GT-R turbos on the VQ37
 

I already watched that video among countless others researching this problem.. The only thing I can see is that I might of used a wrong oil filter stud causing the oil to never flow back to the engine after it is filtered. I did try 3 filters of varying brands before taking the Mocal plate off and it worked instantly afterwards.

Wouldn't it be better to just delete the Mocal plate for now and go without it?
Also having to trial and error 3 different oil filters and not being sure about a stud seems risky to try and fix this problem.
Perhaps you might just need to take it to and expert shop at this stage so as not to risk anything further. Just a suggestion now you've got this far on this project. :tiphat:

Hey man, get your base tune yet?

The tuner finally came back from vacation and my base tune is tomorrow afternoon. I pretty much finished everything I hope and just waiting for smaller inlet filters as the ones I bought are too tight of a squeeze.

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So excite!

Finally finished my base tune and ran the car with boost. I will be buying his GTR map sensor to SD tune it also (good idea?)

The car runs awesome and i will be tuning it more on the street as soon as my new filters come in. Ran it on wastegate boost (4psi) and it was awesome!

Dyno tune is in a week or two depending on the dyno's availability.

Grate job! Glad that it worked out.

CONGRATS man!!!!! Really impressive build.

As far as your question - my tuner (JTRAN) did not, to my knowledge, upgrade my MAP sensor so I think I am on a straight MAF tune. I think that choice is up to the tuner you choose... but it looks like Seb@SpecialtyZ prefers SD and people have had great results with his tunes.

Thank you! I can't wait till I can finally go WOT on this car but just hearing it spool is awesome.

Unfortunately I was trying to be stealthy but it looks like that's impossible as the turbos spool so loud and the BOVs are also really loud haha

https://uploads.tapatalk-cdn.com/201...bb839d443a.jpg

Running around the neighborhood with no front bumper showing off the intercooler is not stealth. :rofl2:

I'm still checking everything over! Bumper won't go back on until after the dyno tune so I can make sure there's nothing leaking etc



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Just a short video for you guys!


I drove the car around 50 miles on the base tune and so far so good.

I will be checking the car over on a lift tomorrow (friends shop) just to make sure that everythings good then i will be going to the tuner for more street tuning.

sounds $@%#ing awesome.

Dope

If I knew how to add a rep I would

Middle icon below the user's avatar (to the left of the Report button).

GT-R turbos on the VQ37
 

Turns out that the wastegate spring pressure is 8psi.. so I'm just going to skip buying a boost controller for now.

Got my boost gauge, oil pressure guage, and maybe going to order an AFR guage just for safety. Car runs awesome midrange but still can't go WOT yet.


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Team No-Boost-Controller unite!

AFR shouldn't be a maybe. I'd also add a fuel pressure gauge to your list.

I don't run one... but you are probably right. I am just kind of anti-gauge. So I just did boost to make sure I don't lose a wastegate line or something and don't worry about the rest. I don't have the attention span to pay attention.

:iagree: the AFR gauge is a most! can save you from a broken engine. Is one of the first gauge that I install on my Sti with the boost gauge ;)

I will get one as soon as i can afford it! I promise guys:driving:

One thing that worried me after finally fixing that oil pressure problem is that the car smokes on deceleration. I figured something must of went wrong as the car was ran without oil pressure.. Anyways, that was running cheapo walmart 5w30 oil.


I just did a final oil change with M1 0w40 and a good quality filter along with fixing a slight kink in the oil return line and guess what! no more smoke and it doesn't stink as i drive around anymore :tup::tup::happydance:

Now i'm just waiting for the tuner to schedule the damn dyno! He's been telling me he's busy for a week now.. :confused:

Finally got more street tuning yesterday and did a few WOT pulls. I don't think I've ever been in a car faster than this to be honest. Only problem so far is that it's running too much boost (assuming map sensor is accurate) so my fuel injectors aren't big enough haha
It spools to 8psi by about 2800 and then keeps going to 12 psi at 4k and stops climbing there.

https://youtu.be/VsTKDqG8Nmo


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those little turbos are spooling hard on you...

Some options off the top of my head, in the order preferred:

1) Get more fuel and make more power =)

2) See if you can reduce the tension on the wastegate springs

3) See if the wastegate flapper is large enough to port the wastegate out for more flow

4) Make your exhaust more restrictive - what exhaust are you running from the turbo back?

Aside from that, you can also consider the far more expensive options of plumbing in external wastegates or upgrading to much larger turbos =)

I'm sure someone smarter than me will chime in with more options as well =)

I wonder if your tuner can pull some timing to keep it from spooling so much on you? That is pure speculation as I do not really understand the technical aspects of tuning in this scenario.

Also, can you tell your camera holder that landscape is superior to portrait? =)

And...clarification on #2 above. Does it spool to 8psi then slowly climb to 12psi at redline? If so, wastegate tension won't help.. as you are just out-flowing them even with the flappers wide open.

GT-R turbos on the VQ37
 

I know I tell him all the time but he never listens!


Also, it looks as if like the wastegate is opening at 12 psi and not 8. I will check what's happening tonight.


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So I just did a log today to 5500 rpm (GTR map sensor)

The tune is running very low timing for now just for safety. Does this look like boost creep to you guys or just a higher psi spring?

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It looks pretty clear to me that your wastegates are set to ~12psi. It builds smoothly to that target and levels off.

I did some googling and it appears a stock GTR runs ~12psi... so it seems reasonable to me... though not exactly what I would have expected.

The million dollar question here is - can you change the springs on the OEM actuators, or adjust the tensioning?

Unfortunately not. I did research exactly that and everybody including my turbo said that running on just wastegate pressure (0 duty cycle in his gtr) it ran at about 8-9 psi. It's really weird that it's 12 psi on my car.


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Doing some more googling the answers seem a little all over the place.. though I haven't seen anyone say anything as low as 8-9... What model year did your turbos come from?

Here is the most informed-sounding (for what its worth) post:
Max boost for 2014 GT-R? - R35 GT-R - GT-R Life

I am seeing a lot of 11, 12, 13psi posts from people. I'd be inclined to trust that kind of number since it's backed up by your own data. The curve you posted looks pretty cut and dry to me... Does not look like boost creep to me at all.

Remember that the 3.8 and 3.7 are different motors. And the 3.7 is not a FI design. Any number of thing could cause the boost increase. Biggest I think is the difference in combustion ratios of the two. GT-R is 9 to 1, Z is 11 to 1.

This is true but I am not sure it applies in this case... If it was boost creep then these factors could certainly contribute. But to me this looks like his wastegates are opening at 12psi and they are activated purely on pressure alone...

Here is a great post from Visconti Tuning... It differs between years and it differs between gears. (Hence why it looks like most GTR owners have no idea how much boost they make in stock form)

Stock Turbos PSI - Engine - GT-R Life

The thing is, that's the PSI including the oem boost solenoid which does adjust boost to a certain level.


Another interesting thing I found is this chart. Look at the standard actuator psi!
https://uploads.tapatalk-cdn.com/201...29e3bf533e.jpg


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Not sure about that chart... kind of suggests that the spring pressure is 4psi but the boost control will take it up to 18psi... That's kind of out of whack... At that kind of differential I would start worrying that the pressure of the exhaust itself would push the wastegate open.

That being said.. if the standard boost floor was around 12psi I would expect the wastegate pressure to be a little less than that... but I can also think of reasons why you would want to set it up right on the target.

On way to test for sure is to pull your downpipes and run a regulated air pressure hose to your wastegates and slowly adjust until you see them start to open.... that would certainly take all the guessing out of it.

That's true. I will be verifying that the map reading is accurate with a boost guage just incase.


One more thing for you! Where did you route your wastegate lines? Mine is just ugly looking right now but I was thinking of running Hardline across the engine similar to the GTR setup.


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Last time I had to trouble shoot something like this on my old evo 3, I used one of those hand pressure/vacuum pumps and took note of when the actuator rod stared moving.

I didn't do anything fancy... I put a barb in the passenger side charge pipe (as instructed by the Gamma manual) and ran that up to about the middle of the front of the intake manifold, then tee'd them from there back down to each wastegate. Just like the BOV, my goal here was just to have an equal length of line going to each...

I did something similar. I guess I'll just keep it as is and see how it holds up.

Got my new 1000cc injectors installed today. Hoping this solves running out of fuel at the top end. I will be also getting a fuel pressure guage just to check on how safe it is. https://uploads.tapatalk-cdn.com/201...217916e318.jpg


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