Honda Legend V6 SOHC, WHY?

[Twofouronenite]

No.

 

No reason to go for DOHC if the "patented" SOHC ivtec can already control 4 valves per cylinder plus variable timing and lift control to achieve what dohc vvt-iL does. The logic is like this: If one can drive a car smoothly with one leg to operate gas and brake, there is little reason to use both leg seperately for brake and gas.

 

Less friction and less weight is not a bad thing. It is the same misconception people have that twin exhaust tip is more powerful than single exhaust tip.

 

More of J engine: http://en.wikipedia.org/wiki/Honda_j_engine

 

Legend is still using the older J35 without VCM but higer power and torque (309ps, 370nm) with higher compression and need premium petrol 98 or 100. Legend fc is higher because it is 4WD!

 

Legend J35 non VCM (premium petrol)

 

 

Accord J35 VCM (regular petrol)

 

 

The newer J35 with VCM in accord/inspire is economy tuned. Lower compression, lower power (280ps, 342nm) but able to take regular 95 petrol. The key is ability to take lower RON petrol which lower down the operating cost for owner. The legend is made for premium sector who can better afford premium petrol.

 

VCM is unique to Honda still. It really works to lower fc and lower pollutant but yet giving high power. More of vcm: http://www.honda.co.jp/tech/auto/vcm/

 

J30 and J35 has no shortage of torque. I am using one and can testify that there is no vacuum like smaller engine. The torque is more than enough even from 1000rpm. There are times when the front wheel spins uncontrollably from start due to high torque.

 

Thanks for the graphs. Wow, seem the Legend engine tq is not significantly affected by the higher rpm range as compare to the Accord. Did noe Legend is 4WD too.

 

[Chickensoup]

For a V6 like the Legend's, SOHC means 1 camshaft per bank of cylinders. So there are actually 2 camshafts in the engine.

 

It's just like how Toyota used to call its DOHC V6 engines 'Quad Cam'. Yes, there were 4 camshafts but it was a bit misleading for buyers who would automatically think it's better than 'Twin Cam'.

I think the meaning to DOHC - Double Over Head Cam should be referring to a bank of cylinders. Not total no. of cams an engine have.

 

Just like 16valve engine, 4 cylinder x 4 valves per cylinder = 16. We don't misinterpret as 8 cylinders x 2 valve per cylinder and call it 16 valve engine.

 

In the DOHC design, the cam lobe operates directly onto the valve tappet, one cam for inlet and one cam for exhaust, hence can rev higher. While in SOHC - Single Over Head Cam design, one camshaft operates both inlet and exhaust via lifters, so at high revs the lifters may not be able to follow the cam motion. Hence lower revs design for SOHC engines but still good up to 7,000rpm.

Edited January 12, 2009 by Chickensoup

[Bulls_is_back]

With VCM on, it is like running a 2.3L (4 cylinder mode) and 1.8L (3cylinder mode).

I do understand the flexibility of having an engine like this but it simply doesn't make sense in Singapore as one is still paying for the 3.5L road tax. Furthermore to get into the power saving mode, one has to be really gentle on the throttle which defeats the purpose of getting a powerful 3.5L engine where a 2L or 2.4L (accord) will suffice when driven gently.

 

I think the Swedes really got it right with their LPT such as the Saab 2.0LPT and Volvo S60 2.0T (lower road tax). With a tall gear ratio, they can cruise at sub 2000rpm@100km/h without boosting to get pretty good highway fuel economy, while having really good low end torque for quick in gear acceleration. Lets face it, all these cars are highway cruisers (rather than track machines). The car will reach speeds where the driver's b*lls turn to jelly before the engines run out of breathe (in the case of LPT). Yes, they run on Ron 95 too. But when driven hard or stuck in jams, sti or evo like FC is entirely possible, just like a big heavy 3.5L.

 

If the driven wheel spin uncontrollably (stock car) from start, it means that the car needs better traction control software.

 

The newer J35 with VCM in accord/inspire is economy tuned. Lower compression, lower power (280ps, 342nm) but able to take regular 95 petrol. The key is ability to take lower RON petrol which lower down the operating cost for owner. The legend is made for premium sector who can better afford premium petrol.

 

J30 and J35 has no shortage of torque. I am using one and can testify that there is no vacuum like smaller engine. The torque is more than enough even from 1000rpm. There are times when the front wheel spins uncontrollably from start due to high torque.

 

[Mt88]

With VCM on, it is like running a 2.3L (4 cylinder mode) and 1.8L (3cylinder mode).

I do understand the flexibility of having an engine like this but it simply doesn't make sense in Singapore as one is still paying for the 3.5L road tax. Furthermore to get into the power saving mode, one has to be really gentle on the throttle which defeats the purpose of getting a powerful 3.5L engine where a 2L or 2.4L (accord) will suffice when driven gently.

 

I think the Swedes really got it right with their LPT such as the Saab 2.0LPT and Volvo S60 2.0T (lower road tax). With a tall gear ratio, they can cruise at sub 2000rpm@100km/h without boosting to get pretty good highway fuel economy, while having really good low end torque for quick in gear acceleration. Lets face it, all these cars are highway cruisers (rather than track machines). The car will reach speeds where the driver's b*lls turn to jelly before the engines run out of breathe (in the case of LPT). Yes, they run on Ron 95 too. But when driven hard or stuck in jams, sti or evo like FC is entirely possible, just like a big heavy 3.5L.

 

If the driven wheel spin uncontrollably (stock car) from start, it means that the car needs better traction control software.

 

Dont get it wrong. Once the electronic activated, uncontrolable traction is no longer a problem. It is just me that want to have a little fun by turning it off. Just want to convey a point that the raw torque of j engine is enough ;)

 

As you said it, mass car are essentially ment for cruiser rather than track. Therefore the concern of SOHC and DOHC is irrelevant for day to day car.

 

As cruiser is where VCM shines. Having a large power doesnt mean one has to fully utilized all its full power all the time. Thats too kiasu lah :) The key of VCM is to have power when one need it and have the economy and low emission when not needed like cruising. The user have some kind of option and control to the car fc and emission unlike non vcm engine. Tax and cost are another matter. Luxury and refinement cannot be equate 1 to 1 therefore I think 3.5L appeals to a different segment. In my experience a smaller force induction engine especially the four pots can never subtitute the refinement of v6 and raw torque of larger engine.

 

May I know why LPT in oppose of FPT? Why not supercharger and turbo combi ala TSI engine? Here is the 2.0t chart. I notice that the torque band quickly falters after 4000rpm and the lack of it on lower rpm?

 

[Mt88]

seem the Legend engine tq is not significantly affected by the higher rpm range as compare to the Accord.

 

It has a different camshaft tuning and different ecu to the eco-tuned vcm version. The very reason why the same engine is choosen for US Accord coupe (shame the thrist).

 

Here is what one can expect from that engine:

 

 

 

 

[Paddie]

I think the meaning to DOHC - Double Over Head Cam should be referring to a bank of cylinders. Not total no. of cams an engine have.

 

Just like 16valve engine, 4 cylinder x 4 valves per cylinder = 16. We don't misinterpret as 8 cylinders x 2 valve per cylinder and call it 16 valve engine.

 

Yes that's what I meant... DOHC means twin cams per bank. SOHC means single cam per bank = 2 camshafts in a V engine.

 

But I don't get what you said about 16 valve engine. An 8-cylinder engine with 2 valves per cylinder is indeed 16V, and there's nothing wrong with calling it such.

[Chickensoup]

Yes that's what I meant... DOHC means twin cams per bank. SOHC means single cam per bank = 2 camshafts in a V engine.

 

But I don't get what you said about 16 valve engine. An 8-cylinder engine with 2 valves per cylinder is indeed 16V, and there's nothing wrong with calling it such.

When we call 16 valve engine, it usually means a 4 cylinder engine with 4 valves per cylinder. We don't normally call a 8 cylinder engine with only 2 valves per cylinder as a 16 valve engine, although you are technically right.

[Sturtles]

It has a different camshaft tuning and different ecu to the eco-tuned vcm version. The very reason why the same engine is choosen for US Accord coupe (shame the thrist).

 

Here is what one can expect from that engine:

 

 

If this is the honda's 3.5L engine, its definite a superbly linear acceleration. those small block turbocharged cars simply do not have this level of drivability.

 

Perfect car for cruising on the highway. Still some work to be done on overtaking power though.

[Mt88]

If this is the honda's 3.5L engine, its definite a superbly linear acceleration. those small block turbocharged cars simply do not have this level of drivability.

 

Perfect car for cruising on the highway. Still some work to be done on overtaking power though.

 

That is a 1.9 ton honda elysion prestige that use an identical SOHC J35 engine in jdm Legend minus the cumbersome sh-4wd. Overtaking ability is not a problem (will be if overtaking lambo ). Notice the extra torque band from 4000-6000rpm where the kick in normally happens during overtaking? That is the speciality of premium tuned i-vtec unlike others where the torque band falters. A sweet engine for day to day usage.

 

Edited January 13, 2009 by Mt88

[Twofouronenite]

It has a different camshaft tuning and different ecu to the eco-tuned vcm version. The very reason why the same engine is choosen for US Accord coupe (shame the thrist).

 

Here is what one can expect from that engine:

 

 

Saw the vid. That could not be more than 7 secs!

[Twofouronenite]

When we call 16 valve engine, it usually means a 4 cylinder engine with 4 valves per cylinder. We don't normally call a 8 cylinder engine with only 2 valves per cylinder as a 16 valve engine, although you are technically right.

Think u r confused here. Paddie did not mention on the number of valves here. Just saying the engine got 2 cam shaft per bank of cylinders.

 

[Chickensoup]

Think u r confused here. Paddie did not mention on the number of valves here. Just saying the engine got 2 cam shaft per bank of cylinders.

That is his 1st statement. Even in V- engine layout, SOHC design, means 2 cams in total. We don't call it Twim cam design either as in DOHC.

 

I am referring to his 2nd statement where Paddie said confused.

[Twofouronenite]

That is his 1st statement. Even in V- engine layout, SOHC design, means 2 cams in total. We don't call it Twim cam design either as in DOHC.

 

I am referring to his 2nd statement where Paddie said confused.

We are taking about cams not valves leh? He was referring to 2 cam in DOHC. Nothing wrong here either. And there 2 cam in the SOHC since it is V configuration.

[Chickensoup]

We are taking about cams not valves leh? He was referring to 2 cam in DOHC. Nothing wrong here either. And there 2 cam in the SOHC since it is V configuration.

If you are referring to English language Twin means 2 but in engines and in engineering terms Twin means in a pair. The pair got to be in the same bank or in the same cylinder head to qualify as a twin cam engine. SOHC in V configuartion is a total of 2 camshafts in one engine which has 2 cylinder heads. So it should not be mis-contrude as a Twin Cam design.

[Twofouronenite]

For a V6 like the Legend's, SOHC means 1 camshaft per bank of cylinders. So there are actually 2 camshafts in the engine.

 

It's just like how Toyota used to call its DOHC V6 engines 'Quad Cam'. Yes, there were 4 camshafts but it was a bit misleading for buyers who would automatically think it's better than 'Twin Cam'.

 

 

If you are referring to English language Twin means 2 but in engines and in engineering terms Twin means in a pair. The pair got to be in the same bank or in the same cylinder head to qualify as a twin cam engine. SOHC in V configuartion is a total of 2 camshafts in one engine which has 2 cylinder heads. So it should not be mis-contrude as a Twin Cam design.

 

If you are referring to the statement, He's not referring to the SOHC in V configuration as Twin Cam, but as "Twin Cam". Ha ha!

[Paddie]

When we call 16 valve engine, it usually means a 4 cylinder engine with 4 valves per cylinder. We don't normally call a 8 cylinder engine with only 2 valves per cylinder as a 16 valve engine, although you are technically right.

 

http://prescottacf.org/dodge/30-dodge-char...-16v-344hp.html

 

:)

[Paddie]

If you are referring to the statement, He's not referring to the SOHC in V configuration as Twin Cam, but as "Twin Cam". Ha ha!

 

Yup I never said that SOHC in V-engine is twin cam, only that there are 2 camshafts in the engine.

 

And I also said that Toyota used to (not sure if it still does) call its DOHC V engines 'quad cam'.

[Victorco]

guess every1 is a bit blur in how engine arrangement are call.

 

technical term of how to call the arrangement is as follow if i am not wrong correct me if i am.

 

a in-line 4 with 16 valve and 2 camshaft is call

inline-4 16V DOHC or twin cams . it mean there is 4 cylinder with 4 valve each with TWO cams above it controlling 2 in and 2 out separately.

or if it's a 8valve then it's call inline-4 8v DOHC

 

a in-line 4 with 16 valve and 1 camshaft is call

inline-4 16V SOHC. it mean there is 4 cylinder with 4 valve each with ONE cams above it controlling 2 in and 2 out together.

 

 

a V6 with 24valve and 4 camshaft is call

V6 24V DOHC or quadcam is arrange in 3 cylinder per side and 4 valve in each cylinder with TWO cams at each side controlling 2 in and 2 out valve per cylinder each.

 

a V6 with 24valve and 2 camshaft is call

V6 24V SOHC is arrange in 3 cylinder per side and 4 valve in each cylinder with ONE cams at each side controlling both in and out valve per cylinder each.

 

if there is more cylinder it will be stated there so no worries that u will mistake a 16V as a 8 cylinder with 2 valve each and it will be call inline-8 or V8 16V. but normally now days a inline-8 is quite impossible as the size will be HUGE so it now V8 normally and it 32V instead of 16 for better performance and FC.

 

a boxer engine also can have 2 camshaft but it's a SOHC rather then a DOHC or twincam. cos boxer work in opp side instead of up and down motion.

Edited January 14, 2009 by Victorco