Gas Saving Modification

[ghosthunter]

I googled a bit and a lot of people have tried putting grooves on their heads with good results. I wanna know if there is a shop where I can have this done. I really would like to try it.

Here are a few links for those who are interested:

http://www.jeremiahsviolins.com/grooves.htm

http://forums.turbobricks.com/showth...t=66779&page=7

http://www.mazda626.net/index.php?sh...ded&pid=255078

Instead of waiting a decade before seeing anything similar would reach the commercial market, why not convert to LPG and save money on fuel today?

[niky]

Actually, looking through and reading through the dozens of threads on tuner and enthusiast forums, it seems that there's a possibility this might work... or at least not destroy the engine.

The theory of the grooves is that as the piston travels downwards, the grooves cause extra turbulence, which ensures a more even mix of the air and fuel.

As the piston travels back upwards, the grooves, which are aligned to where the spark plug is or slightly off-center of the spark plug, form a channel for the squelch... pushing and concentrating the air-fuel mixture at the center of the combustion chamber.

Unfortunately, there's tons of anecdotal evidence, and no clear dynograph evidence (most of the dynos are of engines that are rebuilt and given high-compression internals at the same time that the job is done).

I'm thinking that it's possible the extra turbulence helps prevent detonation at low rpms that high compression engines are prone to, but by itself, grooving the head may do nothing for your regular street motor.

Another builder has his own technique of doing this... grooving the intake valve area to cause turbulence in the air-fuel mixture before it enters the chamber.

While all of these things may help at idle, I don't know how good it'll work at high rpms. The aforementioned Mazda VTCS, which helps provide good combustion at idle, is often removed by Mazda gearheads as it limits top-end power.

And from some of the dyno evidence, Singh's grooves might do the same.

[norrissee]

I haven't tested the grooves yet but I tried using "lean-burn-mode" on my engine when it is low on load (cruising/idling)

Right now I have it set to A/F 16:1 closed loop fueling during idle and light load cruising up to 5k rpm only from 5k rpm up it still goes back to open loop fueling.

This is also ECU controlled so when you go WOT it still goes back to the desired A/F mixture set on the AF map. So no loss of HP and still get fuel savings

Previous mileage (stock A/F maps): 1 liter is to 5 km.
Current mileage (mod A/F maps and have closed loop set to 16:1): 1 liter is to 7km.

Also currently testing the mods below and no figures on the mileage yet since I decided to commute to work on a daily basis hehehe

- changed switchpoint from warm up mode to regular running mode from 31 deg c coolant temp to 28 deg c coolant temp. Earlier closed loop running.

- leaned out (just a bit) fuel enrichment table values which is based on coolant temperature.

- lowered idle point fuel cut, which is the point wherein the ecu would tell the injectors to stop giving fuel above a certain rpm when you let off the gas pedal, from 1.5k rpm to 1.3k rpm so i could coast longer with the injectors off ;) hehehe

I'm hoping these could get me up to at least 9-10km/l. These are all city driving figures I should get higher mileage on highway where it stays on the 16:1 a/f constantly hehehe

By the way, engine is a 1st generation 4G63T off a 90s Eclipse. Stock everything, boost set at 15 psi and rechipped the ecu.

[jpatricks1]

My friend has a spare 4afe cylinder head lying around. I might just try grooving the heads or the intake valve as suggested one of these days.

My goal is fuel efficiency naman and not power so I don't mind losing some HP so long as I use less fuel.

Sir niky which builder are you referring to about the grooved intake valves? I might just give it a try one of these days. If it doesn't work, salpak ko na lang yung lumang head hehehe. TIA

[jpatricks1]

Did some googling, is this what you mentioned sir?

http://www.allpar.com/fix/holler/valve-prepping.html

http://www.allpar.com/fix/holler/head-porting2.html

[Asus700]

Actually, looking through and reading through the dozens of threads on tuner and enthusiast forums, it seems that there's a possibility this might work... or at least not destroy the engine.

The theory of the grooves is that as the piston travels downwards, the grooves cause extra turbulence, which ensures a more even mix of the air and fuel.

As the piston travels back upwards, the grooves, which are aligned to where the spark plug is or slightly off-center of the spark plug, form a channel for the squelch... pushing and concentrating the air-fuel mixture at the center of the combustion chamber.

Unfortunately, there's tons of anecdotal evidence, and no clear dynograph evidence (most of the dynos are of engines that are rebuilt and given high-compression internals at the same time that the job is done).

I'm thinking that it's possible the extra turbulence helps prevent detonation at low rpms that high compression engines are prone to, but by itself, grooving the head may do nothing for your regular street motor.

Another builder has his own technique of doing this... grooving the intake valve area to cause turbulence in the air-fuel mixture before it enters the chamber.

While all of these things may help at idle, I don't know how good it'll work at high rpms. The aforementioned Mazda VTCS, which helps provide good combustion at idle, is often removed by Mazda gearheads as it limits top-end power.

And from some of the dyno evidence, Singh's grooves might do the same.

looks very interesting...

[snowbound]

the only gas saving modification i know is for gas engine using carbs. you can replace stocks carbs with carbs from fuel efficient cars. my friend's terrano, it has an FC of 14km/l after using the kia B1 carb. another friend, FC of his L300 van is 14-16km/l when he used a suzuki multicab carb. most gasoline fed cars here in davao city have kia carbs on board for fuel efficiency.

[forcemajeure]

hhhhmm kia carbs? babagal kaya ako?

[lnce420]

the only gas saving modification i know is for gas engine using carbs. you can replace stocks carbs with carbs from fuel efficient cars. my friend's terrano, it has an FC of 14km/l after using the kia B1 carb. another friend, FC of his L300 van is 14-16km/l when he used a suzuki multicab carb. most gasoline fed cars here in davao city have kia carbs on board for fuel efficiency.

its so amazing that an L300 would have FC of 14-16km/l
any cons about doing this?
atchaka ano ang obvious na effect sa performance ng sasakyan? babagal nga ba?

[mazingerZ]

Hindi naman parang sakal yung mangyari? Di ba yung jets ng multicab is mas smaller compared to stock jets ng L300?