Jump to content
SAU Community

Hypergear Turbochargers and High flow Services Development thread


Recommended Posts

My cold starts idle at around 10 on my wideband. I kind of actually can't stand the lean popping but I always thought it was something which shouldn't be happening. My car is sucking alot of air, -95 according to my profec b. My old car sat on around 85. When this one idles at 85, I know I popped off a vac line somewhere.

Ill take away some fuel and see what she does.

Link to comment
Share on other sites

I have no idea. It reads positive boost, for example, as 100 which is 10.0psi. 155 would be 15.5psi. It reads vacuum as -95 on idle, -50 maybe on cruising, so I have nfi.

Most likely -9.6mmHg then, that is fairly low. My skyline reads about negative 14-15 and negative 20 when backing off at higher rpm.

Link to comment
Share on other sites

Might be inches of mercury and not millimeters, and hence -0.99 inches, but that = -25mmHg which is far too high vacuum.

I'm stumped, it should be either of these units, I don't even know what else you can measure vacuum in. It is possible that 9.9 is just the maximum reading and it can't read any higher vacuum than that, when you back off at high revs does it read a number higher than 99 ?

Link to comment
Share on other sites

99 is the highest number it reads in negative pressure, vacuum. Then it bounces back to idle. My other boost gauge shows -20 vacuum when on idle. For me I ignore these figures. I listen to the engine and I can hear if it's idling right and feel it through that chassis. Feels good as is.

Link to comment
Share on other sites

It works like this .

You can't measure a vacuum because it is nothing zip zero zilch . Anything abouve a total vacuum is positive pressure even if it isn't as high as sea level atmospheric pressure here on earth .

The confusion exists because cork head humans got in the habit of measuring air pressure using two different base lines or datums .

1) Absolute Pressure Psi"a" . The correct way is to say a total vacuum is zero and anything above is positive pressure and it puts sea level airpressure at around 100 kpa/1000 millibars/14.7 psi (same). Some engine management systems read off absolute pressure with a manifold pressure sensor so 0 would be a total vacuum and 100 kpa sea level atmospheric pressure . Abouve 100 kpa is said to be positive pressure ONLY because its higher than atmospheric pressure . Anything from 1 to infinity is positive compared to absolute 0 .

2) Gauge Pressure Psi"g" . This is where pressure is referenced using sea level air pressure as 0 . When you have a compound gauge it trys to show you pressure thats lower than its 0 when the pressure is lower than atmospheric . They are really just a means of making a distinction between atmospheric pressure and anything thats added to it .

The silly thing is gauge pressure can make people think you can have a negative pressure when in fact technically speaking you can't have less than nothing .

From a tuning perspective I think absolute pressure (psia) is better to use because the graduations rising from absolute zero are easier to comprehend than ones rising either side away from an atmospheric pressure 0 datum .

Next time you look at a turbos compressor map pay attention to the pressure ratio (PR) scale . Because these pressures are a ratio of anything above atmospheric pressure to atmospheric pressure they will say for example PR = 2 when a compound guage shows 100 kpa/15 psi . This is because the first 1 bar (bar means barometric sea level air pressure) is just this and the second bar is the pressure above atmospheric .

An absolute pressure gauge would show atmospheric pressure as 100 kpa/15 psi and the second bar as 200 kpa/30 psi .

A .

Link to comment
Share on other sites

Also explains why 20psi with all factors the same isn't double the air of 10psi, it is actually 24.7 and 34.7 psi, so a ~1.3x increase in air, not 2x increase in air.

And explains why you make less power the higher up a mountain you go.

Edited by Rolls
Link to comment
Share on other sites

hey not sure if in right thread but since i have a hypergear turbo i thought id ask My atr43g3 turbo run at 18psi straight from the actuator but when i replaced the head gasket the exhaust cam was found to be 2 teeth out. Since i have put them back to proper timing car now boosts at 15psi Just wondering if thats happened to anyone else?

Link to comment
Share on other sites

Less restriction, hence same airflow produces less boost. You are probably making the same power yes?

edit: You said exhaust cam not intake cam, it has now advanced the exhaust timing, hence less energy is wasted out the exhaust, the turbo then sees less energy and spools less hence less boost.

Makes sense to me, your car is probably running much efficiently, however it is probably slightly laggier in regards to boost response, it will flow better in the high rpm now though.

Your power curve will have shifted towards redline slightly, you will make more power though, that is if you get it retuned on 18psi, DEFINITELY get it retuned, the load points will have completely changed, you could be detonating driving it like that.

Edited by Rolls
Link to comment
Share on other sites

Bugger another tuning session lol Makes sense though as the car is more lag down low but i haven't tried to feel whats up high

Also the tuner at the time overloaded the timing in the car by about 10 degress ( 35 degress at 6500 rpm ) I have backed timing off the whole chart down to 24 degress at 6500max after most of the spark plugs got destroyed with the head gasket.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • The two diagrams are equivalent. The R32 one is just one sheet out of about 3 showing everything in the whole car all at once. And without knowing the functionality that occurs in the modules, they are both equally opaque.
    • 8v - 2.48ms 9v - 2.15ms 10v - 1.74ms 11v - 1.41ms 12v - 1.15ms 13v - 0.99ms 14v - 0.89ms 15v - 0.82ms 16v - 0.81ms I'm running these values on my RB20 Neo with 570cc Denso R35 stock jets and it's great. Also bought a set for my Legnum VR4, love these injectors!
    • Thanks for your reply,  Those blue/green wires running to the actuator aren't attached to anything, so I'm not sure how the central locking is still working. I will have to take a good look tomorrow, I don't have the car with me. After googling it seems like a pretty common aftermarket actuator which even uses the same green/blue wires the immobiliser required. i'll test everything tomorrow and if it's working i'll melt the solder, strip it, resolder and neaten it all up with some heat shrink. I don't have to understand it if it works hahaha I just don't want a fire/ short circuit. That R32 diagram looks more like a continuity chart? Can you make sense of this form the R34 manual? 10V is probably due to very flat battery, i'll recheck as well tomorrow, I did have to jump start it haha. Thanks again!  
    • So, COM doesn't mean comms. It means common. What common itself means will depend on the type of device. For a two directional actuator (ie, one that can push and pull on the same output rod) then the common will typically just be the earth connection. There will be at least 2 other wires. If you put 12V on one of the other wires, then the actuator will push. On the other 12V wire, it will pull. Can't quite make out what is going on with the wiring of your actuator. It appears to have several wires at the actuator plug, but there only appears to be 2 wires where its loom approaches the door control module, with at least one of the others cut off. I don't know these actuators off by heart. I'd have to look at a wiring diagram for one before knowing what the wires were about, and that's despite me having to replace one in my car not all that long ago. Just not interesting enough to have dedicated memory set aside for trivia like that any more. That actuator is an aftermarket one, not the original one, which probably died and was replaced. That might require some sort of bodge job on wiring to make it work. Although nothing should justify the bodginess of the bodge job done. As to the soldering job on the door module's loom plug. Ahhahhahaha. Yes, very nasty. Again, I cant tell you what any of those wires do. You'd need to study the R34 wiring diagram (if you can find one that shows the door module). I don't think I have any. I'd have to study the R32 diagram to start to understand what mine is doing, and again, even though I've had a problem with mine for the last 25 years (where it locks the passenger door when the driver's window reaches top or bottom of travel) I'm just not interested enough to try to to work it out. So long as it's not burning down, it's fine with me. Here's the R32 GTR diagram, which, confusingly, has rear door lock actuators and window motors on it!! As you can see, unless you understand the functions of the door lock timer and the power window amplifier, you'll never be able to work out how it works just from the diagram. I don't imagine that the R34 one is any better. Hopefully an R34 aware bod can help. FWIW, the two wires that are cut and joined look like they are both power supply - so hopefully it is not fatal to join them. The 10V you measured on the cut off free end of one of them is concerning. You'd expect 12V, and it might be the reason for the bodge job joining them together.
×
×
  • Create New...