I have an LO 3 motor that i recently changed plugs, wires, and also installed nitrous on (120 hp shot). I did run 15.3 in the qtr with the bottle being cold and not at regular pressure. I recently ran a 17.7 and the car hesitates after 2500 or 3000 rpm's. The plugs it had were R45TS (a standard 350 plug), and I changed to a CR45TS because that is what my friend at the dealer told me it listed for. This new plug is supposed to be a hotter burning plug. ^ out of 8 plugs recently have developed a brown and thick sticky substance around where the ceramic meets the metal part of the plug. I was wondering if my loss of time/performance could be due to the fact that with the nitrous possibly the plugs are actually "leaking" cylinder pressure and are at fault for my poor performance? Any help is really appreciated because now I own a camaro that runs like crap.

 

Say goodbye 305.

No, I don't know man. I think Pablo would know, he wrote something about plugs so that is my guess. Pablo where u at?

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Eric Natzke
91 Firebird 305 TBI (ZZ4 summer of "01")
ASCD Ram Air Hood-3" custom exaust-Flowmaster 80 Series-No Cat-Edelbrock TES Headers (coated)-March Pulleys-TBI Spacer-K&N Open ELement-TransGo Shift Kit-B&M Supercooler 28,000 GVW-Hypertech Thermomaster-160 Stat-3:42 GM Gears-Auburn Posi Unit-Edlebrock Strut Tower Brace-MSD Superconducters-Accel Cap & Rotor-Rapidfire Plugs-265/50/R15 Tires-Emmison's all Gone
http://members.aol.com/j007golden/91firebird.html

 

The plugs all look like they are burning properly and there are no leaks whatso ever from the outside of the motor.

 

First I'm no expert on nitrous but maybe some of this will help or give you some ides of other things to check out when using the nitrous.

I assume you've checked your timing also? How new is your coil and distributer? If it's the original components you may want to look into how well the coil and/or distributer is performing on a scan machine. See if the coil is putting out the proper voltage and the distibuter is distributing the proper fire to all the plugs and the dwell time for the distributer. This could cause problems on your upper rpm range. Do the plugs look the same way even if you don't use the nitrous? What about the nitrous your running, do you have a MSD box that will help retard the timing when you hit the nitrous? 120hp shot of nitrous is getting close to the upper limits you want to use on a stock motor with high miles. Someone should be able to give you some advice on options to use with the nitrous such as a new computer chip, MSD box, ect. I've always ran ACCEL u-groove plugs (350 plugs) and never had any problems. I used them in my original 305 and my present 350. How high of miles do you have on your car? When I took my original 305 to be machined I had no leaks on my motor on the only smoke occured at start up from the valve guides. However, 2 of my cylinders were bad out of round and therefore the motor had to be bored 0.030 over. If I had used nitrous on this motor I would probably have sent it to an early grave.

when you say hesitates after 2500-3000 rpm is this when you are using the nitrous? This may not be related but if it is when you are using the nitrous it's my guess that the manifold has something to do with the hesitation because it wasn't designed to flow that well and adding nitrous is almost like sticking a 350 engine in the car with the stock 305 manifold. My 350 would hesitate and start to bog if I was acclerating moderatley when it hit 2800-3000 rpm but would clear up if I just nailed the gas. When I changed my stock intake to the Holley Intake a few weeks ago I no longer have that annoying hesitation b/c the engine can finally breath!

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1988 TA 300+hp 350 w/ TBI and Holley TB unit, Holley projection intake,
WC T-5, 3.42 gears w/ Auburn posi. MSD 6A, edelbrock TES headers, dynomax 3" cat and cat-back system, ACCEL coil, polyurethane bushings all around, aluminum driveshaft, Mr. Gasket open air cleaner.

1993 S-10 w/ 4.3L V6 TBI, slightly bigger cam, Mild polish job and 3 angle valve job on heads, Edlebrock TES headers, Dynomax cat back, MSD 6A, ADS chip

2000 Kawasaki KX 125

 

this is with or without the nitrous, i was told to do a compression test, but i do not have access to that tool. I have a retard box for the nitrous.

 

you are supposed to use a COLDER plug with nitrous! See this is what i mean by KNOWING about your nitrous application meaning all the difference between blowing the motor or not Thanks for proving my point! (though its definately not good for you, and everyone makes mistakes so dont worry about it you probably havent seriously damaged anything)

You used plugs TWO STEPS HOTTER than the stock plug, that sticky stuff between the porcelain and the center electrode is probably the bonding agent between the metal and porcelain that MELTED out because the plug got so hot. A hotter plug keeps more heat which is NOT what you want with nitrous. Hotter = Knock. Stock is r43 TS and if i were you id look for an R42 to keep out of knock with the juice

does the center electrode look like the edges are rounded off? is the porcelain chipped? if so thats a sign of severe knocking which is very possible and likely with such a hot plug and the use of nitrous

[This message has been edited by Pablo (edited November 08, 2000).]