VQ35 FI limits / recommendations

[Dave_Lum]

At what HP points (approximately) is it suggested to start upgrading parts with TT setup? It seems ~410hp is the upper lmit for stock internals? At what point do you need to go to higher flow injectors? A return fuel system? I would also be interested on anyone running "mid level" compression ratio - stock being 10.3 and many aftermaket pistons at 8.5:1, it seems a 9.0-9.5:1 forged piston would be reasonable for the low 500rwhp range? Other comments along thee lines aer also welcome.

[wperdigon]

well I think one of the biggest limitations of the z with regards to forced induction is the lack of fuel - a complete fuel system is needed - return line, larger injectors, rails, pump - i know cj motorsports make a really good kit and would only recommend their kit since you don't have to modify the rails to fit like other kits you do

[Deathmage]

Zup Dave, welcome to the forum. The Threshold level of our stock rods and pistons are actually, believe to be only around 360ish at the wheels (I've read this in my turbo magazine and one others, a long time ago).
People are running 420ish with no prob. so far.
A stock block can handle more than 25 psi.
You need to do some math for the compression ratio. Too many variable to have a number given.
http://www.turbofast.com.au/TFcompB.html

[idrive]

I also would like to add that it depends on how your power is being applied. With turbos (moreso TT setups) you are getting a huge surge of power early. While with a single turbo or a S/C system your power is either not as high or a lot more linear due to the behavor of such systems. S/C systems do not generate max boost until they reach the upper rpms so the power delivery is much smoother and more similar to stock power curves as far drivebility goes but with more power of course. If you want something that adds power but at a more reliable rate without an immediate need to "build" the engine, I would suggest a single turbo kit or a S/C. There is plenty of info on here (search the 350z forum) about the pros and cons of each system applied specifically to the 350z.

Good luck and best of all try to put all of your plans on paper first instead of just buying parts aimlessly, also more importantly budget out your time and research shops that you may use to do the work. Sometimes they will put you intouch with some of the cars/owners they have done work for so you can talk to their customers about their own experiences.

[palmerwmd]

1)At what HP points (approximately) is it suggested to start upgrading parts with TT setup?
2)It seems ~410hp is the upper lmit for stock internals?
3)At what point do you need to go to higher flow injectors? A return fuel system?
4)I would also be interested on anyone running "mid level" compression ratio - stock being 10.3 and many aftermaket pistons at 8.5:1, it seems a 9.0-9.5:1 forged piston would be reasonable for the low 500rwhp range?
5)Other comments along thee lines aer also welcome.



1) folks have even running up to 400 whp (and more, with some supporting Mods) on stock internals w/o problems.
Some feel that not just a good tune and fuel supply are key but flashing over the advananced timing map of teh stock ecu to prevent a map switch that leaves your tuning basis, can be key.

2) Some folks have more but that a pretty good median as other have busted engines on less (but often could be traced down to poor fuel/tune etc)

3) Well technically the injectors are overcycled at anything much above 300 hp.
On stock injectors I still manage to run with a good tune at 360 whp, but when I ran 411 whp I was leaning out and really needed a complete fuel system upgrade, bigger injectors, return system, and a way to run those bigger injectors

4) Some folks have done this, often with great success, 9.0 is a popular compression ratio on our cars and will work well with the goals you mentioned.
Also Check our G35 brother forum here, same engine same platform.

A project of interest to you:
http://forums.freshalloy.com/ubbthreads/showflat.php?Cat=&Board=UBB25&Number=68044667&page =0&view=collapsed&sb=5&o=&fpart=1#Post68045972

[Dave_Lum]

1) folks have even running up to 400 whp (and more, with some supporting Mods) on stock internals w/o problems.
Some feel that not just a good tune and fuel supply are key but flashing over the advananced timing map of teh stock ecu to prevent a map switch that leaves your tuning basis, can be key.

2) Some folks have more but that a pretty good median as other have busted engines on less (but often could be traced down to poor fuel/tune etc)

3) Well technically the injectors are overcycled at anything much above 300 hp.
On stock injectors I still manage to run with a good tune at 360 whp, but when I ran 411 whp I was leaning out and really needed a complete fuel system upgrade, bigger injectors, return system, and a way to run those bigger injectors

4) Some folks have done this, often with great success, 9.0 is a popular compression ratio on our cars and will work well with the goals you mentioned.
Also Check our G35 brother forum here, same engine same platform.

A project of interest to you:
http://forums.freshalloy.com/ubbthreads/showflat.php?Cat=&Board=UBB25&Number=68044667&page =0&view=collapsed&sb=5&o=&fpart=1#Post68045972




Perfect! The guy going from supercharger to TT has my sentiments exactly - I am not looking for a dyno queen but something with more power *everywhere* than my VG30DETT. All a pipe dream at the moment, but still...

Yep I know the G35 is the same platform (in fact I like it better than the Z) but figured as a whole guys with a Z are more likely to mod their cars.

[idrive]

So you're the famous vg30dett 510 swap, beautiful car. I'm sure you're aware of your cars popular status, glad to have you here on FA!

[Dave_Lum]

So you're the famous vg30dett 510 swap, beautiful car. I'm sure you're aware of your cars popular status, glad to have you here on FA!



Uhh. Famous? As far as I know only "famous" in 510 circles for now, but in the spring HP books is coming out with a brand-new book on turbocharging and my 510 is one of several turbocharging examples given. The author is Mark Warner, keep an eye out!

Thanks for the welcome http://forums.freshalloy.com/images/graemlins/smile.gif

[PerformanceTony]

For stock internals, there really isn't a certain HP line that you don't want to cross, some people have blown their motors on low-mid 300HP levels, others take their stock motors to mid 400hp levels. Some people get away with it, others just don't.

It is common to think that thing such as con-rod bolts should be replaced under high stress/boost levels. I personally wouldn't be comfortable with stock internals over 350WHP, and If i were shooting for that level, i'd look to upgrade. Simply for peace of mind. Even if it's ok for the motor to take it, it's just all about peace of mind and longevity.

And a lot of it has to do with the tuning of course... But I'm all about reliabilty.

[idrive]

Yea you're 510 would show up quite a bit on other web forums as one of the best if not the best vg swap into a 510, it truly is a remarkable job you did.

[Dave_Lum]

Thanks, although I can only take credit for some of the rack & pinion conversion (related to the NA VG30DE that was there first). I merely funded the project while some very talented friends took this on as a challenge.