Red Heartbeat

iTrader: (9)

I had the nastiest nitrous backfire on my moneymaker kit. I have basically a 1998 stock T/A LS1 engine with a comp cam specs 232/228 610/595 113, 243 heads with dual manley springs and titanium retainers good for .650 lift. I run a Walbro 255 in-tank fuel pump regulated by a Corvette return-style internally regulated fuel filter. I am only running 24 degrees of total timing. The pills installed for the kit are the standard pills used for a 150hp shot. I don't have a pressure gauge but it was plenty hot that ill-fated day. The backfire knocked out the no. 7 plug insulator and it fell into the cylinder taking out a valve and seat along the way when the valve slammed shut on it and then the piston packed it tight on it's way up.

Oh yeah, it was a freshly filled bottle, my second one on this kit. The plugs I was running were NGK TR55s. I have since changed to TR6s after the rebuild.

Any idea what could have caused the backfire?

383LQ4SS

iTrader: (33)

Please describe this backfire. Did you blow up the intake into pieces? or just hear a POP out the tailpipe?

It appears to me your TR55s may have been too hot a plug and came apart. At a minimum you should have been running TR6. Also...never spray a kit you dont have any idea what the pressure is. if it was "plenty hot" outside that may mean 900 psi...or it could mean 1200 psi. The bottle pressure is critical to you overall HP rating and the AF ratio.
How are you activating the system? RPM window switch? At what rpm does it engage?

My guess is your plugs where too hot and you were lean.

Fixes are:
get a gauge
get TR6 plugs
tune it on a dyno with a wideband, note the bottle pressure at your optimal tune and alwasy run that bottle pressure with those particular jets
Dont leave things to chance

Red Heartbeat

iTrader: (9)

Backfired through the intake. Blew the air cleaner off of it and bent the throttle body blade into a c-shape. Also, blew the plug for the EGR mount. All those loose areas saved the intake. Yeah, TR55s. Now running TR6s.

Red Heartbeat

iTrader: (9)

The activation was a toggle switch and I have a full throttle pedal activation switch to verify full throttle when the "ON" toggle is active. I have a 3600 RPM Vig stall converter to make sure it doesn't come on when there is too little RPM going on.

TwoFast4Lv

iTrader: (8)

Yeah...might want to back that timing down

CAT3

iTrader: (9)

Timing shouldnt be an issue at all with 150shot, unless your running **** gas, or have messed up system. Pressure...man o man..as Al stated, jetting vs pressure is crucial on a wet kit more so. I burnt some plugs before, found out later the pressure was over 1400psi...when I swapped jets to run my target AFR at only 900psi, big fricken difference.

blacktransam

iTrader: (13)

yeah bottle pressure i bet did it..

Mike

NXRICKY

iTrader: (1)

The broke porcylin or insulator is could be the cause of the back fire. NOW what caused the that to break, detination thats for sure. That is the only thing I know of that bust's up plugs.
Start with checking all the jets, nitrous and fuel. see if there is any trash in them. also check the noids for piston swelling on fuel or trash in the nitrous. Without a gauge on the bottle you have no way of knowing the psi in the bottle. As AL and others have noted.
Since you have already ran one bottle throu the system with no troubles it leads me to believe 1 of 3 things.
Tune up went way off base. ( bad fuel, too much nitrous or fuel)
The motor lugged. ( just because you have a stall does not mean you can lugg an engine.
Bad plug and it was its time to go.

after typeing that I read this.

this statment means the throttle blade was closed when this happened. Check the nitrous noid for trash. The plugs damage could be just that plug damage and may have happened before you lifted. closing the blade, nitrous noid with a little leak, plug trash hangs the intake valve open and BOOM.


I am thinking that one could have lead to the other but no sure since the boom happened while off the throttle...

Ricky

Nitro Dave's Nitrous Outlet

iTrader: (25)

OK,
AS stated above here are the things you need to know.
Bottle pressure and air fuel.

Are you using the 150 jetting for the money maker or are you using the standard 150 jetting that goes to the NX kits. The money maker jetting is different than the other kits.

Tr55s are deffintly a no no.

If you do not have a window switch get one..
Dave

Red Heartbeat

iTrader: (9)

How can you regulate the pressure if it gets too high? I understand heat for too low. 100 degree evenings down here in Texas can really heat up a bottle but I see guys at the track running NOS in the heat all the time. How do you get the pressure down? What is the best bottle pressure to tune the engine? Is there a regulator similar to the ones on my oxy-acetylene rig that will help if over-pressure?

Nitro Dave's Nitrous Outlet

iTrader: (25)

Ideal bottle pressure is about 1,000 to 1050 psi.

YOu can purge the system to bring down the bottle pressure. Or put a cool wet towl on the bottle.

To much bottle pressure can cause the solenoids to hang open.
Dave

Red Heartbeat

iTrader: (9)

I am using the standard NX jetting. I looked and looked and found no different jetting list for the money maker and posted a couple times for a jetting list but it seems nobody had one or they were using standard jetting or were not going to show their hand that they owned one of the kits. Can you post the jetting list?

TwoFast4Lv

iTrader: (8)

While I agree with every thing else said here I do think even with a 150 kit you should be pulling some timing. 24 is alot for a good running LSx based car running a 150 shot IMHO I just think the SAFE bet would be to take just a hair out. Just in case you have a Issue like you pointed out.

Nitro Dave's Nitrous Outlet

iTrader: (25)

Ohh theres your main problem then. I try to watch the boards but we are way to busy to stay on top of them all the time. You should have called us. Never guess on jetting. That could have just cost you your engine.

Im assuming you are running high presure at 55psi

HP--N--F
50-41--24
100-57-31
150-70-35
200-82-40
250-88-42
300-99-49

Let me know if you need any help.
Dave

Red Heartbeat

iTrader: (9)

58 lbs of fuel pressure, constantly, according to the gauge and the internally regulated Corvette fuel filter. I guess that would fatten the fuel up which is always safer in my books.

Nitro Dave's Nitrous Outlet

iTrader: (25)

Ok go with the jetting above.
Dave

Red Heartbeat

iTrader: (9)

I'll have to order some more jet then, since the 20920 kit doesn't have many of those listed.

Nitro Dave's Nitrous Outlet

iTrader: (25)

No problem. We stock all the jets. I just sent you a pm on somethings to go over.
Dave

Cliff

iTrader: (19)

Sounds like a activation switch is also needed. Just because you have a 3600 stall and a wot switch does not mean your nitrous will wait to activate above 3000 rpm's. I made the same mistake and my nitrous engaged below 3000 rpm's and took out the complete top end of my motor.

Red Heartbeat

iTrader: (9)

I am going to get an RPM switch. When it blew I purged at the line and turned the NOS power switch off. I then staged and when it hit about 3500 RPM I turned the solenoids back on via the power switch. I think it was just too lean due to running the pills NX suggested for their kit instead of the pills Dave says I need to be running, plus the bottle pressure had to of been too high. I need a gauge or some kind of regulator.