Turbo BS Thread

In this scenario, is the MAF pre or post turbo/s?

Also, the Tee going to air box will, before the check valve, unless at minimum a -8AN, will not be large enough a vent hose. It will also pull in vain from the air box, which would be unmetered. Unless that is placed post MAF. Without drawing it out, this is how it looks to work in my head.

Overall. Your plan could be made to work with refinement. However it is unnecessarily overly complicated. If the MAF is pre turbo, then you'll still get film buildup on the turbo and intercooler, but much less than without a catch can.

The method I proposed to pre-turbo, is far simpler, and easier to troubleshoot. No check valves needed. It is either under vacuum, or under super vacuum when the turbo spools. Which is actually quite beneficial, as it reduced the air acting as a resistance against the underside of the combustion side.

 

Hey everyone a young friend of the family ended up buying a sr20 swapped 240sx for too much and I am trying to help him sort out the issue of the engine rpms dropping when shifting almost to the point of dee stalling and stalling even sometimes. The issue is that I don’t have experience with this or other setups with turbos or their associated trouble shooting techniques. Here’s pics of his engine bay:



He also saw a video that the owner of a SR20 swap was having the same or similar issue and fixed it by relocating the MAF. I don’t see his MAF in his pics so I’m not sure if the guy in the video is having the same problem.

https://youtu.be/Y0h1Vl5upDQ

Any advice is helpful. I can help him with anything short of welding aluminum.

edit: I found that he has an aftermarket ecu with a map sensor.

 

I was about to say that it looks like there is a MAP sensor on there.

The catch can is open on one port. The line tss's onto the valve cover. Where does the other part of that tee go?

 

I reaaaaally want to work on that. Looks like fun!

 

Does anyone know if the 2rz/3rz injectors fit and work with a 05-12 2TR-FE? Trying to find 850-1000cc injectors but the highest I've found is 750cc on Fiveomotorsports.

Also curious if the fuel rails are compatible, or semi compatible with some fab

 

I seem to remember hearing about a 1075 cc or similar from somewhere, I can't recall where though now.

 

Did some research and created an easy guide for anyone to calculate their fuel injector size for their builds, works for any vehicle but I haven't seen any of this info here and thought it would be useful


How to choose the correct Fuel Injectors for your horsepower goals - Naturally aspirated and turbocharged/supercharged



1lb/hr = 10.5cc/min


.5lb/hr of fuel per 1 horsepower



How much fuel do I need to make ____ horsepower?

• Calculate flow rate for injectors at desired horsepower
  
  
  • Desired Horsepower ÷ Number of cylinders/injectors = Horsepower per cylinder
    
    
  • Horsepower per cylinder ÷ 2 = Flow Rate per Injector ( lb/hr )
    
    
  • Flow Rate per injector lb/hr × 10.5 = Flow Rate per Injector ( cc/min )
    

• Example: 2.7L 2TR-FE 4 Cylinder engine, desired horsepower = 250HP
  
  
  • 250hp ÷ 4 cylinders = 62.5hp/cylinder
    
    
  • 62.5hp/cylinder ÷ 2 = 31.25lb/hr
    
    
  • 31.25lb/hr × 10.5 = 328.125cc/min
    

“But.. But what about the turbo???”


Forced induction creates pressure in the intake manifold. Adding cylinder pressure decreases fuel injector pressure, which requires more fuel pressure to maintain a proper a/f ratio, which is why it’s important to have the correct fuel pressure and injectors that are slightly oversized so they’re not working at their 100% flow.


More air = more fuel

• Flow Rate per Injector ÷ .80 will give you the correct size for your forced induction application
  
  
• Example: 2.7L 2TR-FE 4 Cylinder engine, desired horsepower = 250HP
  
  
  • 250hp ÷ 4 cylinders = 62.5hp/cylinder
    
    
  • 62.5hp/cylinder ÷ 2 = 31.25lb/hr
    
    
  • 31.25lb/hr × 10.5 = 328.125cc/min
    
    
  • 328.125cc/min ÷ .80 = 410.16cc/min
    
    
  • Size up to a 450cc injector
    
    
  • Pshhhh noises with a happy truck
    

Always size up if you can, better to have the flow and not need it than go lean

 

You know you can just Google fuel injector calculator and get a billion websites that will do this for you, right?

 

I got a few different results from websites and wanted to learn it for myself and understand the process a little better.

 

Adding a boost line to the fuel pressure regulator will create a 1:1 increase in pressure as boost increases which will also compensate for the excess cylinder pressure, it already has a vacuum line ran to it from the factory so it sees vacuum when need be as well

 

You see different results depending on how simple or complex the calculator is. They'll all get you in the right ballpark, and they don't always make injectors that are exactly what the calculator spits out.

It's good that you took the time to learn what the different numbers are. However, even your numbers are a generalization. BSFC (brake specific fuel consumption), that 0.5/0.8 number, varies based on engine, efficiency, etc. Fuel pressure also affects fuel injector size.

 

Torspd, MAF is Pre-turbo, at airbox, so is only a slight vacuum.

Tee to air-box has another ck-valve, sucked closed during intake vacuum, BUT under boost/higher crankcase pressure>> the manifold line ck-valve closes due to boost and the ck in to the air-box would then bleed off crankcase pressure, as well as the opposite valve cover vent reversing and venting to post MAF (Pre-turbo). Are two Ck-valves, but creates a fail safe so leaking ck valve cannot Boost-pressurize the crankcase.

yes some film buildup opportunity at turbo, but none when intake has vacuum, and split duty when crankcase is pressurized. Unless oil passes thru both filters at airbox (uncertain, but suppose it might).

This one you proposed? Filter>valve cover in>other valve cover out> catch can>hose or tube pre-turbo.

The filter>valve cover in would need to be post MAF for metered air (or maybe eliminate any air inlet?). But also this means everything that gets past the Catch Can is consumed through the turbo/intercooler. Assuming that a sizable amount of driving is non-boost, the complexity might be worth utilizing manifold vacuum, when available. Although with a very Effective catch can; yours might be awesome. Will the seals of the crankcase hold up to Super Vacuum?

 

This one completely eliminate the ecu on how it was wired on my 99.

Harness was 500 plus 60 per added sensor.

I'll start hooking it up soon.

 

www.rceng.com

www.injectordynamics.com

Look for the calculators there.

 

That's how roots s/c systems work.

For our V6's, I recommend a -8AN hose. We can get away with -6AN, but once boost is pushing towards 15 psi+, -8AN is wanted.

 

You might try giving injector dynamics a call. I think i remember someone with a 2TR-FE running some 1050cc’s a while back.

 

I'd love to see an update when you do

 

How do you plumb turbo coolant lines and actually take advantage of the thermal siphon effect. Using a T doesn't seem to be ideal as water will take the path of least resistance. And plumbing inline of something would leave both hoses either high or low.

Coolant is only flowing through the heater core when the heat is on, correct?

 

I used the throttle body coolant lines on my 5vz fwiw. @Reh5108

 

It doesn’t have to be a solid stream of water to cool. I’ve seen equipment at my work that was water cooled overheat. We put a ball valve on the discharge side and pinched it off some and no more overheating. Seems counterintuitive but it redneck worked just slowing down the flow. Some turbos don’t even have a water line and are strictly oil lubed and cooled.

Never even thought of this. Good idea.