legacycentral bbs

I was just sayin'... Turbo lag (and off-boost performance) is the most significant weakeness of a turbo motor in my opinion, especially with relatively low compression. Nitrous oxide injection can eliminate turbo lag.

Thats why I said reduce

Now if you created a setup that took a signal from the vehicle speed sensor + tachometer and throttle position and it auto boosted at low speed low throttle high rpm then I would do it. The nitrous would last along time this way.

ciper - Yeah, that kind of thing is exactly what I'm talking about.

I think the slickest way to do it would be to use a little reluctor to measure turbine speed, and inject nitrous only when turbine speed is low and throttle opening is high.

czo79 wrote:I've thought about putting a nitrous kit in my GT...I can't decide wet or dry...

I thought dry kits were for N/A and wet kits were for FI. If that's not the case will someone enlighten me?

vrg3: Explain more how you would measure turbine speed

I don't have anything specific... I've just heard of systems that watch a small alternating current signal generated by a coil on the turbo housing (the blades of the turbine or compressor moving by change the magnetic flux through the coil). It's similar in principle to the crank and cam angle sensors and the ABS wheel speed sensors.

You could probably do just as well using compressor outlet pressure as an indicator of turbo speed at much lower cost and complexity though.

couldn't you also do it based on your vacuum/boost gauge. Like if you're at wot and like 0psi or less it'd activate.

Yeah, but you'd also want it to activate when you're at part throttle if the turbo isn't fully spooled up, right? Compressor outlet pressure is a better indication of how fast the turbo's spinning than manifold pressure.

Actually, if you really wanted to know the rotational speed of the turbine, I guess you could measure airflow via the MAF sensor and measure compressor outlet pressure with a MAP sensor placed upstream of the throttle body (and intercooler if present), and then look up rotational speed on the compressor map.

Good idea, so pressure sensor when reading say 16psi or below and 90% or above throttle! That would be really easy!

yeah i mean, it deosn't have to be only at wot or at a certain psi. what's the advantages of knowing how fast the turbo is spinning aposed to just knowing the boost/vacuum?

I'm not saying that you couldn't infer the same information from TPS and MAP measurements. It just might be harder. The point is that you need to take into account the fact that the throttle plate is a pressure drop.

For example, if your desired peak boost level is 16 psi, and your throttle is halfway open, you might have the turbo fully spooled up while only measuring 9 psi in the manifold. Under such circumstances you wouldn't want to be injecting nitrous.

But, yeah, a simplistic setup might multiply throttle percentage by peak boost and use that as a threshold against manifold pressure.

Matt - The difference between dry and wet kits is just whether or not fuel is injected with the nitrous oxide. Wet kits inject both mixed together, so the intake manifold is "wet" with fuel. Dry kits inject just the nitrous oxide gas and manipulate the car's stock fuel system (by adjusting fuel pressure, injector pulse width, or both) to get the right amount of fuel.

Either system can be used with N/A or FI. Wet systems don't always work so well on N/A cars because the manifolds aren't designed to allow fuel to flow freely through them; the problem is somewhat mitigated with FI because of the turbulence and increased flow. Dry systems often require fuel system upgrades though, like larger injectors and engine management modification.

gotcha

the reason i cant do anything except nos is because 1. i dont have much money and i would like to get an intercooler but i dont want to cut a hole in my hood to acomadate a tmic and a fmic is 600 for the instal+ the price of the intercooler you wish to buy. and a exhaust is 1600 for a turbo back and 650 for the cobb exhaust unless you want a crush bent exhaust from midas or master muffler. and if i could get a better turbo for less than 600 that was straight bolt on i would but the way the oe turbo is clocked it just aint happnin. oh and i dont need a civic i already have one that out handles my sube for now at least. i just ordered whiteline and agx combo from pdm and brembos. all that set me back to the point that nos is my last resort. yes i want to unleash the full potential of the turbo but the steps up for now at least cost more than the car is worth.

why doesn't your hood have a scoop?

as for your reasoning, see my other post.

azn2nr wrote: i dont have much money and i would like to get an intercooler but i dont want to cut a hole in my hood to acomadate a tmic and a fmic is 600 for the instal+ the price of the intercooler you wish to buy. and a exhaust is 1600 for a turbo back and 650 for the cobb exhaust unless you want a crush bent exhaust from midas or master muffler. and if i could get a better turbo for less than 600 that was straight bolt on i would but the way the oe turbo is clocked it just aint happnin.

1. You definitely don't need to cut a hole in your hood to fit a tmic...
2. 1600$ for an exaust?? You can buy a 3" WRX DP then go to any decent exaust shop and get a 3" made for less than a quarter of the price for the "turbo back"
3. No turbo is just "straight bolt on"

I guess what I'm trying to say is not that N2O is bad, or that you shouldn't get it, but that you would be much better off doing an IC/Catless Exhaust/Boost Control/FCD, which WILL unleash the full potential of the stock turbo.

i dont have a hood scoop because i rearended a lady who slamed on her brakes for no reason and mine decidid not to work. so now i have a silver n/a hood and a gap between my hood and headligths cuz i was too cheap to get a new ratior support and just pulled the bent one stright as posible. and yes a muffler shop and build a exhaust for cheap but a large exhaust with crush bends is just about as good as a stock system with mandrel bends. and also i read that a wrx dp dosent fit on our cars but the hks headers and up pipe did. if you could clairify that would be great.