What if...

[DaveK]

Just thinking. If GM had carried on with the ZR-1/LT-5 etc. what features would everyone like to see in a 'new' ZR-1 now.

My list would be something like.

- Appearance close to the C4, prefer the longer look to the C5s & C6s
- 427 CI Quad OHC, wouldnt change much really on basic design
- approx 600 bhp
- Individual coil packs
- 6 speed semi-automatic transmission
- Stiffer chassis using the frame rail technology of the C5/6
- Displacement on demand to keep the fuel bills down when cruising
- Fully active suspension
- Launch control
- Carbon fibre body
- Titanium alloy in key areas
- analog instruments

[Aurora40]

Well, some of the things the Northstar has, and other GM technologies that will likely show up on the Northstar in the future would most likely have shown up on a modern LT5:

coil-on-plug ignition
composite intake manifold
variable valve timing (might be very different on the N* than today if they'd gone ahead with the Lotus style they were experimenting with instead of the cam phasing type on the current N*)
direct injection
supercharged and intercooled possibly
6-speed auto option

I suspect things like active suspension wouldn't happen in favor of Magnetic Ride Control. Body and weight improvments would likely be like the C6 Z06.

[4DSZR1]

....6-speed auto option

As long as we're dreaming, I say the 7-speed ZF in the BMW M5... electric shift manual, 80 miliseconds shifts. hoooorah

[tpepmeie]

As long as we're dreaming, I say the 7-speed ZF in the BMW M5... electric shift manual, 80 miliseconds shifts. hoooorah

Yes, those come with an alarming rate of failures! Fortunately mine has not shown the dreaded red cog of death Malfunction light.

Back on topic, I think variable valve timing was a given, as well as dual MAF, surely electronic throttle control, perhaps individual butterflies.

To match the best from Munich in terms of specific output, the car would have to come stock with at least 520 hp @ 7000 rpm (350 cid). Certainly not too far-fetched, given current offerings.

Todd

[Aurora40]

Was looking at this for an unrelated thing. The Northstar was somewhat similar to the LT5, at least in basic design, when it came out in '93. Here are some of the improvements they made in 2000:

Revised combustion chambers are superior to previous designs in terms of both tumble motion of the incoming fuel-air mixture and burn rate. The intake and exhaust valves have been resized. Larger intake valves improve the engine’s breathing ability, while smaller exhaust valves increase flow velocity, an aid to catalyst light off.

While the new combustion chamber design helps maximize fuel efficiency, even larger gains are made by the addition of roller-follower devices between each cam lobe and valve stem. Compared to the previous Northstar’s direct valve actuation, the result is a substantial reduction in friction. During moderate driving conditions, the torque necessary to turn Northstar’s four camshafts is reduced by 50 percent or more.

The Northstar also benefits from a new ignition system that delivers power to the spark plugs directly instead of through wiring. A cassette containing four ignition coils linked by short secondary leads to adjoining spark plugs now attaches atop each cylinder head cover.

In addition to improved reliability, the new ignition system permits scheduling the magnitude of the voltage sent to the spark plugs. High voltage is used during full-load, high rpm and heavy EGR (exhaust gas recirculation) conditions to guarantee complete combustion. The energy level is reduced to minimize electrical loads and radio frequency interference during light-load conditions, such as medium speed cruising. The result is extended spark-plug life and a peak energy capacity that is 130 percent higher than the system it replaced.

From: http://media.gm.com/division/cadillac/products/00cadillac/seville/00press.html

[Bell Curve]

:cool:

[Jeffvette]

- 6 speed semi-automatic transmission


To bad the GM auto 6 sped is garbage.

[DaveK]

So if they improved the Northstar so much how come my 98 Aurora with nearly 2 litres less engine is no more fuel efficient than my 91 ZR-1 :thumbsdo:

Is the GM 6 Speed that bad Jeff? I've read mixed write ups on them.

[Aurora40]

So if they improved the Northstar so much how come my 98 Aurora with nearly 2 litres less engine is no more fuel efficient than my 91 ZR-1 :thumbsdo:

Is the GM 6 Speed that bad Jeff? I've read mixed write ups on them.
Because those changes were made in 2000. As far as fuel economy, your ZR-1 doesn't weigh 3967 lbs or have an automatic tranny. Also, what kind of driving do you do? I get about ~20mpg on average in my '02 Aurora, and about ~15mpg on average in the ZR-1, both mostly just commuting to work (15 mile drive, takes about 30 mins).

I'm sure on the highway cruising the limit, the Z would top the Aurora due to the smaller frontal area, similar Cd, much taller gearing, and probably less driveline loss (though the tires vs the auto with lockup might be a tossup)

[Jeffvette]

Is the GM 6 Speed that bad Jeff? I've read mixed write ups on them.

It's a damn tiptronic. It's basically a shiftable auto (think of just going from 1 to 2 to D and then OD). If it was clutch based like the units Ferrari used, it would be soooooo much better.

[DaveK]

I do mostly the commuting to work in the Aurora, similar drive to yours Aurora - so far not had chance to drive the ZR-1 far enough to tell. I was working on the basis of the govt figures (http://www.fueleconomy.gov/) which shows both having combined rating of 20mpg.

I understand your dislike now Jeff. I assumed it was a clutch based affair like the European semi-autos I've seen - might as well have a regular auto in that case.

[Kevin]

It's a damn tiptronic. It's basically a shiftable auto (think of just going from 1 to 2 to D and then OD). If it was clutch based like the units Ferrari used, it would be soooooo much better.
the VW GTI uses clutches

[Aurora40]

I understand your dislike now Jeff. I assumed it was a clutch based affair like the European semi-autos I've seen - might as well have a regular auto in that case.
It is a regular hydra-matic, torque-converter auto. I believe you still can put it in Drive, etc, and toodle on your way. The paddles are just a way to give the driver more control over the automatic if they want. I don't see how it's a bad thing, you don't have to use them. It's simply a 6-speed instead of a 4-speed. I guess I don't see the problem with that?

I agree though that GM should look into some of these more modern semi-manual trannies like the dual clutch stuff, etc. I don't think GM manufactures any (certainly not many) manual trannies, so it wouldn't be a case of them developing anything, rather of them buying it. I seem to recall stuff like the DSG VW/Audi uses can't handle a lot of power? They don't use it on any V8s or bigger I don't believe.

If they had gone with something like the F1-style tranny Ferrari uses in lieu of the 6L80, I suspect many Cadillac owners would be pissed off. The 6-speed auto is also used in the STS-V and XLR-V. Those auto-manual things are reportedly not at all smooth for everyday driving. They are purely a performance item with a rather stiff trade-off. In fact, Maserati is now introducing a traditional automatic tranny on their Quattroporte due to the roughness of the Cambiocorsa (paddle-shift automatic clutch like Ferrari) transmission.

[tomtom72]

I'm sorry for this but If GM still made the LT5 we would still be able to get parts for it......that work!:blahblah:

Okay I'll turn off my rant now!:o :mrgreen: