16v questions

[jasondew]

i've got a couple of questions about tuning my 190e 2.3-16.

concerning the O2 sensor: the O2 sensor is located after the precats but before the cat. on my vehicle i have eliminated the cat. if i eliminate the precats will the O2 sensor send the engine a signal that the mixture is too rich causing leaning? also, if i use an aftermarket air/fuel meter running off of the O2 sensor will the readings be accurate since the exhaust will have already gone through the precats? do i need to add another O2 sensor before the precats to get an accurate reading from the air/fuel meter for tuning purposes?

cams and forced induction: i've posted this topic before and gotten mixed opinions about what type if cam lift, duration, and overlap are best for a forced induction motor. this is of course the 2.3-16 motor. the comp ratio will be kept at the american spec of 9.7:1. okay, so i know that on a NA engine wilder cams allow more fuel and air into the engine making more power at high RPM while reducing the output at lower RPMs. it seems the same would be true with a forced induction motor. but, the total output on a FI motor is likely going to be limited by boost, which will be limited by pre-ignition or spark knock, whichever occurs first. my understanding is that on a FI motor detonation will occur when the same amount of fuel and air is stuffed into the engine irrespective of whether the cams allowed the fuel and air in or the FI forced the fuel and air in. basically, for max area under the torque curve, shouldn't i just turn up the boost instead of buying hotter cams? it seems like my peak attainable torque will be the same no matter what the cam profile i have. if i install wilder cams i think i would only be losing torque in the low RPM range but not gaining any in the upper RPM range. is this correct or am i missing something?

thanks

[Glen]

There's a book by Hugh MacInnes called Turbochargers that does a pretty good job of explaining how to design a turbo system and as I recall there's a section on cam selection. This is an older book so I'm sure there is better information available if you go looking for it.

I just did a quick search and found another possibility:
Maximum Boost, by Corky Bell

Good luck.