doclees
New Member
Shut up. Just shut up. You had me at "lambda"
. Great more homework. Found this - http://img8.imageshack.us/img8/396/curvem.png Maybe one is out here for the SHO engine.
How to make an efficient engine
- Thread starter doclees
- Start date
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Shut up. Just shut up. You had me at "lambda"
. Great more homework. Found this - http://img8.imageshack.us/img8/396/curvem.png Maybe one is out here for the SHO engine.
HotRodKid
mmmmm ... turbo
we tuned Somedude's turbo sho for something like 16:1 @ part throttle and got very respectable mile from it. It was rather easy to do also, as for the most part its a simple modification to the AFR table.
There wasnt much (if any) driveability problems with the setup, a reasonable kick to the speed pedal instantly bumped the load % to the point where the ecu instantly switched to the richer parts of the AFR map.
Of course, we didn't give a flying frack about passing NYS emissions with that car, it was already missing its converters, there was a huge honkin turbo in the fender, and we blocked off the EGR and at the same time we shut it off in the ECU.
There wasnt much (if any) driveability problems with the setup, a reasonable kick to the speed pedal instantly bumped the load % to the point where the ecu instantly switched to the richer parts of the AFR map.
Of course, we didn't give a flying frack about passing NYS emissions with that car, it was already missing its converters, there was a huge honkin turbo in the fender, and we blocked off the EGR and at the same time we shut it off in the ECU.
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pjtoledo
'ol man in the SHO
Hey Corey, long time no see.
:wave:
Perry
:wave:
Perry
gmail
Well-Known Member
speaking of F/I cars
if you have the proper sized turbo it will add a good bit to mpg
**** except for the lift of the stock cams the duration is about dead nuts on for what you would want for a turbo set of cams
if you have the proper sized turbo it will add a good bit to mpg
**** except for the lift of the stock cams the duration is about dead nuts on for what you would want for a turbo set of cams
SeanMc
NoMoSHO
Buy a Prius and use the SHO as a weekend car. Bam, better mileage 
.
.gmail
Well-Known Member
**** prius they dont get that good of fuel mileage for the lack of everything desirable.
**** the SOHC saturn gets the same fuel mileage or better and i bet would take a prius anyday of the week
**** the SOHC saturn gets the same fuel mileage or better and i bet would take a prius anyday of the week
YZF-Ford
SHO Member
Miracles!
SHOtime2511
CGP
Check your tire pressure.
doclees
New Member
I seem to find a general consensus that for every 150# weight reduction you gain 1mpg which would mean about 37.6 mpgs theoretical. Add in another 28% theoretical reduction if RPM's go from 2500 to 1800 would gain 10.5 mpg. So my goal is now 48 mpgs. Sounds like fun. A 250 hp, 2000#, 48mpg sports car. Almost as good as my Triumph Speedmaster.
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gmail
Well-Known Member
i guess its possible but id recommend not bogging it down to much since you really shouldnt run a load under 2k
also i would say keep it 3.0 not 3.2 since less displacement will help in mpg on something that small you dont need anything more
also doing the math and real world normally dont ever work out the same... many other factors like aerodynamics, gearing etc
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doclees
New Member
yea I was thinking about the 3.2. Maybe do the conversion for my 89 and make a 3.0 with 3.2 cams.
Why not run a load under 2K? On a flat my 89 does fine at 40-45 ish in 5th at around 1800 rmps. Got to shift at the first sign of a hill. So I figured with 1000# less, 1800 rpms would feel like it has torque.
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gmail
Well-Known Member
you do relise the 3.2 cams have less lift right? if i recall its like .010 less lift.
you shouldnt lug the engine and more so one with problems with rod bearings.
under 2k you have less oil pressure.
here i got a good read for you on the dangers of lugging
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1143775
also to mention something i forgot, chances are the engine is not efficent at that low of rpm.
i forget the way to find out mathematically but im sure if you looked you would find it.
basicly its something along the lines of taking the peak tq curve and doing something like 30% of that or something i really forget but basicly it would be somewhere between 2k and 3500 mark.
actually right where they designed the SHO to run at like 55 down the road is about perfect
you shouldnt lug the engine and more so one with problems with rod bearings.
under 2k you have less oil pressure.
here i got a good read for you on the dangers of lugging
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1143775
also to mention something i forgot, chances are the engine is not efficent at that low of rpm.
i forget the way to find out mathematically but im sure if you looked you would find it.
basicly its something along the lines of taking the peak tq curve and doing something like 30% of that or something i really forget but basicly it would be somewhere between 2k and 3500 mark.
actually right where they designed the SHO to run at like 55 down the road is about perfect
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doclees
New Member
Well duh to me. We have that nice red mark at 55 mph ( I don't use it). I'll check the rpms today. But this may still be a compromise between highway performance and mpgs. This car wasn't marketed as an economy car. If nothing else I've got to assume oil flow is more than addaquit at this rpm/load range. Good place to start. I'll need to go for a highway run at 55mph for an hour or so and see how much gas I use and how many people I **** off.
Earlier I had a link to a graph showing minimal fuel usage with rpm for a V8, GM I think. Need one for the SHO.
I can't imagine 1800 rpms to be an issue for engine load on a 2000# car. My 89 still can slowly accelerate in 5th at 1800 on a country road without feeling put upon.
Now oil flow. I don't know. Seems logical that 1800 rpms without lugging wouldn't be an issue. If that was the case wouldn't idle have killed these engines long ago?
yes on the 3.2 cams. I don't know how that would change fuel usage. Drop hp yes.
Earlier I had a link to a graph showing minimal fuel usage with rpm for a V8, GM I think. Need one for the SHO.
I can't imagine 1800 rpms to be an issue for engine load on a 2000# car. My 89 still can slowly accelerate in 5th at 1800 on a country road without feeling put upon.
Now oil flow. I don't know. Seems logical that 1800 rpms without lugging wouldn't be an issue. If that was the case wouldn't idle have killed these engines long ago?
yes on the 3.2 cams. I don't know how that would change fuel usage. Drop hp yes.
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Am I the only person who has an issue with this statement? Who buys a performance vehicle to choke it up and save the planet? That's almost as bad as buying an economy car that was designed for good gas mileage (ie. HONDA), and pretending it's fast.
doclees
New Member
BUMP
I don't know. Who does buy a performance vehicle to choke it up and save the planet? Not me. I'll be long gone. Which poses the question: what mileage would a Prius get without those heavy batteries and electric motor??
That was the national freeway speed at the time. It does not necessarily mean the best fuel milage for the car.
thegreatbriguy
SHO Member
smaller wheels and tires (skinnier). find some regular taurus 14 or 15 inch and drive around with a lot of coasting. I've gotten 33 mpg in my 89 with some 15 inch basketweaves and no back seat. not a whole lot of exciting driving though.
jelloslug
Digital
45 to 50 MPG all the time in a midsized car is "not that good"?
gmail
Well-Known Member
at 1800 rpm the oil pressure dont jump up like it does at 2k i have a aftermarket oil pressure gauge and it hits 40 psi at 2k but before that it sits much lower... id have to check to see what it is at warm at 1800 but it should still be around 20+
idle is only 12.5 on a fresh 3.2 and 12 or slightly less on a 3.0 as per the service manual.
that low of pressure is almost unheard of.. **** my jeep 4.0 sees 30ish at idle and soon as you hit 1400 it goes to 45 plus and stays there the rest of the range.
but for what you said about idle not killing a engine its not true many engines do indeed get hurt from long idle periods... crown vic p71 (police package) have a raised idle to make up for the long idle times to help the fluids moving around like coolant and oil pressure.
but also there is no load on a engine that idles.
me personally i dont do anything to further possibly harm a engine with known bearing problems.
thats true but also in the same they design cars for better fuel mileage at that speed since it was the national speed limit at the time
also in aerodynamics 55mph is much more efficent then 60 if i remember everytime you go up by like 10 mph it doubles the drag in wind resistance.
ernie would probley know better then me on that one.
the reason that 55 was the national speed limit back in the day was because it helped save fuel remember the fuel crisis back in the 70's. a study shown that in the wide selection of cars adveraged better fuel mileage at that speed.
so from a car that was built back in that era would shown it was designed to achieve the best mpg at that speed.
now granted its not to a T on that one being so many variables but its a good place to start.
drive it at 55 i bet you will see better mileage then 90.
now all my driving was done at 60 65 mph in my SHO and i know i gotten around at least 30 mpg and honestly thats good for me i dont need more.
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