Hey guys,i have a 305 Iroc that has 140k on it,she ran pretty strong,i decided that i would put an adjustable wet manifold kit from NOS on it and have had 2 nitrous backfires.The first time was right after we hooked it up,it blew the airbox to bits and destroyed the MAF.The next time there was the same damage and i believe the intake manifold gasket is done off because the car wont stay running and it backfires through the intake,is it the gasket or something else?I checked the rockers and they are fine,i even swapped my Tpi set up,i am wondering what casued this,i would think a lean condition but i didn't have the Air/Fuel guage hooked up so i dont know if it was that.There was also gas in the oil,did i burn a hole on top of the piston?

 

maybe the engine needs a rebuild?

 

If it is shot then its time for a 350.

 

if there is gas in the oil it could be evident of blown rings........although i think this is also true with antifreeze.......since i'm not an expert i'll leave it up to someone who is.

but, either way it sounds like you were either running to much of a shot or you were lean.........if you were rich you just would have fouled out a plug or something not so severe........

good luck with it, it doesn't sound good.

 

Do a compression check, if you don't know how to do one ask and I will go through the steps in another form. If the compression check comes out fine take a look at the plugs, see if there is any sign of a problem on them. If all that checks out fine you might be just popping gaskets. If you pop a gasket you will run lean. The reason is the MAF is not metering enough fuel for the air that is present in the cylinders. I highly suggest you go with an air fuel gauge and and exhaust temp gauge and learn how to read them, they can be life savers when it comes to checking the state of tune in your engine. If you are gonna spend the money to put that much into the nitrous kit and all that goes with it, splurge on the gauges that will tell you what is happeneing when it is engaged.

Sean

 

Ahhhh the Old Backfire!! I have numerously done this, blowing the screens of the MAF right back to the airbox and actually blowing the Elbow straight inhalf

K why did you spray it the 2nd time? Im sure you didnt get a new maf either? The other ? is why in the hell would you do it with a 140k on it? You are asking for trouble, unless it was properly maintained.

Start with the simple things, first if you said you see gas in the oil change it, if there is a backfire, check your plugs, unhook your battery for about 5 minutes and let the computer reset. If all this doesnt do the trick then most likely its SOL. I would also check your timing for the hell of it. Oh ya if you used you MAF that got blowing up, and the wires are destroyed, then this is your problem right there, unhook it and let it run in closed loop.

 

did u retard the timing? 1 degree for every 50hp... Detonation will kill u... Definetly do a wet and dry compression check before working on intake.

 

I checked the plugs and they smelled of fuel,they were fouled and i changed them,i also changed the oil too,the MAF was swapped after the first backfire.I have the Air/Fuel guage but just got lazy and didn't hook it up.I am running juice on my motor because it has a 140k on it and eventually i wanted to swap it but it went faster then expected,i am just curious as to why it happened so i know better when i put the motor in,my questions are curiousity and plus it would be nice to get the 305 back on its feet to play with it again.

 

what would be the point of trans temp guage......?

 

What causes a backfire???

 

Exhaust temp. gauge works almost like a wideband 02, in general the hotter the exhaust temp the leaner the car is running.

 

I had some "off the line" problems with my #5151 NOS kit that I noticed it worked fine with the engine above about 2800-3000 rpm. then after talking to some people here on this site, some say "I have no problem" others say "oh yeah, I have that problem too" they attribute it to the TPI and its dry flow intake design. even NOS admits that it can be a problem sometimes. I wonder if this is what happened to you.

 

Most of the high horsepower Japanese tuning shops run a wideband o2 sensor and a exhaust temp gauge, keeping the engine in the "sweet spot" means you get the best out of the total performance. For a turbocharged engine (most here are an inline 6 cyl) they run an exhaust temp gauge prior to the turbo, ussuall right before or right after the flange where the turbo bolts onto the exhaust, sweet spot is 850-900° Celcious, and A/F ratio is 13.2-13.5 The cheap A/F gauges will never be able to tell you the true readings of your engine, such as the Autometer LED style or the Cyberdyne LED, a true sweeping gauge that comes with its own sensor and does not piggyback on the factory sensor is more accurate. If you want real accuracy then go with a MoTeC unit, the sensor retails for $600 and the box to read it runs close to $3100....


Sean

 

save yourself some money and go see someone at a freightliner dealership. the freightliners with cummins engines have an optional exhaust temp system. you can buy the probes and guage for just a couple hundred bucks, and theyre pretty easy to install. the only hard part is welding bungs in the exhaust for the probes.

 

Did you hit the button while the car was setting there under idle conditions? If you did the bottle pressure flow was greater than what the engine the engine could take in and the nitrous and gas mixture were pushed out to the MAF where that little wire burns white hot and you guessed it BOOOOOOOOOOOOM!!!! Always be under full throttle when you the button.

 

:lala:
That is all the more i have to say about that.

 

It is nice to see people are starting to upgrade from the slower japanese computers to the faster processor speed "american style" (I know MoTec is not american) ECM systems like MoTec, F.A.S.T., Accel, and AEM utilizing that motorola based chip system in even import cars now. And that the import cars are starting to use wideband style systems like the US race cars too. people that slam the import cars will eventually have to stop as thier technology gap begins to close and eventually high horse power (and speed) comes to lower priced import cars too.