Est. HP gains from a 70mm Throttle body?

[L8R_H8R]

I have a 96 prelude and i was wondering what kinda hp gains i could expect from a 70mm throttle body?

[CivicSpoon]

Expect to loose power if you don't have higher compression/wilder cams or FI.

[L8R_H8R]

well, say i were to have all that

[Schister66]

then you'd gain more power, but by the sounds of it, you don't have any of the above....you'll gain top end, but sacrifice mid range....your best bet is a new IM, header, or cams.....TB just isn't going to help a lot.....especially since the stock mani only accomodates a 60mm or somthing like that

[aznbmxxxer]

i put a bbk 70mm on my friends si. the car just had itr cams, intake, header, exhaust, and it made the car a lot slower.

[banditkiller]

Going with to big a tb on a non f/i car that isnt built will cause a loss in power simply do to the fact that you lose intake velocity. Think of a garden hose, a 1 inch garden hose at say 50 psi will cause more pressure and therefor a faster rate of flow. No compare that same 50 psi on a fire hose. Because of the loss of pressure there is a loss in velocity, causing the water to merely trickle out. Thats the best way I can think to describe it.

[TurboGSR96]

because the car didnt have any porting work done too

[GoRi]

Originally Posted by banditkiller

Going with to big a tb on a non f/i car that isnt built will cause a loss in power simply do to the fact that you lose intake velocity. Think of a garden hose, a 1 inch garden hose at say 50 psi will cause more pressure and therefor a faster rate of flow. No compare that same 50 psi on a fire hose. Because of the loss of pressure there is a loss in velocity, causing the water to merely trickle out. Thats the best way I can think to describe it.

so what if the tb was smaller in diameter would dat help gain anything?

[CivicSpoon]

No. Honda put those size throttle bodies on it for a reason. Take the B-series for example. If a smaller throttle body would have made more power, they would have used the same t-bodies as the D-series.

[TurboGSR96]

Originally Posted by GoRi

so what if the tb was smaller in diameter would dat help gain anything?

Funny......Cant say im suprised but funny none the less.

[TurboGSR96]

Originally Posted by aznbmxxxer

i put a bbk 70mm on my friends si. the car just had itr cams, intake, header, exhaust, and it made the car a lot slower.

What about an intake manifold......cant stuff 70mm worth of air through a 60mm hole, somethings gotta give...

[hxgaser]

Amount of fuel/air mixture that can get into a combustion chamber for a naturally aspirated motor has a limit. Think of a syringe... If you pull the syringe piston, amount of liquid coming up the syringe cylinder is always the same. So even if one has a larger throttle body, the actual volume of air and fuel mixture that can get into the cylinder is still the same. In addition, by having a larger TB, the mixture is now lean. Too much oxygen... Of course the engine management trys to enrich the mixture due to leaning detected by the oxygen sensor and dumps more fuel in. This increase the total mixture volumn that is running through the intake, but that total volumne can't get into the cylinders. So a flooding condition is essentially created. Hence the reduced performance.
Of course if you compress the charge air via forced induction, then you can cram more of the mixture into the cylinder.