Vekemans

Hello have a question its might be stupid to some of you I just got a 2000 prelude 5speed. I was wonder how much whp would 4-2-1 header and 3 inch exhaust and cold air intake would do????? I dont have any where close to run it on a dyno if any one has done it and know or knows some one who has let me know thank for your time

Aradin

CAI isn't going to do that much. 4-2-1 header will not do much on it's own either. The OEM header is a 4-2-1 design and most aftermarket 4-2-1s are simply shiny OEM replacements. You will, however, see some healthy gains from a 3" exhaust. You can further improve upon that by doing a 2.5" collector mod on your header. Alternatively you can look into a Tri-y header as they have larger diameter piping and a larger collector. The collector mod(on your stock header, or an aftermarket 4-2-1) with a 3" exhaust are proven to show gains. You may get in the 190whp range, maybe close to 200 if it's a super healthy engine. A dyno tune will be required to take full advantage of any mods that you do.

Tachi

Speaking from experience, unless you are flowing the exhaust to really need a 3" system, its going to hurt[your ears] more than its going to help. Most of the Hytech and Bisimoto replicas on eBay (the PLM 4-2-1 and Ram-horn) headers use a 2.5" final collector. If you're not going to live on the autocross or dragstrip, a 2.5" exhaust is the best balance between flow for the H22 and sound for you. And a H22 with a stock top-end runs out of breath higher up anyway. Aradin is correct, there is Dynometer evidence that a 3" system generates repeatable, significant power, but at what cost?

Intakes don't usually do much by themselves either. Enough to definitely not be a run-to-run margin of error, but they help the top end breath. As a mod by itself the intake is more for driver-audible sound and to hear the Vtec crossover better. My suggestion would be to remove the resonator assembly in the bumper and just leave the airbox and hose. If you do want a shiny cold air intake, I would buy the cheapest pipe you can off eBay and then grab a velocity stack from Vibrant or BPI and cap it with an AEM 21-2097DK filter.

An intake and replacing the exhaust is all about you can do without a dyno. Its the limit of what the stock computer can account for. You will feel a difference from this and it will sound good. I'm sorry I don't have specific dyno graphs for what the modifications will do but really its going to be more about how it feels. A dyno graph is just a number. You have a good car on your hands, just take care of it and it will provide.

TimiK

without proper engine management its pretty pointless and then with it its getting pricey

get rather good suspension setup - power mods eat you wallet and gains are not that good

Vekemans

Thanks everyone I just try to get the most out of it without putting a turbo on it cuz I know its going to hurt it sooner than later and I going to put a good set of coil overs on it with full adjustment and after looking up everything n going over it u guys r right about everything like I said I just trying to get the most with out supercharger or turbo and one more thing is spending the extra money for upgrading the ECU worth it ???????

Tachi

First off, please for the sake of the people you're asking information from, slow down and punctuate. You can take an extra two minutes to add in proper spelling and punctuation.It is difficult to read your last post.

About the coilovers, no matter what your car's suspension is getting old. I would put money and effort into replacing the bushings before Coilovers. Old rubber makes a suspension feel softer than it is. If you daily drive the car, use OEM/Rubber bushings. Then invest in a set of good coilovers. Cheap coilovers will wear out or blow faster. Full adjustability isn't needed unless you have the track experience to know what you want.

ECU tuning doesn't have to be expensive. I don't know where you are but here in the states you can buy chipped ECU's for $150 range, base-map loaded, and $300-500 for dyno tuning. Not really necessary or worth it unless you seriously modify the breathing of the engine.

Mykizism

CAI, Header and Exhaust are good bolt on parts that can be fun to install and help pep your ride. The power you will gain wont be much if any, but will allow your car to breath and sound a bit more aggressive. Not sure if slapping on random parts will help the car run any better than oem. I would say it would run worse.