putting on horsepower won't work until you reflash you pcm and put it on a dyno?Read!

I got a 1996 buick Riveria I put in a costom mufflers and and costom cold air intake.. someone told me that Anything you do do your car won't add horse power because the pcm limits the horse power to only its standard hp and that in order for the mufflers and cold air intake to kick in the horsepower I have to reflash the pcm so it will reconize the upgrades and I have to put it on a dyno or something......is this TRUE??????

They were refering to a prom chip. There is some code you need for these to add HP and torque. If you add a cold air intake, the IAC will read a sufficient increase in air flow, sending that info to the ECM thus increasing power. Same should be for a less restrictive aftermarket exhaust system.

So I already have the increase in horsepower? and if I get a 3.8 inch pulley I don't need to do anything fancy pcm work?

So I already have the increase in horsepower? and if I get a 3.8 inch pulley I don't need to do anything fancy pcm work?


by getting a 3.8" pulley, you will add nothing. That is the stock size pulley. You want a 3.4.

oops my bad I must of been tired

Actually, “chips or proms” are no longer used since the conversion to OBD11 in 1996. Any car with an OBD11 PCM would need to have the PCM reflashed. Minor upgrades can enhance performance up to a certain point, however to realize the full potential of all upgrades, the fuel and timing curves need to be altered to accommodate the increased air flow and fuel requirements.
My Z28 is a OBD1 PCM and uses a prom. I have quite a few engine modifications including headers, free flow exhaust, cam, heads, gears, iginition, 1.6 roller rockers, ported intake, CAI and numerous other upgrades. I have four different proms that I use depending on whether I run N/A or N02 or want faster timing curves or increased total timing. I usually carry all proms to the strip and can change them between runs, in less than two minutes. Changes are dependant on ambient temp, track conditions, and if I decide to run the juice. My proms were all burnt to my specifications and Dyno tested on my car, so I know what each one will do.

modifying an OBD II vehicle with CAI,headers,or even adding a s/c will increase the hp and torque if they are done right. ie adding larger fuel inj. when adding a s/c. and the pcm will add more fuel to accomidate for the colder air or higher flow but you will see better increases in hp/tq and less KR if you have someone make you a custom pcm to add even more fuel/timing advance if they are needed. every car is different and each will respond differently to the same mods, thats where tuneing the engine for optimal perfomance comes in and it must be dyno'd to do that so the tuner can see if any difference is made when spark is advanced or more air is added. so in short you can add mods to you riviera and see increases in hp and tq (these are evident in both a real dyno and the butt dyno) without having the pcm "flashed" or reprog'd for perfomance. but if you are looking for the most "bang from the mods" get a custom pcm from someone like Intense or DHP. i should also mention that your cars pcm will learn on its own and adjust itself over time depending on your driving habits. for ex if you are always racing then it will stay in performance shift mode and you will have a rich fuel mix which will hurt you mileage if you decide to take it nice and easy all of a sudden until your pcm "learns" you drive like a grandma and it will got to econ shift mode less fuel/more air, etc.

so sence my car is a 1996 Buick Riviera that means I have a OBD11 in my car?? therefore I need to get my pcm reflashed to get the airflows full power??? where can I get my 1996 buick riveria s/c pcm reflashed?? I looked everywhere they most places only can do the 1997's and up.

yes you have OBD 2 pcm and by having it reflashed you will only see gains of 2-3 hp unless you have a lot of mods that all work together most people dont get custom pcm's if all they have is headers and CAI. btw did you make your CAI yourself? and if your looking for power why did you install mufflers and not 3" DP or high flow cat?

I was gonna do that sometime but I did the mufflers first I got magna flow mufflers because I went to a muffler shop and the guy said that the mufflers I have on there now is where alot of the power is being lost so I got new mangaflow mufflers and ill prob be getting exhust or cats How much hp would new cats or exhust give me? and if I get a 3.4 ich pulley will that be a big difference?

a 3.4" pulley will give a big difference in power 20-25hp, the cat and full exhaust will give about 20hp as well. the mufflers on the riviera flow pretty well, in fact those and the cat are the least restrictive parts. the guy at the shop should have just gone with a 3" DP and 2" full pipes and removed the T bend. if you get a CAI make it yourself b/c there are no aftermarket parts for the riviera that offer a true CAI they make them w/o the air box(jus a cone filter in the open that sux in hot air=less power) and most of the ones i have seen go from a 3" to a 2.5 or even a 2" intake pipe which is more restrictive than stock. if you get the 3.4" pulley make sure you do something to reduce KR (colder plugs,CAI,exhaust, and 180* t-stat should be sufficent)and you may want to invest in a scan tool to check your engine out to make sure it can handle the extra boost.

a 3.4" pulley will give a big difference in power 20-25hp, the cat and full exhaust will give about 20hp as well. the mufflers on the riviera flow pretty well, in fact those and the cat are the least restrictive parts. the guy at the shop should have just gone with a 3" DP and 2" full pipes and removed the T bend. if you get a CAI make it yourself b/c there are no aftermarket parts for the riviera that offer a true CAI they make them w/o the air box(jus a cone filter in the open that sux in hot air=less power) and most of the ones i have seen go from a 3" to a 2.5 or even a 2" intake pipe which is more restrictive than stock. if you get the 3.4" pulley make sure you do something to reduce KR (colder plugs,CAI,exhaust, and 180* t-stat should be sufficent)and you may want to invest in a scan tool to check your engine out to make sure it can handle the extra boost.