Lsvtecy0

i'm trying to get some ideas of what else i should be upgrading to make a little more power. motor is a freshly rebuilt b18c5 pretty much stock 81x87 just has jun3 cams and gears, supertech valve train, jdm itr 4-1 header - 2.50" exhaust, 650cc injectors and hondata, its only making 210whp right now but i want more. what would be the next best bang for my buck upgrade? I am trying to pick between a throttle body, skunk2 manifold, better header or maybe a 3" exhaust? I know these jun3 cams like to breathe, just looking for some input thanks !!

Chance EG

2.5" exhaust on NA B series isn't bad. Not sure if you'd get much more going up in size.

Skunk2 header or one of the 1320 SMSP/Toda replica headers would be nice. Skunk2 Ultra Street with a matching 74mm throttle body would help with the cams. Keep in mind you're probably already at the upper limits of that engine though with the current compression and displacement, but that will probably put you closer to 220WHP on the same dyno and make more power everywhere.

Lsvtecy0

i'd be good with 220. what do you rekon i can squeeze another 10hp with?

2x0

e85?

DumpdEJ6

Nitrous.

Lsvtecy0

its on e85 already and no nitrous cowboy i just built this thing not trying to blow it up that quick

Chance EG

If you mean another 10HP on top of 220, for a total of 230, I don't think you'd get that without going to 12.5:1 or higher compression (which on E85 you'd certainly be able to support), slightly bigger cams (Jun Stage 3's are very close to Pro2's from Skunk if I'm reading things right), or more displacement.

If you recently built the engine and just want a bit more juice, I'd just look into the parts I listed above, basic bolt ons and call it a day. I think they'd compliment your build well. Sheepy also makes an NA B series header that would undoubtedly excel, but it's expensive and (IMO) overkill for a street car which would in all likelihood have minimal (if any) gains over the more basic off the shelf designs.

No point overcomplicating what's already a good build/engine.

Lsvtecy0

yes just another 10hp for a total of 220 would be my end goal for this setup. do you think the 74mm tb would be ok for my setup it's not too big is it? and do those require a matching ultra street manifold? as far as header I think I might stick with my itr 4-1 for now

Chance EG

I say 74mm because that's the size the ultra street comes with from Skunk. With your setup, I don't think you'll sacrifice much at all or possibly anything at all down low (and by "low", I mean like under 3K RPM).

I still think a header would be a good idea, but that's up to you. A good 4-2-1 design would give you more bottom and mid range and likely keep the top where it is now. Hard for me to really do any more than guesstimate on this at this point though.

DumpdEJ6

I think what everyone is saying is that 210whp out of an 81x87 is pretty good already, and with NA power you hit the point of diminishing returns on investment pretty quickly, which is right around the point where you are now.

You could always change up headers and see if that makes a difference, not sure what your muffler is like but you could run resonators and a straight pipe, might improve it a bit.

What intake tubing have you got? You could try a velocity stack, with or without a filter, (recommend with a filter for street driving) that could give you a couple extra HP.

Aside from the TB and intake manifold swap that you were considering, (and really, only swapping them out and dynoing it will tell) there isn't a lot you can do without raising compression/adding some sort of forced induction.

For what it's worth, a small 40-60 shot with professional tuning should still be very reliable, especially with e85 fuel and Hondata s300 v3. That's exactly what I'm planning for my 200whp LS/VTEC motor, except I'm shooting for 100 shot.