Filed under: SUVs, Trucks/Pickups, Green, Toyota
Toyota developing clean-diesel V8 for Tundra/Sequoia
by Chris Shunk on May 29th 2008 at 8:28AM 
Click above for high-res gallery of the Diesel Dually Tundra
Toyota has earned its reputation for producing fuel efficient vehicles, but one dent in the Japanese automaker's armor has been the gas-guzzling Tundra and Sequoia. To help rectify the situation, Toyota Engineers have been working hard on a 4.5L clean-diesel powerplant that will substantially improve fuel economy for the body-on-frame trucks. The 4.5L engine is reportedly scheduled to arrive Stateside by 2010, and it's a no-brainer in light of the fact that both Ford and GM are offering similarly sized oil-burners for their trucks and SUVs.
You may remember the Dually Tundra fantasy truck that was shown last year at SEMA. Well, this news means the mega-sized diesel may not be far from reality. Inside Line is also reporting that Toyota may be delivering a monstrous 7.0L diesel for a commercial-grade Tundra, with a possible production date around 2011-2012. Toyota still hasn't given the go-ahead for a heavy duty Tundra, so the king-sized diesel powerplant likely will arrive only if the larger Tundra does, too.
[Source: Inside Line]
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Reader Comments (Page 1 of 2)
DJ 8:47AM (5/29/2008)
I would love to see Toyota take this one step further and offer a two-stage diesel hybrid in the Sequoia. Use the electric motors for highway cruising. They could probably get somewhere in the mid to upper 30's in MPG for the highway.
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Jared 10:42AM (5/29/2008)
Diesel electric hybrid would be completely uneconomical. First, a diesel engine that meets Tier 2 Bin 5 emissions standard costs at least $3000 more than a gas engine of comparable power. The Tahoe 2-mode hybrid is approximately $10,000 more expensive than the non-hybrid model. Add in the diesel engine, and the initial cost is even greater.
Further more, the main area where hybrids give added efficiency is in the city, with a lot of stop and go traffic. Gas engines are particularly uneconomical when idling. So the Prius uses a very economical atkinson cycle engine on the highway, shuts off the gas engine at idle, and uses the high torque electric motor to add torque when accelerating from a stop.
In contrast, diesel engines are much more efficient than gas engines at the idle. Diesel engines have much more torque than gas engines. So while the electric motor dovetails nicely with the weaknesses of the atkinson cycle engine, it is mostly duplicative of the strengths of the diesel engine. Consequently, I doubt that a diesel hybrid will really have that much added benefits over a simple diesel.
Dan 2:05PM (5/29/2008)
Electric assist hybrids are just dead weight on the highway.
Any mileage improvements you see there against a conventional car are coming from the narrow, low traction tires and aerodynamic tweaks.
Or on the EPA treadmilll test, coming from the fact they aren't trying to simulate constant speed cruise.
With a diesel you might be able to get this beast to 30mpg on dead flat pavement at 40mph.
mike 8:50AM (5/29/2008)
What is substantially.....is it GM and Ford type of substantially, meaning 2 or 3 MPG?
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sw 8:59AM (5/29/2008)
Probably a lot more. It wouldn't make sense for Toyota to stick a mild hybrid in their truck. I was surprised when GM did it. I also don't recall Ford ever having a hybrid truck.
Aprime 12:39PM (5/29/2008)
2-3MPG with gas at these levels is substential over time.
Will 8:58AM (5/29/2008)
I know it has nothing to do with the diesel story above, but wow- that flat gray paint job looks unbelievably badass.
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homunculus 9:12AM (5/29/2008)
I agree, matte paint jobs usually look terrible, but that looks flippin' sweet.
why not the LS2LS7? 11:28AM (5/29/2008)
That's not flat. It's not even eggshell. It's satin.
I dunno if it works for me.
Blake 9:49AM (5/29/2008)
4.5L, huh?
Hmm...
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LMBVette 9:50AM (5/29/2008)
With diesel being nearly $1 more per gallon, the diesel advantage in mpg is almost a draw.
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AngeloD 10:04AM (5/29/2008)
Diesels higher cost is not due to any extra refining cost. It's due to U.S. refineries being designed to maximize gasoline production per barrel and not diesel.
If enough diesel powered cars and trucks are sold in the US, some producers will meet that market need with more, and cheaper diesel fuel.
Diesel engines typically last a lot longer than do gasoline motors, so there is that cost savings to factor in as well.
Toyota's going to need other upgrades, like a stronger frame, on the Tundra if they want a bigger slice of the commercial market.
Shawn 10:15AM (5/29/2008)
so AngeloD, are you saying that with increasing demand, the prices will go down? Another thing is...do you really seem them cutting gasoline production to make more diesel and then charging you less for it?
tankd0g 12:09PM (5/29/2008)
Diesel is essentially a waste product of refining gasoline, there was a time when no one wanted it and it was cheaper than tap water, now everyone wants it and it's as expensive as hell. Until renewable replacemnts come along the price of diesel is always going to be higher than gasolne because you get less of it out of a barrel. The up side is that bio-diesel is less of a pipe dream than bio-ethanol.
SimbaDogg 6:20PM (5/29/2008)
@Shawn...
i dont think you get what he was trying to say, look at is this way (excuse the rhyming)
if a refinery can only product 10 units of either gasoline and diesel in any combination, but they're finding that the demand for gas is up 50% whereas the demand for diesel is only up 20%...they're probably go from a 50:50 mix to a 70:30 mix. (Production possibilities curve...economics).
So since demand is going up for gasoline...and the supply is going up as well, you're going to see an upwards shift in price, which we have obviously seen. But since the demand for diesel has gone up, but the supply is also down (ouch) you find demand up, supply down which will give you an even larger increase in price...which we have seen also.
AZMike 10:44AM (5/29/2008)
it always amazes me to see how many folks drink the diesel Kool-Aid.
no, folks, diesels in big pickups don't get 30 MPG. depending on how you really drive, don't expect over 20, empty, if that.
after owning five diesel trucks from every American manufacturer, I switched back to gasoline engines exclusively.
I now have a Ram with the HEMI engine with MDS (cylinder deactivation). I am towing a 5,000 pound+ trailer all over the US about 90% of the time I use this vehicle. it's two years old, and is just shy of 95,000 miles.
my average fuel economy while towing (I check every tank) is 17.2 MPG. my average MPG empty is 19.1 MPG. I've had the MPG as high as 21.9. by the way, the MPG towing is with all 8 cylinders working, as the MDS deactivates when towing.
now, let's look at a diesel. to start, the average cost of the diesel engine is between $6,700-$8,000. on GM diesels, you'll also have to pony up for the Allison automatic transmission, which is over $2,000.
and folks, don't forget; when you see those gauges stacked on the left A-pillar in a diesel pickup, this vehicle has most likely had a lot of modifications made. most of these trucks are getting about 12MPG (I always ask when I see them stopped). the first modification usually made is cranking up the injector pump. I've never seen any cases of adding additional fuel to an engine that increses fuel economy, have you?
let's talk about repairs, too. since all the domestic diesels are built by outside manufacturers (Cummins for Dodge, Isuzu for GM, and Navistar for Ford), all parts are basically "double-dipped". what this means is that Navistar gets their markup, and Ford gets theirs, Cummins get their markup, and Dodge gets theirs, etc. parts are, needless to say, very expensive. there are very few of the most simple repairs that won't be at least $1,000.
now, lets sum this up:
-diesel option is very expensive.
-diesel repairs are much more than a gasoline engine. your $25 oil change with a gasoline engine will now be $70-$90 with a diesel. "double-dipped" parts, too.
-noise, smell, and smoke. don't get any diesel fuel on your shoes (it's easy to do), as your interior will now smell like diesel, too. the search for diesel in many parts of the country once you get off interstates.
-higher fuel cost. expect to pay 80 cents to $1 more per gallon for diesel.
-economy is about the same as a comparable gasoline engine.
I had to laugh a few months ago when a neighbor borrowed my truck and trailer to rescue a friend that had a breakdown.
lo and behold, a week later he came home with a new Dodge with the Cummins Diesel. I just talked to him two days ago, and he said he "was kinda disappointed' with the diesel, which is the new Bluetec version. apparently, there was been quite a few problems with this new version, and he's averaging about 14 MPG, empty.
perhaps it would behoove Toyota (and Nissan and Ford) to adopt a simple cylinder deactivation system like Dodge and GM have done with their gasoline engines. it's a lot cheaper than having a diesel in many ways.
AZMike
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Paul P. 1:08PM (5/29/2008)
One thing to realize is these smaller diesels on their way out are very different from the diesels used in 2500/3500 trucks. They're being designed for gas mileage (like the older diesels) and to be a cheaper option. Unlike the current duramax/powerstroke/cummins, which are designed mostly for power. Think more a long the lines of the Mercedes diesel....a $1,000 option with ~30% better fuel economy.
Personally, I have a '95 Suburban with the pre-duramax 6.5L diesel that I love. I get 22mpg pulling a 7,000lb trailer. My buddies newer gas suburban pulling a similar load gets about 13, even unloaded he is only getting about 17/18 highway. If the newer diesel gets similar or better mileage than my engine, I would buy another diesel suburban in a heartbeat.
Dan 2:00PM (5/29/2008)
If economy is about the same as a gasoline engine, there's something wrong with the diesel. Like it being hooked up to a 3/4 ton truck and the gas engine to a 1/2 ton.
Getting 18-20 empty in a 3/4 ton is pretty good when the gas engine would be getting 15.
On the rest of your points, dead on. Diesel is not a panacea for the consumer.
For the federal requirements that mandate high miles per gallon without specifying a gallon of what, it's a godsend.
AZMike 2:06PM (5/29/2008)
Dan,
you might want to check the recent test of a Ford F350 diesel here on Autoblog a few weeks back. they reported 10 miles per gallon.
AZMike
Dan 4:27PM (5/29/2008)
CR tested 3/4 ton trucks last fall, the diesel Silverado got 21 mpg on the highway @ 65. Better than any 1/2 ton truck tested.
The SRW F-250 they tested got 16 on the same test. Weighed over 4 tons too.