Engine Modification 101?

[ghosthunter]

Class in session....

basic upgrades are intake / headers / exhaust ... also sometimes termed as I/H/E mods.

intake mods:
This would include a basic cone-type filter upgrade that might or might not include tubing.

There are some downsides of having a open cone filter. One major problem is hot air coming from your engine bay being "inhaled" by your intake. This can lower HP output as much as 10hp against the supposed gains of 5HP offered by the cone filter. An example is the GA16DE engine. Its sensitive to intake air temperatures.

A solution is to get air from outside the engine bay. hence you can see some cars with their air filters in their bumpers or front fenders or even replacing a headlight with funnel feeding air to the air filter. Also wrapping your headers with header wraps will help a lot to keeping under-hood temperatures down.

header mods:
Often power gained (or losted) can be found here once all the other mods are done. Be careful in choosing which type of headers to get. There are generally two types: 4-1 & 4-2-1. I have also seen 4-3-1 but no idea if it does anything for performance. BTW when I say 4-2-1 it means itw four pipes merging to two and then merging into a single pipe.

4-1 headers - generally best for high reving engines with peak torque at the redline like honda & mitsu engines.

4-2-1 headers - compromise for maximizing midrange torque. Nissan and Mazda engines would be ideal to have these. In these headers, gasses merge more smoothly instead of simply being dumped into a single big pipe. Downside with this setup is there is more turbulence in the flow of hot exhaust gasses which would produce some amounts of back pressure.

You can have the benefits of both headers if you can get 4-2-1 headers with longer pipes. This would help making the exhaust gasses flow smoother. Also make sure the interior of the welds in your headers are smooth to the flow.

BTW, headers give off a lot of heat into the engine bay. Having header wraps will help keep your engine bay cooler.

exhaust mods: (mufflers,piping)
Depending on your engine, having a freeflow exhaust muffler can add or reduce your engine's power. Example is the 4AFE from the corolla. This engine requires a bit of exhaust back pressure to maintain midrange torque. Too much freeflow and your car will feel like its running on a 1.2 liter engine instead of the 1.6 engine.

Nissan Sentra GA16DE engines benefit greatly from having freeflow exhausts although you will experience a drop in top-end torque, its made up by a more responsive rev up and more midrange torque.

For most 1.6 liter engine running normally aspirated, the ideal would be about 2 inch diameter piping. Why? If your pipes are too small, the gasses would have to squeeze thru bottlenecks in your piping. Too big and your exhaust gasses would loose their velocity as they move thru your pipes and impede flow further up-pipe. The same problem occurs if the gasses get cold too fast thru your pipes.

summary:
In the GA16DE, with basic I/H/E mods, you can raise the HP from 110 stock to 123HP. That's still with the engine block and intake manifold stock and untouched. The ideal setup would include the ff:

-cone type filter attached to stock intake pipe & air sensor
-4-2-1 headers and wrapped in header wrap.
-exhaust piping of 2 inches in diameter
-free flow muffler
-add a medium to large sized resonator to quiet down the exhaust noise too.

In the Mitsu Lancer, it would be about the same except I would suggest a 4-1 long pipe headers instead of a 4-2-1. Gains will not equal that from the sentra though.

For the Corolla with 4AFE engine, some degree of exhaust restriction would be recommended. I would suggest a muffler with some internal baffles (instead of the freeflow type). I also noted that the 4AFE seems to be sensitive to the temperature of the intake air so a cold air intake (as to just having a simple open cone type air filter) would help to some degree. But note that this is not a performance engine so don't expect to be outrunning a Civic Vti with a 4AFE with i/h/e mods only.

I know I didn't cover all the stuff in depth, I am kinda short on time right now... just post your questions here and I'll try to answer them as best as I can.

[indieguru]

dami talaga alam ni ghosthunter! detailed pa per brand! galing!:D

jst posted an article also regarding the topic. might be of further help. here's the link:

http://motoringzone.com/modules/news/article.php?storyid=31

hope it helps!

[meleagant8]

thanks ghost hunter!

neways, ask ko lang, i have a mitsu lancer 1.3, does changing my exhaust pipes to 2in can help improve the acceleration?

btw, ano po ba usually ung mga stock size ng exhaust pipes?

[ghosthunter]

thanks ghost hunter!

neways, ask ko lang, i have a mitsu lancer 1.3, does changing my exhaust pipes to 2in can help improve the acceleration?

btw, ano po ba usually ung mga stock size ng exhaust pipes?

Hmmm, in my post, I usually refered to 1.6 engines because of the potential on these engines. A 1.3 liter engine has a smaller potential. Often times doing the same type of mods for a 1.6 to a 1.3 engine will just result in a noisier car and slightly more fuel consumption with minimal performance gains.

So for your car, the best mods in my opinion that can be done would be a cone type filter with a freeflow muffler. Keep your headers & exhaust pipes stock. I think you car is using a carbed engine? If so, a cone filter might not fit, but there are K&N replacements for your stock filter.

[FrankDrebin]

a very helpful infos indeed!

keep them coming!

[ssaloon]

tnx ghosthunter!

do the power gains you mentioned apply to 2.0L cars as well? i heard that if ever i upgrade my exhaust pipings, i should increase it to no more than 2.25". is this correct?

[ssaloon]

indieguru::: great site! simple lang mga gamit na terms kaya daling intindihin! tnx bro!

[ghosthunter]

tnx ghosthunter!

do the power gains you mentioned apply to 2.0L cars as well? i heard that if ever i upgrade my exhaust pipings, i should increase it to no more than 2.25". is this correct?

yup, pipings up to 2.25 inches only.

But if its for the last model Corona or the box type Nissan Bluebird, its a lost cause.

[ssaloon]

actually it's for a 96 galant ss

i already use aftermarket intake and exhaust. havent upgraded my headers and pipings yet. what would u recommend for my car?

[ghosthunter]

since your max torque is around 3000rpm while your redline is at 6000rpm, I would suggest 4-2-1 headers and have them wrapped to reduce heat. If you have the choice, get headers with longer pipes. You can upgrade your pipings later.