how to tune my plate system

Been reading and trying to learn about this whole nitrous thing. First off, let me say that I am not running a 1/8th, 1/4, or any type of asphalt car. I am running a mud drag truck that is going a max of 200'. My motor is a little D0VE headed 466 that makes good power (was dyno'd at 630hp@6800) and I'm spraying a 250 setup right from the NOS specs for the jetting for a Cheater kit (93/93) but when I put the recomended -10 plug with the 950psi bottle pressure and retarding my timing to 20* total (picked the medium for my well ported heads but I know they are no superstars either) the truck ran like a dog. Pulled plugs after getting towed back to the pit and they were a little dark like it was on the rich side. Playing around and making sure my nitrous system fuel pressure was set at 5.5psi, going to a #9 NGK and only pulling 4* of timing, the truck ran the fastest it's ever been. I ran a 3.8 second pass in a 150' pit with about 15-18" deep red VA clay on my cut tires! Pulled the plugs and they were the ashy grey, but a little on the white side. But I was told by a few other guys that run nitrous regularly that it sounded like i was leaning out on the end. I want to keep my motor safe, but want to keep it competitive, so here's where the questions come in.

1. I am running the -4an nitrous lines from the bottle all the way past the solinoid to the plate. Is it worth stepping up to a -6an lines? at least to the solinoid or all the way?

2. My fuel lines are 1/2" aluminum in the middle with -8an from the tank to the Holley blue pump to the aluminum tube, then to the regulator and stepped down to a -6an line to the solinod and from there to the -4 lines that came with the kit, should I bump that line up to at least the -6an?

3. If I'm running lean on the spray, should I go a little bigger on the fuel jet to help fatten it up or should I adjust the carb? I also run N/A classes, so I try to focus my tune for that and use the spray as a "bonus" for the 4-6 second hit. I don't go lean on the all motor runs, so was looking more to the plate system.

4. My nitrous system fuel regulator is the little holley dead head regulator, is it worth swapping over to a bypass style to keep more consistant fuel pressure for the hit?

I'm willing to play around some, but just want to keep my tunes stay a little on the conservative side to save the motor. I'm sure I'll have more questions to answer and ask, but figure this will be a good starting point.

how many fuel pumps? one to motor and one to Nitrous fuel regulator?

As far as going lean i do not think that is happening unless you are on one fuel pump for motor and nitrous.

a cheater plate at 93 squared should be extremely rich, you are maxing out the plate IMO i think you are masking the plugs by using timing to offset the rich burning fuel.

what is the base timing set at on the truck?
Do you know how much cranking compression the motor has?
What are the specs on he cam?
What Type of fuel are you runnin?

The holley regulator is fine

I have 2 fuel pumps. An Aeromotive A1000 to the motor with the Aeromotive regulator. The nitrous system has the Holley blue and regulator.

The best base timing is at 33* total on motor. With the flat top pistons, zero decked block, .041 compressed gaskets and slightly milled d0ve-c heads, I should be around 11.7:1 compression. Cam specs are solid roller cam 110lsa 268/277 @ .050 750/760 lift. Fuel, before the nitrous, i was running 110 beacuse it's easier for me to get than 104. With the 250 shot, I jumped to Sonoco 116 to be on the safe side.

My motor build is here:

https://www.429-460.com/t5399-466-ranger-build

Okay i may get burned for this but this is my suggestion and i have run this tune up in a cheater plate on a SBF and i have sprayed a BBF with over 400 of NOS with a direct port system with very good results

fuel pressure 5psi flowed with a 73 jet
Fuel Jet in plate 82
Nitrous jet 93

base timing down to 20 degrees to start with NITROUS ON

Make a pass then read plugs (heat in straps)

add timing back in motor as plug shows

your plug should clean the grey off and be white in color with just a hint of fuel ring at the very base of the porcelein.

number one improvement for plate order a Induction Solutions Selonoid he had them on sale to YB members just tell them you saw it on YB.

The only thing that concerns me is your tune was for a drag car. The setups for 1/8th and 1/4 mile cars is totally different than for a short distance mud drag truck. It's part of why I'm seeing it act so sluggish when I try to use the NOS tunes from their site. Was hoping to get some of the other mud guys that run nitrous to chime in.

send the plate and solinoids to Steve and get the stuff flowed. Or get a new plate and solinoids from him. That way you will know where your at, alot of the old plates are not very accurate.

That's probably going to be the solution. Gonna keep the a460 heads in the box for now and keep playing with the 466 for a bit. Might hold everything and get a set of domed pistions for it and let it eat.

kjett wrote:The only thing that concerns me is your tune was for a drag car. The setups for 1/8th and 1/4 mile cars is totally different than for a short distance mud drag truck. It's part of why I'm seeing it act so sluggish when I try to use the NOS tunes from their site. Was hoping to get some of the other mud guys that run nitrous to chime in.

i can assure that with a 10-11 jet spread with 5 - 5.5 fuel psi (82 -93) in a 200 foot pit , you wont use the word sluggish ........... but getting back to giving tunes out on the internet can be dangerous Send your plate to Steve to have all your parts and pieces flowed and blueprinted

Bruno,

As soon as I get a few weeks of down time between races, I'm going to send the stuff down to get set up. Or I may just say heck with it and have him set me up a fogger system and ditch the plate all together

kjett wrote:The only thing that concerns me is your tune was for a drag car. The setups for 1/8th and 1/4 mile cars is totally different than for a short distance mud drag truck. It's part of why I'm seeing it act so sluggish when I try to use the NOS tunes from their site. Was hoping to get some of the other mud guys that run nitrous to chime in.

I was just trying to help. but regardless, MUD, SAND, DRAG, BONNEVILLE . Nitrous does not know any different. its all about the correct air fuel ratio and the timing in the motor. A properly flowed plate will give you the help you need. Good Luck

I seem to remember reading at one time that the factory NOS tunes were extremely rich to keep a person from detroying an engine. Wouldnt a rich tune cause the truck to be sluggish?

PS I know little to nothing about nitrous so if i am wrong please say so.

You are correct. They are rich tunes to keep the newbies like me from destroying parts.


On a side note. I went out and checked, I am running a 93 nitrous and 83 fuel jets. I attributing my pass a few weeks ago to to crappy air and my lack of initiative to re-tune as the day went on. Last week it ran really really well, but the air temp/humidity was good. Guess after I get it flowed I'll have to get a weather station and re-tune for all that mess.

Hey Guys,
I would have to agree so far with what's been said. The NOS tunes need work to really perform in most cases..

Basically the nitrous solenoid is maxed out for one.

The fuel jet will require quite a change in most cases to even get a decent nitrous to fuel ratio.

As far as the tune, using a "drag car" tune in a mud application is not an issue. From what I have found working with mud and sand drag stuf, you can get away with a more aggressive tune in a mud or sand drag application then you can a drag car..

Here's a deal on a larger line upgrade if it would help you out...

http://www.induction-solutions.com/shop/product_info.php?products_id=292

As for the plugs, I doubt your even anywhere close to lean from the description you give of your plugs ?? Here's a set of plug i just had handy that sound like they would be cleaner then what you describe ??? But are not lean at all....



We'd be happy to help you in what ever way works for you. Hope this helps as well.. SJ

Steve,

Mine looked about the same with the -9 plugs, and only pulling 4* of timing. When I ran the -10 plugs and pulled the 10* that the directions gave they were all black and sooted up like it was way rich. I think I'm close, just need to do some tweeks to make it right and keep the motor safe and happy. If I make it through the rest of the season, I'm sending my stuff down your way to get loved on!

I'll be around if we can help.. Thanks, SJ