DOD

[jmore1276]

I was reading (somewhere) about the 07 GMT 360's. It said they would feature displacement on Demand technology. Does anyone know if this is true and if these engines are designed for it or will be redesigned? I was under the impression it only worked (at this point) on push rod engines. The ATLAS family is DOHC. Thanx in advance for replies....

[hyperv6]

I thougth I read that too. I could see it as being possible as they do use hyd cam followers. Either that or it will only be offer on a V8?

[91z4me]

The XV12 concept engine from a few years ago was DOHC and it had a working DOD system on it. The engine was designed by GM and built by Cosworth. I imagine the Ultra V8s will employ the same system. I don't think the Atlas series will see DOD simply because it would be out of balance because it doesn't have an opposing bank to counter the combustion. If it were done I would imagine that different cylinders in the row would be shut off at different times instead of the same ones at each time.

[cmattson]

My understanding is that the ultra V8 is the Northstar replacement. I've heard SOHC, and DOHC. I've heard 4.7l in size. Now, I read your quote of:

I imagine the Ultra V8s

and I see the V8 in plural form. As in more than one. Is that a typo, or is the "Ultra V8" a series of engines (as "Atlas" or "Vortec" is, or as I'd wish "Duramax" would be)? Anybody have any info on this engine(s)? When is it expected to debut? I'm wholly ignorant on this thing (and yes, if you haven't guessed it, it's bothering me).

Honda uses variable cyl. system on their V6 -- so I wouldn't rule out GM's D-O-D (in some form) on a future DOHC engine. Edited November 7, 2005 by cmattson

[Northstar]

I think there's only one Ultra V8, but I don't know for sure. There's probably different output amounts and probably one for RWD and one for FWD (Lambdas get it and Cadillacs will, so it has to be either both RWD and FWD compatible or two versions). As for debut date, probably whenever the Lambdas debut (probably LA or NAIAS) so probably 2 months away.

[jmore1276]

The designs of the current Northstar between FWD and RWD are sgnifigantly different. In order for the RWD to work they had to redesign the oil gallories for better cooling. I don't know if they just did it across the board or just for the RWD, but I do know they had to do it for RWD. I used to work at the Tonawanda Engine plant (Transfered to Van Plant) and I remember talk about the ecotech getting direct injection in 07. I'm asssuming that may big one of the major upgrades of the Ultra v8. I'm very impressed with the duramax deisel (which is where the direct injection tech came from-I believe) in our vans. I heard they were going to offer displacements of 6.4 and 6.9 in the future which makes sense as our vans have to DE-TUNE the Duramax in order not to kill the Trani. The Allison is much too large to fit in the van. It seems a waste to de-tune a 6.6 down to 225 hp when you can lower the displacement and save more diesel.

[jmore1276]

I am off subject..........bad jmore

[cmattson]

You gonna change your username, Northy? "UltraV8" doesn't do much for me, but hey--it's your username..

[91z4me]

My understanding is that the ultra V8 is the Northstar replacement.  I've heard SOHC, and DOHC.  I've heard 4.7l in size.  Now, I read your quote of:

and I see the V8 in plural form.  As in more than one.  Is that a typo, or is the "Ultra V8" a series of engines (as "Atlas" or "Vortec" is, or as I'd wish "Duramax" would be)?  Anybody have any info on this engine(s)?  When is it expected to debut?  I'm wholly ignorant on this thing (and yes, if you haven't guessed it, it's bothering me).

Honda uses variable cyl. system on their V6 -- so I wouldn't rule out GM's D-O-D (in some form) on a future DOHC engine.

[post="39546"]<{POST_SNAPBACK}>[/post]

It is my speculation that there will be 2 different Ultras. I can't see Caddy going to SOHC so I speculate that Buick and Saturn will use the SOHC engine and the DOHC will go to Caddy. It could also be that DOHC will be for RWD and SOHC for FWD, SOHC takes up less space.

[cmattson]

It is my speculation that there will be 2 different Ultras. I can't see Caddy going to SOHC so I speculate that Buick and Saturn will use the SOHC engine and the DOHC will go to Caddy. It could also be that DOHC will be for RWD and SOHC for FWD, SOHC takes up less space.

That's pretty good speculation. I could see that myself. One of the big knocks against DOHC configurations is their large dimensions. When designing an engine, you'd ideally want to spread it's development costs across multiple vehicles -- so it would seem logical that the Ultra would be used beyond Cadillac. It would also seem logical that you'd want something "extra" for Cadillac as well. A SOHC variety for Buick (or Pontiac, or Saturn) would allow you to still share a chunk of the components -- and realize savings much the way you do with the I4,I5,I6 Atlas engines or the Vortec V8 siblings.

[jmore1276]

I would love to see GM bring out a SOHC but I don't see them doing it. Unless that is the reason for the hold up on the 3 valve. I don't think so though, as the 3 valve cam in block would cost 1/3 the money of a SOHC. Plus with the VVT tech and all...but ya never know..It would make sense to distinguish Caddy from Buick and so forth instead of just de-tuning all the time, like with the Vortecs.

[91z4me]

I think the SOHC would be 3 valve like Ford has done with the new 4.6 VVT.

[Northstar]

You gonna change your username, Northy?  "UltraV8" doesn't do much for me, but hey--it's your username..

[post="39751"]<{POST_SNAPBACK}>[/post]

Haha, I thought about that, maybe I'll just change it to Northie but I think the Northstar engine will still be around for a while.

[intrigued]

Ive never heard of this "ultra v8" what is it?

[76ChevyTrucker]

Nor have I, but a replacement for the tried and true Northstar engine is about time coming...considering.

[jmore1276]

Ive never heard of this "ultra v8" what is it?

[post="40054"]<{POST_SNAPBACK}>[/post]

It is a 4.7l replacement for the NorhStar. One major refignment would likely be Direct injection. I believe the Ecotech (2.0,2.2,2.4) is getting Direct Injection in 07 or 08.

[Teh Ricer Civic!]

Ok first off Honda has had 4v SOHC engines forever, so i dont know where you guys are getting that they are limited to 2v. Honda has DoD on an I4 runnin on 3cyls and it runs fine, id imagine a I6 on 3cyl would get excellent mileage and could be more balanced than the I4. However putting 3v on a OHV engine should roughly give the same performance as a SOHC engine... but the revvs will probably still be more limited than the SOHC design.

[capriceman]

yeah it'll work. It just cuts off the fuel injectiontor and spark for that cylinder It just figureing out which squence to get it working . like 1 doesnt fire but 3 does. Its not like the shut have the block off. they just cut fuel.