I have been reading for a while on the 350z forums and they are having a tough time with boost. People are blowing engines at 5lbs of boost and 6lbs of boost. One guy dynoed his turbo with 9lbs and made only 377whp. We have 3.0 maxima turbo guys making the same power with the same psi. Whats the deal? I am guessing it has to be the ecu and tuning, maybe it is more complicated. We have near the same compression and other features, but all that extra power in N/A form is nowhere to be found when boosted. I understand that boosted VQ35 make alot more torque, but where is the power?

 

I think they are having problems with tuning. People are throwing rods when the get a little over 400 whp.

 

whats the compression ration on the 3.5?


I know those sweet 3.5s have returnless fuel.

 

they have 10.3:1 compression.

 

I bet it is ALL ecu/timing related. It's drive by wire too?


And maybe throw in the longer stroke theroy. I have no real facts, just my 2 cent thoughts.

 

i see it as this:

the 3.0 is a over engineered engine by Nissan. Originally running a vq30deT version in japan. The vq35de is a variation/child of the vq30.

but nissan in order to produce the 287 hp number for the 350z had a hard time trying to extract every ounce of power from the engine. The result: bumped compression, different intake manifold, aggressive timing and fuel maps all with a engine with an original output of 255hp. 350z/g35 coupe's without proper break in periods have resulted in blown engines, something I have seen in person. Also, the ECU tends to over compensate and is very unfriendly towards modifications/changes.

vq35 has better flowing heads, variable cam timing, beefier rods, extra displacement, and a bunch of other goodies. But my belief is that is virtually tapped out. A 350z with nismo crap up the butt (cams, pistons, exhaust, intake, etc) can't tap out much more than stock numbers in proportional comparison with the vq30de/-k.

Therefore, a more fragile engine in comparsion to the vq30de/-k (fairly stout engine) despite the technological advancements and extra displacement

 

i posted a thread a while ago about how Top Secret chose the VQ30 over the VQ35 for their turbo 350z. It produced 690ps (700hp or so)...and since it's top secret, i doubt they did it because of a lack of funds...

 

The returnless fuel line doesn't help much. Some companies are trying to get some fuel rails made so we (or I should say the 350z guys) can have a return fuel line setup. I think bags is somewhat correct about the ecu/timing theory. Some people are considering going to full standalone engine management with the HKS F-Con V pro. I would have to say it is very frusterating boosting the 3.5L and I would have much rather been working with a 96-99 maxima. I have boosted up to 9 lbs though and still haven't thrown any rods (knock on wood...I do have a spare engine just in case though). My e-manage is coming in today and I will be installing it shortly. Hopefully I can successfully retard timing without frying any coils. I also need to get a 350z injector and compare it to my injectors to see if it will fit. If it does, I will probably upgrade to the power enterprise injectors with a TS ecu reflash.

 

From what I've heard from a buddy planning on going FI on his 350z (BriGuyMax) from this board it is mostly issues with the stock ECU. For instance the vortech sc kit for the 350 comes with an fpr and not much else, using the stock ecu and such is just asking for trouble. The few that he's told me about that have actually tuned the cars appropriately are making very good power. Much more so than our cars at similar boost levels.

 

That was because the lower piston speed of the Vq30. They were looking for top speed, not acceleration. It was either stroked or bored out to 3.2 liters.

 

The folks on my350z.com have blown their motors at low boost becaue of tuning, and I believe from not taking enough timing out. Some people there are running up to 9psi with motors still intact, with the proper tuning of course. If I recall the rods are the weakest link and begin to go around 450 whp.

 

ME and dixit have been the only ones to be able to run the emanage ignition harness without burning coils the only way to do it is to put resistors in each line for each coil pack, otherwise fried chicken all over the place! ask dixit he can tell u where to get the resistors

 

I don't know if diodes are the same as resistors, or if hooking up a 2k2 maxima would be the same as a 350z, but here is what they do: Howto: Install the GReddy ignition harness on the 350z.

 

Thanks for the help guys. That's the same writup I was going to use from the 350z forum (no fried chicken here, unless it's KFC). Hopefully radioshack has all six diodes so I can install this tomorrow and tune on Saturday.

Where are you guys putting the e-manage?
I was thinking in the glove compartment box.

 

thats what we did

Mine sits on top of the ecu but i may move it to the glove box.