CK6Speed

iTrader: (1)

That surprised me a lot as well. To think, if they put a DOHC 3.5L i-VTEC engine in the RL it could be pusing 325-330 HP and 290-300 lb-ft torque right now. That should drop times by about half a second right there. Introduce a nicely geared 6-Speed tranny and drop time by another 0.2 second maybe. Oh, well. Maybe that will come out in a year or two.

SteVTEC

Cam phasing would mainly optimize the low-end and mid-range, but not necessarily give you any more peak torque. It'd still probably make the same 260 lb-ft @ 5000 rpm peak, but the VTC would give you another 10-20 lb-ft or so off the line and all throughout the low/mid rev range. It'd be a pretty noticeable difference and you'd get huge gains in area under the curve, but peak numbers might not even change. Maybe they'd get it up to 265-270 lb-ft, but not a huge jump up to 290-300 lb-ft. The most advanced naturally aspirated street engines today are pushing about 80 lb-ft/L and that's with variable everything, high compression ( > 11.0:1), direct injection, etc, the whole 9 yards. So 280 lb-ft would be the absolute upper limit I think. But to get that they'd have to make some tradeoffs. 7000 rpm on a SOHC requires stiffer valve springs and that increases internal friction and takes away torque. If they dropped the rev ceiling to 6000-6300 rpm they could gain the torque back, but at the expense of their high-revving horsepower. Honda would never tradeoff horsepower for torque. It's not in their philosophy.

I would still love to see a DOHC i-VTEC V6 from Honda though. It could give them a leg up on Toyota and Nissan, and then maybe Toyota/Lex would spin a VVTL-i 2GR-FSE, and Nissan might spin a VQ35DE with Neo-VVL (their Japanese market variable lift system).

oh baby....

TRDFantasy

Beautifully said . Fact is, Honda's philosophy on engines is indeed why all their engines exhibit similar characteristics. I also think that Honda does not have a broad range of engine building experience, compared to Toyota or Nissan. Honda has stuck to what they know, and have not tried a new or a broader engine building philosophy, because they do not have experience for that I think.

Toyota is often underestimated when it comes to building great engines ... much emphasis these days seems to be given to Honda, or Nissan's VQ. I think the new GR engines from Toyota will prove to be more menacing then many believe.

I estimate that the 2GR-FSE can achieve around 280 lb-ft of torque at a fairly low RPM thanks to Direct Injection.

Just a question to clarify .. the 2GR-FSE has dual VVT-i ..... but it does not have lift, am I correct? Would it then be reasonable to assume futures GRs will see lift added?

flipside909

Correct no variable lift, otherwise it would be designated 2GR-FSE Dual VVTL-i...which would make for a very Honda-esqe torqueless high revving motor i.e. 2ZZ-GE.

TRDFantasy

Heh .. but I though lift helps somewhat broaden the power band ... does it sacrifice low end grunt as well?

SteVTEC

I partially disagree.

Honda has always been an engine building company first. But they're also extremely arrogant and haughty at the same time. They believe in their way and philosophy, and it's almost like they have to be dragged kicking and screaming to do anything other than what they want. It was not until Honda was nearly out of business in Europe that they finally developed a turbodiesel for that market which is essential. But in the development papers for the engine, the engineers that wrote it couldn't resist making a few snide anti-diesel remarks in their own diesel engine development paper! I was shocked, but it proves their arrogance. At any rate, their great 4-cylinders prove that they can build 1st class engines. Nobody builds better 4-cylinder engines than Honda. Not even Toyota, IMHO. So the technical expertise is certainly there, but maybe the enthusiasm (for V6's) is not?

The other thing is that Honda is definitely ruled by the bean counters. Everybody on the Honda forums will say differently including at "The Temple" but there are signs everywhere. Why else would they use 2-step SOHC VTEC on their "premium" lineup of cars when even their 4-bangers have DOHC i-VTEC? So the $50k RL gets SOHC VTEC, but the $18k Civic Si gets DOHC i-VTEC? WTH?

This reminds me of the time many years ago when I was in high school and working at a Staples store in the electronics department. One day the HP sales rep was in asking if I had any questions on their products and I said yeah. "Why don't all these Pavilion computers have any L2 cache in them? It costs like nothing and without it the performance of the computer is crippled. My DX4-100 runs Windows faster than these things!" You know what the sales rep said to me? "Well if the customer doesn't know what it is then we don't give it to them."



This is all gut instinct, but that's honestly the vibe that I'm feeling from Honda. Their customers think they've got it all with the big peak horsepower figures, but meanwhile new RL owners are wondering where the hell their 260 lb-ft of torque is and why they have to really hammer it to get it up to speed. In the meantime, the M35 will give better performance with less peak horsepower due to less emphasis on the peak horsepower number and more emphasis on what actually makes the car move which is torque and the powerband, and the tools needed to optimize it properly (DOHC VVT cam phasing!)

Despite what my hater club says about me, I'm actually still a big Honda fan but am just frustrated that they're not more competetive in the V6 market, for whatever the reason is.

I've owned one each of the Japanese Big 3 V6 engines, a Nissan VQ30DE ('99 Maxima), Toyota 1MZ-FE ('02 Highlander), and a Honda J30A1 ('01 Accord V6). The MZ is definitely a brawny engine, but its downfall is that it has the personality of a blender. It does its job exceptionally well but it's a no frills engine. The Nissan VQ practically begs you to push it and is very entertaining and also exceptionally smooth. The Honda J I had was total weaksauce. It's almost like Honda didn't even try. It had a nice VTEC growl but that's it. The J30A4 (03+ Accord V6) is tons better and also a Ward's 10 Best engines winner, but it's still way down on torque since now everybody else has moved to higher displacements except Honda.

The GR is more of a standout. At least in the Avalon it's making very competetive power (280hp/260tq) on a par with the VQ, but has better fuel mileage at 31 mpg hwy. The Maxima and TL, its most direct competitors, both have less rated power and poorer overall mileage figures. I think the GR has a great shot at a Ward's 10 Best engines slot. Maybe the VQ oughta get bumped but it's still an excellent engine so something else will probably get bumped off of the list. The 1MZ-FE did make Ward's 10 Best, but only for like 1 or 2 years in the 96 or 97 timeframe. And I understand why.

Nissan managed 274 lb-ft on the Gen-III VQ35DE in the 350z, and that's with intake only VVT, relatively mild 10.3:1 compression, and port injection. So 280 lb-ft from a 2GR-FSE is definitely feasible.

I don't think we'll see variable lift on a 2GR though. Both the Nissan VQ and the Toyota GR engines are pretty beefy V6 engines with large bore spacings. They're still pretty oversquare at 3.5L displacements and that allows for lots of valve area. They don't need variable lift to make 300hp. In comparison the Honda J35 is a much shorter engine with pretty narrow (98 mm) bore spacings (the VQ is 108 mm for reference). It's undersquare at 3.5L and has less valve area to work with, so it needs variable lift to achieve 300hp. If the power wars continue north of 300hp in the V6 class, the Honda J35 is at a distinct disadvantage here whereas Toyota and Nissan can continue to push power up much more easily. At 300hp in the VQ, it's still only running 10.3:1 compression and no variable lift whereas the RL engine is running 11.0:1 and already has variable lift. Honda is pushing the snot out of those things and still coming up short.

SteVTEC

It does broaden the powerband. By normalizing the torque curves of the Avalon and TL engine to a percentage of peak torque, you can see the difference quite easily.



That's all that VTEC does on the TL.

2-step VTEC sacrifices low/mid-range torque vs the competition because they lack the capability to vary the cam phasing. On a 2JZ-GE with VVT-i @ 2000 rpm, the phaser goes from 0* (full retard) at coast to about 35* advanced at full throttle. The overlap with the exhaust valve helps with scavenging and the earlier intake valve closure as a result of the advancing ensures that the valve is closed before the WOT air volume has a chance to bounce back out of the intake port. That's where the improved VE comes from on variable phase VVT engines. And they can set that optimially for every possible RPM and load condition. 2-step SOHC VTEC can't do any of that. Variable intake manifolds help, but still don't give the full benefits of a variable phase VVT system.

The TL could match the torquey feel of the 2GR, but not without massively shortened gearing. They would have to go from the stock auto 4.428 final to something around 4.80-5.00:1. Nobody would be complaining about torque then, but fuel economy would also be miserable without regearing the entire transmission. The TL gets 20/29 mpg on the 4.428's. The Avalon gets 22/31 mpg on its gearset and has plenty of torque. Dual VVT-i is definitley a big help there too. That's another thing that 2-step SOHC VTEC can't optimize.

SteVTEC

Here's the 2JZ VVT-i Phase Map. Had the doc open....

CK6Speed

iTrader: (1)

Very interesting. I guess you are right about the torque figures especially in the SOHC i-VTEC. I still speculate that a DOHC i-VTEC might be able to squeeze out just a little more though, but I really don't know. I was just speculating based on the evolution from the C25 all the way up to the DOHC VTEC C32B. Then again, the J30 is already 8 years old so while I still think the J35 still has more to offer, it could be time for Honda to start looking into building a new V6 engine. I don't see them bumping displacement up in the J engine any higher. Maybe a J36, but that is about it. Unfortunately, the new RL, while I personally drove it and think it has adequate power and actually quite nice and moves you along just fine, I don't think Honda can afford to keep the same engine power for too long. Maybe by the third year they will definagely have to bump up the power and torque Either by bumping it to a J36, or adding at least i-VTEC, or best case DOHC i-VTEC. I don't see them introducing a new engine line though, so it looks like we are stuck with the J engine for at lest another 4-5 years. After that retire the engine and give us something new. Another option that I am very open to is hybrid electric power. Adding the electic motor can easily compensate the low end torque, and then just tune the engine for max high end efficiency. I can live with that.

SteVTEC

Well yeah, they should be able to squeeze some more torque from it, but it wouldn't be anything drastic like 290-300 lb-ft. That would be possibly naturally aspirated from a 3.5 street engine with technologies that are on the horizon (camless valvetrain, variable compression, etc) but those are all a good 5-10 years off minimum. And you realize of course that when you go from a C25 SOHC VTEC to a C32B DOHC VTEC you're talking about two totally different engines. The block is the same but that's about it. The C32B has a higher compression ratio, entirely different head designs, cams, valvetrain, and I believe some of the internals are forged titanium as well. Apples to oranges. So yes you could gain some peak torque, but my main point was that overall you're gaining area under the curve and not so much peak torque or peak horsepower. You're optimizing the power that the existing engine makes by allowing it to be made over a much wider range of RPM's.

I don't think Honda would do a re-spin of their J engines just to get a J36, unless they upgraded everything to a 3.6 as well (Pilot, Ody, MDX, RL, etc). But your point on hybrid powertrains is a good one. The Accord V6 Hybrid is probably one of Honda's best cars right now. But the performance boost it gets comes at the expense of nearly $6k vs the regular Accord. $4k difference in MSRP, but it's going for MSRP right now vs near invoice for the regular model. You're not really saving anything, just giving your money to Honda instead of the oil companies. I'd still rather give my money to Honda though, so it's definitely on my list.

CK6Speed

iTrader: (1)

Actually that is exactly what I was hinting at. The base is the same but reworked to achieve the final end result. Yes, I understand that it is using titanium rod and a much stronger bottom end as well as a reworked head, but that is the point I was trying to make. All thay yo describe IMHO is part of the engine evolution. They can do the same to the J engine. Now, I'm not talking about what is feasable financially, but what is the potential technically. I mean, when we talk about adding a DOHC head to the J engine that pretty much means a complety new head design as far as I know. Keep in mind, I'm not at knowledgable about engines as you are I realize the cost is always a determining factor when companies decide to evolve their engines, but I don't think it will cost as much as it did back in 1990 with the NSX engine compared to today. I think we can all agree that Honda probably will never build such an engine though. But I do agree that I rather have a broad powerband and give up the peak numbers. That is why I love my C30 engine so much. While it looks weak on paper, the power band curve to the wheels is broad and flat. Not too mention adding the TYPE-R gears which may not help the 1/4 mile, but sure does make driving around town feel better

CK6Speed

iTrader: (1)

Actually, that is not a bad idea at all. When you think of it, all those cars that use the J35 surely could use a rework. Now that they got the Rideline truck, if Honda wants to keep the V6 for a while a bump in displacement is actually a smart idea. Just like how Lexus upgraded from a 4.0 400 to a 4.3 430, or a 3.0 300 to the 3.3 330, I wouldn't mind seeing that entire line listed get a bump to 3.6. It would actually make sense.

LexFather

I want to personally thank SteVTEC to making it over here to CarChat. I've seen some of his work on other forums and he knows his stuff. Welcome to Clublexus.

UDel

One of the main reasons Honda/Acura uses SOHC 6 cylinders is because they tend to get better gas mileage and can be smaller and lighter. Honda does not need a bump in horsepower and engine design because most people are very impressed with their engines and there is some complaints that they are getting too powerful for their predominately FWD lineup. What's wrong with getting more horsepower from the same displacement. Many people complain that 3.8 liters is too big for a proper v-6 and they have already used a 3.5 liter is some cars. If they can get 240 hp from a 3 liter and 270 from 3.2 liter then why not. Some people like to get that reward for going higher into the power band. Nissans DOHC VQ is very torquey but it gets pretty poor gas mileage and has been getting rougher as displacement increases. I have seen people complain in Freshalloy about this. Honda uses DOHC in its high performance cars like the NSX and S2000 but it is not needed in sporty luxury cars for now at least until they introduce a RWD platform for a 6,8,10 cylinder performance or luxury car. Mercedes uses SOHC on their v-8 and was using it on their 6 cylinders.

SteVTEC

Time for some myth busting...

Honda Accord J30A4: 3.0L SOHC, 240hp, 212 lb-ft: 20 / 30 mpg EPA
Nissan Altima VQ35DE: 3.5L DOHC, 250hp, 249 lb-ft: 20 / 30 mpg EPA

The Nissan has DOHC, more power, and the same mileage as the Accord. The earlier version with the 4A tranny was not as efficient, but last year Nissan updated the car with a 5A same as Accord) and it gets the same mileage as the Accord.

Acura TL J32A3: 3.2L SOHC, 270hp, 238 lb-ft: 20 / 28 mpg EPA
Nissan Maxima VQ35DE: 3.5L DOHC, 265hp, 255 lb-ft: 20 / 28 mpg EPA
Toyota Avalon 2GR-FE: 3.5L DOHC, 280hp, 260 lb-ft: 22 / 31 mpg EPA

Same thing here, only the Toyota 2GR beats both and gets better mileage, and it's only the port injected version.


I know it's been widely repeated by the Honda guys that SOHC is "more efficient" but that's a myth. Maybe from a cost perspective, but not in terms of power generation or fuel efficiency. The fact of the matter is, the VVT systems are far more flexible and advanced when you have DOHC, and that in turn leads to much more efficient and clean burning engine designs while also giving you more power. Yes, DOHC heads are a tad larger than SOHC and also more expensive to produce, though.


The Nissan guys complain about mileage because they enjoy all of the extra torque too much. Same thing with a Honda guy that can't stay out of VTEC. If you're makng more power, you're burning more fuel period. Driven the same way though, the engines get pretty much the same fuel economy. What's the point of getting a torquey 3.5L engine if you don't enjoy it once in awhile though? Ditto for a Honda that's never flogged into VTEC from time to time.