350 RWHP + 20MPG combined...can it be done?
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Joined: Sep 2002
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From: New Jersey
i guess thats why VVT is being developed so much...too bad car companies are too scared to use it on any engine more then 3 liters and 4 cylinders.....
if i were to use a "mild" cam as opposed to a very aggresive high duration/lift cam i might be able to salvage some MPG....i want streetability, and im not aiming for unreasonabley high HP...ill see what i can do....probably call comp cams and see what they say...thnx for the info
if i were to use a "mild" cam as opposed to a very aggresive high duration/lift cam i might be able to salvage some MPG....i want streetability, and im not aiming for unreasonabley high HP...ill see what i can do....probably call comp cams and see what they say...thnx for the info
* and im still getting right around 19-21 mpg, sometime 24-25 if i stay off of it.
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From: New Jersey
I am 99% sure I'm going to go carbed because it just seems like unless I shell out alot of money to upgrade the TPI it's going to choke me out of horsepower. Is there any difference between a 350 or 305 TPI setup?
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I ran 12.91@109 completely untuned, and got 22 mpg on the way there and the way home. Once i get everything dialed in i expect to see some low 12's and 110+. I'm running a 355 with trickflow heads, a Comp Xe274 cam, Performer RPM intake and a Speed demon 750 double pumper. I'm using a T-56 with 4.10s, and 2000 rpm is about 80mph (my cruising speed
).
It's very possible to do, you just have to pick your parts wisely and know how to tune.
Eric
).It's very possible to do, you just have to pick your parts wisely and know how to tune.
Eric
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From: Calgary, Alberta, Republic of Western Canada
Originally posted by StealthElephant
I was just wondering if there was a way to make an "efficient" engine. Meaning, when you are in WOT it makes alot of power, but is ALSO build in a way that it can cruise around as a daily driver. If you only need "X" amount of power, then you use "Y" amount of fuel. Thus if your just driving around your using less fuel. Why must more HP mean worse MPG.....your not driving around USING 400HP, so why should your engine be feeding it more fuel....someone want to try to explain this to me. Does anyone understand how my brain is trying to reason this? Sure, your PEAK HP occurs at "Z" using "Y"' amount of fuel. Your not driving at peak HP all the time, so why must you use more fuel then ANY other car driving around the same way you are? Get me.....two cars, one with 500HP, one with 200HP, when at WOT car 1 is pouring X amount of fuel to accelerate, eating gas. Car 2 is pouring X amount of fuel to accerlater, much less because the engine simply doesn't make power and can't process any more. But at cruise why should either car use more fuel, shouldn't a higher HP engine get BETTER MPG when not at WOT, because it's built better that it can make power easier. I mean, 200HP or 400HP, when BOTH are making 100HP shouldn't they BOTH be using the same amount of fuel, so if your car is making 135HP (im just making up numbers) to cruise at 45MPH, shouldn't ALL engines use the same amount of fuel to make 135HP to cruise, but simply a better build engine can flow air, and combust more fuel when at WOT to create more power. I'm sure torque comes in somewhere, and I must sound like an idiot trying to "reason" it out like this.
I was just wondering if there was a way to make an "efficient" engine. Meaning, when you are in WOT it makes alot of power, but is ALSO build in a way that it can cruise around as a daily driver. If you only need "X" amount of power, then you use "Y" amount of fuel. Thus if your just driving around your using less fuel. Why must more HP mean worse MPG.....your not driving around USING 400HP, so why should your engine be feeding it more fuel....someone want to try to explain this to me. Does anyone understand how my brain is trying to reason this? Sure, your PEAK HP occurs at "Z" using "Y"' amount of fuel. Your not driving at peak HP all the time, so why must you use more fuel then ANY other car driving around the same way you are? Get me.....two cars, one with 500HP, one with 200HP, when at WOT car 1 is pouring X amount of fuel to accelerate, eating gas. Car 2 is pouring X amount of fuel to accerlater, much less because the engine simply doesn't make power and can't process any more. But at cruise why should either car use more fuel, shouldn't a higher HP engine get BETTER MPG when not at WOT, because it's built better that it can make power easier. I mean, 200HP or 400HP, when BOTH are making 100HP shouldn't they BOTH be using the same amount of fuel, so if your car is making 135HP (im just making up numbers) to cruise at 45MPH, shouldn't ALL engines use the same amount of fuel to make 135HP to cruise, but simply a better build engine can flow air, and combust more fuel when at WOT to create more power. I'm sure torque comes in somewhere, and I must sound like an idiot trying to "reason" it out like this.
Much of your gas guzzling will be due to a radical camshaft. If you don't run at 5500 rpm very often, does it really matter whether your engine makes an extra 30 hp there or not?
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From: New Jersey
im just wondering why a car with less HP uses less fuel while going the same speed, i want to know why you can make less power, but go the same speed using less fuel,.....but as it was explained to me it's a matter of tuning.....sorta impossible with a carb, but with EFI you can tune the motor to use the correct A/F ratio for gas milage, but still have your WOT power.....
my original question is if you have two motors, one makes 300HP, one makes 400HP, shouldn't they BOTH use the same amount of fuel when making 250HP, it's just the 400HP motor was built better and so when your riding it, it has a higher peak.....
is it a matter of powerband? meaning, since you cruise around in 1000-2500RPM, if your motor pulls on the top end you suffer decreased efficiency in the lower end, which you drive for the most part....if that is the case, how can you get a happy medium or high end grunt for the track but still maintain a decent crusing RPM.....my car does 35MPH @ 1000RPM even since i did the cam swap....is that good or bad?
my original question is if you have two motors, one makes 300HP, one makes 400HP, shouldn't they BOTH use the same amount of fuel when making 250HP, it's just the 400HP motor was built better and so when your riding it, it has a higher peak.....
is it a matter of powerband? meaning, since you cruise around in 1000-2500RPM, if your motor pulls on the top end you suffer decreased efficiency in the lower end, which you drive for the most part....if that is the case, how can you get a happy medium or high end grunt for the track but still maintain a decent crusing RPM.....my car does 35MPH @ 1000RPM even since i did the cam swap....is that good or bad?
Last edited by StealthElephant; Apr 7, 2003 at 07:25 PM.
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From: New Jersey
well assuming both cars are the same weight and have the same trans etc etc, shouldn't both engines require the SAME amount of fuel to sustain the same HP, and even if that isn't true, shouldn't the performance built engine have better combustion properties allowing it to better atomize and burn the fuel/air.....again, i go back to the powerband issue that problem dominates the whole arugement.....in the end it all comes back to the cam
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