I'm trying to think of what I can do next to add some more horsepower. I put in a new exhaust and intake but I'm not sure what my next step should be. I was thinking maybe a new computer would be a good way to add more hp now but I'm not too sure, any suggestions as to what to do next?

 

What kind of car is it? What kind of gains do you expect? The only real upgrade you can do to a stock Honda is make the exhaust system as efficient as possible, but don't expect more than 10hp gains. Either do a swap, or Go turbo, but do Itt right. Anything else is just a waste of money in my opinion.

 

honestly, all an intake and exhaust will do is shift the powerband. they don't technically add any horsepower, except for maybe a couple here and there throughout the powerband (usually at the top, where its needed the least on our little D-series...)

if you really want more horsepower, either do a swap or go turbo. Or both. Bolt-on's don't really do much for our tiny honda motors like they do for v-8's and mustangs. Sorry to break it to ya!

 

When you say "exhaust", did you already replace the exhaust manifold (header)? If not, it'd be the next logical thing to replace. If you've already replaced the header and aren't quite ready to go with forced induction, perhaps a more aggressive camshaft and an aftermarket intake manifold is in order? Modifying the ECU really won't help with just an intake, header, and exhaust.

And to add to what shandles was saying about bolt-ons not really doing much, it's simply because Honda designs their cars well; cars that see large gains from bolt-ons are only seeing those gains because there was a bottleneck somewhere in one of the original components, whether it be a poorly designed (as far as power goes) intake, poorly designed exhaust manifolds, or a restrictive exhaust system.

 

^^ To go off what reaper said, I think a stage 1 camshaft will help out with power, but I believe it would shift the powerband up a little bit. Also, the stock valve springs and retainers should work fine with a stage 1. Anything more, and you should be installing upgraded valve springs and retainers. I strongly recommend some sort of tuning if you install a camshaft, which can get expensive.

Let us know what year and model Civic you have as well as what your budget is. How much extra power are you trying to gain?

Also, I think I would shy away from an aftermarket intake manifold. I had one in my D16y8 with a stage2 camshaft and my throttle response (with a 60mm TB) was destroyed in addition to my lower end power. I would stick with an OEM D16z6 Intake manifold or an OEM D16y8 manifold depending on what year vehicle you have. If you have a Y7 motor, I would suggest upgrading to the y8 intake manifold. Search around for how to guides on performing this swap.