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Posted: 8/24/2005 7:34:13 PM EDT
[#1]
Once you start pushing a turbo 4 hard enough to make 300+ whp good gas mileage is a thing of the past. If you want that power and mpg a 6 speed LS1 F-body is the only thing that comes close. 300+ to the wheels and about 27mpg on the highway.
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Posted: 8/24/2005 7:47:54 PM EDT
[#2]
Unless you put it on the bottle. You won't have the 300 horse power at the wheels all the time..just when you need it.
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Posted: 8/25/2005 12:33:05 AM EDT
[#3]
300hp & 30+mpg?....
Don't know of any factory cars that will do this. But it's been done. A guy I know has been getting 30mpg (apx.) in an 1987ish corvette. All I know is that it has a custom-made 7 speed trans...and that its fuel-injected. Everything else is pretty much top-secret. It's well over 300whp too. Another guy I know is building up a 87-ish Ford TurboCoupe for 350hp. Don't know if it'll get 30mpg...but it won't be far off. |
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Posted: 8/25/2005 1:31:54 AM EDT
[#4]
2006 Chevrolet Impala SS
303hp 5.3litre V8 w/ an estimated 28mpg. Pretty darn close. |
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Posted: 8/25/2005 2:43:18 AM EDT
[#5]
the new Charger with the Hemi is at 25 mpg and 340 hp. It does it the same way the new Impala does, by shutting off half the cylinders when cruising. |
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Posted: 8/25/2005 3:32:18 AM EDT
[#6]
So in other words when you want 300hp you get 15mpg for fuel economy. |
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Posted: 8/25/2005 3:42:47 AM EDT
[#7]
Probably less actually, but that's entirely the point. Have you ever looked at a dyno curve? Ever notice how the HP increases with RPM until it peaks and then comes back down? How often do you think you ever get, or even need to get, the RPMs to that point? You don't need 300 hp all the time. Extra cylinders that are just banging away while you're cruising on the highway are doing nothing but wasting gas. Do you think you're going to somehow go on a 200 mile road trip and run the whole time at peak HP? I'm just hoping that the technology in these newer cars is reliable. The cylinder shut-off thing has been tried before with little success. Presumably technology has advanced since then and Dodge and Chevy have it figured out this time. Since the Chrysler 300 Hemi also uses this technology I would expect we would have heard about it if there were any short-term problems. Now all that remains to be seen is how well the system works withh 100k on the odometer. |
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Posted: 8/25/2005 5:53:29 AM EDT
[#8]
The numbers cited for the Impala and Charger are brake horsepower, are they not? Net would be less, wouldn't it?
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Posted: 8/25/2005 6:03:52 AM EDT
[#9]
I just read the "ETA" in the original post. Based on that requirement it's a pretty nonsensical question. For 300 RWHP you'd need probably more than 350 hp at the crank. There are few cars that even make that.
However, when the Charger SRT8 comes out it will be putting out 400hp+ at the crank, and still getting the 25mpg highway due to the cylinder shut-off. |
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Posted: 8/25/2005 6:40:57 PM EDT
[#10]
The numbers quoted above (303 and 340) are SAE Net HP at the crankshaft, as rated by the factory. |
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Posted: 8/25/2005 8:18:42 PM EDT
[#11]
I dont know, there are a couple of guys with omnis that are much closer than anything listed here so far. I know of at least one guy that is only a few HP shy of 300 to the wheels and he is getting about 28-29 to the gallon. I think that I will have a very efficient setup to make the power, and one guy that knows these cars really well is of the belief that I would have to be a "total retard" not to put down over 300HP. I think that with the right tuning of the LM, I can reach my goal. The real shame in all of this madness is that I am working with what would have been considered state of the art in the late 70s, and I am running with the cars of today. Sure, I have a little less weight to haul around, but we have not come as far as I think we could have in the last 30 years. |
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Posted: 8/26/2005 3:20:15 PM EDT
[#12]
Think about it for a second. A new Dodge SRT-4 has a very similar engine setup to your Omni. They put down around 240whp stock. They do not get 30mpg. I guarantee the new Dodge is going to run more effeciently than your old Omni after whatever you do to it. Sure the Omni is lighter but that isn't going to make that much of a difference. Anybody that is telling you they are making 300whp and getting 30mpg from a turbo 4 is blowing smoke up your ass. I would be surprised to see 20mpg. The Omni barely made that mpg stock. Adding 150 or more whp is not going to improve gas mileage.
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Posted: 8/26/2005 3:38:16 PM EDT
[#13]
lexus is relasing a line of hybrid cars starting w/ a "sport" es w/ a v6 NA and elecrtic assist
claming 450 plus hp w/ 40 plus mpg wait for the lexus gs/ls hybrids..think 500/550 hp and 40 mpg cant wait more technology..make it faster ......mmmmmmm your problem is that in order to make 300 WHP that thing needs to be on boil... and to get MPG that thing needs to be driven like a granny.... but im shur you allready know this... |
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Posted: 8/26/2005 3:42:32 PM EDT
[#14]
Downhill, wind at your back ?
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Posted: 8/26/2005 8:34:17 PM EDT
[#15]
I have read reports of some SRT4 owners getting around 30MPG on the freeway. To say that the SRT4 motor and my 2.2 are very similar is a farse. They both have 4 cyls, and a turbo sitting on a manifold at the rear of the engine I guess. I actually put up a post on turbododge.com, and there are a few guys who have done it, and those that have come very close. It would seem that the 16 valve guys have a much easier time with it than those that only have 8 like myself. At least I know that it is very doable and I wont be out in totally uncharted waters. I think that many people are forgetting that when not in boost I still have a 2.2 in a 2400lb. car which is a recipie for 35MPGs all day long. My huge turbo makes for a very efficient cruiser as it reduces backpressure greatly, and in turn creates more flow and power. On race gas, I should be able to put down well in excess of 300WHP, so we will see. |
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Posted: 8/26/2005 9:04:49 PM EDT
[#16]
You asked if you could make 300whp and get 30mpg. You never stated that the 300whp would be on race gas and most likely higher than everyday levels of boost. IMO in 300whp tune even cruising at 60 on the highway you wont get 30mpg but I guess we wont know until you try it. Just to give you an example. I drive an 03 Nissan SER Spec V. It has all the bolt ons and puts out about 170whp and 170wtq. It has a 6 speed tranny which is a big andvantage over your 5 speed for gas mileage. The Nissan Qr25 engine is a low compression low RPM 4 cylinder and I can just barely break 30mpg on the highway in 6th if I stay at about 70-75. You think if I added a turbo kit and another 100whp or so my gas mileage would improve?
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Posted: 8/28/2005 3:39:43 PM EDT
[#17]
You really only burn more gas when the motor is in boost. You would not pick up any added gas milage, but on the freeway, no boost, the only down side would be the added restriction of the turbine housing. I will let everyone know how it works out. After reading all of the positive replies at TD.com, I am not too worried about my goal, it will just be a matter of how much over 30MPG I will get. |
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Posted: 8/28/2005 8:15:07 PM EDT
[#18]
Even on the freeway you will be in boost. Not full boost but boost nonetheless. I suppose if you were to keep the car at 30mph and off boost all the time you could make 30mpg but if you actually ever touch the gas I think your mileage is going to suck. Fact is the car was right around 30mpg brand new from the factory. You will get worse mileage than when the car was brand spanking new without a doubt.
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Posted: 8/29/2005 6:30:44 AM EDT
[#19]
All of this is why, assuming the technology works properly, the Dodge and Chevy system of shutting down cylinders is really the best way to go. There won't be any situation of being at "a little bit of boost" or anything else.
The Charger SRT-8 will very likely make 300 RWHP and get 25+ mpg on the highway. It will also do it with a full warranty, onboard navigation system, and that "new car smell". |
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Posted: 8/29/2005 7:19:00 AM EDT
[#20]
If I had a turbo with a turbine wheel the size of a pea, that would probbaly be the case. Even when I had the Mitsubishi TDO4H on my 2.5L shadow, I got 34 MPG on the freeway. I was not putting out any boost unless I put my foot down to pass someone. When cruising, I was most certainly in vac. The turbo that I have on the omni is so much larger than the mitsu turbo I had on the shadow, that it is hilarious. That should actually make the freeway efficency a little better due to the less restrictive turbine housing, and stage II wheel. |
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Posted: 8/29/2005 9:54:44 AM EDT
[#21]
Actually, my Corvette is capable of that. I normally average about 23 mpg, and that's pounding it a bit. If I reset and take it easy, I can pull over 30 mpg - with a 350 hp engine (crank shaft). Some of the guys on the Corvette boards are claiming 35 mpg - but they must be driving 45 mph www.c5forum.com/cgi-bin/ultimatebb.cgi/topic/2/2917/2.html#000020 |
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Posted: 8/29/2005 12:26:28 PM EDT
[#22]
The Chevy website claims 400 HP and 28 mpg highway. |
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Posted: 8/29/2005 1:11:46 PM EDT
[#23]
I brain faded - my last Corvette was 300hp, my '02 is 350 hp. I was just adding 50 hp for the new one - hence, I was off by 50 hp. ANYWAY, my 350hp (crank, at least 300hp rwhp) can do 30 mpg |
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Posted: 8/29/2005 1:16:11 PM EDT
[#24]
GET BOTH How many people get high-hp cars, and never use more than the top 1/2" of the pedal? Even those that do like to use the hp, probably spend more time cruising at a steady speed, then using the peppy acceleration. |
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Posted: 8/29/2005 1:21:18 PM EDT
[#25]
One of the incarnations of my blown 96 Trans Am (355ci, 14 psig, appropriate heads, cam, and PCM programming) made 611 RWHP and averaged 27 MPG on the highway (6 speed, 3.42 torsen diff, .50:1 6th gear). I once hit 31 MPG on a cross country trip at an average speed of 77 MPH for that fill-up.
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Posted: 8/29/2005 1:27:40 PM EDT
[#26]
MTI 427 Corvette. 600 crank HP, 500+ RWHP, 25 mpg on the highway, and its naturally aspirated.
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Posted: 8/29/2005 6:46:38 PM EDT
[#27]
Yep, but when you want it............ WAHOO BABY! |
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Posted: 8/29/2005 7:09:13 PM EDT
[#28]
On one of the "car shows" on TV a guy had the 350 and 6 speed out of a 'vette in a sort-of one off fiberglass 30ish Ford rod bodies. He claimed to have attained 32 mpg highway and I would "think" this combo may have put pretty damn close to 300 at the rear wheels. It probably didn't weigh 3,000 lb. either. Anybody remember what year the Cadillac was the (turn on, turn off) 8/6/4 cylinder model? I know I test drove one once off a used car lot. It actually ran pretty well.
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Posted: 8/29/2005 9:30:07 PM EDT
[#29]
Im close to 400HP at the wheels and I get around 18/19 city and 21/23 highway with the mustang.
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Posted: 8/29/2005 9:30:44 PM EDT
[#30]
Nice! |
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Posted: 8/29/2005 9:51:06 PM EDT
[#31]
MTI does some great work. I have dealt with them when I had my F-Body. They are good people too.
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Posted: 8/29/2005 9:54:57 PM EDT
[#32]
Which was my point, cylinder deactivation engine probably won't even be noticed by most people. If they work as promised, and are durable, they could be great, esp. if you want to 
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Posted: 8/29/2005 10:03:35 PM EDT
[#33]
Historically that is the problem. Most cylinder shutoff systems have not worked as promised and were far from being durable or reliable. Nothing but headaches. Hopefully in 2005 they have gotten it down. I guess only time will tell. |
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Posted: 8/29/2005 11:08:12 PM EDT
[#34]
I remember the Cadillac V-4-6-8, are there others that were mass porduced? |
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