d15b vtec
 

right help needed please
im after more power of the d15b vtec if pos
only aloud Honda parts
got light flywheel
3" 4,2,1 pipe
not aloud turbo


would different inlet help or injectors of prelude ect

Being limited to Honda parts doesn't help much here. A few things that might help are a D16y8 intake manifold, possibly a bigger throttle body from something like a B18B, too big of a TB from another B or H swap would also bolt up but would probably be too big and rob you of power. Bigger injectors from a H22 wouldn't work unless you reprogrammed the ECU and even then, probably be overkill.

I'm guessing you are racing and have to stay within certain rules and regulations?

Are you allowed to modify the parts at all? Things like port matching the intake manifold at the intake ports and throttle body side to a slightly bigger TB can help bring air in, obviously a port and polished head is great as well.

Does you engine have to be a D15? Can you swap the block to a D17? It is possible to build a stroker motor by using that bottom end, tho it's a bit of work.

Can't go over 1.6 engine
What about getting rid of limiters and remapping

What about bringing vtec in early so it in as I'm pulling out of bend

well switching to a 1.6 wouldn't really do much so I guess that's a moot point. As for remapping, you could move VTEC down a little but I don't know if that will really net any gains. Typically when dyno tuning an engine, the tuner will do a few runs with VTEC disabled and then again with VTEC set really low, then compare the numbers to see where VTEC on actually makes more power then off, making this the desired crossover point. My few builds have ended up with a higher point than stock. Tho mine have always been bigger cams, block etc. I've never been confined by race regulations.

I would look into what you can do with the trans personally. What gears/trans do you have? Are you constantly racing on one track? or a few? what type of racing? Some circle track and Auto X guys might like taller gears of in your case a non VTEC trans. Choosing a taller gear set sorta gives you a wider power band, tho less mechanical advantage. Depending on the track tho, say an Auto X car really might stay in second gear the whole course, but has a close ratio box he'd have to shift, maybe at a not so great time, or find themselves deciding to hang a gear, or shift up right before having to down shift down for a corner again anyway, circle track maybe a taller gear and you can just stay in one gear and above VTEC rather than dropping out of VTEC but being to high of RPM to justify down shifting.

All that said, maybe you can build the motor in a manner that will allow a higher redline, so you have a wider power band that way as well. I've heard of several people going to 8000 even 8500 on stock internals and being fine on race cars but that is a risk I've never taken, again tho I tend to replace springs and cams on my builds.

Is there lot better cams out there
Yes think got there with gears oval track
Run 195/50 15
Tryed 195/55
Gave better top end but lost the grunt out of bend that's why trying to improve power a bit

Thanks

As far as I'm aware, the D15b vtec cam was the most aggressive D series cam. I think short of swapping gear sets, which even that I'm not sure what your options would be, I think getting a D16y8 intake manifold and a good intake tube/filter are about the only areas you could improve. Look for a y8 manifold and if you're allowed, open up the port to the size of a bigger throttle body from a B18 non VTEC motor. Get a 2.5" intake tube, should be good size compared to the B18' TB. A D16 bottom might give a slight increase in torque, but $2-400 for one just to make such a small gain and that's not including the cost of parts/installing it.

what do recon can do if use any parts




thanks for help mate