range of hte MAF that we are concerned with perhaps at the expense of resolution. This is ok, as almost all high-boost cars out there run on a 16x16 fuel map... so the resolution is ultimately limited by the map of your ecu...unless of course you use the F-cn with it's 32x32 map... Either way..the loss of resolution is not detrimental..

George....
Thanks for the offers. I talked with Roshawn (sorry, I know I am misspelling his name) at Brainstorm, and he said that he won't be able to tune the car because it is an automatic... I thought that I will do this for the time being until i get a chance to visit with Peter stateside and have him set up my car....

Going deep...
Thanks... As far as the pistons go..I will be going with Arias and with a stock piston size this time (as I will boring out brand new sleeves....)

Jow, damen, accordfreak, et al...
Thanks for the words of encouragement... I have always been very careful... while I can never have the expertise that Peter does, I was trying to have low yet respectable boost levels run reliably until a more permanent EM solution came along.... It was certainly bad luck, but also one that would not have been a factor were it not for the rookie mistake that i made....

Calimarc...
Thanks... glad i could help But belive you me... I do NOT have the budget ot make these mistakes....

Charles...
The MAF was in the stock location... I abandoned that 'single charge tube' MAF idea pretty quickly since our discussion....

G3pro...
With a 16:1 A/F.... no J&S can help you... I was however using it, yes, and was running very conservative timing (1.2-1.3 degrees retarded per psi + 2-4 degrees rpm-based retard).

Everyone else.... Iw ill keep you posted...

Thanks
Gurgen

 

Gurgen , when you go back to ARIAS fro your new 9.3s , you may want to inquire about the custom dish they are doing for me @ 9.0. The custom dish basically reduces the squish volume and leaves most of the OEM quench pad intact, simialr to the Z1 design. Basically a superior shape for street/strip use on pump gas. They'll do this special dish at no extra charge beyond the simpler "typical" custom shape.

 

gurgen:
can you give us a little more history here:
1) how long had u been driving your newly rebuild engine?...what was the break in like? (ex: how many times did you change the oil, etc?)

2) is there some difference in an 03 g35 as compared to a 03/04 350z that would force u to "take it easy" on a build forged motor?

3) what type of engine management will you be using...does the PE not accomplish what you need? is this another part of the reason for the issues at 70% throttle?

4) what as the tune like? or did you not have it tuned yet? am i missing something?

THANKS for sharing your story...sorry again for the frustration you must be experiencing!
-TODD

 

G3Pro..
I'll ask about that... thanks for the info..

Todd... allow me to clarify a few things.
PE does NOT come with any sort of engine management... you will need to add your own in form of a TS reflash or piggyback/standalone...

1) I did a normal break in for about 700 miles before we started tuning and had about 8xx by the time Iwent to the track. I essentially started with low rpm drives, gradually working into the higher rpm territory and higher loads...

2) no difference....

3) FOr now...I am using TS reflashes for engine managemnt. It is a great challenge, however, to try to fit a larger MAF housing, as it changes the voltage and upsets the A/F balance.. therefore, the fuel tables need to corrected,,

4) YEs, essentially what I was describing in my last long post is the step-by-step tuning process... The map that we used was not a correct one....

 

I actually saw that piston prototype first-hand during my visit to Arias.

Most pistons manufacturers will tell you that squish area concerns are more the area of N/A cars. Once you move to high performance F.I applications, the benifits of that piston design are debatable. You will make more power with the more typical dished design. But true, Arias doesnt charge anything more for that type of piston...just the $110 custom fee that you would pay for customer compression anyways.

 

Ahh, I think I understand now. So with FI, and a domed piston, one might be able to get more power by running one more degree of timming then having a more effiecent compression?

 

at very very serious power levels, maybe...not at the levels most people, even with very powerfuly Z's, would ever see a difference - the biggest single varibale in how much power these cars will be capable of will be engine management

 

thanks gurgen..that definately clears things up...i was a bit confused there

again, good luck with the motor!

 

WRT squish and quench pad on Turbo cars, Audi for example use the technique on all their emissions compliant ,pump gas engines,
Result is reduced emissions and improved detonation tolerance. Audi was the first manufacturer to obtain ULEV status on a Turbo car the 1.8T. Baic gist is that similar knock tolerance can be had with more timing advance and a leaner mixture under boost.

 

Domed and FI = bad, dished and FI = good. Domed piston crowns are useful for high CR NA apps on race gas.
A domed shape would be counter productive in minimization oif detonation on lower octane pump gas.

It is just that slight mods to the dish geometry can yield better knock tolerance on "both" NA and non NA applications. However; as the static CR is reduced the tweaking becomes "less" of a benfit , but the benfit has been shown to be beneficial by OEMs running FI with Static CRs >9:1.

 

Interesting news since I sent Beeri one of our custom designed pistons about a week after SEMA because he said he could reduce the weight. Its been nearly two months and Beeri has not contacted me about the results of his efforts or even bothered to return the one I sent him, but he is apparently selling the design that we provided him.

Maybe it has something to do with the fact that Z1 went public with the clearance issue so that fewer people would have problems with the Arias pistons. Of course I e-mailed Beeri first and he responded saying he would call me ... but he never did.

 

Dang, I was way off. Thanx for spelling it out for me!

 

ARAIS isn't selling your design as far as I know, I personally made specific requests for a 9:1 personal build. I did find some of the characteristics of your your dish design to be attractive as well as some specific inputs from my shop.
I for one did really appreciate your shareing the skirt clearance issue you saved a bunch of us major head-aches. Thanx.

 

G3po,

I appreciate your comments, I just find it awefully coincidental considering the circumstances. Ours was not a proprietary design and we held no patents on it, I just wish Arias handled it differently.

Best of luck with your motor and your car, it will be nice to see some high horsepower Z's out there!

 

He is not selling the piston...it was a protype that he made at the request of a customer...one of the guys in my GB wanted that design.

Lorca, why do you never pass on the opporunity to bash Arias?

First of all, I wouldnt exactly say that you went public with the clearance issue. I talked to Berry the very first day we heard about one of YOUR engines being damaged by the piston design. You didnt "uncover" the issue until one your customer's engines was damaged after they installed and started it up! You just beat me to the punch on posting the outcome. And to imply that me or Arias would keep the clearance issue private is absolutely proposterous

Second,it is interesting to note that your company failed to take ANY responsibility for the damaged motor, even though a good competent machine shop would have caught the tight clearance issue. You essentially told the customer to f'off...after spending a couple thousand or whatever on the rebuild labor. Not to mention there were other errors in your engine assembly process...such as balancing the pistons by drilling the center of the piston...vs. the meaty sides of the piston. And the tops of your customers pistons were gauged and essentially looked they they were dropped or damaged. I saw pics of the pistons after you put them in the block....guess you figured nobody would open up the motor again to see your sloppy work???

Third, Arias has stood 100% stood behind their error, and corrected everyone's pistons for no charge (even covered shipping both ways) and even offered compensation to one person for their added incured expense.

I am not going to bring names into this discussion to protect their privacy....but Lorca....give me a break here. Just becuase YOU dont sell Arias pistons, you make disparaging comments about them. That is really immature in my opinion, and a poor business practice. Yes, I sell Arias pistons, but I have NEVER critisized any other pistons manufacurer, or any other vendor of pistons.

Sorry for the flame....but this is how I feel. IMHO, you would be the LAST shop I would ever bring my engine into...which is the main reason I am getting my engine done elsewhere.