There have been quite a few instances of broken rods in VQ35 engines that have FI. It seems to happen more often in TT installations than SC. It also appears to affect cylinder #5 or #6 more than the other cylinders (some have suggested the plenum may be a factor here), and usually at pressures > 8psi.

However, there have been instances of failure where the pressure is down around 6psi and where the AF has not appeared to be too lean.

The nizpro TT setup posted a few months ago came in at c.$40,000 with modified internals.

Peter, how much extra would the APS TT kit cost with stronger rods/bolts/pistons (perhaps with compression dropped to maybe 9.5:1 - a figure I think you nominated in another thread).

Cheers,

Neil

 

You beat me to it Provo.

I was going to ask the same question. It may appear that the talk about the rods and pistons not being able to handle FI may be correct.

What I find quite humorous is that some of the people with blown motors are still disputing about whether the damage is covered by warranty and that the onus is on Nissan to prove that FI did not cause the damage.

My view is that once you undertake such modifications you should be prepared to accept the consequences.

I am still a possible candidate if APS do release a robust TT system, however the Unichip option along with my current mods may now be a relatively safe option.

Peter, if you do read this post, can you please comment as to whether the Unichip upgrade is based around 98RON petrol and tuned to any existing mods on the car. Do you also have a good tuner in Perth?

 

G'day Neil, Yes the con rod/piston failure problem may well be cuased by running the engine too lean on air fuel ratios...........this can/will cause detonation and hammer the big end bearings on the particular cylinders which are too lean.

I don't believe that any of the after market companies selling FI in the states (this includes all of the supercharger people) have addressed the fuel system adequately for FI applications.

You see most FI systems are generally built to a user friendly price tag not engineered to the highest level which FI demands. If you view the APS TT system fuel componenets you will see that APS has gone to great lengths to provide a complete fuel system and this is cricital in forced induction applications...........as a lean condition can cause serious damage to pistions, valves and big end bearings (hence in some cases con rod failure).

The other important factore to understand is the fuel quality in the US........the fuel ranges from 91 octane on the west coast to 94 octane on the east coast...........now unless the engine is thoroughly tuned for the lower fuel octane you are going to see many problems on the west coast of the US........unfortunatly there is not much depth in the US in engine management tuning due to a shortage of true load based dynos..........you can't tune or map fuel injection on a typical US made dyno jet dyno..... as these dynos are inertia based and can't hold engine load.

Now this said I don't believe that lower comp pistons and stronger con rods are required for FI on the Z engine if the fuel system is designed correctly, the engine utilises high octane premium unleaded fuel, the engine management is tuned correctly, and the turbo pressure is kept to a sensible level, say no more than say 7 to 8 psi turbo pressure.

Now to answer your question on a piston and con rod upgrade this obiviously depends on the quality of con rod and piston utilised..........most car owners would not pay for the quality of piston and con rods that APS utilises in big engine upgrades,though for those who would I would estimate an additional 12K for the engine build, blueprint and balance including quality pistons and con rods.

Peter

APS

 

G'day Malcolm................the Unichip can be mapped/tuned to suit all fuel octanes though the best power will be achieved on 98 RON fuel.

In Perth the best premium unleaded is the BP ultimate (though I much prefer Mobil 98 synergy for the eastern states).

APS has not yet released the Unichip to suit the Z engine.........we are still testing a number of Z cars to ensure the Unichip computer is 100% compatible for the Z's stock ECU........I can say to date that all of the road and dyno testing has been very positive.

Will let you guys know when the computer is released.

Thanks

Peter

 

Peter, why Mobil synergy over BP Ultimate?

 

I'll take a guess and say it's because of the mixing of fuels and the additives they use?

As always

H

 

We have conducted a lot of testing lately on the different fuels over the last 12 months and we have found that the power is more consistent on the Mobil syneregy 98 RON Fuel.

Now the Mobil syneregy is only refined In Victoria and is only sold in Vivtoria, NSW, and some parts of south Aust.

Shell Optimax is only refined in NSW and is only sold in STH QLD, NSW and Victoria.

BP Ultimate is refined in WA and QLD and the BP Ultimate is definitely the best fuel in Perth (I know this as we spent a number of days in perth testing different premium fuels).

So if you're in parts of the Australia where the 98 syneregy is sold in my view this is the most consistent 98 RON fuel.

If you want to discuss this in more detail please take this to pm's and I don't want to risk my neck in a public forum, never know who is reading this info.

Hope this helps.

Peter

 

mobil for my car ONLY, even though there aren't many around compare to others.... Even those boys at my dealer told me so too..... never try out BP though, so cannot really say anything about it...

cheers,

richie

 

BP has spent far more than anyone else on modern clean fuels technology, and the BP Ultimate is the cleanest fuel you can buy. Don't know why you would stick with Mobil - they are yet to do anything about new clean fuels production.

BP Ultimate

 

Well only because we have spent a heap of time testing different brands of premium unleaded fuel over the last 12 momths... on the dyno,race track, and the road across a small number of high performance cars including the GT3 Porsche, Porsche 996 TT, Porsche BoxsterS, STI,evo 6 7 and 8, and the 350Z in both N/A and TT spec.The Mobilf 98 synergy fuel was the most consistent fuel (best performance) and I know what fuel was the worst performer...........if you believe differently.........then that's of course.........your perogative.

Peter

APS

 

What was the worst? Shell?

 

You have PM.

Peter

 

Why PM when you can just say it right here, if there's a need to PM, you can share it with me as well

 

Fuel quality is always going to vary, even between stations. Saying one is consistently better than another is difficult if not impossible unless you tested samples from stations across a wide geographic area.

I know from personal experience I received the worst batch of fuel I've ever experienced from the local Mobil and it was the 98 Synergy stuff. Does that mean all Mobil fuel is crap? Of course not but I'll never use that station again.

 

If you know which fuel is consistently worse then you can at least avoid that brand altogether.

At a Caltex station once, buying food, they had signs up saying that they didn't use Ethanol in their fuel so I asked the guy if that was true and he said it wasn't.

 

Apsilon,
Was this batch of crap fuel put in the Zed? If so, what was the problem? Was it water contaminated?

BTW, thanks to Peter for responses in this thread (please PM me the same info you sent nuff - I've got the option of Shell Optimax, Mobil Synergy and Caltex Vortex in Ararat)

Regards,

Neil

 

Caltex Vortex is'nt 98 octane.

Stick with Optimax, Synergy or Ultimate.

FRIZ

 

No, it was a couple of years back in the MX-5. Problem was pinging under almost any throttle opening. I immediately drained the tank and filled up again elsewhere which fixed the problem. I reported the problem to Mobil and they investigated but said they didn't find anything. I can just imagine what would've happened to anyone who didn't recognise the problem and just kept driving around. Never found out what was actually wrong with the fuel but I've never been back there since and seeing as it's the only Mobil local to me I've never used Mobil since.