Fuel economy vs gas prices

[Aaron]

GM owns Isuzu though don't they?

At any rate, the transmissions are outsourced, so that may be one part of it.

Just an idea, it could be something else entirely.

[The Dark Side of Will]

Don't think they own Isuzu. I'm not sure if they have a controlling interest or just a strategic agreement.

Until very recently, GM owned Allison. They only sold that brand off this year.

Vortec 8100 better than the Duramax? BBWWAAHHHHHAHAHAHAHAHAHAHHAHAHAHAH

What a crock of shit.

[Aaron]

Ok, they at least had some sort of agreement, because like the older pickups looked identical to S10s.

That's what GM was trying to convince me of. The 8100 has an advantage, it's quieter and gas is much cheaper, but it just can't compare in other ways. Hell, there's a video of a guy running a Duramax WOT on the highway for like 20 miles, with the coolant temp gauge pegged overheating the entire time, and the engine still wouldn't blow up. Amazing.

[The Dark Side of Will]

The current Isuzu pickups are just rebadged Colorado/Canyons. I think they're available with Isuzu diesels in international markets, though. :cussing:

[Atilla the Fun]

As for the vette, Banks has a drag s-10 funny truck that has a DuraMax turning at least 5000 rpm and running 7.7-second quarter mile times. As for the 6.6 in a Suburban, there's nothing stopping those of you with money from doing it yourself.

[Atilla the Fun]

Do you even have any particular cam in mind for this 347.5 cubic inch disaster?

[Nashco]

I've heard about that. I've also heard that it's going to start off in Suburbans.

Why on earth can GM not fit a 6.6 Duramax + 4L85E or Allison or whatever transmission they use with the thing into Suburbans is beyond me. The chassis is the same as the pickup trucks'...

Would be hilarious to build a diesel Vette and run 9's or 10's.

The Duramax comes with the Allison, the Allison requires a body lift to accomodate the larger trans...that's my understanding. Apparently it wasn't worth the hassle for GM to do that on the Suburban, not enough demand. I'd love a Duramax Suburban, I currently have a diesel Suburban (my second) with the 6.5 TD engine. It's not horrible, but it's definitely no Duramax! The Duramax has been swapped into new Suburbans (there are even companies that will do it), it's no more involved than swapping it into a gas pickup as I understand it.

Vortec 8100 better than the Duramax? BBWWAAHHHHHAHAHAHAHAHAHAHHAHAHAHAH

What a crock of shit.

Actually, from an investment perspective, the big block gas engines make a lot of sense right now for business owners. The new diesels (with ATD) have a huge upcharge on top of the previous upcharge you'd expect for the diesel powertrain. When you factor in the high cost of diesel these days, the diesel won't pay itself off unless you drive a lot and require high hauling capacity. For a truck that won't see a ton of miles or load (city businesses) and/or is expected to be replaced in a couple of years anyway, the diesel doesn't make sense from an investment perspective.

Thankfully, many businesses still consider long-term investments, small businesses (and individuals) still buy diesels when that's their preference for whatever reason (dollars aside), and long haul/high mileage vehicles still see huge gains with a diesel....so we still get lots of super cool diesel technology in trucks.

BTW, this is all speaking to medium/heavy duty stuff. GM's site is whygas.com and it has some merit to it for very specific situations. BTW Will, modernized diesels don't really have the clatter, the injection is so precisely controlled that they can greatly minimize it. Have you seen the Audi racer? Not only is it usually the quietest car on the track, but it's clean as a whistle.

[/threadjack]

Bryce

[Atilla the Fun]

I gave a lot of thought to this last night. The O.E.M.s are after the same thing, so what you need to do is go to work for one of them. But really, aside from initial price, the vortec heads have no advantage over a coated pair of AFR 180cc heads. For vortec heads, assuming I did my best porting to them, I'd call COMP for a 12-000-8 hydraulic roller, with lobe 3311 intake and lobe 3108 exhaust, on a 110 degree lobe separation angle, installed with a belt or gear drive, no chain, at 110 degree intake centerline. For the AFR 180s, The starting point should be the 3011 lobe for the intake, and the 3033 lobe for the exhaust, on a 110 degree separation, installed at 107. This thing could see up to 395 HP at 5500 rpm, 30 mpg, and run 13s. Certainly a 13.9 with a loose torque converter. Because the converter can lock up for mileage where you're running at part throttle, a looser converter will help you stay out of detonation, particularly at say 2/3 throttle at lower rpm in third gear. Assuming most good 700R-4s and a good ring-and-pinion will eat 22%, that should still be 300 rwhp, corrected to sea level. For a 6000 rpm cam, lobes 3014 intake and 3035 exhaust, on a 112 degree separation, installed at 110 would do it, and could break 12.9s. For something in between, 3013/3034 110 at 108.

[Atilla the Fun]

Oops, install vortec cam at 108

[Atilla the Fun]

And only 1.50:1 intake rockers for the vortec. Any more than that and you stall the port, and it doesn't un-stall until the valve is back to like .350" off it's seat.

[The Dark Side of Will]

I've been busy at home recently and for can't post more than a few words at work.

Thanks for your inputs.

I was going to start with the 270H-R10 that the magazine build used. That way I'll keep variance from a known working combo to a minimum.

That cam is a hyd roller with 270 degree lobes on a 110 lobe center, so it might be similar to one of the setups you just suggested.

Is there an index of Comp lobes online so that I could look up what each of those lobes are?

Would you mind laying out your reasoning for each suggestion? Thanks.

This engine's definitely going to have a timing chain. The application will not tolerate a noisy gear drive and the quiet gear/belt drives are not in the budget.

At what lift do the Vortec ports stall? Does that require machining the guides/spring pockets?

[The Dark Side of Will]

The Duramax comes with the Allison, the Allison requires a body lift to accomodate the larger trans...that's my understanding. Apparently it wasn't worth the hassle for GM to do that on the Suburban, not enough demand. I'd love a Duramax Suburban, I currently have a diesel Suburban (my second) with the 6.5 TD engine. It's not horrible, but it's definitely no Duramax! The Duramax has been swapped into new Suburbans (there are even companies that will do it), it's no more involved than swapping it into a gas pickup as I understand it.

I don't see as many Excusions as Suburbans, but it does seem like they're about 75% diesel, so that option sold pretty well for Ford.
Not sure why a body lift on the Suburban is such a big deal. GM's been at a competitive disadvantage relative to Ford in terms of diesel applications for a while now. Basically, GM only offers the Duramax in pickup trucks and medium duty trucks, but Ford has the Powerstroke in pickups and medium duty trucks as well as the Excursion, full size Vans, and maybe a couple of other apps I'm forgetting.

A Duramax Tahoe or Powerstroke Expedition would be sweet.

So just like with manual transmissions, GM doesn't take smaller markets seriously. I used to have a travelling job. We had a bunch of full size vans that we would drive until the wheels fell off. The newer GM vans had 6.0 Vortecs in them. The Duramax would have been a great choice for that company because of how long they kept the vans and how much they got driven.

[Nashco]

The Duramax comes with the Allison, the Allison requires a body lift to accomodate the larger trans...that's my understanding. Apparently it wasn't worth the hassle for GM to do that on the Suburban, not enough demand. I'd love a Duramax Suburban, I currently have a diesel Suburban (my second) with the 6.5 TD engine. It's not horrible, but it's definitely no Duramax! The Duramax has been swapped into new Suburbans (there are even companies that will do it), it's no more involved than swapping it into a gas pickup as I understand it.

I don't see as many Excusions as Suburbans, but it does seem like they're about 75% diesel, so that option sold pretty well for Ford.
Not sure why a body lift on the Suburban is such a big deal. GM's been at a competitive disadvantage relative to Ford in terms of diesel applications for a while now. Basically, GM only offers the Duramax in pickup trucks and medium duty trucks, but Ford has the Powerstroke in pickups and medium duty trucks as well as the Excursion, full size Vans, and maybe a couple of other apps I'm forgetting.

A Duramax Tahoe or Powerstroke Expedition would be sweet.

So just like with manual transmissions, GM doesn't take smaller markets seriously. I used to have a travelling job. We had a bunch of full size vans that we would drive until the wheels fell off. The newer GM vans had 6.0 Vortecs in them. The Duramax would have been a great choice for that company because of how long they kept the vans and how much they got driven.

The Excursion..??? You mean the Extinction? The truck that Ford wasn't making any profit on so they stopped making it after only five model years? The same rig that was replaced by the extended length Expedition (EL) that is a gas-only truck? Even with the diesel, that thing was only able to match the gas Suburban for fuel economy. I think GM was on to something at the time, since they're in the business to turn a profit (not make cars you and I would like).

The body lift is a big deal because it also requires a bunch of rework to body parts like bumpers, grill, etc. to make up for the new gap, which ends up with a snowball effect on added costs for a low volume option. As mentioned, the next gen GM diesel V8 is packaged pretty funky so that it takes up about the same amount of space as the LSx and the next chassis are being designed to accomodate the diesel, this way they can use the engine in more chassis with less rework to improve the business case.

If you guys needed big vans with decent fuel economy, you should have been using a Sprinter.

Bryce

[Atilla the Fun]

I left that notebook at home this morning, but yes, comp does have the lobe index online, I just haven't found how to get to it since they redesigned their website, so I'm working off year-old printouts, but I'll get you the info. Next point: the AFR heads do much better with a single pattern cam than even Vortecs that I've done my best porting to on the exhaust side and nothing on the intake side. I've flowed literally dozens of production truck vortec heads, And it's difficult to get flow at .500" valve lift to not be less than at .475". This puzzled me, so I grabbed a stock one and tried it at 475, at 480, at 485, and so on, on all4 of it's intake ports. Then I slid in a good aftermarket valve, and repeated. With good springs, you can get past .500" intake lift without having to machine the heads, but really, there's good reason to not lift the valve past .475" That means a .480"-rated cam, as the lifter absorbs about .004"-.006", which is why advertised duration is rated that way. Yes, you can puta higher lift with vortecs and make power, but you're not getting any advantage, and you're actually reducing effective cylinder filling. Vortecs like you to leave the intake ports alone, but get undercut, swirl-polished valves and put a small 30-degree back cut on them. That's as good as the intake ports are gonna get for the average person.

[Atilla the Fun]

Okay, this is info Will asked for. Most traditional engines get broader powerbands with dual pattern cams. Even with AFR heads, which have about the best exhaust flow. Some think this can over-scavenge the exhaust, but I'm not going there, as I have done no research myself on this. Haven't had the opportunity and resources at the same time. That said, IF Will ports the exhaust ports himself as I advised BlueShift, and am willing to re-post here, My first cam for Will, is a custom grind from COMP Cams. Lobe #3311 intake specs at 258 dur. @ .006", 206 @ .050" 128 @ .200" with lift of .320" which is .480" with 1.50:1 rockers. Great. The exhaust lobe #3108 is 270/215/133 and .333=.500. as an alternate cam; 3324 intake specs as 259/210/131 and .316=.474, 3313 exhaust specs as 270/218/139 and .330=.495. The first cam I said a 110 degree lobe separation, install at 108 degree intake centerline. I like it better for mileage without detonation. As for the timing of the cam, I've tried lots of chains, and the only one I'd use is the Manley. Even after a season of 6500 rpm racing, it had less than 2 degrees of play in it according to the degree wheel. But Will wants variable valve timing, and the cheapest way to do this with a SBC is to use the CAM CORRECT. I looked at www.competitionproducts.com, as they usually have tyhe best prices on SBC stuff, and the PN CC1000K is going for $110. But if you must be cheap, my second choice in normal chainery is the Cloyes StreetRoller. And for small timing adjustments, the offset woodruff keys for the crankshaft are just $4 ea.

[The Dark Side of Will]

How does the Cam Correct work?
http://www.competitionproducts.com/prod ... umber=8271

[Atilla the Fun]

not a clue, I believe the cam should never move around relative to the crank IF you can spec your cam right. But your link is to the entry level kit. The next level kit comes with three different chains, with various amounts of slack in them. This kit includes no chain, so there really isn't any good reason to get it. The third level includes a bunch of springs and an extra adjuster of some sort. COMP CAMS used to list these, don't know if they invented it, or what. Based on the advertising, I imagine that at higher rpm it causes some delaying action, the same as installing the cam retarded, but at low rpm, the same as advanced. This thing should come with instructions that should tell you alot more, and combined with a bigger cam and Rhoads lifters, you might be able to get an unbelievable powerband. I'm intrigued by the Rhoads lifters.

[The Dark Side of Will]

I just redid some numbers and I was wrong about DCR on the Hot Rod 347.
They used 270H-R10, with is single pattern w/ 270 degree total duration and 110 lobe sep. If installed straight up (110 ICL), it will give a 65 ABDC IVC. This gives a DCR of 8.5, which is just within the accepted range for premium pump gas. Thus the impressive characteristic of the build is that they were able to run the engine on 87 instead of 91.

For some reason, my initial run of the numbers gave me 55 ABDC and 9.2 DCR.

Of course the same engine with a more accepted 10:1 SCR would have 7.6 DCR. The Hot Rod 347 really may just a case of optimizing compression for the application more than a radical concept.

With a 258 total duration, 110 lobe sep and 108 ICL (2 degrees advanced, right?), the IVC is 57 degrees and DCR becomes 9.0

I'd still like to build this engine initially to be as close to the magazine build as possible (270H-R10 cam), but this new info alters the subsequent development plan. I'm pretty confident the engine will run on 93 just fine. With Atilla's info, I can change the cam for a more aggressive DCR as part of the development effort. Thanks.

I wasn't saying I wanted VVT on this engine... just that I think I could play with the control algorithms with great benefit. Like I said earlier, I don't think that varying cam phasing by RPM is appropriate. The cam phasing should be varied by manifold pressure to maximize dynamic compression without detonation.

I need to do an LS4 swap.

[THE PUNISHER]

The new 4.5Ltr Diesel is smaller and makes more power. It helps GM to avoid costly chassis mods. They are dropping the isuzu built duramax in an effort to further apply the vertical integration business model. They have also courted allison to build them smaller / stronger trannies. The cost incurred by re-designing the tranny becomes a wash when you consider the chassis mods that have to be done.

There will be a bigger diesel offered, but it will be GM Built.


Having spend the last 9 mos and 20,000 miles driving a diesel VW , i can't see using anything else as a daily driver.

The cost of diesel will self correct , the reason we see such a spike in it right now is due to manufacturing in India and China


Diesel here in canada costs less then 10% more than regular. But my car goes 600 miles on a tank , whereas my previous , non Vtec Civic coupe would go about 1/2 that..

Diesel oil change is more $$ , but less frequent..


I just love the diesel.. even with my muffler removed , it's quiet on the highway. It has ass loads of low end grunt. it will go 120mph...


One of those things you gotta drive to understand.


All my GM info comes from working in their marketing dept.

[The Dark Side of Will]

I've been thinking of building a TDI Fiero and enjoying 40+ mpg in a commuter that handles well.

Hell, I wonder if anyone's selling an Elise with blown engine? That would be even moreso.

Or maybe a TDI Ariel Atom or similar chassis...