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Location:
Brunswick, W.A.
Registered:
December 2003
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1JZ boost raise
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Thu, 04 December 2003 12:43
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I have a stock jza70 supra and am planning to get a boost controller and would like to how much i could raise it and can run SAFELY on it? it has the usuals pod, zorst... any ideas?
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Location:
Wollongong
Registered:
May 2002
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Re: 1JZ boost raise
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Thu, 04 December 2003 13:00
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Try not to go past 14psi... the ceramic turbine wheels like to deteriorate after that.
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Location:
Brunswick, W.A.
Registered:
December 2003
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Re: 1JZ boost raise
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Thu, 04 December 2003 13:06
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cool, cheers. its still a "new" car for me... so im still learning stuuf with it and want to do all the usuals to it, maybe even a fmic next??? who knows
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Location:
Brunswick, W.A.
Registered:
December 2003
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Re: 1JZ boost raise
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Thu, 04 December 2003 13:18
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Also... does the TT setup on the 1j's, 1 spin first to reduce lag and then the second spools up and do they both stay on after both have spooled up? Or do they both start spooling at the same time? It feels like the first statement but i just wanna to know, because one would think this would only be a good setup with the second turbo being larger than the first but both of them are CT12A's. Am i making sense?
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Location:
Perth
Registered:
July 2003
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Re: 1JZ boost raise
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Thu, 04 December 2003 14:59
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No - they are in parallel (ie both spool at the same time). If you have a close look at the exhaust manifold you'll see the first 3 cylinders feed the first turbo, and the last 3 feed the second turbo.
The 2JZ-GTE has sequential turbos.
Regards
Peter
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: 1JZ boost raise
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Thu, 04 December 2003 15:19
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perfect sense
the setup you're talking about is the 2jz setup - a baby turbo that comes on early, and a bigger one that comes in at 3800 - the 1jz has two turbos, same size, and both come on at the same time
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Location:
Newcastle, NSW, Australia
Registered:
May 2002
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Re: 1JZ boost raise
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Thu, 04 December 2003 21:01
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We regularly run the 1J's at 16psi without a hint of problems and have been doing this for years. While I keep hearing stories about turbos self destructing after 14psi I have never heard from anyone who actually suffered this fate (not withstanding the odd idiot who boosts them to 20+psi or runs around with no air filter to get more 'power').
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Location:
Perth
Registered:
October 2003
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Re: 1JZ boost raise
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Thu, 04 December 2003 23:26
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I think the computer has a 13psi boost cut, that will have to be overcome?
Does anyone know what the pressure drop across the JZA70 or soarer intercooler is? If it is pretty restrictive this could cause alot of turbo breakages, the crappy dumps wouldnt help either all that backpressure. Say if you a running the boost at 16psi (almost always measured in the inlet manifold) with the stock cooler and dump, the turbos might be pushing as much as 19psi. Sound possible?
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: 1JZ boost raise
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Fri, 05 December 2003 00:19
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very much so.
but if you decide to pump the boost up that much without going for a bigger bov and much better IC, you're asking for trouble
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Location:
Perth
Registered:
October 2002
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Re: 1JZ boost raise
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Fri, 05 December 2003 02:11
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Leaving aside turbine wheel failure issues, at what pressure do the ct12's fall out of their efficiency band? I'm assuming that much more than 16psi on a stocker would be a waste of time anyway.
cheers,
Justin
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: 1JZ boost raise
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Fri, 05 December 2003 02:14
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the newcastle boys generally figure 17psi is the limit - anything more is pointless.
I've heard rumours that they start to lose efficiency after 15psi - but not sure
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Location:
Melbourne
Registered:
May 2002
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Re: 1JZ boost raise
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Fri, 05 December 2003 06:38
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13psi computer limit sounds right. i think thats the reason for my kick backs, need a cut deffender i guess.
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Location:
Sydney Miranda / Perth Mu...
Registered:
November 2003
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Re: 1JZ boost raise
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Fri, 05 December 2003 07:48
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Just a question,
Does adding a Dump pipe bring the Boost level up at all...
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Location:
Brunswick, W.A.
Registered:
December 2003
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Re: 1JZ boost raise
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Fri, 05 December 2003 11:01
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Thanks for ya help guys one last Q & A from me. Umm sometimes when I hit about 180kmh the car seems to cut out and then it comes back again and then it cuts out again and does this repeatedly. But other times it will continue well over 220 without a problem. It does not have a speed limiter anymore. Would this be overboosting or fuel cut?
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Location:
Melbourne
Registered:
May 2002
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Re: 1JZ boost raise
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Fri, 05 December 2003 11:45
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the dump pipe i believe will only help your engine breath better less restriction, it may in kind raise the boost but i would think the computer would compensate for the extra freedom and restricket the boost to the set level.
i reckon it would be the fuel defence cut. does it happen when ur flooring it? if so u'd be like me an need a FDC.
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I supported Toymods
Location:
Perth
Registered:
May 2002
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Re: 1JZ boost raise
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Fri, 05 December 2003 12:48
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| draven wrote on Thu, 04 December 2003 23:19 |
perfect sense
the setup you're talking about is the 2jz setup - a baby turbo that comes on early, and a bigger one that comes in at 3800 - the 1jz has two turbos, same size, and both come on at the same time
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That's incorrect. Both the turbos on the 2JZGTE are the same size i.e. either CT12B's or CT20A's depending on where they came from. The first one receives all the exhaust flow until later in the revs when the second turbo starts receiving the flow as well.
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Location:
Perth
Registered:
October 2003
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Re: 1JZ boost raise
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Fri, 05 December 2003 13:58
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| MIKE_JZA70_TYPE_R wrote on Fri, 05 December 2003 15:48 |
Just a question,
Does adding a Dump pipe bring the Boost level up at all...
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Yep it will as long as it is of better design than the original. Like increasing the exhaust size the dumps will decrease the back pressure on the exhaust wheel, and hence it will be able to spin more freely. But as said it can only increase the boost until the computer cut limit.
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Location:
melbourne
Registered:
July 2003
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Re: 1JZ boost raise
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Sat, 06 December 2003 06:10
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 im no expert but i think *ustcallmefrank* is correct about that one
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Location:
melbourne
Registered:
July 2003
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Re: 1JZ boost raise
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Sat, 06 December 2003 06:10
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im no expert but i think *ustcallmefrank* is correct about that one
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: 1JZ boost raise
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Sat, 06 December 2003 06:43
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wow
learn something new every day
next question that always bugs me about the 2jz - why does the (turbo I assume) start whistling when the second turbo kicks in?
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Location:
Brisbane
Registered:
May 2002
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Re: 1JZ boost raise
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Sat, 06 December 2003 16:06
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Mine whistles like mad all the time... not just when the second turbo kicks in!
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Location:
UK
Registered:
May 2002
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Re: 1JZ boost raise
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Sat, 06 December 2003 16:06
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| ReQuieM wrote on Fri, 05 December 2003 06:38 |
13psi computer limit sounds right. i think thats the reason for my kick backs, need a cut deffender i guess.
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Fuel cut on the 1JZ is around 14.6psi, just before the pressure that the map maxes out.
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Location:
Sydney
Registered:
May 2002
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Re: 1JZ boost raise
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Sun, 07 December 2003 11:52
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Adi
After spending a few years on forums and following threads on 1J's, I too was of the understanding that the factory MAP topped out about 1 bar.
Interestingly, I just had the tuning on my car completed in the last week - the Power FC in my Soarer and it was using the factory MAP signal for load inputs by it's nature ; now the interesting part is that it records the max levels and I asked to have the ECU mapped all the way up 85% duty cycle on my 550cc injectors which happened to be 1.44bar or 21psi and the Power FC registered boost beyond 1 bar and recorded the max as 1.44 bar.
This of course goes against what has been noted on the forums all this time - do you know if anyone has actually measured the input boost and output voltages of the factory MAP sensor on 1J's or if there are in fact numerous differing units amongst the various donor vehicles - ie Soarer, Supra, Chaser etc?
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Location:
UK
Registered:
May 2002
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