NITROUS OXIDE ( nos / n2o ) advice forum

Trev I know a way he could get rid of the fuel build up is if he ran his nitrous like I do and that would help pull most off the fuel from the injector and I would switch to 2 sol. 1 for each bank with shorter more effciant lines.

Just food for thought...

To answer the question of where the build up comes from, two main sources. It is associated mainly with startup. I use a gasoline squirter to prime the engine that is located about 8 inches from the throttle body. When I maintain a tight throttle opening, that gasoline will turn to a spray as it passes the throttle blade during cranking. Some, if not most of it, simply drops to the floor of the plenum. The other main source is water build up. The alcohol causing such a cold interior in the plenum, especially during cold start up, creates some frost build up that eventually melts into water and collects. If I run the engine in a manner (make a pass) that allows the engine to get really warmed up (hard to do with an alcohol engine unless you do a full pass) the build up will evaporate away without draining. I prefer to drain it though, before a pass, the reason being that I don't want that pool of water, and 'gasoline' first time of the day, suddenly turning to a vapor and running through the engine at high load. Not sure what could potentially go wrong in a situation like that and don't want to find out. I'm sure some of it is simply fuel spitting back out from the intake ports also, do to reversion and pressure pulsing, but water is the main content. Another neat consequence of having to drain the plenum is that I can monitor what is going on in the plenum. One very good example is when one time I drained it and I had an abnormal amount of water. Can anyone quess where it came from? Not engine coolant. Luckily, that instance allowed me to catch a very potential problem that might very well have hurt the engine.

The plate at the middle of the internal fuel rail is nothing more than a slip over support. There are small bolt holes on the top of each side that secure the support plate to the plate of the upper plenum cover. For now, I've left it without any cutouts just to see how it affects things. If I need to, I'll cut some pass through openings in it so it's less of an interference to flow. The design of the upper piece of the manifold does require some use of devices to equalize the air flow to all the ports. I was debating whether or not to post the pic of the inside of the upper piece and figured if your wanted to see it, you'd ask. I'll get to it.

Donnie

You may want to consider tapping into the plenum else where and add a petcock or saomething to create a vacum leak during warm up and this will heat the engine up faster and with less condisation.20 plus years ago I was running a alky set up and I had problems warming it up on cool weather and did the above and it really help getting the eng temp up.

I understand what you're suggesting, but because I'm running a speed density EMS, the vacuum leak would do nothing more than raise the idle. Any change in manifold pressure is compensated by the fuel VE table. I suppose I could program, and I've thought of this before, a small area (rpm/map) in the VE table that I could run leaner and just step up the idle into that area to have it, basically, automatically run leaner. Actually, the engine does fine to warmup and maintain a good 150 to 160 degrees F before a burnout. A little better than a mechanical injection setup.That just doesn't seem to burn off that puddle in the plenum fast enough.

Sorry I forgot that your running EFI, but you stated you could change your mapping .Is your 1st pass your slowest ?

All very interesting and not what i was expecting.

Glad I didn't guess.

I'm also guessing the source of the extra water is going to be something outside my realm of experience, so I'll wait for your expose but I can only imagine it's from the fuel, as coolant and fuel are the only 2 'normal' liquid sources in the engine.

Ps. You were right about me asking. lol


Regards

Yes, it is. Some of the reason being the engine is blowing out some carbon buildup from being on gasoline during storage. I love tinkering with this engine, and when it's on the gasoline, I play with the engine management. It runs well enough to move the car around, but I'm sure I'll eventually have a gas program that's dialed in as well as the alcohol program. Dual fuel race car. Thinking of the environment.

I'll give it a day or so to give people a chance to offer a guess. A clue is to read back through the thread. The answer is there. It caught me off guard too.

Then you should look to Ricky and Brent Dyer and use Corn Fuel...lol I love it and like Trever is with N2O Ricky and Brent are the equal with ethonal.

I switched this year with there help and I love what I am seeing so far.We are running E85 and 13% is racing gas .Do you see alot of fuel and water in your oil?

Before adding a 4 vane moroso air pump, I would need to change the oil after a days worth of racing. Mainly water contamination. Now I can go 5 meets before changing it and that's just because I'm being cautious. The oil still looks great! I have the air pump setup to circulate air through the engine. The breather on the opposite valve cover is open. I'm not building crankcase vacuum at this point. In the future, I may play with that a little. With the EFI setup, I can run a tighter ship on the mixture and I'm sure it's causing much less fuel contamination than mechanical injection.

View of engine out of the car.


Earlier nitrous fuel plumbing setup.

More detailed pics of the intake.

You can see the drain fitting boss at the bottom, rear of the plenum.

I think this picture of the intake just looks wicked.

More pics.

You can see the compact design for the nitrous nozzles that I had to use in the background. Sealed by o-rings. Held in position by hold downs. Not threaded. The majority of the manifold is a bolt together, modular design. The intake plenum, runners, runner entries and intake flanges unbolt from each other.

Airflow distribution vane at the rear of the drop down. Helped quite a bit from simple testing on the bench.


The mounting holes for the internal fuel rail support are not in these earlier pictures. They are located at halfway, front to rear, on either side, on the flats. The other holes you see there are just pressure take off fittings.

You're teasing me now by keeping me waiting for the inside shot of the upper manifold. lol

There it is for you.

I've got to say there are some outstanding examples of engineering excellence in your creation.

OK - I now have enough info to design a solution.

We have 2 options for the ultimate system design/function;

Option 1 consists of
3 prs of Pulsoids mounted on the central axis between the cylinder banks above the manifold as low as possible.
The output from each of these would be split in to 2 and feed one cylinder on each bank, either internally or externally

Option 2 consists of
6 prs of Pulsoids mounted off the outter edge of the manifold.
Each output from the nitrous would feed each cylinder through our unique discharge system, that would be positioned where your current internal fuel discharge nozzles are currently positioned.
Each fuel feed could be connected to your current fuel discharge nozzles.

The only thing against these options is that they are overkill unless you intend to take full advantage of what they can deliver.
However pulsed response will be OUTSTANDING and deliver outstanding control.

Having said all that I HESITATE to make the following suggestion, because the outstanding standard of the engineering on your engine cries out for a nitrous system to the same standard but I'm reasonable confident that a single Crossfire injector system, would do a more than adequate job (contrary to what many people may think), unless you intend to lean on the nitrous delivery.
Just for your information, we've often achieved MUCH better results using our single Crossfire injector systems, than our conventional direct port systems achieve when modest power increases are required.

I look forward to your response.

Regards

Donnie have you ever tried a differant support for the fuel rail. Example like a center support and both ends. Air and fuel do funny thing within the plenum. How far down does the support go now?

Please know i not trying to knock anything you have now only trying to help.

Right I'm guessing it was a cracked intercooler.

Regards

No. No. Constructive criticizm is always welcome and I greatly do appreciate it. It makes me think. I actually did struggle with the design of the support for a day or so. Usually, I will spend a week on a design, waking up the next morning with light bulbs going off in my head. You know what I mean. But, I was in a crunch with this fuel system change. An important race event was coming up and I was eager to attend and do more test and tuning. It was a simple, fast solution. The support does not go to the bottom of the plenum. There is clearance below the support for flow and it locates at least an inch and a half ahead of the distribution vane that's welded to the inside of the cover. It looks like it could help more at keeping a pile up of flow ending up at the rear of the plenum, so I'm just going to give it a try and see what happens.
If you see anything else that doesn't look right, don't hold back. I do appreciate the effort to help.

Correct!

Forgive me. I'm getting through your book very slowly and haven't gotten to the part that explains the crossfire system. I assume it's a single point injection system that would fill the complete plenum with mixture. I would really rather stay away from that. With a waste spark ignition system and the amount of cam duration and overlap I'm running, I would not want to experience an intake backfire with a nitrous mix in as large a plenum as I'm using. I'm going to digest the other suggestions a bit more.

Thanks Trev

Well even with 1 1/2 clearnce and its only air there is reverstion in that manifold so you may at a later date and time want to mount it at the ends , you might be ok with it there but just food for thought.

I would mount 2 pair of Pulsoids to each side with and use a Max extreme and you would get more that way with the same size jetting and get 20 to 30% more power easy.