Jump to content
SAU Community

Recommended Posts

Has anyone got a website handy that explains all about, Timers, BOV, FMIC etc.

I'm new to Skylines and turbo..... and well we all gotta learn sometime.

Normally i'd search for an answer to this question no doubt its been asked before, but have you ever tried to search for 'turbo' on this forum you get like 3000 results, heh.

Link to comment
https://www.sau.com.au/forums/topic/35150-after-some-turbo-info/
Share on other sites

Hmm, well I dont know about any websites. Have you tried a search engine, like google?

I can try and help a bit here if you like, as I know the frustration at typing common words.

Turbo timers - delays the engine switching off after you turn off the ignition. This is to allow the turbo to cool down. If it doesnt cool properly, the heat in the turbo can cook the oil in it, this is sometimes reffered to as 'coking'. the oil being coked on the inside of the turbo catridge can cause it to seize, thus the turbo will cease to work and need rebuilding.

the cartridge is where the bearings are between the compressor (inlet side) and turbine (exhaust side), and has a shaft through it mounted on bearings that allows the turbo to spin

Two main types of turbo timer, manual, where you set how long the car should idle for, or automatic, where the timer calculates how long to keep the engine running. Usually an auto timer will allow manual operation as well if desired.

BOV - when a turbo is making boost (positive pressure, so the air is compressed) and you take your foot off the throttle, the compressed air cannot move into the plenum (the plenum is after the throttle body, and distributes the air via 'runners' to the cylinders). A BOV will allow that air to be returned infront of the turbo or to atmosphere.

Without a BOV, the compressed air will revert back through the compressor, causing it to slow very quickly. This can cause alot of stress on the turbo, as they can spin at well over 100,000rpm. Another down side is that it takes time for a turbo to spool up again after being slowed, so it may induce what is called lag, where the exhaust gasses will take a moment to bring the turbo back up to speed.

Older cars didnt have BOVs, but nowadays all turbo cars (that I know of) in production have them for longevity, and for the sake of reducing lag.

FMIC - front mount intercoolers allow better cooling of the charge air (the air out of the turbo). It is like a big radiator to cool the air before it goes into the engine. Most stock intercoolers are very poor in design, and will not remove much heat from the charge air. You need to understand that when air is compressed it heats up. this is done firstly at the turbo, secondly when the piston compresses the air fuel mix as it moves upwards - two lots of heating compared to a NA engine only heating the air once.

Two big benefits from cooling the charge air.

- Firstly, the warmer the air, the more prone it is to detonation. Detonation is the spontaneous ignition of the fuel air mix in the cylinder, before the flame front started by the spark plug sparking. Fuel and air, when mixed, if heated enough will spontaneously combust - it is a violent explosion, compared to a controlled burn caused by the spark plug - it has the potential to smash pistons and hammer bearings). It is absolutely of the highest importance to prevent detonation. It is also called pinging or knocking.

- Secondly, the cooler the air, the denser it is, the more Oxygen, which means the fuel can burn better. this produces more power - just like when you drive your car on a cool morning compared with a hot afternoon.

Possible downsides to an intercooler is that if it is too big for the application, it may increase the time taken to build boost pressure, as the larger the area that the compressed air must fill, the longer it takes to fill. Just about any intercooler is going to be better than the stock ones on a GTSt, the GTRs however get very good intercoolers for applications up to around 300kw.

A poorly designed intercooler can be a waste of money too, as alot of science goes into designing a cooler to cool well whilst not causing a large pressure drop at higher boost levels - pressure drops can be caused by poor flow characteristics, such as the stock GTSt cooler:)

well theres some beginnings, I am sure you will only have more questions now, so fire away:) and welcome to the world of turbo cars and SAU

I suggest you just trawl through all the posts here. Stick more to the forced induction performance section.

You'll see links to other websites along the way; go there! There's no easy answer. If there was you wouldn't remember it anyway. Repetition works Jive. Repetition works Jive. Repetition works Jive. Repetition works Jive.

Happy surfing.

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

    • Update 3: Hi all It's been a while. Quite a lot of things happened in the meantime, among other things the car is (almost) back together and ready to be started again. Things that I fixed or changed: Full turbo removal, fitting back the OEM turbo oil hardlines. Had to do quite a bit of research and parts shopping to get every last piece that I need and make it work with the GT2860 turbos, but it does work and is not hard to do. Proves that the previous owner(s) just did not want to. While I was there I set the preload for the wastegates to 0,9bar to hopefully make it easier for the tuner to hit the 370hp I need for the legal inspections that will follow later on. Boost can always go up if necessary. Fitted a AN10 line from the catch can to the intake hose to make the catchcan and hopefully the cam covers a slight vacuum to have less restrictive oil returns from the head and not have mud build up as harshly in the lines and catch can. Removed the entire front interior just shy of the dashboard itself to clean up some of the absolutely horrendous wiring, (hopefully) fix the bumpy tacho and put in LED bulbs while I was there. Also put in bulbs where there was none before, like the airbag one. I also used that chance to remove the LED rpm gauge on the steering column, which was also wired in absolute horror show fashion. Moved the 4in1 Prosport gauge from sitting in front of the OEM oil pressure gauge to the center console vents, I used a 3D printed vent piece to hold that gauge there. The HKB steering wheel boss was likely on incorrectly as I sometimes noticed the indicator reset being uneven for left vs. right. In the meantime also installed an airbag delete resistor, as one should. Installed Cube Speed premium short shifter. Feels pretty nice, hope it'll work great too when I actually get to drive. Also put on a fancy Dragon Ball shift knob, cause why not. My buddy was kind enough to weld the rust hole in the back, it was basically rusted through in the lowermost corner of the passenger side trunk area where the wheel arch, trunk panel and rear quarter all meet. Obviously there is still a lot of crustiness in various areas but as long as it's not rusted out I'll just treat and isolate the corrosion and pretend it's not there. Also had to put down a new ground wire for the rear subframe as the original one was BARELY there. Probably a bit controversial depending on who you ask about this... but I ended up just covering the crack in the side of the engine block, the one above the oil feed, with JB Weld. I used a generous amount and roughed up the whole area with a Dremel before, so I hope this will hold the coolant where it should be for the foreseeable future. Did a cam cover gasket job as the half moons were a bit leaky, and there too one could see the people who worked on this car before me were absolute tools. The same half moons were probably used like 3 times without even cleaning the old RTV off. Dremeled out the inside of the flange where the turbine housing mates onto the exhaust manifolds so the diameter matches, as the OEM exhaust manifolds are even narrower than the turbine housings as we all know. Even if this doesn't do much, I had them out anyways, so can't harm. Ideally one would port-match both the turbo and the manifold to the gasket size but I really didn't feel up to disassembling the turbine housings. Wrapped turbo outlet dumps in heat wrap band. Will do the frontpipe again as well as now the oil leak which promted me to tear apart half the engine in the first place is hopefully fixed. Fitted an ATI super damper to get rid of the worn old harmonic balancer. Surely one of the easiest and most worth to do mods. But torquing that ARP bolt to spec was a bitch without being able to lock the flywheel. Did some minor adjustments in the ECU tables to change some things I didn't like, like the launch control that was ALWAYS active. Treated rusty spots and surface corrosion on places I could get to and on many spots under the car, not pretty or ideal but good enough for now. Removed the N1 rear spats and the carbon surrounding for the tailpipe to put them back on with new adhesive as the old one was lifting in many spots, not pretty. Took out the passenger rear lamp housing... what do you know. Amateur work screwed me again here as they were glued in hard and removing it took a lot of force, so I broke one of the housing bolts off. And when removing the adhesive from the chassis the paint came right off too. Thankfully all the damaged area won't be visible later, but whoever did the very limited bodywork on this car needs to have their limbs chopped off piece by piece.   Quite a list if I do say so myself, but a lot of time was spent just discovering new shit that is wrong with the car and finding a solution or parts to fix it. My last problem that I now have the headache of dealing with is that the exhaust studs on the turbo outlets are M10x1.25 threaded, but the previous owner already put on regular M10 nuts so the threads are... weird. I only found this out the hard way. So now I will just try if I can in any way fit the front pipe regardless, if not I'll have to redo the studs with the turbos installed. Lesson learned for the future: Redo ALL studs you put your hands on, especially if they are old and the previous owners were inept maniacs. Thanks for reading if you did, will update when the engine runs again. Hope nothing breaks or leaks and I can do a test drive.
    • No those pads are DBA too  but they have colors too. I look at the and imo the green "street" are the best.
    • I’m not sure what happened I told them about sonic tunes free OTS tune and the next the I know .. I was booted..   To funny 
    • Yea - I mean I've seen my fuel pump which is decades old and uh, while I'm not saying this with real knowledge... but I sure get the ick at using anything in the fuel system that produced the state of that pump. Many years ago I went through multiple pumps (and strainers) before I dropped the tank to clean it out with extreme violence. I'm talking the car would do maybe 50km before coming to a halt, which resulted in me cleaning out the filter with some brake cleaner and going on my way. None of my stuff ever looked like what came out of your fuel tank. I don't think I'd be happy with it unless every single component was replaced (or at least checked/cleaned/confirmed to be clean here).
    • I'm not going to recommend an EBC pad. I don't like them. Just about anything else would suit me better. I've been using Intima pads for a while now.
×
×
  • Create New...