Best next step after intake-header upgrade on Astina

[isa1023]

[SIZE=1]From bonestock 4-2-1 headers ...[/SIZE]

After a mushroom-type filter and 4-1 header upgrade (as per SMT's recommendation), I noticed a torque gain in the low and mid rpms (ironic for a 4-1 manifold) but my tach-o-dyno says nothing has changed.

My 2500 rpm still does 80 kph after the upgrade, considering a margin of error since nothing was calibrated after the 17s mags-low profile tire change.

One notable improvement is that I can now use the higher mids (4000 rpm to 6000rpm redline) which gave no power at all (literally) prior to the header upgrade. And which is exactly the reason I chose 4-1 config.

I noticed an improvement in fuel economy, although not that substantial to brag about.

Exhaust sound got more bassy even on the stock muffler. This I like.



After telling him of the muffler mod plan, Jay Sison (SMT) suggested I install a JASMA chambered type with 2" inlet.

*****

Going to my query, what's the next best possible "breathing" upgrade I could use?

I'm looking at either cone-type CAI or JASMA chambered muff.

Shall I upsize the piping to 2" as well?

Shall I lose considerable backpressure with a 2" inlet JASMA muff?

I'm after more torque at the mids.

Want can I do to improve ignition for power or torque?



[SIZE=1]Honestly, I don't feel like it's a 1600 engine. It's awfully weak, not even standing a chance in sprint against the other car I use (Sentra 1.3 GX).[/SIZE]

[ghosthunter]

[SIZE=1]From bonestock 4-2-1 headers ...[/SIZE]

After a mushroom-type filter ....

Is that the cleanable foam type filter? The foam tends to compress under suction which leads to increased restriction at the intake during higher rpms under load.

...and 4-1 header upgrade (as per SMT's recommendation), I noticed a torque gain in the low and mid rpms (ironic for a 4-1 manifold) but my tach-o-dyno says nothing has changed.

My 2500 rpm still does 80 kph after the upgrade, considering a margin of error since nothing was calibrated after the 17s mags-low profile tire change.

rpm vs speed ratio will not change since this is mechanically linked.

Too really know if you gained or lost any power, you will need a real dyno or a virtual dyno like a G-Tech Meter or V-BOX.

Also the 17 inch wheels are too heavy for a 1.6L engine to turn effectively. Reducing the wheels to light weight 15s will gain you some performance.

Going to my query, what's the next best possible "breathing" upgrade I could use?

I'm looking at either cone-type CAI or JASMA chambered muff.

Shall I upsize the piping to 2" as well?

Shall I lose considerable backpressure with a 2" inlet JASMA muff?

I'm after more torque at the mids.

Want can I do to improve ignition for power or torque?

Hmmm, old school mods....

Going for piping too big for your engine will just result in power loss because of lower exhaust gas velocity through the bigger piping and loss of heat. For 1.6L engine, I remember the piping should be 1.75inch in diameter and mandrel bends (no no to crush bent tubing). Minimize bends if possible and have it thermal wrapped to prevent heat loss to maintain exhaust gas velocity throughout the length of the exhaust system.

As for the muffler, I usually have mine custom made. A flow-through design based around the shape of the stock muffler with the recommended piping size for the engine displacement. Muffler tip is a simple rolled lip stainless tube.

Clean, simple, effective, understated and not too noisy.

CAI is fine but make sure the tube size and length is tuned for your engine. If in doubt, make it as simple as possible with minimum length and bends required.

Ignition mods? I used to have high tension wires but sometimes stock wires are better. I also used to have a MSD ignition controller (this might be helpful if you advance your ignition timing a lot).

Advancing the ignition timing helps getting more power but this hurts fuel economy. Advance the timing too much, the engine will start knocking. Using higher octane gasoline lets you have more timing advance.

[SIZE=1]Honestly, I don't feel like it's a 1600 engine. It's awfully weak, not even standing a chance in sprint against the other car I use (Sentra 1.3 GX).[/SIZE]

Major reason for the weak performance is the big heavy wheels.

[isa1023]

Is that the cleanable foam type filter? The foam tends to compress under suction which leads to increased restriction at the intake during higher rpms under load.

No sir, it looks like a dispensable generic foam type filter bolt-on to the carburator. I think this is due replacement already.

rpm vs speed ratio will not change since this is mechanically linked.

Too really know if you gained or lost any power, you will need a real dyno or a virtual dyno like a G-Tech Meter or V-BOX.

Noted

Also the 17 inch wheels are too heavy for a 1.6L engine to turn effectively. Reducing the wheels to light weight 15s will gain you some performance.

True.

Plus it begins to give a bumpy ride even after replacement of new shock absobers and new tires.

I also noticed that it's harder to turn the steering wheel.

It's 205/40R17.

[SIZE=1]OT: Buti nalang hindi masyado ramdam yung power loss dun sa Sentra GX, naka-17s din po kasi siya.[/SIZE]

For 1.6L engine, I remember the piping should be 1.75inch in diameter and mandrel bends (no no to crush bent tubing).

I'm not sure if the stock piping is 1.75" but will definitely note this. SMT says it may be the last in the modification list.

Mandrel-bent only? Is the stock piping already mandrel-bent? Guess I've no choice then but to go to Mufflerland.

Brodeth is just too expensive for me.

Minimize bends if possible and have it thermal wrapped to prevent heat loss to maintain exhaust gas velocity throughout the length of the exhaust system.

Does that mean I go for straight pipes?

I want to retain the cat and resonator in the middle anyway.

Can't afford too much exhaust noise.

As for the muffler, I usually have mine custom made. A flow-through design based around the shape of the stock muffler with the recommended piping size for the engine displacement. Muffler tip is a simple rolled lip stainless tube.

Yeah I remember this on my old Honda posts. So is this better or same than surplus Jasma?

CAI is fine but make sure the tube size and length is tuned for your engine. If in doubt, make it as simple as possible with minimum length and bends required.

A car accessories shop in Banawe will give me a set of carb adapter, Simota cone and an odd plastic-like (?) flexible hose (similar to a washing maching hose) that can be stretched way down to the bumper.

I'm not sure if it's that effective though.

Advancing the ignition timing helps getting more power but this hurts fuel economy. Advance the timing too much, the engine will start knocking. Using higher octane gasoline lets you have more timing advance.

I'll try to advance it a bit when I top up Seaoil Extreme.

Major reason for the weak performance is the big heavy wheels.

This is one of the reasons why I'm seriously looking for 13x8 mags (currently on 17x7).

Kahit yung Advan copy lang, but on low profile tires pa rin.

I used to think 17s looked good on the Astina, but not anymore.

From the front side view, it looks like bicycle tires to me.

More alloy, less rubber.

I think 15s or smaller are more than appropriate.

Hope that makes a substantial difference.

I'd probably just take out the new Dunlops for future use in the Sentra.

Thanks for the reply. Very helpful.

I think I'm heading out for a set of 13s wheels and leave the exhaust pipes alone for now.

[isa1023]

Is that the cleanable foam type filter? The foam tends to compress under suction which leads to increased restriction at the intake during higher rpms under load.

Confirmed

It compresses and is the source of lack of power after 3000 with load on engine.

It kind of acts as my "rev limiter".

Also the 17 inch wheels are too heavy for a 1.6L engine to turn effectively. Reducing the wheels to light weight 15s will gain you some performance.

Just reverted to 14s (185/65r14)yesterday and yes, the difference in power and steering is significantly noticable.

Although I lost confidence a bit of going fast on corners.

The car use to handle very well when it still had the wide low profiles.

Maybe lowering and stiffening the ride a bit will do some magic.

CAI is fine but make sure the tube size and length is tuned for your engine. If in doubt, make it as simple as possible with minimum length and bends required.

This mod is next in line. I'm kind of fickle-minded to proceed with the washing-machine hose type of cone filter intake kit I saw in Banawe last month.

Major reason for the weak performance is the big heavy wheels.

This is one of the reasons why I'm seriously looking for 13x8 mags (currently on 17x7).

I think 15s or smaller are more than appropriate.

Hope that makes a substantial difference.

Affirmative!

Downsizing the wheels alone gave me back some performance.

I'll never overdo it again.

I think the sticker on the door says the car is designed to run on 13s only, but I'm sticking with the 14s for convenience.

I'm happy now with the regained performance.

Thanks.

[ghosthunter]

Confirmed

It compresses and is the source of lack of power after 3000 with load on engine.

It kind of acts as my "rev limiter".

It's more like horsepower robber than a rev limiter.

You can change it to the cone type filter (K&N or similar) which works better than the foam type element.

Just reverted to 14s (185/65r14)yesterday and yes, the difference in power and steering is significantly noticable.

Although I lost confidence a bit of going fast on corners.

The car use to handle very well when it still had the wide low profiles.

Maybe lowering and stiffening the ride a bit will do some magic.

Lowering will not help as much.

Changing your 14s to 15inch wheels with low profile tires (ex: 195/50/R15) will greatly improve handling. If want a bit of comfort at the cost of little handling sharpness, go for 195/55/R15 tires.

This mod is next in line. I'm kind of fickle-minded to proceed with the washing-machine hose type of cone filter intake kit I saw in Banawe last month.

Flex-type hose will rob you of engine power by making the intake airflow turbulent. It should be as smooth (internally) as possible.

[isa1023]

Update on this:
4-1 headers from SMT
Stock piping
2" inlet JASMA chambered muffler (as preferred by Jay of SMT)
Plate-type air filter
15s lightweight mags on 50-series tires

There was a big noticeable improvement in low-end torque after replacing the mushroom filter with the paper-mesh type, but I'm having problems at the top-end! It won't rev any harder than 5000 rpm on fifth gear, although I'm not flooring/pushing it.

It still can redline to 65000 using the lower four gears.

Would the tube-cone filter type make noticeable gains from the plate-type filter?



On the carburetor overhaul, we found that I'm using a carb from the 1300cc engine (Mazda B3) with smaller-than-spec secondary jets to supply AF to my 1600cc! I think that explains the lack of top-end torque on top gear.

*****

Handling of the 195/50R15 wheels is fairly comparable to the wider 215/40R17s, although I haven't tried cornering on the 90+ kph speeds yet due to some doubts on my busted engine mounts which are due replacement anytime soon.

I never tried anything crazy when I was temporarily using the 14s wheels.



Next upgrade would be stronger brakes on the front (slotted discs), although I might keep the rear drums as they are.

[isa1023]

It's more like horsepower robber than a rev limiter.

You can change it to the cone type filter (K&N or similar) which works better than the foam type element.

Problem with this is engine bay space ...

It looks like I can't fit a strut bar with the plate or cone filter on.

[isa1023]

Charles (SMT) is suggesting to remove the cat and the two mid-resonators and replace them with a single 24" resonator and bigger diameter pipes.

With the removal of those restrictions and a bigger, straighter pipe, he promised an increase in mid to top-end at the expense of little low-end torque lost, with very little to no change in fuel consumption.

I'm still thinking twice about it since 1600s are more prone to losing backpressure than 1300s, and especially considering the current fuel price ...

On second thought, shall I pursue the piping upgrade and catalytic converter removal?

I'm thinking that since I'm retaining the current "economy" carb jets, I won't see much change on fuel consumption on the low-end torque, which I use most for driving to work.