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i finally got around to doing the #1 turbo mod works great and has lots more torque. but i have a few questions. first it hits just about 16 psi which is fine but then falls to 12psi when heading into transition. i capped everything and ran it right at the actuater like stu has his setup. also my secondary electiric fan is always on when the car is running? any imput appreciated. stu if you see this as well throw in some input if possible. thanks.
 

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Does it stay at 12psi to redline or just during the transition?

If it is just during the transition, this is normal. In stock form, the valve you are bypassing pulses open to slowly allow the turbo to prespool and also controlling the amount of boost on the first turbo.

I did a mechanical fix to temporarily solve this by using a manual boost controller. The best fix is to use a second boost EBC, or other device that can pulse that valve.

This will allow for a smoother transition, and less of a loss of boost. I think this is what Stu finally went with. I plan on using the AEM boost control option, but I frankly have been to lazy to tune it in yet.


HTH,

Howard
 

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Discussion Starter #3
no i also have a ebc, which goes to 18 psi once both turbos are running. i spoke with stu on it and he said its normal to go down 1 to 1 1/2 psi. im at 14.5 right now it drops to 13 psi and jumps up to 18 psi on trasistion.
 

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no i also have a ebc, which goes to 18 psi once both turbos are running. i spoke with stu on it and he said its normal to go down 1 to 1 1/2 psi. im at 14.5 right now it drops to 13 psi and jumps up to 18 psi on trasistion.

1- 1/2 is indeed normal, but your original post said you saw 16psi, and then dropped to 12. 4 psi is not.

Glad to hear you got it working though.
 

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Supranian
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I haven't heard of this mod????? Is this the same as the true twin conversion???
 

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1 to 1/2 psi is normal as Hwilli said.

chriso: This is a mod where you run a boost controller to the EBV and increase boost on the first turbo. You can fine tune it to smoothen out the transition and get bags more torque lower in the rev range.
 

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Blue Thunder
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i did this mod awhile back...but instead of reaching down by the firewall, i just traced the hose up top and ran my boost controller up there near the intake hose...took maybe 5 minutes tops.
 

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Stock Twins King
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i did this mod awhile back...but instead of reaching down by the firewall, i just traced the hose up top and ran my boost controller up there near the intake hose...took maybe 5 minutes tops.
No offense.........but I have to call BS on this...........Only way this would work is if you were in TTC.........then having this controller would be worthless. Your controlling "pre" pressure tank pressure by doing it this way.
 

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here's some pics of what i did....if there's a difference stu, let me know. i have it set at 15psi on the first turbo and the second one is set at 17psi. i'm running 2 boost controllers (one turboxs and the other is an electronic apexi). i haven't seen any problems, but if you see that this is wrong or harmful, lmk...



 

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Doughboy247 - that's exactly what I've done and where I have my MBC setup and it does control the boost the 1st turbo makes.

Stu: If you could confirm this is correct?
 

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jdm junk collector
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Has anyone tried this with the JDM twins?

I have been playing around with a boost controller on mine (JDM engineset). It has an Aftermarket ecu SARD


With the stock plumbing with no boost controller it goes to a bar on the first turbo and stays there when the second turbo comes on.

If i hook up the boost controller HKS EVCII the way HKS recommends it i hit 1 bar and then goes to the moon on the second turbo 25+ psi .

I now have the HKS hooked up to just the front turbo the way you would do any boost controller and it now goes to 10 psi and i can control the second turbo all i want from 1 bar to 1.5 bar.

I'm assuming that the aftermarket ecu is controlling some of my boost,

I'm looking to hook up the second boost controller (manual) the way stu shows it and see what results i get.

any input on this would be great as after i have experienced 1 bar on the first turbo i cant go back. :tongue:
 

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Has anyone tried this with the JDM twins?
I'm running this mod on my JDM twins. I'm seeing 14.5psi on the first turbo and 18psi when the 2nd comes online.

I have been playing around with a boost controller on mine (JDM engineset). It has an Aftermarket ecu SARD
I would find out what's been changed in the aftermarket ECU. IIRC the ECU doesn't control boost.

With the stock plumbing with no boost controller it goes to a bar on the first turbo and stays there when the second turbo comes on.

If i hook up the boost controller HKS EVCII the way HKS recommends it i hit 1 bar and then goes to the moon on the second turbo 25+ psi .
This doesn't sound right to me. I've essentially got the same setup as you but even when I had no boost controllers installed I was seeing 24psi after both turbo's came on. I was fully decatted with no Restrictor Ring on a 4" turboback. With the boost controllers I got quite a bit of extra oomph but ended up seeing 24/25psi at full throttle at 80mph or so.

I now have the HKS hooked up to just the front turbo the way you would do any boost controller and it now goes to 10 psi and i can control the second turbo all i want from 1 bar to 1.5 bar.
The front turbo is the one you want to hook it up to as it's the 2nd turbo. This is correct but what are you using for your exhaust? (3"? 4"? catted? decatted?)

I'm assuming that the aftermarket ecu is controlling some of my boost
We don't have electronically controlled boost control on the JDM 2JZ-GTE's - boost is controlled purely by exhaust backpressure. However, there is an electronic safeguard which is the Boost Cut/Fuel Cut that occurs over 1.0 bar.

I'm looking to hook up the second boost controller (manual) the way stu shows it and see what results i get.
You will absolutely LOVE IT! It gives you lots of low down torque and also smoothens the transition between the 1st/2nd turbo. Instead of a violent "hit" you'll instead get a smoother transition where the "hit" is almost eliminated but you can still feel it when the 2nd turbo comes online. Makes it more manageable around bends, etc where you've just gone WOT.

any input on this would be great as after i have experienced 1 bar on the first turbo i cant go back. :tongue:
I know the feeling! I'd say do it how Doughboy247 has done it as that's how I've done it but I'd rather let Stu confirm it's done right before saying it's okay to go ahead with.
 

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Yeah except this mod decreases the life of your turbos and TCC increases it.
I disagree on this statement. Reasons below:

1) Most people would know that the shaft's on the USDM/EuroSpec turbo's are weak. It's the shaft that breaks when you stress them out too much. On BPU cars, normally what will happen is the 1st turbo will build boost (near enough stock boost - 0.8bar) then the 2nd turbo will hit in HARD due to it setup for 18psi. This hard "hit" you get when the 2nd turbo comes online can is due to the gap in boost between the 1st and 2nd turbo's - where when the car is stock you'll have a gap of around 1-2psi between the 1st and 2nd turbo. This hard "hit" is the 2nd turbo spinning up VERY fast to provide you with the 18psi of boost (@BPU). This hard "hit" can help shorten the life on your turbo due to the immense forces put on the shaft/wheel/etc of the 2nd turbo to spin up VERY fast.

2) This mod would actually increase the life of the 2nd turbo by preventing this hard transition. It will also give you tons of low down torque and build up boost quicker.

Also if you're a sensible driver - one who does not go around swerving in and out of traffic and ACTUALLY ENJOY your car (not go WOT every couple of seconds unless you have to ;)) your turbo life would not be decreased.
 

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I disagree on this statement. Reasons below:

1) Most people would know that the shaft's on the USDM/EuroSpec turbo's are weak. It's the shaft that breaks when you stress them out too much. On BPU cars, normally what will happen is the 1st turbo will build boost (near enough stock boost - 0.8bar) then the 2nd turbo will hit in HARD due to it setup for 18psi. This hard "hit" you get when the 2nd turbo comes online can is due to the gap in boost between the 1st and 2nd turbo's - where when the car is stock you'll have a gap of around 1-2psi between the 1st and 2nd turbo. This hard "hit" is the 2nd turbo spinning up VERY fast to provide you with the 18psi of boost (@BPU). This hard "hit" can help shorten the life on your turbo due to the immense forces put on the shaft/wheel/etc of the 2nd turbo to spin up VERY fast.

2) This mod would actually increase the life of the 2nd turbo by preventing this hard transition. It will also give you tons of low down torque and build up boost quicker.

Also if you're a sensible driver - one who does not go around swerving in and out of traffic and ACTUALLY ENJOY your car (not go WOT every couple of seconds unless you have to ;)) your turbo life would not be decreased.
You are still slam starting your second turbo though, which decreases it's life. In TCC they both spool normally at 4k and #1 turbo life is increased because it's not being used at all until WOT.

I might be thinking of a different mod but I don't think I am.
 

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mitulparmar787, thanks for the in put. And im glad i found some one with the JDM set up.

Im running a 3" Downpipe no 1st cat Out to Dual 2.5 mufflers.
Im working on getting more info on the ECU.


During some of my testing the car would over boost with different vacuum routing, but if i plumb it to stock it will boost 1.0 1nd stay there. Im going to confirm that one more time.

During these over boost sessions i even fell for the restrictor ring and i couldn't get the boost to go down. Whats your take on the restrict ring?

Any how when i get some time im going for it and ill let and ill bring you up to speed on it.
 
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