More Cadillac engine rumors

[Bruce Nunnally]

Background: (and similar)

http://www.gminsidenews.com/forums/showthread.php?t=35305

So it sounds like the 2008 engine line up for the 08 CTS may be:

3.6L 255hp engine replaced by 3.6L Direct injection V6 making 305-315 hp

2.8L 210hp engine replaced by 3.0L Direct injection V6 making 250 hp? (3.0Lx305hp/3.6L)

The redesigned 08 CTS may gain 200-400lbs with widening to the STS width.

(A car loses 0.1s per 100 lbs, and improves 0.1s per 5 hp in acceleration for comparison, so a 400lb heavier CTS has a ~20 hp disadvantage, easily overcome by the addition of 50-60hp.)

The evolution or replacement of the Northstar is apparently back on. The rumor is the 4.8L Ultra-V8 is on the way. This engine appears to be a V8 variant of the 3.6L DOHC VVT 255 hp alloytec engine and 2.4L DOHV I4 ecotec 177hp. Scaled from those engines, it might make 340hp, which is hardly news or remarkable.

Although as a direct injected variant of the ~305 hp direct injected 3.6L engine the UltraV8 would manage 400+ hp (4.8L x 305hp/3.6L). Probably this engine would still be branded Northstar when released in Cadillacs btw.

Direct injection added 15% to the 3.6L according to the press release, so a direct injected RWD variant of the Northstar would hit 368hp. (320hp x 1.15). But an UltraV8 variant at 400hp seems a better fit for Cadillac. The Escalades broke 400hp already for goodness sake.

I think we are well into the era of 4's hitting 200hp, V6's 300hp,

and V8's need to be 400+ hp, so this seems a reasonable design goal.

On the unobtainable front, with the new Solstice GXP/Sky Redline turbo I4's making 260hp, a 4.4L V8 with the same efficiency in hp/liter for the STS-V or XLR-V would make 570+ hp.

The next base Covette LS3 might have 450hp instead of the 400hp LS2 as in the CTS-V. The next performance variant of the Corvette apparently will carry a supercharged LS3 engine for 650hp or so. Why note what the Corvettes are doing? This opens up a lot of room for the other GM brands to operate under without challenging the top Corvette in power to weight.

The current guess is that the redesigned CTS-V in 2009/2010 will carry a Cadillac powertrain, perhaps the 4.4L Supercharged Northstar, instead of the Corvette's LS2. I suppose part of the reason to widen the CTS is to allow for the northstar to fit? Since the STS and CTS share the same platform, an STS-V8 is a logical choice if you wanted a CTS Northstar however, (to me at least).

[JasonA]

That's all good news. But I wish GM (and other domestic brands) would standardize on engines. Take Nissan for example. No matter if you're buying a smallish Altima or a Quest minivan, if you check the "V-6" option, you get the very same VQ35DE as the rest of them. The Murano. The Z car. The Maxima. They all use the same engine, albeit in slightly different tunes, obviously. GM should be using the 3.6L DOHC in every V-6 car it makes. They should be using either the Northstar or the LSx engines in every single V-8 vehicle they build. They've finally standardized on the Ecotec I-4 for their smaller vehicles, which I applaud.

I do agree with keeping the 4200/3500/2800 inline engine series for the trucks, but only as an exception to the rule.

For their cars, GM has no fewer than SIX different V-6 engines. 2.8L DOHC, 3.4L OHV, 3.5L OHV, 3.6L DOHC, 3.8L OHV, 3.9L OHV. Some share engine "platforms" (like the 2.8/3.6), but there are at least THREE completely different engines in there...the 2.8/3.6, the 3800 series from Buick, and at least one other platform for the three other OHV engines.

For years, GM (and other domestic brands) have kept the "good" engines for the more expensive brands. NO! That not only cheapens the rest of your line, but also prevents most of the buying public from getting the "good stuff". $25k at Honda gets you an Accord with a slick V-6 with sub-6 second 0-60 times. What does that same $25k get you at GM? An Impala with a 3800? I like the 3800 pushrod engine, but the buying public wants those zoomy engines. The G6 is pretty good, but they put the old school 3.4L engine in there. Give ALL your V-6 vehicles the 3.6L engine. Give ALL your V-8 vehicles either the Northstar or the LSx engine (depending on app). I like what GM did with the Northstar. Make all your FWD Cadillacs Northstar-powered. Two versions...one for torque, one for horsepower, put in their appropriate applications. Do that with the rest of your vehicles, GM.

Simplify. Give everyone your best. Succeed.

[justgreat]

it's amazing how time catches up with technology. back in the early 90's mitsubishi developed and marketed a direct injection 4 cylinder engine for their home market. they never brought it over to this country because of surging and driveablity issues. it was something that had always fascinated me. my alfa romeo had port injection back in the 70's and that was a big deal, back then....but i often wondered why they never put the injector directly into the cylinder head.

when i started to frequent this site after getting my 90 seville i posed the question to al k. and his response was that the gains in power were minimal and that they did indeed have problems with the engine management during different drive cycles.

now, you have a v6 3.5 liters (lexus) making 305 hp and meeting all fed requirments.

if i hadn't been rear ended and had my beloved seville totalled, i would definitely have waited for the di of the 3.6, instead of the 255hp i ended up with. it's a great engine and it's amazing how much performance caddy got out of the motor (alot of it comes from the 3.42 final drive, it turns over 2k at 60 mph and in this day of economy gearing, that's pretty steep) but 300hp has nice ring to it.

jackg

06 sts6

[Bruce Nunnally]

The current direct injection engines are actually both direct injected and port injected -- two sets of injectors. So the problem of direct injection at low rpm is overcome by using port injection, then the engine switches to direct injection at higher rpms. Expensive, but successful and gains 15% power and cleaner emissions.

The OHV engines are in theory less expensive to manufacture than the DOHC engine, and easier to package. The high-end / lux market wants DOHC engines which are perceived as higher technology and smoother revving. The OHV engines, especially with the nice things GM has done with the 3.9L even getting VVT added, help keep the price points for the cars they are used in.

I think GM is starting to use the 3.6L high feature V6 in more and more applications, however, so maybe the cost is not all that much more than the high value V6.

I for one would prefer to see Cadillacs use engines in common with performance GM lines, so that we would benefit from more aftermarket performance items. Apparently Cadillac's perception is that Cadillac owners prefer that the Cadillac line have exclusive platforms and engines, for fear an owner will look under the hood and realize his expensive CTS-V has a darn chevy engine in it.

When I see a GM car that I know shares the transmission or rear end or other parts with the CTS, I feel more of a sense of kinship, not revulsion.