Last post on Nov 05, 2013 at 12:08 PM
You are in the Acura RL
What is this discussion about?
Acura RL, Sedan
#2854 of 7386 Re: robertsmx [saugatak #1387]
Jun 21, 2004 (6:34 am)
Having seen the numbers from you that match my guesstimate, I assume your concern regarding RL’s torque numbers being a pie in the sky (or not) has been addressed. My guesstimate is based on assumption that RL will use 3.5-liter version of the V6 used in TL.
Going beyond the peak numbers, let us analyze the 3.5/V6 used in MDX using the official dynograph.
In Japan, the engine is rated at 260 PS 5800 rpm / 345 Nm (about 255 lb.-ft) 3500 to 5000 rpm. North American version got a boost in peak power output to 265 HP for 2004 (but the Japanese version has stayed put to 2003 level).
At about 1200 rpm, the engine is producing 300 Nm (87% of the peak torque). Between 2000 rpm and 5800 rpm, the engine’s torque output varies about 5-8% with near flat (peak) torque output from 3500 rpm to 5000 rpm. This is a classic example of a Flat AND Broad torque curve, and out to prove it doesn’t matter where the engine produces peak torque, because it is more about “a range”.
At 10.0:1, the 3.5/V6 in MDX is far from being a “very high compression” engine. In fact, the compression ratio is identical to the 3.5/V6 used in Odyssey & Pilot. For RL, I suspect, the compression will be as high, if not higher, than in the TL (about 11.0:1). This will help boost the output beyond the MDX-levels.
There are three stages in the output from MDX’s 3.5/V6. The first is the usual tuning, to maximize low-end torque output, the second stage gets a boost from the variable intake manifold, and finally, the third stage gets a boost from VTEC. This is not unlike the 260 HP/3.2-liter V6 we saw in last generation Acura TL (and CL) Type-S. The TL-S engine was rated at 260 HP at 6100 rpm, and 232 lb.-ft at 3500 rpm to 5500 rpm.
In the end, I suspect Acura RL’s 3.5/V6 to deliver 235-240 lb.-ft at an engine speed, as low as 2000 rpm, and continue to develop within 5-8% of the peak torque between 2000 and 6500 rpm.
#2855 of 7386 Re: robertsmx [robertsmx #1414]
Jun 21, 2004 (6:52 am)
If you are correct, and I hope you are, the need for a V8 will be even further reduced, IMHO.
#2856 of 7386 Re: A different thought [markcincinnati #1397]
Jun 21, 2004 (7:08 am)
To improve its acceleration, assuming my guess that the torque ratings will be "OK" or "good" but not "oh wow, impressive," Acura may have elected to lower the final drive ratio and made 5th gear a bit taller "overdrive" (in an effort to raise its combined MPG). A six speed transmission with both 5th and 6th being overdriven, but 5th only mildly so, would somewhat counter and "mask" the hunting that could have been engineered in if such an approach is actually taken.
Acura went 5-speed auto with 2000 TL (1999 TL had 4-speed, which was the norm back then), and something I noticed didn’t sit well with me and that had to do with the added weight. The new TL gained about 50 lb.
I can still see some improvement of going up from 4 to 5 speeds, especially given that the gear ratio spread (between first and final gear ratios) is virtually unchanged meaning the addition gear actually helped close down the spacing. But if every cog ends up adding 50 lb. with diminishing returns, I don’t know if I would like the idea of going to six or seven speeds. Why not just go CVT instead and for those who care, use a preset 7-speed ratios from it?
In Acura/Honda 5-sp auto, the transition from cruising in the tall overdrive mode to acceleration mode forces an upshift from fifth to third. If it were a six speed auto, “sixth” could replace “fifth” and “fourth” could replace “third”. But since the gearing is going to be closer, there will be times when an additional shift will occur during acceleration.
So, pros and cons of 5-sp versus 6-sp versus 7-sp is very debatable. It is probably more about academics than practicality.
As far as RL is concerned, Acura will probably stick with the existing 5-speed gear ratios. In the first, RL will likely carry an overall drive ratio of 11.35-11.55:1 (like it does in TL and MDX). The net thrust at the wheels will likely stay the same because although the car gains in torque by about 10% (compared to TL) it will also gain weight by about 10% (compared to TL). The maximum thrust in RL in first gear is likely to be about 0.60-0.62g, which is quite good. So, it is not going to feel like a muscle car off the line.
Somewhere I have read (a long time ago) that in a front driver, 0.60g can be considered a limit for traction purposes (both, Accord V6 6-speed Manual and TL 6-speed manual exceed that). With AWD, in RL, “launch traction” is unlikely to be an issue. And then, AWD will be engaged everytime the throttle is depressed the way it works in MDX’s VTM-4 system (somewhere between 30-70% of the torque may be routed to the rear wheels).
#2857 of 7386 Re: robertsmx [markcincinnati #1415]
Jun 21, 2004 (7:32 am)
I think the “need a V8” argument will be handled by Honda in its own way, and using a hybrid. If observations are true, with V8 available as an option, the eight banger woos few buyers compared to its six-cylinder counterpart. This gives little incentive to develop a V8 unless it is to be shared with some other vehicles in the lineup.
This is purely a guess, but a V8 option typically adds a premium of about $4-5K. That’s enough for reasonably powerful and advanced hybrid system. So, with a base engine that can share bits and pieces with others, and a hybrid system that can be shared as well, it makes sense to go the hybrid way.
The 3.5/V6 in the new RL could simply be the J35A tweaked for 300 HP (tweaks similar to those in TL’s 3.2/V6 will help accomplish that). Or, it could be an all-new 3.5-liter DOHC I-VTEC V6, something Honda showcased three years ago (2001 Honda Dual Note). The Dual Note’s 3.5/V6 was also rated at 300 HP.
Both engines are compatible with Honda’s IMA (knowing that Honda Accord’s J30A is being mated to IMA for launch this Fall, unless it happens to be an “all-new” engine as well which I doubt given the development efforts on J30A in Japanese market).
A “twice as powerful” version of the ultra-thin brushless DC motor used in Civic Hybrid could add 70-80 lb.-ft at low-low engine speeds, more than compensating for the low end torque that would come from a 4.0-4.5 liter V8 when compared to a 3.5- liter V6. Even if there is no gain in the top end, if the peak torque hovers around 310-325 lb.-ft 2000 rpm, it is sure to make a “must have V8” argument moot (this is not to say that it won’t be brought up).
#2858 of 7386 Re: A different thought [robertsmx #1416]
Jun 21, 2004 (7:54 am)
The 6 speed tiptronic, steptronic, positronic, or whatever the big three German manufacturers call it, weighed in at 44 pounds less than the outgoing 5 speed tiptronic. The supposed benefit to the 6speed was to keep the engine in the torque sweet spot mostly during gears 1 - 5 with 6th being more overdriven.
BMW's 7 speed and Audis Multitronic both offer some interesting aruments to the "how many speeds are enough" debate.
I am not as concerned, now, about the 3.5L in the new RL based on the recent posts pertaining to torque. 5spds will be fine, 6spds will be eventually required for marketing purposes (not that six speeds will be limited to marketing purposes, however).
Jun 21, 2004 (7:58 am)
It is possible that the old trannies were quite heavy compared to the new to start with. So, weight gain or loss is still debatable compared to perceived (or real) benefits.
I have participated in some debates that pertain to counts, albeit not just when it comes to cylinders (and in this case, cogs), but also number of valves...
5-valve per cylinder layout that Audi/VW (and Ferrari) seem to prefer over the usual 4-valve per cylinder.
Advantage to having 5 versus 4 has been very debatable.
#2860 of 7386 Re: robertsmx [robertsmx #1414]
Jun 21, 2004 (8:18 am)
As always an excellent contribution. I look at all the numbers and try to interpret them and yet right now I long to drive this car more than anything else.
Perhaps it is because yesterday I drove back and forth to Indianapolis to see the US GP race and I enjoyed enormously my Accord EX-L. It was the first 'long haul' trip I took in it (~185 miles) along with a couple of friends.
Not only keeping it at avertage of 75-80 mph was a breeze (and kept us below 3 hrs, including stops, to reach destination) but it was delightfully responsive when I had to overtake at 90-100 mph.
Indeed the car behaviour was such that my passenger in the back (owner of a >200 HP FWD american vehicle equipped with a V6) kept commenting that the car behaved as it was powered by a V6 (and this even after I told him that indeed it was a lowly I-4 engine that was carrying us around).
So I guess my point is that for as much we love to see 'nice numbers' I still believe that nothing can 'do justice' to how a vevhicle really drives. I guess is another facet of the same recurring topic of 'how great' european RWD cars feel when you are behind their steering wheel.
Anyway to add to the pleasant experience the car consumed far less than the stated 28 mpg (~31 mpg) and with few exceptions road noise was limited such that we could enjoy my CD mixes with volume set at 13 (those who have the new digital panels know this is in the level kept for city driving).
Now if I can get so much from the Accord I do not see how the RL is going to fail to be a pleaser. I can understand that there are lots of very good cars out there but I feel that at the proposed price (and the present day knowledge of tech spec) this Car is going to 'kick butts'.
Just my thougths, kudos to whoever will think differently and buy something else!!
Jun 21, 2004 (8:21 am)
By the way as soon as I will download pictures from yesterda I'll see if I can post some here. It was a great present for father's day to have a podium with 2 Ferrrari and Honda on it. I plan to go there again next year so let me hear from you if you are interested!
Jun 21, 2004 (8:42 am)
I have heard that Mercedes is retiring its 3 valve SOHC design. Is this true?
#2863 of 7386 Re: [lexusguy #1422]
Jun 21, 2004 (8:53 am)
Seeing that 2005 C-Class will have the C55 AMG in its lineup, I doubt the 3-valve SOHC layout is being retired anytime soon. The C55 will use 5.5 liter 24-valve SOHC V8.