Performance Tires vs Performance Suspension?

I am hard on tires.  I enjoy driving safely but accelerating briskly from a stop, and not slowing down for corners.    In fact, an ideal passage through a corner is if you hit the apex and just scrub off enough speed to keep the car on track.   That process, scrubbing off enough speed, is part of the problem, because it also tends to means shorter tire life.

As I once mentioned to a friend, if the tires are not squealing as you proceed through the corner, you are not challenging the car.

My current 2005 Cadillac CTS 3.6L has the FE1 (soft) suspension, and the same size wheels and tires all the way around, 225/55R16s.    The car came with Goodyear tires, which I replaced with some take-off OEM Goodyear tires which then were replaced with some Kumho’s and now I have some Continental Touring tires on it.  You begin to see the problem.

Further complicating my planning is that the current performance Cadillacs have staggered wheels/tires, so the rear wheels and tires are larger than the front wheels and tires.  So one cannot rotate the tires front to rear, thus extending the life a bit.

But a key issue is that while the tires on the 2005 Cadillac CTS tend to cost around $110 each, modern high performance tires as used on the V-series tend to run $200-250 each.  Yes, they are great tires.  Yes, they put up great skidpad numbers and help acceleration.  Yes, they are expensive.  And if you are a frequent tire buyer (which I prefer to tire addict) then the expensive part can come up a lot.

Now, I have considered that part of the problem is in fact the FE1 suspension is not designed for the more sporty driving, but is designed for more comfort.  So if I move to a Cadillac that was designed with the expectation of more cornering it perhaps would lead to less tire wear.  I keep trying to find comfort in that line of thought at least.

Meanwhile, I probably need to start saving up for new tires.

Power versus MPG

In selecting my next Cadillac, I am drawn the to highest performance models available within my budget.  More is always better right?

My model for the ‘right’ 0-60 time for a sport sedan is 5.5 to 6  seconds this year.   Performance of cars as a whole changes over time, as automobile performance improves.

The current CTS DI 3.6L will do 0-60 mph in 6.3-6.5 sec.  The CTS should be below 6 seconds with 304 hp, but it also gained a bit of weight with added features, and has fuel economy minded gearing.  Yes I recognize that is kind of in the same range, but let’s assume for this discussion that quicker is important.  So the CTS 3.6L is just on the upper edge of my desired performance envelope, and is right in the right zone for MPG.

Now, the 2006-2009 STS-V with 469 hp will go 0-60 in around 5 sec, or as Cadillac measured in under 5 seconds.  However, this model gets 19 mpg highway compared to the CTS DI 3.6L V6 MPG of 28 MPG highway.

One compromise candidate is the 2005-2009 STS 4.6L V8, with the 320 hp VVT Northstar.  This sedan gets very close to 0-60 mph in 6 sec in most tests, and has fair fuel economy at 24 mpg highway.

The new Gen2 CTS-V with 556 hp supercharged 6.2L V8 will do 0-60 mph in under 4 seconds with a Cadillac test driver, or just over 4 seconds with a magazine writer driving.  The new CTS-V is still outside of my budget however, and also gets 19 mpg highway.

The 2006-2007 Cadillac CTS-V with 6L LS2 V8 engines would do 0-60 in under 5 seconds, and are rated at 24 mpg highway.  So these are interesting, but they will soon be out of warranty.  I like to keep my daily driver under warranty, so if there is an issue I can simply drop it off for service, pick up a loaner car, and be on my way.  These are also only available in manual transmissions.  A manual is okay for me, but is challenging for other members of my household.

So this thought process leaves me wondering if I should change my target from “as quick as possible” to “as quick as possible and still get more than 24 mpg highway”, or similar.

In this range that 5 mpg costs around $1000 per year given my mileage per year and average gas prices.  So would you pay $1000 per year for another 150 hp, or 47% more power?  I suppose over the 5 years I plan to drive the car that is less than the cost of a Supercharger or similar power adder.

How many MPG is more power worth to you?

6 Guns Shifting into Overdrive

The 2009 Cadillac CTS-V arrived with a supercharged 6.2L OHV V8 engine, the mighty LSA.  It also brought back an ‘expected’ Cadillac feature to the CTS-V line — an optional Automatic transmission.  But wait, what automatic transmission can be strapped to the back of a freight train like the LSA and live?  Enter the 6L90 Heavy Duty Automatic 6 speed Transmission to the world of sports cars.

2010 Hydra-Matic 6L90 (MYD) Six Speed RWD/AWD Automatic Transmission for Cadillac CTS-V

Overview

The Hydra-Matic 6L90 is six-speed automatic transmission for rear- and four-wheel-drive trucks, designed with modular flexibility and compatibility with advanced electronic controls. It is a heavy-duty version of the 6L80 six-speed automatic, with a strengthened input gear-set which has two additional pinion gears for six total, and a strengthened output gearset, that uses wider gears than the 6L80.  The 6L90 flexibility extends to the clutches where the 6L90 has one more clutch plate than the 6L80 in each clutch for heavy duty applications.

The 6L90 has the capability for adaptive shift controls and other features such as grade braking, and Driver Shift Control with tap up/tap down shifting as found in the CTS-V. A wide overall ratio spread of 6.04:1 allows a “steep” first gear, as well as very “tall” overdrive top gear for low-rpm highway cruising. With this wide ratio spread, acceleration is maximized, as is fuel economy. Engine noise is also lower during cruising. Both fifth and sixth gears are “overdrive” gears, for example.

As in the 6L80, gear changes from second to sixth gears are accomplished with clutch-to-clutch control, where an oncoming clutch is engaged and an “offgoing” clutch is released in a precise manner to achieve the ratio change. The first-to-second up-shift, however, is a freewheeling action, where the second gear clutch engages while the first gear one-way clutch spins freely. This allows a greater degree of smoothness at lower vehicle speeds. The clutch-to-clutch shifting and single freewheeler allows significant reductions in packaging requirements.

Advances in transmission control modules allow the modules to exist reliably inside the transmission, where temperatures remain fairly constant compared to a body-mounted module. The transmission and module are assembled together, so no additional steps are necessary during vehicle assembly.

The 32-bit transmission control module (TCM) monitors transmission performance and compensates for normal wear in components such as clutch plates, so transmission performance remains consistent for the life of the transmission. The control module also “tests” the components of the transmission following assembly to optimize the interaction of the components. The module is compatible with future global applications.

2010 Hydra-Matic 6L90 Transmission ( MYD )
Type: Six speed RWD / AWD, electronically controlled automatic overdrive transmission with torque converter clutch. Clutch-to-clutch architecture, with integral Electro / Hydraulic Controls Module
Maximum engine power: 452 bhp ( 337 kW ), Diesel: 300bhp ( 223kW ) – Truck
555 bhp ( 414 kW ) – Passenger car
Maximum engine torque: 531 lb-ft ( 720 Nm ), Diesel: 520 lb-ft ( 705 Nm ) – Truck
550 lb-ft ( 746 Nm ) – Passenger car
Maximum gearbox torque: 885 lb-ft ( 1200 Nm )
Gear ratios: MYD
First: 4.03
Second: 2.36
Third: 1.53
Fourth: 1.15
Fifth: 0.85
Sixth: 0.67
Reverse: -3.06
Maximum shift speed 6200 rpm
Maximum Validated Weights: ( Target ) GVW: 15000 lb ( 6803 kg ), GCVW: 21000 lb ( 9525 kg )
7-position quadrant: P, R, N, D, X, X, X ( X = available calibratable range position )
Case description: 3-piece ( Bell, main, extension )
Case material: die cast aluminum
Shift pattern: (2) Three-way on/off solenoids
Shift quality: Five variable bleed solenoid
Torque converter clutch: Variable Bleed Solenoid ECCC
Converter size: 300mm ( reference )
Fluid type: DEXRON® VI
Fluid capacity: w/ 300mm converter 300mm: 13.0L ( 10.8kg )
Transmission weight: w/ 300mm converter Wet: 109kg ( 240lb ) estimated
Pressure taps available: line pressure
Assembly Site: GMPT Ypsilanti, MI

GMPT Toledo, OH

GMPT Silao, MX
Applications: Chevrolet Suburban H.D.
GMC Yukon XL H.D.
Chevrolet Silverado HD
GMC Sierra HD

Cadillac CTS-V

Chevrolet Express

GMC Savana
Available Control Features: Multiple Shift Patterns ( Selectable )

Driver Shift Control ( Tap Up / Tap Down )

Enhanced Performance Algorithm Shifting ( PAS )

Selectable Tow / Haul Mode

Engine Torque Management On All Shifts

Altitude and Temperature Compensation

Adaptive Shift Time

Neutral Idle

Reverse Lockout

Automatic Grade Braking
Additional Features: OBDII / EOBD

Integral Electro/Hydraulic Controls Module ( Tehcm )

Control Interface Protocol – GMLAN

So, that begs the question — was the transmission rated to fit the engine output, or is the engine tuned to that output level because that is the maximum capability of the transmission?