What's with the fuel mileage?

[harddrivin1le]

My Z28 produces more than 300 HP AT THE REAR WHEELS and is EPA rated @ 19 city/28 highway...I personally average low to mid 20's in mixed driving while still managing to stay ahead of the pack.

That's from a 5.7 liter, "low tech pushrod engine" that's driving a heavier car.

Acura/Honda make some fine automobiles, but their hi-po 4 cylinders are horrible in terms of fuel economy.

Their own TYPE S TL with the 3.2 liter V6/ 5 speed auto gets 29 MPG - the same as the 6 speed manual TSX...

Too bad Honda and GM can't join forces to build something like a rear wheel drive TSX powered by an LS1/LS6...

I bet they'd sell more than a few of those...

[Ray]

i agree they can make one asome car if they joined forces.

[NIGHTHAWK-TSX]

I have 2 questions.
1. What year Z28 do you have?
2. Is it auto or 6 speed?

[harddrivin1le]

Originally posted by NIGHTHAWK-TSX
I have 2 questions.
1. What year Z28 do you have?
2. Is it auto or 6 speed?

It's a '99 Z28 (LS1) equipped with the 1LE package (just 1 of 66 equipped with the 6 speed manual). The 1LE cars are the lightest of them all because that option didn't allow weight adding options (like T-roofs, power seats and windows, etc).

It's fitted with a pair of JBA "shortie" headers, a SLP muffler, aftermarket air intake and several other "tweaks" (including a Recaro seat, subframe connectors, ROYAL PURPLE throughout and a B&M "ripper" shifter.")

I've played with plenty of cars.

And believe me when I tell you that the SRT-4 Neon is a pretty quick car. It wasn't AS fast as me (ran it well into triple digits from a rolling start 5 times), but it was "right there" (pretty much)...I pulled out perhaps 1 car length on him every ~ 7 seconds @ triple digits...

Bone stock they're trapping @ 102 MPH. Guys have gotten through the traps in the mid 13s with nothing more than slicks (the car is front drive and has an open diff, so off the line traction is an issue).

Here's the recent CAR AND DRIVER road test results of an SRT-4.

[harddrivin1le]

Note the 60 MPH to 130 MPH acceleration segment: 20.6 seconds!:

The only (stock) Acura that will outrun that is an NSX. And truth be told, not by a WHOLE lot.

[NIGHTHAWK-TSX]

In regards to the fuel economy question there are some factors you need to consider. One of them being weight. The TSX's weight is around 3200lbs and the Z28 is around 3400-3600lbs depending on the options. There isn't much difference. The next equation is gearing. As a 3x F-body owner I know alot about the Trans-Am and Camaro. The gearing on your car should 3.42. This being the 6speed. The 6th gear and the CAGS help give the Z28 a decent fuel return. The TSX with the auto trans. gives a fuel return of 23/city and 32/hwy. Not bad.

[harddrivin1le]

Originally posted by NIGHTHAWK-TSX
In regards to the fuel economy question there are some factors you need to consider. One of them being weight. The TSX's weight is around 3200lbs and the Z28 is around 3400-3600lbs depending on the options. There isn't much difference. The next equation is gearing. As a 3x F-body owner I know alot about the Trans-Am and Camaro. The gearing on your car should 3.42. This being the 6speed. The 6th gear and the CAGS help give the Z28 a decent fuel return. The TSX with the auto trans. gives a fuel return of 23/city and 32/hwy. Not bad.

6 speed to 6 speed, the Camaro gets just 1 MPG less on the highway. The Camaro can handle that kind of gearing (3.42 and a .50:1 overdrive 6th) because it makes big power @ low RPMS due to an abundance of low end torque.

Small engines have to REV to make enough power to push the car down the road due their relative lack of low end torque.

And ENERGY = 1/2 M * V^2

So the added revs (and higher engine velocities that accompany them) more than offset the advantage of lighter engine internals (mass), resulting in disproportionately high fuel usage (energy).

And that's why the power to MPG ratio of smallish engines is relatively poor on the highway.

CAGS DOES NOTHING FOR THE EPA HIGHWAY FIGURE!

And consider the huge differences in power and torque between the two!

6th gear is too aggressive in the TSX (4.76 axle ratio with a .659 6th ratio). It's CLEARLY set-up to provide reasonable responsiveness in 6th gear @ ~ 60 MPH. That's why it gets sub-par highway mileage. I'd rather have ~ 33 MPG and downshift if required; that's what a manual tranny is all about. 6th should be a pure economy gear.

[NIGHTHAWK-TSX]

I thought we were talking about the EPA figures for both city and highway. CAGS helps in the city and the 6th gear help on the highway. If GM didn't use the 6speed with CAGS and instead used a 5speed the EPA would slap a gas guzzler tax on them. I don't think anyone would argue the fact that a 4 cylinder has to work hard to make decent hp and torque.

[harddrivin1le]

Originally posted by NIGHTHAWK-TSX
I thought we were talking about the EPA figures for both city and highway. CAGS helps in the city and the 6th gear help on the highway. If GM didn't use the 6speed with CAGS and instead used a 5speed the EPA would slap a gas guzzler tax on them. I don't think anyone would argue the fact that a 4 cylinder has to work hard to make decent hp and torque.

I get low to mid 20s in mixed driving and my CAGS is disconnected. The engine has more than enough low end torque to shift from 1st to 4th; I do that on my own when I want to.

There is no need to use 2nd or 3rd on the way to 4th when pulling away from a light. All CAGS does is mandate what should be common sense. It's not magic.

The Neon SRT-4 is a 4 cylinder; it costs ~ $7K less, makes a LOT more power (and torque) and gets 22 city/30 mpg highway with a FIVE (5) speed manual. That's despite the fact that a turbocharged engine with a relatively low compression ratio does not favor good fuel economy.

http://www.edmunds.com/new/2003/dodg...enav..8.Dodge*

6th should be a pure cruising/economy gear in the TSX (~ 3,250 RPM @ 90 MPH would be about right). Anyone who wants "on demand" passing power @ 60 MPH can either cruise in 5th or (god forbid) DOWNSHIFT. Designing 6th gear around that "requirement" is stupid and that's why the car only gets 29 MPG highway. The fact that the (less efficient) automatic version of the same car gets BETTER mileage (32 MPG) proves that.

The 240 HP, 3.0 liter V6, 6 speed Accord coupe will WALK AWAY from the TSX, despite the fact that it's heavier. And it gets better highway mileage as well (30 MPG)! The Accord (with leather) doesn't exactly resemble a homeless shelter in terms of fit, finish and luxury item, either.

I think I'd choose the Accord instead and would then IMMEDIATELY fit it with 4 Konis and more aggressive rubber...That would take the TSX anywhere and at anytime for about the same money.

[NIGHTHAWK-TSX]

The same could be asked of the Ford SVT Focus. It also has a 6speed but only has a 2.0L I4 and it gets 22city/28highway!

[harddrivin1le]

Originally posted by NIGHTHAWK-TSX
The same could be asked of the Ford SVT Focus. It also has a 6speed but only has a 2.0L I4 and it gets 22city/28highway!

That's junk.

And it doesn't cost ~ $28K, either.

[NIGHTHAWK-TSX]

How about the EVO? It has a 2.0L I4 and a 5speed and it only returns 18city/26highway and it cost more than the TSX.

[harddrivin1le]

Originally posted by NIGHTHAWK-TSX
How about the EVO? It has a 2.0L I4 and a 5speed and it only returns 18city/26highway and it cost more than the TSX.

But it will SUCK THE HEADLIGHTS out of the TSX!

You failed to mention that part.

See, I can justify a little less fuel economy for a LOT MORE performance. (Evo xs. TSX)

I can't justify a little less fuel economy for a LOT LESS performance. (TSX vs. SRT-4)

[harddrivin1le]

Originally posted by NIGHTHAWK-TSX
How about the EVO? It has a 2.0L I4 and a 5speed and it only returns 18city/26highway and it cost more than the TSX.

Take a look at the how the V6/6 speed Accord performs. The TSX won't touch that:

http://www.motortrend.com/roadtests/...rd/index4.html

[Dingo]

TSX is a great car I have never drove anything better!