Power target for next Cadillac CTS?

The current Cadillac CTS sedan has all the right ingredients to be a very hot dish.  The Performance variant of the CTS Sedan makes a handy 304 hp at 6,400 rpm and 273 lb-ft at 5,200 rpm.  It has a direct injection 3.6L V6, FE3 tuned sport suspension, and performance brakes.  So is it as quick as it should be?

I know, if you want really quick, buy a CTS-V.  Got it.  But is the CTS Sedan putting up the numbers that it should?

Cadillac claims a 0-60 time for the current CTS of under 6.5 seconds.  Magazine tests of the FE3 Performance model have confirmed a 0-60 time of 6.3 seconds.

Let’s compare the CTS Sedan performance to the BMW 335i Sedan.  Yes, I recognize that the CTS is larger than the 335i, more the size of the BMW 5-series.  But I think that BMW 335i performance is really what Cadillac needs to be achieving with the CTS Sedan.  BMW are also masters at magazine numbers / comparison tests, so they are a good benchmark for benchmark racing.

Cadillac CTS BMW 335i
HP: 304 hp at 6400 rpm 300 hp at 5800 rpm*
Torque: 273 lb-ft at 5200 rpm 300 lb-ft at 1500 rpm
Car weight: 4,063 lbs 3,620 lbs
0-60 mph 6.3 sec 5.1 sec
0-100 mph 16.1 sec 12.7 sec
Skidpad 0.87 g 0.89 g
Power/Weight: 13.37 12.07

*Dyno Tests: Automobile Magazine dyno tested a 2007 BMW 335i and found that it was making 340-350 hp and 360 lb-ft of torque, much better results than BMW specs this engine for.  The Cadillac CTS’ LLT engine is SAE certified at 304 hp, so we know that is the true and accurate result.

Weight: weight is a side-effect of larger size. The CTS carries an extra 400 lbs compared to the BMW. Generally 0-60 mph times in this size car are effected at 0.1 sec per 100 lbs, so that is 0.4 seconds of disadvantage.  Given that the CTS Buyers want the CTS to be a fullsize sedan, and want all the luxury and safety features, Cadillac needs to add some power to the 3.6L.

Power: At the current weight, to achieve the same (Mfr claimed) power to weight ratio of the 335i, the LLT 3.6L engine needs to produce around 337 hp.  How can Cadillac achieve this?  The new 3L V6 makes 270 hp; if the 3.6L were tuned to achieve the same hp/liter as the 3L is doing now, or 90 hp/liter, the 3.6L would produce 324 hp instead of 304 hp.  Then for the Sport model of CTS I would specify a performance-tuned exhaust, and a performance-tuned intake.  Together those should put the Performance model above 345 hp normally aspirated.

However, if the BMW is actually making 345 hp, then to overcome the weight difference Cadillac needs a 380 hp powerplant.  Given choices, I would release a Turbo 3.6L as a mid-CTS model.  Such an engine might make 400 hp in production based on GM’s showcars claiming 425hp from that configuration.  That would solve the power/weight issue nicely for the CTS sedan or the upcoming CTS coupe.

Gearing:  I am interested to see how the upcoming CTS Coupe does with a more aggressive final drive ratio

Summary: Is the current Cadillac putting up the proper numbers? With equal power to the BMW claimed HP but at the current weight disadvantage, the CTS should do 0-60 mph in around 5.5 sec.  However, the BMW 3L Twin-turbo, at least the ones presented for comparison testing, is producing around 40 hp more than the Cadillac.  Again, by thumb rule 10 hp makes about 0.2 sec difference in 0-60 times.  So a 40 hp difference can change the 0-60 time by 0.8 sec if all goes well.  Therefore the current CTS if it were as efficient as the BMW at 0-60 mph, but at the current CTS weight, and down 40 hp compared to the BMW test models, should be able to do 0-60 mph in around 6.3 sec.  And it turns out, that is approximately what it does do.

Conclusion — Targets: I suggest that the target for the CTS however should be 0-60 mph in 5.5 sec.  That would put it squarely in the mid-range of what is considered sport sedan territory these days.  That probably means a tune-up to the LLT V6, send in the Supercharged Version, or release a V8 option below the CTS-V that gives the base sedan close to 400 hp.

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