Upgrades to the D15b SOHC engine?

**je.tansengco** · January 18th, 2011 06:50 PM

noticeable ba effects ng K&N air intake upgrade? hehe

**ghosthunter** · January 18th, 2011 07:30 PM

Originally Posted by je.tansengco

sir, mga magkano ung freeflow muffler? meron din po ba doon sa speedlab?

I suggest you give them a call or an email so they can tell you what they currently have for your car and price as well.

**renzo_d10** · January 18th, 2011 07:41 PM

H3 Autoworks ftw.

**je.tansengco** · January 18th, 2011 08:42 PM

mga sir, ano mga kotse niyo? paano gawing maingay ung car, ung parang growling ung tunog.

**je.tansengco** · January 20th, 2011 02:57 AM

1 3/4 inch exhaust piping
freeflow muffler

mga sir, nabili ko na ung K&N Air Filter, although i have yet to notice its effects. ask ko lang kung ano ung ginagawa ng 1 3/4 inch exhaust piping? freeflow muffler alam ko na, but wala daw sila sa speedlab.

thanks.

**ghosthunter** · January 20th, 2011 09:37 AM

Originally Posted by je.tansengco

1 3/4 inch exhaust piping
freeflow muffler

mga sir, nabili ko na ung K&N Air Filter, although i have yet to notice its effects. ask ko lang kung ano ung ginagawa ng 1 3/4 inch exhaust piping? freeflow muffler alam ko na, but wala daw sila sa speedlab.

thanks.

Regarding "1.75inch exhaust piping". It is known that increasing the exhaust piping size will benefit an engine's performance by letting it breath better. But going too big will have the opposite effect. There is a right size to maximize the benefits and minimize the problems.

One thing to consider is exhaust gas velocity. Your engine has to push all the gasses in the exhaust pipe out from the headers to the muffler tip. Keeping the exhaust gas velocity relatively high is important to aid the engine but not too high that there is actually too much backpressure. Too big a pipe, the gasses slow down in relation to the cross-sectional area of the pipe. If they slow down, they also potentially loose their heat, making resulting in even more slow down of the gasses. This results in more backpressure at the engine and it has to work harder to push the gasses out.

The correct size will maintain gas velocity until it exits the tailpipe. It will also minimize radiant heat loss during its time in the piping.

**je.tansengco** · January 21st, 2011 02:36 AM

how does a car owner determine the right aftermarket muffler size for his car? may measurements ba na ginagawa or sa mga shops nalang dapat dalhin?

**ghosthunter** · January 21st, 2011 09:19 AM

Originally Posted by je.tansengco

how does a car owner determine the right aftermarket muffler size for his car? may measurements ba na ginagawa or sa mga shops nalang dapat dalhin?

There are some "rules of thumb" based on type of engine, engine displacement and if the engine is normally aspirated or forced induction.

**dahve** · January 21st, 2011 09:17 PM

Originally Posted by ghosthunter

Mods:
cone air filter
4-1 headers
1 3/4 inch exhaust piping
freeflow muffler
ignition timing advance

sir ghosthunter paano gawin yung ignition timing advance nang hindi tumotope? ganun kasi gawa ko kaso pag 4th gear at bigla todo apak sa accelerator tumotope, ganun din sa 5th gear. honda lxi auto ko.

**ghosthunter** · January 21st, 2011 10:24 PM

Originally Posted by dahve

sir ghosthunter paano gawin yung ignition timing advance nang hindi tumotope? ganun kasi gawa ko kaso pag 4th gear at bigla todo apak sa accelerator tumotope, ganun din sa 5th gear. honda lxi auto ko.

Just advance it until you get tope then adjust it back one or two degrees. If you want more advance, you will need to use gasoline with higher octane rating.

You can also check the fuel injector cycle, it might already be maxed out resulting in a leaner air-fuel mix resulting in "tope" at max or near max throttle. If that is the case, you can upgrade to higher flow injectors or increase the fuel pressure (adjustable fuel pressure regulators).