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"Which intake manifold is better for a d15B with slight modifications?"

Started by jper_patrick, March 21, 2008, 08:53:14 PM

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jper_patrick

Guys can you help me on this. Kasi some say mas mgnda na daw yung intake manifold ng d15b yung iba naman Vti intake manifold. Ang plan na build ko lang Naturally Aspirated d na ako magtuturbo. Sa d-series.org at SOHChonda.com deabted topic kasi ito. Yung Vti intake manifold daw "type-r" for the d engines. Kayo ano sa tingin nyo?

speedyfix

what mods have you done na ba? there are probably other mods that will give you better power.
Migs - 09175347636
Shop - 7226117

www.speedyfixph.com

308 P. Guevarra corner Seaview St San Juan

BlueVic_8354

Quote from: jper_patrick on March 21, 2008, 08:53:14 PM
Guys can you help me on this. Kasi some say mas mgnda na daw yung intake manifold ng d15b yung iba naman Vti intake manifold. Ang plan na build ko lang Naturally Aspirated d na ako magtuturbo. Sa d-series.org at SOHChonda.com deabted topic kasi ito. Yung Vti intake manifold daw "type-r" for the d engines. Kayo ano sa tingin nyo?

dude, ung engine mo is d15b vtec? i think, the intake manifold of d15b is relatively the same with the stock intake of PH16 (ESi) and JDM ZC VTEC. its difference from the local PH16A (VTi) is just on the barrel coming from the throttle body. but the ones that goes to the head is the same. basically ung sa PH16A eh stouter and shorter lang ung barrel. so ung 4 barrels going to the head are compressed together at the main barrel, i don't think that there is relatively difference, its just that 2 ideas were separated by honda. in fact, the after market intake manifolds are both stouter and longer, so honda simply compensated the stoutness and shortness of the main barrel from the other that is longer but not so skinny. i think, the most that you can do is to replace the throttle with that coming from the b-series, rather than change the whoe intake manifold. also it would be a lot cheaper.
My EG-8

[img width=250 heig

jper_patrick

 sir speedy fix meron po akung port and polished d15b head. b series throttle, chrome tuned box, Lx piston, 4-2-1 (smsp design) stainless steel headers, LSD tranny, skunk 2 camgear.. Sa ganitong setup na ba pwede na yung Vti intake manifold??  thanks..

speedyfix

Migs - 09175347636
Shop - 7226117

www.speedyfixph.com

308 P. Guevarra corner Seaview St San Juan

DocHudson

use the D15B IM but don't forget to create the harsh step necessary after the TB.
i managed to make my IM opening 64mm at the most for the 60mm TB i'm using.



jdmcivic


butch11a

another option is a hybrid b16 manifold and throttle welded on a d15 flange ....

DocHudson

it will take a LOT to overwhelm the stock D15B IM and T/B for this engine as NA.
not even the best bolt-on IHE, camgear, etc will...

only when you've changed the entire "lung capacity" and air flow volumes and characteristics (displacement, head and valvework, bigger cam etc),  or boost --- will you have the need to go bigger.

there will definitely be a trade-off if you mod only this area.

example:  You might gain a little bit like 3whp at 6-7k rpm at the expense of an overall drop in power and torque at the lower regions of your stock engine's power curve.  As a consequence, you lose power where you spend time most. 

jdmside

pano pag skunk2 IM? plan ko kc bawiin yung bnew na bnenta ko na skunk2. sa stock d15b vtec ikakabit with header and exhaust and 60mm tb

PlanetSpeedRacing

Quote from: jper_patrick on January 14, 2009, 08:44:26 PM
sir speedy fix meron po akung port and polished d15b head. b series throttle, chrome tuned box, Lx piston, 4-2-1 (smsp design) stainless steel headers, LSD tranny, skunk 2 camgear.. Sa ganitong setup na ba pwede na yung Vti intake manifold??  thanks..

How much power are you aiming to warrant such change in IM from the stock D15B to a D16Y from out local VTi?

jper_patrick

Quote from: PlanetSpeedRacing on January 20, 2009, 08:51:29 PM
How much power are you aiming to warrant such change in IM from the stock D15B to a D16Y from out local VTi?

PlanetSpeedRacing I actually do not know how much power will my Vti intake manifold swap would do.. That is why I'm asking you guys would swapping my d15b im to Vti im would benefit me...

DocHudson

Actually, wala pang nakakapag dyno test specific para dito sa issue na to.
Maganda sana para magawan na ng final documented info.
Walang ibang way other than i-try mo on your own. Get dyno results from both and compare the two graphs.

The D15B (P08) IMs are smaller in overall plenum volume but with longer runners.
The PH16A (P2K) IMs have bigger plenums but with over-all-smaller-and-mismatched runner lengths.

You must pay attention to the fact that Honda designed these IMs for a reason:

The PH16A's head uses swirl intake ports (nakaliko / offset papunta sa valve seat) and camlobes designed to create a vortex action ng intake charge.. to promote better mixture motion and consequently, enhance the engine's lean burn design.
Sa performance standpoint, ang effect nito is that mataas ang low-end torque nitong head/IM/combustion chamber/piston head shape. Ang down side is that hindi sya much of a high rpm breather as a D15B head. At high rpm, the offset ports become a source of restriction somewhat IMHO.

The D15B's head uses a tumble port design - meaning direct, straight, walang offset, walang swirl, etc.
Similar to B-series heads, they have better breathing at high rpm compared to Vti (P2J) heads.

Now, what about their IMs?
IMO, with a head that has superior flow at low end but typically runs out of breath at high rpm, honda decided to make use of an IM with big plenum volume and shorter runners (big straw effect) to help out with its high rpm handicap (Hence Vti)

With a head that has better flow at high rpm but lacks low rpm torque , plus the smaller 1500cc displacment, honda designed the IM in such a way that the small plenum and long runners (small straw effect) will aid in low end flow (Hence D15B)

Why did Honda do this? to achieve smoothness and a balance in power delivery, even if it meant making small compromises in design.

Sooo, I'd say it's best to stick to the stock P08 IM if your engine is a D15B.

I've done a VTi IM swap to a friend's stock D15B before at naging malata humatak. Umuupo sya lalo pag binaon mo sa low rpm.
My butt never liked it.
Try it and prove me wrong pls.

   

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