Just to start with can we stick to combined pressure or it just gets confusing.

 

So is 20-22psi ok on stock setup?

 

Because in a few weeks that's what I'll have. I've done my research and most say that after 28psi you need to seriously start thinking about internals.

 

So I thought a 3-4 psi increase each turbo wasn't over the top. But should give me that little extra kick. And I was just wondering what other people where running.

 

Before anyone asks one of my turbos is shot and while I was changing them I thought I might as well do a few mods and get a little more power.

 

I should be getting 400bhp @ flywheel at this pressure . . . if my maths is right :tongue_smilie:

If in doubt go with what Yowser says, I've never known him to be wrong and he really knows his stuff.

safety boost is 7psi roughly

stock boost is 9psi roughly

many will run 12 psi stock

running 14psi on a stock engine requires a chipped ecu.

you could run a max of 16 psi on stock injectors and a chipped ecu,

stock tubs and injectors prevent you going beyond 370 bhp. thats those "facts" as they are generally accepted. where the rest of it came from i dunno, but yeah running 10psi is marginally over stock.

The stock wastegate actuators open at about 7.5 psi (intake manifold pressure reading), This is the systems stock boost pressure. When the ECU detects no faults, and when the engine is up to temperature , it activates the standard Boost solenoids, to restrict pressure to the actuators, in a similar manner to Boost jets or a Boost controller. This effectively tricks the stock actuators into opening at the 9psi mark, which is the systems extended boost pressure.

Edited June 3, 201213 yr by Yowser

Ha now I've gone from thinking my actuators are set too high, to thinking there set too low.

 

Hmm well my gut instinct was to go for 10psi just because I didn't want to go crazy, just to get a little extra umph. I've had other cars running at higher without issues but I want this to be my longest lasting and last Z/car I'll ever own. I.e money is no object to keep this car going.

The Wastegate actuators may indeed be opening at a larger pressure setting than what is measured, as there is pressure drop across the system, but when referring to boost measurement it is always taken at the Intake Manifold.

 

The stock wastegate actuators open at about 7.5 psi (intake manifold pressure reading), This is the systems stock boost pressure. When the ECU detects no faults, and when the engine is up to temperature , it activates the standard Boost solenoids, to restrict pressure to the actuators, in a similar manner to Boost jets or a Boost controller. This effectively tricks the stock actuators into opening at the 9psi mark, which is the systems extended boost pressure.

 

Ok as I understand . . . over the stock 7.5 psi the boost solenoids will give a little extra boost, by restricting the actuator, to 9psi. Thus a 17% increase.

 

So am I right in saying that I will likely get an approximate increase of 17% over my new 10 psi actuator as well (assuming no ECU errors), therefore about 11.7psi of actual boost pressure?

Ok as I understand . . . over the stock 7.5 psi the boost solenoids will give a little extra boost, by restricting the actuator, to 9psi. Thus a 17% increase.

 

So am I right in saying that I will likely get an approximate increase of 17% over my new 10 psi actuator as well (assuming no ECU errors), therefore about 11.7psi of actual boost pressure?

 

The stock solenoids will still introduce their restriction to the actuator, so you should indeed see a raised 2-3 psi boost level with aftermarket actuators and the stock solenoids.

 

Effectively what you have done though is set your minimum full boost setting at 10psi, rather than 7'ish psi. But you dont really want to tune your desired maximum boost with the actuator.

 

I would recommend investing in an Electronic Boost controller for full control. They have many benefits, including reduced spiking, faster boost build up, built in boost readings, over boost warnings and automatic safety restrictions, multiple boost modes (Valet, wet, overtaking..etc).

Edited June 3, 201213 yr by Yowser

Hi ToyoII,

 

there is definately not a combined boost despite being twin turbo. Boost is Boost. if it were individual, you would have twin gauges.

 

My boost gauge isnt in PSI its in x100mmHg so its -7 to +7 which is the JDM standard as I understand.

 

BUT, if your hitting the +14 psi or +7 x100mmHg - dont go further, iirc the standard boost should be just over 3/4 of the gauge, if your getting to the end its been overboosted already. Personally, Im happy with mine stock. but thats me :P

 

The engine is 20 years old, it may have been bomb proof when new, but not anymore, they arent as reliable and durable as they were when they were new, and can be fragile if taken too far.

 

Yowser knows what he is talking about, and to be honest, Mark knows to, from experiences good and bad. Your on a great forum here, and the people who have posted, are in the know. Im sure Jimmer and JeffTT would have something to say - would trust them over any wiki page, or product description.

That's why I'm on this forum . . . for the great guys on here that are in the know.

 

My stock gauge at the moment is getting to just over 3/4. But I have a knackered turbo and am pretty sure it was closer to the +7x100mmHg than the 3/4 mark when working fully.

 

But I know the stock gauges aren't amazing, just an indicator really.

 

I did buy the actuators from Z1 Motorsport. Which are defiantly in the know too, and I'm pretty sure they wouldn't sell me something that they say can be used with a stock setup, that would blow my engine to bits. Not exactly a great way too get a good rep as a company.

 

So I'm happy with my decision.

 

My engine may be 21 years old but it's only done 69k miles and in my opinion that is a more of a contributing factor in the life of an engine than age.

 

With boost controllers, to be honest, I don't trust them. It only takes one software glitch and you could be putting 20+psi though your engine (bang). Feel safer with good old fashioned mech eng.

Threads like this are what I deal with on a daily basis, calls from owners looking for tech answers when they already have had the wrong answer fed to them via the internet or pub talk,then you get "are you sure" bloody offensive after 15 years in the business of working on zeds !! guys your wasting you time let him blow his engine up and then he will know your all correct.

 

Jeff

You don't get an answer, if you don't ask the question. :stupid:

With boost controllers, to be honest, I don't trust them. It only takes one software glitch and you could be putting 20+psi though your engine (bang). Feel safer with good old fashioned mech eng.

 

I've never heard of an EBC glitching and blowing up someone's engine before (at least not on this forum!) - I've been running one for years without a problem and I'm sure plenty of others on here have done as well. As long as it's set up correctly of course!

My engine may be 21 years old but it's only done 69k miles and in my opinion that is a more of a contributing factor in the life of an engine than age.

 

Id say that was high mileage for a japanese import. Mine has 51,200km on the clock which is about 30,000 miles. Therefore I would at a guess, estimate the engine to have around the equilivent wear and tear as a UK 120,000 miler. (approx 4x more than on the clock)

 

This is as in japan mileage is low, but around 75% of the time they are driving (normally only for commuting) they are in standstill traffic. At this time fans are going, belts are going, pistons are still combusting, fuel pump pumping etc etc... all whilst stood in standstill traffic, in the dry heat of Japan. So basically the chassis has the mileage displayed wear and tear, the engine normally has around 4x more than that.

Yes I'll admit its rare, but I'm happy with just uprating the actuators and I can add one later.

 

Also there not the cheapest and I know people with them and they just end up turning them up and up, getting the bug and wanting more power.

 

May not break the car but it just adds more wear which I want to avoid, hence only a marginal increase that I was looking for.

 

So in conclusion . . . it appears I'm going to be running about 12psi. Which from what other people say there running or have run is not all that extreme - denfinatly won't "let him blow his engine up and then he will know your all correct":

 

"MarkDerby - with a remap u can up the boost to 13/14psi ish",

"bigh - I was running 14 psi with boost jets and upgraded chip, on the dyno it maxed out at 370bhp"

"vodkashots - 14 to 16 on stock is what ive heard countless times."

"Yowser - With a remapped ECU , 14psi is a safe maximum raised boost level with Stock Injectors."

"jaylox - i used to run 16psi boost on stock tubs, remapped ecu"

"z32bolt - you could run a max of 16 psi on stock injectors and a chipped ecu"

 

So thanks for all the info guys, it's kind of put my mind at rest.

 

I'm starting the turbo swap on Tuesday so nice to know I'm not going to spend however long and it all be for nothing. :blush:

Good luck mate. hope all goes well. yes 12psi should be ok. like I said wouldnt go past the 14 on the gauge :D

I pretty sure it will go past 14psi on the gauge (may not though) . . . but the gauge isn't the most accurate :tongue_smilie:

 

As long as my aftermarket gauge / garage gauge says I'm doing 12psi ish I'm happy.

I pretty sure it will go past 14psi on the gauge (may not though) . . . but the gauge isn't the most accurate :tongue_smilie:

 

As long as my aftermarket gauge / garage gauge says I'm doing 12psi ish I'm happy.

 

A wise conclusion following your questions mate!!

 

Good luck with the work and do let us know how you get on....

 

Richard:thumbup1:

well my cherry red zed was running 16psi with a greddy ecu, decat, filter upgrade, boost jets and that was scarily quick, still one of the fastest 300zx's ive been in.

 

They are fast cars anyway, Electronic Boost controller is the way to go, and i wouldn't worry about a software fault causing you to pump 20psi through your turbos, if they crap out it will give you stock boost or just not work and still give you stock boost.

 

denfinatly won't "let him blow his engine up and then he will know your all correct":

 

So thanks for all the info guys, it's kind of put my mind at rest.

 

I'm starting the turbo swap on Tuesday so nice to know I'm not going to spend however long and it all be for nothing. :blush:

 

 

You got this answer because you were not reading and listening to the many voices that have already been there and got the T shirt, asking for the correct advice and then questioning it in such a way that demonstrated your lack of understanding was getting pointless.

 

Jeff

Electronic Boost controller is the way to go, and i wouldn't worry about a software fault causing you to pump 20psi through your turbos, if they crap out it will give you stock boost or just not work and still give you stock boost.

 

Unless the solenoid gets stuck closed and then the turbos will be uncontrolled the very reason the boost solenoids should be used with an ebc, contary to popular thought I know, but it at the very least gives some protection if det occurs and also the boost controller has an easier time of it.

 

Jeff

Unless the solenoid gets stuck closed and then the turbos will be uncontrolled the very reason the boost solenoids should be used with an ebc, contary to popular thought I know, but it at the very least gives some protection if det occurs and also the boost controller has an easier time of it.

 

Jeff

 

I should of made that clear when putting my post up, i have the stock boost solenoids still connected lol

Well I've got the feeling I'm going to be postponing this till next week due to the weather turning. But I'll defiantly let you know how it's going.

 

No doubt I'll have a few more questions soon enough.

:taz: Don't stuff around use a EBC Boost control ,they open at the preset pressure with no bleed off [no loss of boost flow & pressure] and if you are going to run boost higher than 9.5 PSI get your self a NISTune ECU then dyno tune your car or rechip your UCU to a reconized tune.I run a blitz EBC which gives me 4 seperate switchable boost settings inwhitch I have setup to 4 manual selectable settings of 8PSI., 10PSI.,12PSI.&14PSI.running with a NISTune ECU-2 ,with a K&N pop air filter,Cruise brand twin cat back stainles steel exhuest system,then Dyno tuned @ 13PSI.boost which produced 320RWHP .& 590N RW touque.If you run a higher boost without doing the other after market mods your engine will detonate witch will give the results as per MarkDarby's photos above.:oops::headvswal

:taz:Don't stuff around use a EBC Boost control ,they open at the preset pressure with no bleed off [no loss of boost flow & pressure] and if you are going to run boost higher than 9.5 PSI get your self a NISTune ECU then dyno tune your car or rechip your UCU to a reconized tune.I run a blitz EBC which gives me 4 seperate switchable boost settings inwhitch I have setup to 4 manual selectable settings of 8PSI., 10PSI.,12PSI.&14PSI.running with a NISTune ECU-2 ,with a K&N pop air filter,Cruise brand twin cat back stainles steel exhuest system,then Dyno tuned @ 13PSI.boost which produced 320RWHP .& 590N RW touque.If you run a higher boost without doing the other after market mods your engine will detonate witch will give the results as per MarkDarby's photos above:oops::headvswal

Progress so far . . .

 

17psi melted a piston on my Z, Geoff give me the piston back, not sure as a souvenier or a reminder... lol