k i was just wondering this, on a lg4 right if u replace the cam it gives u 40 more hp, and if u slap headers on it that like another 20 hp, so thats like around 60hp there. then there is little stuff to add on that right. now the lg4 is not the best for performance neather is the v6, so if u did all that with a v6 right would it be just the same power gain?

 

Um... in a word... no.

There are a billion variables, and you're looking at two - a cam and headers. No way in hell you'll get 40hp from just a cam, on a stock engine. On a modded engine, that you already have full headers back exhaust, ported heads, and intake mods, THEN you'll get 40hp from it.


The key to power is matching intake/heads/cam/exhaust together.

Throw headers on a stock lg4, and yeah, you might help a little, but if you don't open up the exhaust behind it, you'll not get hardly any gains. This is why intake and exhaust are two of the FIRST upgrades - they may not add much in themselves, but they will open the door when you upgrade heads, and cam, and all.

 

Doward is 110% right. An engine is a system, and upgrading one part only is usually not going to give very big results. Also, just because some company claims that their exhaust adds 15 HP, don't assume that it actually will do so, especially if it is designed for a larger engine than the ones we have.

I love how the street posers (usually import driving kids) 'add up' all their performance gains on their cars. They say:'well,the car was 125 HP to begin with, and I added a cold air induction, which is 10 HP, and an exhaust which is 7 HP, and a High output ignition, which is 5 HP, and a reprogrammed computer which is 20 HP. My engine produces 168 HP now, and I only spent $750 on it!'

All that stuff added to the car probably upped his output by about 15-20 HP total, just like it would on our cars.

If you want to add a cam, or any other part, make sure that you do it with the end game in mind. In other words, always choose parts that will work well with each other, and start on the outside of the engine (intake, exhaust) and work inward (cam, heads).

 

Not even close. I agree with the above. The LG4 may be slug of a V8, but it still has 2.2l more of displacement, that's almost another 2.8l.


If you did the same thing with a V6, you would get less than a 30 bhp gain at the flywheel and maybe 15-20 bhp at the wheels.



Why do you think when companies claim a product can gain up to 40 bhp or something, in very small print it says product was tested on a 5.7l or something, or basically the largest street legal engine for the products application.


Not always the case, but generally speaking, the larger the engine, the larger the gains from bolt ons and accessories.

 

i pretty much agree with all thats said above

a engine is an air pump

the exhaust needs to be upgraded first, because if you cant get it out, how can you put anymore in?

then move onto the intake side

the manifold has an effect on engine output, but nowhere near what the correct cam/head combo has

to use a cam that brings your power range to higher RPM's (for example a range of 3000-7000 RPM) you need heads that will flow ENOUGH air FAST ENOUGH to make the power in this range

stock heads do not flow enough of an amount of air at a velocity fast enough to warrant such a radical cam

something more realistic with stock heads would be the 1500-5500 range say like a XE262 cam

plus the more RPM's you turn, the stronger of a bottom end you will need

stock chevy bottom ends are usually safe for about 6500 RPM, not much more