92 chevy k1500 stepside camshaft help
im about to purchase a 92 stepside for myself, we used to have one with
only a few things done to it, upgraded ignition, intake, exhaust and
headers. Id like to upgrade the camshaft or possibly do a camshaft kit,
never altered from stock on this part of a car tho, not sure which route to
go, nothing super big where ill lose power to the breaks or need a blower,
looking for something mild, im looking at putting some money into the
motor to have it sound nice as well as some power. Any suggestions for a
mild cam that wont rquired machining work done ?
If your making or wanting any major changes to the cam over the stock cam and are unsure about what changes affect your motor your best bet is to talk to a cam supplier. Most of the larger companies have dedicated people to help you chose a cam based on what other modifications you have done or are about to do? The last thing you want to do is add to much lift and bend a pushrod or something worse in a freshly assembled engine.
Also Your biggest hold back will be the ECM. '92 is efi, throttle body injection. You can only mod the truck to a certain point before your power adders a just a waste of money. All of the mods you specify will increase air flow but will quickly reach the limitations of the stock fuel system, running lean is very hard on engines. Pre '96 trucks are OBD1 and you can just simply "chip" them or get it tuned to match your mods (either dyno tune or running your truck with a datalogger and building a tune that can be burnt to a chip). A cheap chip will help, a custom chip will be the best. If you are unable to tune or lack the funds (less and less people are available for this old stuff) you can swap the injectors out for a larger set from the 454 (I think the police package 350 from the cars have a slightly higher flow rate than the truck 350 vs. the 454). When your first switch the truck will run rich as it will use the regular fueling rates but with the mods you want the O2 loop should be able to trim it back to a usable ratio with out going lean. Sorry to hammer you with the crash course for tuning but it makes a world of difference. There is also a aftermarket regulator you can install in the throttle body to increase the pressure slightly. The ECM controls injectors by time, the higher the flow rate the more fuel goes in or the higher the pressure the more fuel goes in. With both alternatives your are tricking the computer to dump more fuel in verses the tune (which may require larger injectors anyway). If you are unsure but want to try moding your fuel a good investment is a air/fuel ratio gauge to monitor your exhaust.
ALright so best bet is to upgrade the fuel injectors the 454 stock if possible? im not going crazy but realistically i wanna put around 3k into it, get it updated fresh parts on it to have it for a bit til i can do a little more, not trying to obtain massive amount of power but a small horsepower gain would be nice as well as a growl from the truck. No need to apologize ill take all the help and advice i can get.
You said the year doesnt have the ECM? Can chip it, do the injectors, air/fuel ratio gague,.. regulator, get ahold of the cam company to find out more info, tune it after all mods are done. Not trying to build a drag truck or anything , just wanna clean it up as much as i can get some new updated parts on it, get a little power out of it, little muscle sound out of it..i know i cant go too big on the cam anyway or id have to worry about machining pistons and worrying about the motor being fucked from the loping, just wanna go mild with that and have somethimg im happy with
The truck hasnt been picked up yet im stuck in a snow storm probally going to get it next weekend but im trying to get all my info and everything straight, the lasdt one we had was a 97 stepside, again only minor things on it. wanna change a bit more on this one to have something im happy with
A 97 would have been the MPFI vortec, the computer is more advanced and can adapt to more changes before a tune is required. In the TBI trucks the ECM (engine control module) has less computing power than a typical graphing calculator. The GM OBD1 ECM's come in a few different styles and yours can be found in multiple vehicles. The individual data for your truck is programed onto a chip (engine, tranny, truck, base running parameters, ......., etc) then the ECM uses that data to inject fuel and control spark timing. The ECM is behind the inner liner in the glove box. The chip (EEPROM) in behind an inspection door. I pull the power to the batts and just swap the chips.
The air/fuel gauge can be bought at most high performance stores or online at summit, jegs, etc. There are many different types ranging in price. Good cheap ones are 200 or more. This is not required but it will pay for itself immediately as you can see exactly when you are under/over fueling. This would let you know at what point in your mods you will need to upsize the injectors. The base ones are just a wide band O2 sensor with a gauge. The more expensive ones can be connected to data logging software which allows the exact O2 to be recorded with other engine parameters to get a better operating base line for a tune. The later for custom tunes and custom burnt chips. Your truck has a O2 sensor but is a narrow band and doesn't help with tuning for power only emissions (it basically just tells the computer weather the exhaust is lean, rich or in a "narrow" sweet spot and not by how much. When the computer sees rich or lean it just trims the fuel output until it comes back. By seeing the exact number you can then modify the actual fuel rates in the chip for that load condition to add more power, the factor O2 would then only trim from your new value. I am by no means a tuner but I would like to someday maybe. Most people just get the datalogging software and a wide band. They then modify there vehicle and record it running and driving around in various conditions. The data is usually sent to a tuner who checks it makes the changes and burns you a chip. The easiest place to find someone knowledgeable on your ECM is to join a forum, they will usually have a member who does it or knows someone who does. These people also may have generic chips to sell that may work for you that are cheaper than a tune. You can buy the gear to do it yourself but there is a learning curve which has caused many blown motors. Tuning these OBD1's is a dying art, I need to get going on it before the equipment is no longer available.
For the cam itself I recommend calling a cam supplier, they will be able to help you. Unless you had the exact list of parts you were putting on and all work you were doing it is a crap shoot. For duration you can research various applications to see what other 350's are getting with the mods you want. Give you an idea of what your new hp/torque curve might be. For lift use caution. If you increase the lift to much to will hit the limitations of your heads fairly quickly. In most cases a stock head wont work with much more lift than stock. 1.) The valve springs can only close the valve at a certain rate, the more the lift the further the valve is pushed the further the spring has to push to close it. You will start to float valves at a lower rpm. 2.) Update the springs then the heads max flow will be hit. Port matching your intake and exhaust will help to a certain extent. Past porting/polishing all heads have a maximum flow rate that will be achieved and cannot be increased with more lift. Engine builders use a flow bench and suck air through the valves, they slowly open the valve until the air flow peaks then use that to determine the required lift of the cam. I'm cautious but hydraulic lifter setups are pretty forgiving and if your careful you can learn as you go as long as you research properly.
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