Car Shopping

[Cova]

I got addicted to heated seats in the RSX.  They get turned on sometime in October, and stay on until May.  The only time I even consider turning them off in the winter is if I get out on the highway - even if traffic sucks and it takes me 30 mins to get to/from work I leave the heated seats on the entire ride.

[Shayne]

What's the ETA on the STI in North America/Canada?  Couldn't be all that quick seeing as it was JUST announced and Japan always gets the first few shipments.  When my brother-in-law was shopping for his STI it was about a 6 month waiting list so he instead bought an Infiniti G35.

I've always been a fan of the STI and Evo.  Hard to drive though when I test drove one a couple years back, not a fan of driving around at 4000 rpm.

[Cova]

What's the ETA on the STI in North America/Canada?  Couldn't be all that quick seeing as it was JUST announced and Japan always gets the first few shipments.  When my brother-in-law was shopping for his STI it was about a 6 month waiting list so he instead bought an Infiniti G35.

I've always been a fan of the STI and Evo.  Hard to drive though when I test drove one a couple years back, not a fan of driving around at 4000 rpm.

The first STI's that'll be arriving here in Edmonton were built in late Nov. and are expected to arrive in January.  And I've got a deposit down already - there are going to be 9 in that first shipment and my name is on 1 of them.

And I don't see why they should be much harder to drive than anything else.  Throttle-control on ice will obviously be a little more tricky considering I'm almost doubling the HP of the RSX, but I don't see any reason to cruise around at 4K RPMs (the break-in period for the engine says to stay under 4K for the first 1000 km's actually).

[Thorin]

Although having to drive at 4,000rpm is a bit of an overstatement, I do agree with your general sentiment Shayne.  The gearing, final drive, and tire diameters show that the engine spins pretty quick at highway speeds.

Gear Ratio 3.636 (1st) 2.375 (2nd) 1.761 (3rd) 1.346 (4th) 1.062 (5th) 0.842 (6th) 3.545 (Reverse)
Final drive axle ratio 3.900
[..]
Tyres 245/40R18

Compute Tire Circumference
245/40R18 means 653.2mm diameter (245mm * 40%/sidewall * 2 sidewalls + (18in * 25.4mm/in) = 653.2mm), which means approximately 2,052.1mm circumference (653.2mm * Pi = 2,052.0883mm).  So the tire travels about 2 meters for each full revolution.

Compute Vehicle Speed from Engine Revolutions, Gear and Final Drive Ratios, and Tire Circumference
- engine revolutions/minute / gear ratio = axle revolutions/minute
- axle revolutions/minute / final drive ratio = tire revolutions/minute
- tire revolutions/minute * tire circumference meters/revolution = distance meters/minute
- distance meters/minute * 60 minutes/hour = distance meters/hour
- distance meters/hour * kilometer/1,000meters = distance kilometers/hour

1st gear: 1,000 / 3.636 = 275 / 3.900 = 70 * 2 = 140 * 60 = 8,400 / 1,000 = 8.4km/h
1,000 rpm =  8.4km/h, 2,000 rpm = 16.8km/h, 3,000 rpm = 25.2km/h, 4,000 rpm = 33.6km/h
2nd gear: 1,000 / 2.375 = 421 / 3.900 = 107 * 2 = 214 * 60 = 12,840 / 1,000 = 12.8km/h
1,000 rpm = 12.8km/h, 2,000 rpm = 25.6km/h, 3,000 rpm = 38.4km/h, 4,000 rpm = 51.2km/h
3rd gear: 1,000 / 1.761 = 567 / 3.900 = 145 * 2 = 290 * 60 = 17,400 / 1,000 = 17.4km/h
1,000 rpm = 17.4km/h, 2,000 rpm = 34.8km/h, 3,000 rpm = 52.2km/h, 4,000 rpm = 69.6km/h
4th gear: 1,000 / 1.346 = 742 / 3.900 = 190 * 2 = 380 * 60 = 22,800 / 1,000 = 22.8km/h
1,000 rpm = 22.8km/h, 2,000 rpm = 45.6km/h, 3,000 rpm = 68.4km/h, 4,000 rpm = 91.2km/h
5th gear: 1,000 / 1.062 = 941 / 3.900 = 241 * 2 = 482 * 60 = 28,920 / 1,000 = 28.9km/h
1,000 rpm =  28.9km/h, 2,000 rpm =  57.8km/h, 3,000 rpm =  86.7km/h, 4,000 rpm = 115.6km/h
6th gear: 1,000 / 0.842 = 1,187 / 3.900 = 304 * 2 = 608 * 60 = 36,480 / 1,000 = 36.4km/h
1,000 rpm =  36.4km/h, 2,000 rpm =  72.8km/h, 3,000 rpm = 109.2km/h, 4,000 rpm = 145.6km/h

So if you're driving at posted speeds and around 4,000rpm, you'd be in 2nd gear driving on residential streets, 3rd gear on St Albert Trail, 4th gear (at about 3,500rpm) on Whitemud Drive, 5th gear (at about 3,500 rpm) on 100km/h highways, and 5th gear (at 4,000rpm) on 110km/h highways.

Obviously you can gear up at slower speeds (4th or 5th gear in the city) and use the overdrive gear (6th) on the highway.  Still, you'll be around 3,300rpm in 6th at 120km/h.

Note that my math is very close but not exact in the work above, as I rounded the tire diameter, axle revolutions, tire revolutions, and distance in km/h down in all cases.

Compared to my Suburban (which has a 3.42 rear end):

Gear ratios (:1):
   First: 3.06
   Second: 1.63
   Third: 1.00
   Fourth: 0.70
   Reverse: 2.29
Final drive ratio (all models, opt.): 3.42:1 ? 4.10:1
[..]
Tires: 1/2-ton: P265/70R17 off-road steel-belted radials

265/70R17 means 802.8mm diameter (265mm * 70%/sidewall * 2 sidewalls + (17in * 25.4mm/in) = 802.8mm), which means approx 2,522mm circumference, or approx 2.5 meters travel per revolution.

1st gear: 1,000 / 3.060 = 326 / 3.420 = 95 * 2.5 = 237 * 60 = 14,220 / 1,000 = 14.2km/h
1,000 rpm =  14.2km/h, 2,000 rpm = 28.4km/h, 3,000 rpm = 42.6km/h, 4,000 rpm = 56.8km/h
2nd gear: 1,000 / 1.630 = 613 / 3.420 = 179 * 2.5 = 447 * 60 = 26,820 / 1,000 = 26.8km/h
1,000 rpm = 26.8km/h, 2,000 rpm = 53.6km/h, 3,000 rpm = 80.4km/h, 4,000 rpm = 107.2km/h
3rd gear: 1,000 / 1.000 = 1,000 / 3.420 = 292 * 2.5 = 730 * 60 = 43,800 / 1,000 = 43.8km/h
1,000 rpm = 43.8km/h, 2,000 rpm = 87.6km/h, 3,000 rpm = 131.4km/h, 4,000 rpm = 175.2km/h
4th gear: 1,000 / 0.700 = 1,428 / 3.420 = 417 * 2.5 = 1,042 * 60 = 62,520 / 1,000 = 62.5km/h
1,000 rpm = 62.5km/h, 2,000 rpm = 125km/h, 3,000 rpm = 187.5km/h, 4,000 rpm = 250km/h

The Suburban has an automatic transmission with a fluid-filled torque converter that causes the engine to spin faster than it would if the transmission was standard (this is what allows you to keep the car in Drive while stopped at a light).  This is noticable during acceleration, but once a speed has been reached there is only a small loss of RPMs between the engine and the transmission.  I haven't bothered to adjust for that in my calculations, but when pulling a trailer or carrying a heavy load (seven adults?) the engine will be running faster at the speeds listed above.

Still, the Suburban runs at 1,900rpm at 120km/h, compared to the STi's 3,300rpm at the same speed.  But hey, you're gonna get that from most small-engined cars.

[Shayne]

its a 2.5L engine delivering huge amounts of HP.  I just noticed that without the revs high the turbo lag was horrid.  I dont think horrid describes it fully though.  Sure you dont have to cruise around at 4000, but if you ever want to pass, or have the revs high enough to shift without stalling you gotta get it up there.  Don't get me wrong though, I LOVE the sound of that turbo spooling up, its just sort of a pain to drive.  Reminds me a lot of the last STR-4 actually (ive read the new one is even worse).  Hard to get the "perfect" launch at a red light without a bunch of practice.

Granted I've owned some rather under powered manuals in my life time (84 Aries, 92 Scoupe, 05 Cobalt) so maybe it's just me.

My wife wants something bigger and preferably an automatic (sore knees after a day of driving).

[Thorin]

I think what you're describing is lack of low-end grunt rather than turbo lag.  "Turbo lag" means the interminable wait between putting your foot down and getting extra air pushed into the engine (creating extra power).  You're simply describing a lack of adequate power at low RPMs; this is due to the boost threshold.  Turbo lag occurs at all RPMs, low or high.

Most small engines (typically four cylinders) have inadequate power at low RPMs.  When you bolt on a supercharger or turbocharger that greatly increases the power at high RPMs, it just becomes more obvious that they're lacking in low-end power.  It is possible to create small engines that have decent power at low RPMs but then they quickly run out of juice at higher RPMs.  And since power is figured out by multiplying torque by RPMs, that's a lot of oomph you'd be losing.

The general rule of thumb is that small engines need to rev high for highway driving while large engines use a lot of gas in town.  You can get one or the other.

[Cova]

You guys need to spend some time on old 2-stroke dirt bikes - will give you a whole new perspective on driving something with a narrow power-band.  Of course, modern 2-stroke engines are much smoother.  And the same thing tends to apply to turbocharged small car engines - 10 years back they had nothing off the line (boost threshold) and horrible turbo-lag whenever you got on the gas.  But modern small turbo-engines typically develop decent torque at reasonably low rev's, and have much more advanced turbo's that spin up faster / generate less lag.  I know for instance between the 07 and 08 STIs peak torque now comes about 400RPMs earlier (4K instead of 4.4).

Anyways - I have lots of experience with very narrow power bands (I've had bikes flip over backwards hitting the power-band unexpectedly in a low gear), and don't anticipate any problems in that regard.

[Thorin]

Do you happen to have torque and power charts for the 07 and 08 STI to compare?  The peak might hit lower, but the curve may be more angular, less flat.

The problem with all published torque and power numbers is that the manufacturer only has to tell you the peak of each.  This tells you nothing of the engine characteristics at RPMs other than where peak torque or power hit.  If the manufacturers were forced to publish the charts we'd be able to see whether a car or truck at low or medium or high RPM has a lot of power or not.  As it is now, they can up the horsepower and torque numbers by simply tuning the engine to have a high torque or horsepower at a certain RPM (I'm looking at you, MazdaSpeed3!)

[Cova]

Its sitting at the dealership now..., should be mine in the next couple days.

[Mr. Analog]

Its sitting at the dealership now..., should be mine in the next couple days.

Congrats man! Looks like a nice machine.

[Cova]

Well I've had it for a while now - love this car.  So far I've put on winter tires/rims, covered every forward-facing area with 3M stuff, and tinted all the windows that I legally can as dark as possible.  A little over 1K km's on it now, so past the official break-in period - its a ton of fun to drive, but I can tell already I don't think my winter tires are gonna last very long 

[Mags]

Probably hard to tell in winter, but how does it stack up performance wise to the Acura?

[Cova]

Probably hard to tell in winter, but how does it stack up performance wise to the Acura?

It's faster in 6" of snow than the acura was on clean dry pavement.