rbloyer

I have in the last few years had a harder time passing emissions (HCs) with my street ported NA motor. Is it possible that my underdrive pulley is a contributing factor to my failing emissions test?

I have an Unorthodx Racing underdrive pulley. For emissions, I run a hose from the air pump directly to my single (Walker) cat. I suspect that the underdrive pulley is not spinning the air pump enough to get the cat hot enough to consume unburned gas. Underdriven accessories spin less right? Another issue that supports my suspicion is that my regular mechanic reports that my CAT doesn't have a heat differential front to back.

misterstyx69

iTrader: (142)

idea.. post your results so someone could look at it and maybe go from there, the fact that it is a Streetport is a factor right there..passing emissions is a bit tricky..you have to lean the car out as much as possible without it stumbling,..did you use "an Additive"(denatured alcohol or methyl hydrate for the test?)..was the car driven 'good" before the test?..it would affect the outcome..not havin the cat hot (from running the car about a half hour before testing) would not allow it to suck up the "crap " in the exhaust..be like it wasn't functioning (to remove "the bad stuff")...

rbloyer

I ran 1 gallon of denatured alcohol with 4 gallons of gas. Does it matter if it's denatured (methyl) or isopropyl alcohol? The car was warmed up all the way when it went in but I didn't run it hard since I was advised not to. I have a microtech LT 10 running the fuel and the tuner who tuned it explained that it should be lean enough. Is it safe to run a rotary hard with alcohol? Is it possible to run straight alcolhol?