Engine mods, what should I do?

Another crazy delete question: IACV?

Coming from motorcycles, this seems like such a crazy over complicated system to control idle. Can I remove this and just control idle through the butterflies?

Cheers.

 

no you cant do that. its complicated because thats what is required to maintain idle during such a variety of condiitons, and also to prevent the motor stalling after closing the throttle

 

So regarding max boost on stock turbos, how long have you been running +18psi? I'm guessing that reliability really only depends how hard its driven and how often its kept there.

I've found that 15psi was more than enough for my crappy tyres :br:

But I have heard that anything over 15 will quickly munch the thrust bearings.

You seem to make a lot more power for the same sort of mods mine has. Was that figure @18psi? Whats your current specs? I'd love to see your boost curve.

 

I used the colour red to explain and bypassed any answered questions

No........ it was just designed by a CAD/ Computer.......and computers don't give a shit where it fits, as long as it works.........and it fits in a CAD program.

JC
:zlove:

 

My stock turbos run 21psi fairly happily, Been running over 17psi for ages.

 

I have been running +18psi since the Z32 dyno comp at UAS on 12th July 2013

That would be my guess too.

I've been using full +18psi boost probably for a couple of seconds every 2nd day for over 2 years now. I'd like to use it for more than a couple of seconds but on full boost you quickly head towards license loosing speed if not collision with a wall.

I had major traction problems on cheap Chinese tyres. I find Goodyear Asymmetric 2 have pretty good traction. But even then at 271 rwkw 1st was mostly useless and 2nd was problematic but the higher gears OK traction wise.

My most recent tune pulled timing to 230 rwkw at 17 psi. Acceleration in 1st was better with less hp though as now I could use the gear.

I'm still currently running the 230 rwkw at 17 psi tune except that I've turned the boost up to 23 psi (at least that is what the manual boost controller is set to - don't know if the turbos actually make that. They certainly won't make it past the midrange).

I also don't know what my current rwkw is though it is obviously more than 230.

I've been running at 23 psi since July 2014 with no trouble so far.

I take it you heard this from a study published in a peer reviewed scientific or engineering journal somewhere? Did they use a large enough sample size of turbos to get statistically significant results?
Or was this based on anecdotal evidence or more likely speculation?

And do you really think things are all just fine till 15 then all hell breaks loose at 16?

As long as we are talking anecdotal evidence: I know my thrust bearings are so far un-munched and I have read of other US stock TT owners who claim to have been running +20 psi (with race fuel in their daily TT) for a long time and having no issues with their stock turbos.
Though someone somewhere may well have turned the boost up and munched their turbos.

Seriously though who knows. Certainly I would suspect that 9spi is better for longevity than 21 psi but how much better I have no idea.

I wouldn't call 10 % more a lot more (244/271=0.9) The difference can be put down to how far to the edge the tuner is willing to go. The 271 rwkw tune was done by Dave Aspery when he was at UAS the 230 rwkw tune was done by Ben now at UAS. I suspect Dave may be more willing to push things than Ben.

With my latest more safer 230 rwkw at 17 psi tune you're beating me at hp per psi. (Albeit I now run at 23psi not 17psi).

My boost curve for the 271 rwkw run is the same as you see in post #22 in this thread (for my 252.1 rwkw in the UAS dyno comp). I actually didn't get a graph with boost on it for that the 271 rwkw tune but the boost setting was the same as the 252 rwkw tune.

Final disclaimer: You will easily destroy your engine at 23 psi on the wrong tune or for that matter at 18 psi on the wrong tune.
Some other pointers. I run cold spark plugs i.e. 8 heat range (8 are supposedly safe for 20 - 28 see http://specialtyz.com/shop/default/300zx/ngk-iridium-ix-spark-plugs.html)

I also run Nulon pro-strength octane booster to boost my octane to over 100 each and every single tank. All but my 230 rwkrw tune was tuned on +100 octane - the 230 rwkw tune was done on 98 (and with a dodgy CAS since replaced).

I've taken some risks regarding boost and survived (so far), if you take the same risk you may not (or you may).

PS: I suspect I'd make more power with more timing and less boost (but I suspect I have this problem: http://www.jimwolftechnology.com/wolfpdf/VG30DETT_CAS_COUPLING_MISALIGNMENT.pdf Contemplating getting round it with a crank trigger.

 

The issue definitely isn't that you 'can't' run more than ~16psi it's just that you see diminishing returns, if you already have supporting exhaust and intercooler upgrades slap on some bigger turbos and you'll have more like 300kw at the same boost, in part because you'll actually have that boost until redline but also thanks to lower back pressure.

The alternative and looking better value for money every day is to follow Nem's and Z32 TT's lead and go E85 with stock turbos and maybe some upgraded wastegate actuators so it actually holds boost.

 

Plenty of the WRX guys push their turbos deep into the red. They seem to be fine. I would imagine like most 300zx turbos the turbine is holding things back at max rpm so actual flow would be less that what you expect anyway.