Hey guys - I don't usually frequent this area/forum much but I know a lot of you run nitrous setups and I am looking for some advice. I have had a NX EFI kit installed on my turbo BMW setup a long time ago (Holset T3 w/ stock engine) and sprayed it a few times but it was a very rudimentary setup - it had a WOT switch and an arm switch. That's it. That was years ago - since then I've built a different setup using a Precision T4 76mm turbo on a built motor, etc.

In the meantime I have picked up both a direct port wet kit (6 cyl) and have my single port wet nozzle as well. I have NX lightning solenoids (stage 6 0.093" orifice, http://www.nitrousexpress.com/produc...ils.php?id=205).

Now, I want to install the system on my car to help spool up. So, I am thinking 50 - 75 shot single port for now without introducing the direct port. I had the direct port installed on the factory plastic manifold and it did not feel secure with boost going through it + holes drilled - I felt like it was dangerous to shoot a wet shot and risk the nozzles blowing out, squirting fuel and nitrous lol.



So, with that, I had an intake made and have been running that for a bit now with direct port methanol injection:





I now have an adequate manifold (that I'd hate to drill and tap, but I guess I could...) and all of the nitrous parts I am re-visiting my setup. I have a couple spare outputs on my ECU (standalone) that I am thinking of using to control the system. The problem is that the outputs can only provide 1A - 4A of current. The nice part, though, is that they let me tap into TPS, load, RPM, etc., without piggybacking signals or messing with wiring.

My thoughts were using an output on the ECU as follows:

http://www.flickr.com/photos/67031861@N08/8321593968/http://www.flickr.com/photos/67031861@N08/8321593968/ by http://www.flickr.com/people/67031861@N08/, on Flickr

Little confusing if you're not familiar but basically it's using RPM as the primary criteria with throttle as 2ndary.

It's showing that the output (AUX1) will be 100% on at 3500 RPM and throttle 100%. You can see the ignition compensation as a percentage but I fixed that to a fixed amount of degrees. I can also add fuel (this brings me to the next question).

Does anyone here have experience doing this? How much fuel would one add? With a wet shot you're really just adding a percentage as well because the fuel nozzle is fixed and changes with fuel pressure - so I should be able to get it pretty darned close doing it this way, yeah?

Questions are:

1. Does anyone know a good X% of fuel per Y HP shot rule?
2. How do you guys control solenoids? I read that they can draw up to 9 - 10A each. My ECU outputs only 1 - 4A over this output. Solid state relay? Circuit using a MOSFET/IGBT transistor?
3. Should I switch over to my direct port system and if so, do people run direct port but dry?

Any insight is greatly appreciated - I have my purge solenoid coming, bottle gauge, etc., all coming - so I'd like to make this happen sooner than later. I just need to figure out the best way to drive the solenoid. Also, for right now, I am going to just hit it on at 100% DC. I was thinking though of trying to pulse a larger shot later on.

Thanks guys.

 

You have an awesome setup man. Looks killer. I would like to note a few things. You need to make sure that the car is truly at a 100% tps as with gm dbw is 87%. Also if you're already at 100% dc without the addition of nitrous then I most certainly would not recommend spraying a dry shot. A wet shot would be dependent upon your fuel system (ie fuel pump). As you know as a starting point you should pull 2 degrees for every 50 hp of nitrous. I would start with adding %25 fuel, make a short pull, and then make adjustments to get a/f in check.

 

Thanks.

Sorry when I said 100% DC, I am talking about duty cycle on the nitrous solenoid, not the injectors. I am running 1,000cc/min injectors per cylinder. My throttle is mechanical so its calibrated that 100% = 100%. I am just unsure of fuel to add. Timing pull is relatively simple.

 

Typical BMW guy trying to make up for lack of cubic inches...

 

Making more power w/ 2.8L than 5.7L

Snappies!

 

I use a wet setup, bu this may help(bfsc below are rich):

car without nitrous:
400hp x 0.5bfsc = 200lb/hr/6cyl = 33.3 lb/hr per cylinder.

car with nitrous
475hp x 0.6bfsc = 285lb/hr/6cyl = 47.5 lb/hr per cylinder

estimated increase= 47.5/33.3 = 1.42, about a 42% increase.

 

That's because I have it on the baby boost setting. One day I'll get serious and spin this blower and make some powa...