peetah

We all know that TL has a much more powerful engine, since it is a 3.2 vs. 2.4 on the TSX. But what is surprising is that the gas mileage are practically the same, even though TL is a heavier car. Is the TL engine that much more efficient? I also noticed that it is a cleaner burning engine (ULEV vs. LEV-2).

Crazytree

I made a thread once about how the TSX engine is a horribly inefficient 4cyl and everyone freaked out.

leo leo

Imo, you can't really compare the two since they have very (almost opposite) characteristics.

The TL and Accord V6 engiens are very powerful (for their class) But the TSX's engine works much more effortlessly imo. (and this is coming from someone who owns a J30A4 )

AZTSXer

I have had two 3 series BMW's, one 2.5L E46 and one 2.8L E36. Both were paragons of fuel economy next to the TSX. The TSX has many other positive attributes that caused my brand switch, but fuel efficiency was not one of them.

jcg878

That reminds me - as a principal complainer of TSX fuel economy, I feel the need to inform the group that I averaged 30 mpg on a recent trip to PA and back 2 weekends ago. So crazy, you and I just have crappy traffic to drive in everyday, methinks.

edit: to put this in context, I average about 20mpg most of the time

dom

Even in -15C here in Toronto I get 24MPG in 90% City driving??

I once heard/read that Honda engines are either great gas or not so great on gas. Someone was once explaining how they had a Civic Coupe Si(Ex) that was horrible on gas compared to his new Acura 1.6EL (which has the exact same engine/tranny). Alot of people agreed with that assesment and the same thing seems to be happening here with the TSX.

gfxdave99

Well do you think when the EPA was doing their MPG testing they were ever going past 4000 rpm? Probably not. Most of us bought our cars cuz they are fun to drive on the high end of the rpm band.. however that doesnt go hand and hand with good gas milage.

Look on the bright side, our cars qualify as LEV's so at least we're not killing the planet when we burn up the dead dinasours...

ClutchPerformer

The main advantage of a bigger engine from a fuel economy standpoint is that you can get things done at lower RPMs (I think gfxdave hinted at this). So in the same driving cycle (EPA), the bigger engine won't necessarily use proportionately more gas.

That being said, the k24 isn't very fuel efficient. And our gear ratios suck. Sorry.

LeMasseHammer

I read last night (in my free AAA motorist magazine, I think) that the BMW M5 gets 18/26 MPG city/highway. I thought it must be a misprint, considering that it's a 500HP, 10-cylinder

Anyway, my mileage has been slowly improving as I approach 10,000 miles on my TSX (21 the first few months to 22 to 23 now). My driving style is still rev-happy, and I'm still 80-90% city driving. My girlfriend's '03 4-cyl Accord coupe only averaged 24 MPG on her last tank (mostly city), and she's just a moderate leadfoot.

BTW at my last fillup, I paid US$2.35/gal for 91 octane fuel. Not complaining, but just FYI

gfxdave99

Okay, i'll stop bitching about paying 1.95 for 93 octane then

provench

Add me to the list of folks that think Honda has not wow'ed anyone with the MPG on the TSX. My CL-S matched what my TSX is getting ... just a shame really. I think (as many have stated) gearing in 6th gear for us 6MT'ers is part to blame.

TinkySD

to complete with bigger displacement/turbo motors the it had to be tuned fairly aggressive, that's pretty much the whole story. For comparison sake

c230 rated at 21/30
a4 1.8t rated at 22/31
m6 s rated at 19/27
is300 users at is300.net get like 18-20mpg regularly.

id888

I'm with Provench.

I don't think folks are making enough of the gearing of the TSX. Yes, there are six cogs, but they are close ratio with a short sixth.

That said, coaxing 200 hp out of four cylinders without forced induction is not easy. Can anyone think of a non-forced induction 4-cyl sedan that has similar power output and better fuel economy?

Accord, Altima, Camry, domestics? I don't think so.

gilboman

b/c the sedans use a V6 with more hp and torque with similar mpg numbers its not really worth it to get a I4 with less hp and torque than a V6 yet not save on gas. Thus leave fuel efficient I4 for the econosedans or small coupes where torque and hp is not that important

TinkySD

That argument doesn't hold water when the tsx consitenly turns in similar or better acceleration times to cars like the a4 1.8t, c230, 9-3 and passing times to cars like the 325 and even m6s.

waTSX

Leo Leo

How do you figure the TSX engine is working more effortlessly than TL/Accord V6's?

My 2000 EX V6 made the same HP as my TSX, but beat it in fuel economy by a good 2 MPG. It seems to me that the V6's are more effortless, making more and better (torque) HP at lower RPM's.

I personally am quite disappointed with the TSX's MPG. Especially considering I have to run premium fuel. Weighing in the cost factor , it would be considerably cheaper to run a new EX V6. Better MPG, cheaper gas, better power by a long shot.

gfxdave99

Too bad they dont offer the i-CTDi here.. it still does 0-60 in 9 sec but gets 52mpg..

Would make a heck of a commuter car

fdl

I'll echo some of the other posts. I dont think the TSX 2.4 is an horribly inefficient engine, its just that its got very agressive gearing, specifically in the 6MT, that result in the very average gas mileage numbers.

The gearing is so messed up in the TSX, 6th and 1st are just disproprtionately high ratio, putting 6th too close to 5th and 1st too far from second. But I have ranted on that issue enough times.

Bottom line is on the highway I am cruising at 3500 rpms.

crisco

While I understand the curiosity, is this really a big factor for someone who owns a TSX? As someone stated earlier, we bought this car because we like to rev it to high rpms. And a 2mpg difference between the TSX and V6 accord adds up to roughly $100 / year (based on 15k miles and $2.00/gallon). As has been stated before on this forum, a heavier V6 in this car would come at the expense of the handling...

dom

Yes you have. At least complain about something valid, like the TSX's lack of power Or trade it in for an automatic.

rb1

I don't think it is that aggressive. My Jetta turns 3100+ RPM at 70 mph in top gear (and still gets better mileage), and the Jetta 2.0 turns 3400 RPM at 70 mph (and still gets better mileage). The TSX turns what, 2950-3000 RPM or so at the same speed? My 3.0L V6 Maxima turned the same RPM at 70 mph! I loved it. (And it still got 30-31 mpg on the highway)

You won't save that much gas by lowering the 6th speed gearing. What you will do is make it harder for the cruise control to maintain speed on hills, and possibly even find that you have to downshift on anything but mild grades.

peetah

I totally agree. Some posts mentioned 36mpg on the freeway with 5AT, which has a higher top gear. No way can I get that in my 6MT. With 6 gears, the car should be responsive AND fuel efficient.

ostrich

I got 25mpg with my last tank (by manual calculation) and that was with mostly city driving. I have just over 2000 miles on the odometer. I thought that was pretty impressive myself.

SiHawk

The horsepower per liter of displacement is almost identical for both engines (83), hence the MPG is very similar.

270 HP/3.2 liters = 84.4 HP per liter

200 HP/2.4 liters = 83.3 HP per liter


Also the curb weights of the TL and TSX are within about 250 lbs, of each other, so again the MPG should be similar, with the only real differences caused by the gearing.

speedyturtle

Although the MPG numbers may look similar when driven in a mild manner, enthusiastic driving (ie redlining, aggressive driving) in the TSX would probably have a milder effect on mileage as compared with a larger V6 like the TL.

= @ 7100 rpm for enthusiasts such as ourselves.

fdl

OK, I have no way to verify your numbers. But assuming they are correct ... just some thoughts ...

I'm assuming this is the 1.8T, so its probably got to keep the rpms that high to keep the turbo spooled.

Thats cuz its a tiny underpowered engine.

Actually I'm pretty sure its higher, maybe 3300.

Hmm...I dont know what to say about that!

peetah

The curiosity is whether TL has a more technologically advanced engine than the TSX. It provides much more torque/hp, burns cleaner and gets the same mileage as the TSX even though TL is about 250 lb. heaviers. But as mentioned earlier, the gearing may be a factor here.

ClutchPerformer

Yes, you would. Why else would the auto TSX get better highway mileage than the 6MT? The only way they differ is the top gear ratio. And apparently they differ enough to overcome the inherent mechanical efficiency advantage of the MT.

And about the cruise control thing: let's say we made our 6th ratio equal to the auto's 5th ratio (from 0.659 to 0.566). We'd get the same or better gas mileage (like we should), and turn less RPMs at cruising speed. And I've never heard any auto TSX owner complain about how their cruise control forces a downshift when going up a hill.

I'd take a 0.566 6th gear ratio in a second. Hell, I'd even pay for it.

rb1

The TSX MT turns a full 25% more RPM in top gear than the AT does. Does it burn 25% more gas? Not even close -- its more like 6%. Meanwhile, your ratio change would slash available torque by 15% and, if I extrapolate the savings from the AT vs. MT, would increase your highway mileage by a pitiful 4% or maybe 1 mpg. Hence my claim, "not that much".

An MT is more efficient generally, but typically not when cruising on the highway when the AT torque converter locks up, so I don't think the MT vs AT efficiency comes in to play when considering highway mileage.

One more interesting point of reference. The TSX overall final drive ratio is 3.137:1, a hair taller than a BMW 325i at 3.15:1. There are heavier cars out there with bigger engines and shorter gearing, so quit yer bitchin'.

fdl

Your logic is a bit flawed here. You need to calculate the percentage relative to the total range of RPM.

So MT RPM/ 7200 vs AT RPM/7200. I dont feel like doing the math but would guess its closer to the 6% difference in mileage.

2.4TSX-R

Acura's manufacturer catalogue
11.6L/100km for TL
10.2L/100km for TSX

Ex: 65 Litres Fuel Tank yields 560 km per tank for TL
65 Litres Fuel Tank yields 637 km per tank for TSX

Conclusion, buying the TSX will save a lot of money on gasline in the long run.

2.4TSX-R

if we wanna compare the TL's engine, we better compare it to the infiniti G35's V6. It's more fair this way.
Actually, talking about the performance, G35's VQ engine wins. Eventhough it has 10hp less than the TL's engine.

2.4TSX-R

I think TL's engine doesn't match with the drivetrain.

FF + big power engine = torque steer + understeer = less fun.

rb1

I don't think so. At the same throttle pressure, the amount of fuel consumed is (at least at these RPM levels), almost exactly proportional to RPM. An engine at full throttle at 4000 RPM is consuming fuel at 4/3 = 33% more fuel than one turning at 3000 RPM.

In the AT vs. MT case, you're looking at slightly higher throttle pressure but lower RPM in the AT vs higher RPM but lower throttle pressure in the MT.

On the average, the AT gets only 2 mpg (=6%) better mileage despite turning 80% of the MT revs.

(As an analogy, I think its reasonable to infer from this that if the AT turned 90% of the MT revs, you'd only save half as much fuel =3%.)

Your TSX gear case cuts the TSX MT 86%, which gives me 14/20 of the "savings" that the AT gets, or .7 * 6% = 4.2% Q.E.D.

TinkySD

some of the difference is also attributed to the 100 extra lbs and 5% less effecient transmission(youll need more throttle for the same power)

rb1

Yes, but as I noted earlier the torque converter locks up when cruising, eliminating the efficiency difference.

majormojo

You know, if we all agree that the TSX doesn't have great fuel economy, it will no longer qualify as an "econobox", tarted up or not.

ClutchPerformer

It's still less efficient. Autos have more gear teeth meshing per revolution.

rb1

WTF? Someone care to quantity how much this is?

Traditional wisdom is that the torque converter is the source of the inefficiency difference between an MT and AT.

(Meanwhile, a belt-driven -- e.g an "infinite" number of teeth -- CVT with no torque converter delivers exactly the same efficiency and mileage as an MT in Audi. )

ClutchPerformer

Traditional wisdom also says "high octane gas will make your car run better/cleaner/more powerful/etc."

Think about how many gear teeth have to mesh with each other when a sun-planet-ring gearset rotates one time (the auto). Compare that with just two gears meshing (the manual).

I'm not saying it's a HUGE difference in efficiency. Good gears are 99+% mechanically efficient (that's why they cost so much). But the more teeth you mesh, the more friction you have. That's all there is to it.

This isn't the same type of friction. And a belt doesn't imply an "infinite" number of teeth. If it did, you'd get an infinite gear reduction and you'd break something. To my knowledge, this only happens with toroidal CVTs (which the Audi is not), but I still don't quite understand how.