a few of us were having a discussion about adding horse power to vehicles. some of us believe that if you add an intake that says it adds 15 hp (for example), and then add an exhaust that adds 30 hp, and then add a header that adds 12-15 hp, you will end up adding somewhere around 50-60 hp. obviously not everything adds the hp to the full extent, but as an example, that is what some of us thought.

the other side of the conversation, the one person who disagreed says that you can't add hp together like that. his example was his saturn. he said that he added the intake, exhaust, clutch, flywheel, port and polished engine, larger pistons and only added 5 hp to his car. his car starts at 125 hp (not to the wheels) and he thinks that now, with all that done, he is at 130 hp (not to the wheels).

does anyone have any technical information that would straighten out this debate on adding horsepower through modifications. i am looking for actual facts, and not just people's opinions. not that opinions are bad, but i need them backed up. can anyone help me out on this one?

 

Sign me up for that 30hp exhaust you were talking about.

 

your figures are way off. Depending on the car, DOHC VTEC honda will gain about 20-25 hp to the wheels with intake/header/exhaust.

 

Call HiTeck then if you want a good exhaust.
Price? If you have to ask, you can't afford!

 

2 words------DYNO TIME !!!!! the only true way to know what you do.

 

gtechpro.com ;x

 

perhaps i wasn't being clear enough - the hp numbers were just examples of adding horsepower on top of horsepower. if you take the mods, can you "add" 15 plus 15, plus 30, and come up with around 60 hp? or will it only increase hp by a few? that is the debate. i do but i don't want to know what my car is doing for hp, i don't know what it was stock before mods. and i know he doesn't know what his dynoed before he modded it all too. i was just wondering if the hp was added together in larger clumps, or if the hp add-ons only added a couple of horse power all together at the end of it.

 

Here is my take on it. Each part you bolt on to add power will make its claim at a specfic spot in the power band. Example= the famous AEM cold air intake. it adds that 10hp in the mid range. Not the peak. Headers good for torque and the exaust is good for the higher rpm stuff. So your powerband on a dyno will look alot like the stock curve, but bigger. It will not add up all in the peak.

 

No, you cannot add up numbers like that. Typically manufacturers post their numbers for crank HP, not WHP. Secondly, they typically measure STOCK vs. their add-on (whatever it may be). What they can't do is tell you what to expect when you do NOT have a stock setup.

For instance, if you do headwork, add Toda cams, add a header, and exhaust, then measure your output, you'll obviously see a major increase in HP!! THEN if you add an AEM CAI on top of that, do you think you'll see another 15hp? I would NOT think so. I would expect to see maybe another 5hp to the wheels. AEM (and others) don't normally claim you will see a certain amount of gain, but usually give you a range of what you MIGHT expect to see (again, usually measured against a stock engine). You CANNOT just add up manufacturers claims for HP increase and expect to see that.

Concerning your friend's Saturn, if he really did all that and only saw 5WHP increase, then something's wrong. Air velocity is key to increasing power, so the flywheel & clutch wouldn't show anything on a dyno, but true porting and polishing of the intake manifold, plus a less restrictive intake and exhaust, should have netted him more than 5hp!! Did he really do a P&P? What kind of larger pistons? Did he measure the CR either before and/or after them? Did he measure anything on a dyno?