Insanely High 4AFE Fuel Consumption

[xMika]

Just like a water hose, you will use your thumb to suppress the water hose to let the water spray out in a higher pressure. This is the same case as the "back-pressure" acted on the exhaust and engine. You suppress the exhaust air-flow, so that you gain low-end torque.

If you have a low-pressure water supply, but the water hose is so big that the water just flow out of it, rather than a rushing-spray motion. So, you loss your low-end torque.

If you have a high-pressure water pressure, you definitely wouldn't a small hose that will block the water flow. Because the "back-pressure" acted on your engine will cause loss of high-end torque and damage your engine in a long run. Thats why turbo engine needs a straight flow muffler with bigger diameter to gain the high-end torque and to achieve a higher boost from the exhaust.

Just my 2 cents and if theres any mistake in my theory, please correct me :)

 

[lkeong88]

I think everco produce stock mufflers for almost all cars in the market. You can try to contact them

 

[muzhaffar]

in 4 stroke engine, during exhaust stroke, exhaust valves open and piston is going up. just certain degree before piston reach the end(top dead centre/TDC), inlet valve start to open. exhaust valve closed at some degree after TDC. at this time, both inlet and exhaust valves open and this is called valve overlap. during this time, if we use straight flow exhaust which have lower restriction, which end up with higher exhaust gas speed, it will create higher depression(or lower pressure) based on the Bernoulli principle(increase in flow/velocity, decrease in pressure). hence some of the air fuel mixture will escape(due to scavenging effect) and it reduce the amount of air and fuel available during power stroke.in s flow, it restrict the flow of exhaust gasses hence decrease the exhaust gas speed. so, the depression is lower and less fresh mixture will escape with the exhaust gasses hence give more power. that's for low speed. at high speed, the time valve overlap become shorter. hence, for s flow exhaust which restrict the flow of the exhaust, the volumetric flow rate of the gasses is lower than straight flow exhaust. so, the amount of the exhaust gasses unable to escape from the combustion chamber is higher. so, at high speed, because of some of exhaust gasses unable to flow out, the fresh air that is inducted is less since the excess exhaust gasses occupied some spaced inside the combustion chamber. hence, less amount of fresh charge to be burned and resulting in less power during high rpm.
in some car, for example bmw e46 with 2 tailpipe, if you look closely, one of the pipe have a valve. i think the valve will close during low rpm and open during high rpm hence give higher restriction during low rpm and lower restriction during high rpm. so, for my opinion, backpressure does not necessarily increase the low end torque but some restriction which cause slower exhaust gas flow does. and it result in higher backpressure.in 2 stroke engine, backpressure is much2 more important..

 

[Veloc]

Thank you lkkeong88, xMika, and Muzhaffar for your very helpful info. Now understand! Sigh~ Means now I have to chose between low-end and top-end.... Can't have both unless I plonk in the 20V huh... Hmm... Well I'll wait till I can afford to fuel the 20V engines.

Btw, most 20V in KK reports FC of Full tank RM80 RON97 ~ 280 - 300km. Is this normal? I thought 20V should be quite economical since it has VVT and the high cam lobes only engages >4.4k rpms. How come 20V has such a bad FC?

---------- Post added at 09:53 AM ---------- 6 hour anti-bump limit - Previous post was at 09:49 AM ----------

lkkeong88, xMika, Muzhaffar and Levin818... So what do you think if I use a plug-in adjustable silencer to increase the back-pressure instead of changing the whole muffler to the stock one? Is there a use? Will is be good?

 

[j_l200s]

Most exhaust shop will ask u this 'what kind of setting u want? pick up or top speed?'. This is where muzhaffar's explanation comes into play :) u can't have the best from both worlds. so, choose 1 :p

my full tank (RM80 RON 97) can yield me ~360-380 km. exhaust system has been changed to FGK 421 and custom straight-flow (not following original route) piping with a straight-flow muffler.

 

[muzhaffar]

Thank you lkkeong88, xMika, and Muzhaffar for your very helpful info. Now understand! Sigh~ Means now I have to chose between low-end and top-end.... Can't have both unless I plonk in the 20V huh... Hmm... Well I'll wait till I can afford to fuel the 20V engines.

Btw, most 20V in KK reports FC of Full tank RM80 RON97 ~ 280 - 300km. Is this normal? I thought 20V should be quite economical since it has VVT and the high cam lobes only engages >4.4k rpms. How come 20V has such a bad FC?

---------- Post added at 09:53 AM ---------- 6 hour anti-bump limit - Previous post was at 09:49 AM ----------

lkkeong88, xMika, Muzhaffar and Levin818... So what do you think if I use a plug-in adjustable silencer to increase the back-pressure instead of changing the whole muffler to the stock one? Is there a use? Will is be good?

actually the fc for 20v engine depend on your right foot..
i use stock blacktop engine with trumpet + 6 speed gearbox.
exhaust fgk twin mufler but already mod and use only 1..
1. gombak - kelantan --> +-450km = rm50 of fuel(rm1.80/litre) drive around 80-100 km/h and rarely floor the throttle
2. gombak - gua musang --> +-300km = full tank(around rm80+) speeding
3. gombak - puchong - bukit beruntung <300km i think = full tank.. full throttle almost all the way..

so, if you want to save fuel in 20v engine, drive like uncle..and drive below 4k rpm..
now the car sold already and i use corona with 3sgte..
the fuel consumption is better since it give more mid end torque and not need to rev until redline to feel the power like i used to do before..

what do you mean by adjustable silencer?
is it throttle body like gadget that is put inside the piping to vary the restriction?
maybe you can use that one but i much concern about the flow patern if we use that device to restrict the flow..
to fabricate the correct exhaust system with the car setting and driver needs is not something easy
and stock exhaust not necessarily the best for our car since the manufacturer trying to cut cost by simplified the exhaust system and also give much more restriction to the exhaust system to dampened the sound and put the expensive catalytic converter that will reduce your power output little bit to meet the homogation standard of the country

 

[seg 7138]

so, 20v 6 speed full tank 300-350km is normal ?

 

[muzhaffar]

if you still follow the speed limit, and didn't did sudden acceleration and decceleration, its quite high for me..except for 100% city driving with heavy traffic flow and always stuck in traffic jam..
if normal driving condition, it is high..
normally i drive from senawang N9 - gombak, around 110++ km if not mistaken(following speed limit), with smooth traffic at plus highway and heavier traffic at mrr2, its cost me less than rm20 for fuel(rm1.80/liter)
my corona with 2.0 turbocharge engine also required around rm20 of fuel(rm2.05/liter)..
and my brother seg with blacktop 6 speed fuel consumption also not bad..
it FC seems lower than my previous car and current car..
both my brother and my previous car use 6 speed blacktop from ae111 gt halfcut without lsd..

 

[xMika]

My 3SFE get 330~350km from 48 litres of RON95. Heavy traffic jam driving condition. Now switched to Vpower97. Will monitor the fc for this tank before trying Esso :)

 

[Veloc]

My 3SFE get 330~350km from 48 litres of RON95. Heavy traffic jam driving condition. Now switched to Vpower97. Will monitor the fc for this tank before trying Esso :)

xMika tai ko ah... 3SFE in what body??? I ask since the first page of forum lo.... Corona?

---------- Post added at 10:04 AM ---------- 6 hour anti-bump limit - Previous post was at 10:00 AM ----------

actually the fc for 20v engine depend on your right foot..
i use stock blacktop engine with trumpet + 6 speed gearbox.
exhaust fgk twin mufler but already mod and use only 1..
1. gombak - kelantan --> +-450km = rm50 of fuel(rm1.80/litre) drive around 80-100 km/h and rarely floor the throttle
2. gombak - gua musang --> +-300km = full tank(around rm80+) speeding
3. gombak - puchong - bukit beruntung <300km i think = full tank.. full throttle almost all the way..

so, if you want to save fuel in 20v engine, drive like uncle..and drive below 4k rpm..
now the car sold already and i use corona with 3sgte..
the fuel consumption is better since it give more mid end torque and not need to rev until redline to feel the power like i used to do before..

what do you mean by adjustable silencer?
is it throttle body like gadget that is put inside the piping to vary the restriction?
maybe you can use that one but i much concern about the flow patern if we use that device to restrict the flow..
to fabricate the correct exhaust system with the car setting and driver needs is not something easy
and stock exhaust not necessarily the best for our car since the manufacturer trying to cut cost by simplified the exhaust system and also give much more restriction to the exhaust system to dampened the sound and put the expensive catalytic converter that will reduce your power output little bit to meet the homogation standard of the country

Yes... Its the "throttle body like gadget" that you can use to vary backpressure. Just requires a turn of a nut to open/close the holes. Do you think that is okay? Can adjust backpresure and the sound that you want. And only cost around RM100 if I order from US... The whole muffler cost more.... Have to weld on a nice exhaust tip again because the ori manufacturer tips like gay.. Check it out here... Got more size than one. There are also other auto accessories to chose from.

<http://www.ioffer.com/i/Universal-Adjustable-Silencer-Exhaust-Muffler-3-5-Tip-70886151>

 

[muzhaffar]

i saw before 1 gadget that throttle bod like, install in the exhaust piping. and it is connected to a cable so we can adjust the opening inside the car cabin. about the effect and effectiveness, i'm not really sure

 

[Veloc]

Sifus... One of my clients is Institut Kemahiran Mara where they teach automotive stuff. they have a lot of engiens and some people donate used cars there. there is one unused AE101 GT lying there and damn... It has a black top. When I pass by, it feels like every fibre crying out... It's like... It has been waiting for me to claim it for a long time...

Sigh~ Leave the beautiful engine apart, I want to ask about other parts... I want to change the rear drums of my car to the disc of the AE101. Is that possible? anyone tried before? Does it fit?

Does the dash board fit in?

Does the exhaust fit? It has twin exhaust actually. But I will take only one after I have permission from the head of department. And most importantly, Can anyone tell me what kind of muffler the AE101 GT uses? Straight or S-flow?

Thank you.

 

[xMika]

@Veloc,

3SFE in ST171, Corona lo .. so its normal to have this fc statistics ?

Changing from rear drums to disc brake is damn easy :) Just get yourself a set of brake calipers and the brake disc.

 

[Veloc]

@Veloc,

3SFE in ST171, Corona lo .. so its normal to have this fc statistics ?

Changing from rear drums to disc brake is damn easy :) Just get yourself a set of brake calipers and the brake disc.

Corona heavy body... The FC should be higher... But I expect around 390km for full tank la.... that is what my friend in kuching achieve with 4AFE in corona. 350km a bit low lerr...

---------- Post added at 05:57 PM ---------- 6 hour anti-bump limit - Previous post was at 05:56 PM ----------

Corona heavy body... The FC should be higher... But I expect around 390km for full tank la.... that is what my friend in kuching achieve with 4AFE in corona. 350km a bit low lerr...

Oh ya... My mechanic advised me to check properly lerr... He say not so easy... Coz my car got ABS. the sensor has to fit in he said... If not will mess up the system...

 

[Dayline668]

Oh ya... My mechanic advised me to check properly lerr... He say not so easy... Coz my car got ABS. the sensor has to fit in he said... If not will mess up the system...

Its plug n play bro.. just get the rear come with abs, early model ae101 dun hav abs, ae111 body hav abs.