Originally Posted by fastboyslim
I just heard a decat can give you about 5bph extra. It is illegal so lets say that is 5bhp off the 20bhp. 15bhp is not looking too good for the amount of money you spend. this is why i started this post, my dad has got loads more bhp for his money. And thats with the lambda sensor removed. Still trying to find out why!
As long as the catalyzer is still in the system, and it's running hot enough, it will take the excexx HC's and Co's and turn them into CO2 and H2O.
BTW, taking the catalyzer from your car isn't illegal, as long as you pass the 4-gas test. This can be done, if you have a properly tuned engine, but obviously is easier with the cat in place.
I can't work my head around why they would remove the lambda probe, which the ecu disregards on full throttle anyway, and leave the cat. Unless the ecu on your dad's pickup doesn't get ignored on full throttle, of course.
Your dad got more HP for his money, but you admit the mileage got worse. That tells me the car is constantly overfueling. All reports from remaps on NA cars here indicate the mileage got better, or in the worst case scenario stayed the same.
BTW, this has all been very academic so far, care to tell us what make and engine size your dad is using? This might shed some more light on the issue.
Hope to continue this thread tomorrow. Like you I'm interested to know how he got his extra 22 BHp.