Turbo theory
12-17-2010, 02:15 PM
#31
12-17-2010, 02:22 PM
#32
I have never calculated the mpg of my truck with the 408 but it has got to be somewhere in the 10 mpg range. Send me some funds and I will drive to Arizona and back and calculate mpg then I can go up a mountain pass and back down with some street driving mixed in and get another mpg range. That would be with the 408 and a tune already in there.
After I install the turbo I can do the same and see if mpg improved or not. No WOT runs though as that would skew the results.
After I install the turbo I can do the same and see if mpg improved or not. No WOT runs though as that would skew the results.
I'd like to reiterate that I am NOT trying to start a shitstorm with this. Blatant disagreement can **** people off...thats not the purpose of this thread. I'm trying to uncover some of the myths and hearsay about turbos...and clearly we have a lot of work to do
12-17-2010, 02:35 PM
#33
What is there to uncover? People see gains when they add a turbo if theyre not crazy with the go pedal, regardless of all your theory and mathematical equations. Its fact that most see constant or gains in mpg when FI is addded not the inverse as you are trying to prove. The vehicles that gain the most are the ones with an inherent lack of tq while na thus the 4.8s really seem to benefit whereas the 6.0s usually stay about the same or a hair better.
People post with real world results and you want to retreat to your formulas that obviously are flawed since people have real world results to the contrary.
People post with real world results and you want to retreat to your formulas that obviously are flawed since people have real world results to the contrary.
12-17-2010, 02:35 PM
#34
I know what you mean as I am in no position o be spending money on gas just to drive around to get a mpg comparison. And it would not be for my pleasure anyways as I take no joy in wasting gas or time driving around. I have had the truck for 3 years and have never filled it up all the way to see what my mpg is so I can't give any before or after results.
If we were talking about the DD Honda I have I fill it up every time it gets low and calculate how much gas I used and how many mile I traveled and do the math to get mpg. I do it every time I fill up.
Gas being about $4 here for 91 it would cost me $100 to fill the truck up. I usually keep it low because I go to the track every chance I get and want the least amount of weight I can get away with. Plus, the truck was stolen last year when I was on vacation so I try and leave it low in case someone else decides to take it.
I might have to pick up a set of wheels in San Diego if I do I may fill it up and see where I am at now.
If we were talking about the DD Honda I have I fill it up every time it gets low and calculate how much gas I used and how many mile I traveled and do the math to get mpg. I do it every time I fill up.
Gas being about $4 here for 91 it would cost me $100 to fill the truck up. I usually keep it low because I go to the track every chance I get and want the least amount of weight I can get away with. Plus, the truck was stolen last year when I was on vacation so I try and leave it low in case someone else decides to take it.
I might have to pick up a set of wheels in San Diego if I do I may fill it up and see where I am at now.
12-17-2010, 02:39 PM
#35
What is there to uncover? People see gains when they add a turbo if theyre not crazy with the go pedal, regardless of all your theory and mathematical equations. Its fact that most see constant or gains in mpg when FI is addded not the inverse as you are trying to prove. The vehicles that gain the most are the ones with an inherent lack of tq while na thus the 4.8s really seem to benefit whereas the 6.0s usually stay about the same or a hair better.
People post with real world results and you want to retreat to your formulas that obviously are flawed since people have real world results to the contrary.
People post with real world results and you want to retreat to your formulas that obviously are flawed since people have real world results to the contrary.
My brother in law has a EC Silvy with a 4.3 and his Suburban with a 5.3 gets better mileage. I think it is because the 4.3 is too small to get the EC to move. It can't even get out of its own way, lol. The 4.3 on the S-10 on the other hand seems just fine. The anemic 4.3 just doesn't have the tq to move the big trucks.
12-17-2010, 03:14 PM
#37
i will be doing a front mount on my 2010 silverado. with the rims i have i cannot hit 20mpg driving to work and back. im at 19-19.5, if it picks up anything it will hit 20. i have a full hptuned pcm now and i will tune my turbo setup.
12-17-2010, 03:16 PM
#38
Exactly.
This is what I wrote in the other thread.
Using that same scenario two identical trucks are at the light. They both want to get to 45 MPH(speed limit) so when the light turns green they both hit the gas peddle to 35%. The truck with the turbo gets to 45 in 5 seconds then lets off the gas enough to maintain that speed. The other guy has to stay in it an extra 2 seconds to reach the same speed. The turbo truck would have used more gas in the 5 seconds than the non-turbo truck but the later has to stay on it for 2 more seconds. So the non-turbo truck has to have the pedal to 35% for 7 seconds vs 5 for the turbo truck. Somehow, the turbo truck manages to save some fuel because of that.
Also, if the two trucks are on the highway and want to overtake another car or are going up a hill and want to maintain their current speed or both they would have to give it more gas. At one point the non-turbo truck would give it sufficient gas to cause the truck to kick down to a lower gear where the turbo truck would stay in gear and still be able to pass or maintain the speed.
On the Black Hemi whenever I would go up a hill I would get sucked into boost(3-5 psi) really fast because of the load. This was not good because there was no tuning originally so you would have boost at 14.7 A/F. The only time the A/F would go down was at WOT.
Those are two possible reasons why you might get better mpg but I can't say for sure as I have never personally tested to confirm.
This is what I wrote in the other thread.
Using that same scenario two identical trucks are at the light. They both want to get to 45 MPH(speed limit) so when the light turns green they both hit the gas peddle to 35%. The truck with the turbo gets to 45 in 5 seconds then lets off the gas enough to maintain that speed. The other guy has to stay in it an extra 2 seconds to reach the same speed. The turbo truck would have used more gas in the 5 seconds than the non-turbo truck but the later has to stay on it for 2 more seconds. So the non-turbo truck has to have the pedal to 35% for 7 seconds vs 5 for the turbo truck. Somehow, the turbo truck manages to save some fuel because of that.
Also, if the two trucks are on the highway and want to overtake another car or are going up a hill and want to maintain their current speed or both they would have to give it more gas. At one point the non-turbo truck would give it sufficient gas to cause the truck to kick down to a lower gear where the turbo truck would stay in gear and still be able to pass or maintain the speed.
On the Black Hemi whenever I would go up a hill I would get sucked into boost(3-5 psi) really fast because of the load. This was not good because there was no tuning originally so you would have boost at 14.7 A/F. The only time the A/F would go down was at WOT.
Those are two possible reasons why you might get better mpg but I can't say for sure as I have never personally tested to confirm.
To make my point, I'll exaggerate the numbers: If you're pulling a trailer with a stock truck, and you get 10 mpg at WOT, and it takes two miles to get up to highway speed, you will have used 1/5 gallon, or 25.6 oz. gas.
Now the same scene except turbo: It takes only one mile to get up to speed, at 8 mpg. You will have used 1/8 gallon, or 16 oz. gas.
Now if both trucks get 14 mpg cruising, the first mile at 8 mpg plus one mile at 14 mpg, to make the turbo go the same distance, the second mile will have used 1/14 gallon, or 9 oz. So after two miles, the turbo truck used a little less (25 oz. vs. 25.6 oz.) gas than the stock truck. Add up every time you accelerate on a trip, and the turbo comes out ahead.
All because it spends less time in PE.
My point about carbureted cars is that you will get better mileage if you get up to speed briskly (not lead-footing, and not the egg under your gas pedal foot crap) than you would if you accelerate slowly to "save gas".
Because it spends less time in "PE".
12-17-2010, 03:53 PM
#39
Less time in "PE" so when I went from 3.42 gears to 3.90 gears in my NA 5.3 my city mileage improved driving normally .........most dont beleive that, I explain I use less throttle to get to cruise ..........or in reality I dont get into PE as much .......correct ?
12-17-2010, 04:08 PM
#40
that's the basics of it. The 3.42's would cause you to move into high load cells in the airflow table and cause your target AFR to lower (adding more gas, so lowering your air to fuel ratio). The 3.9's can just as well lower your MPG, you are spinning the motor more and the feel of the better power typically causes most to use their right foot a little more. But staying out of those higher load cells thus cause lower AFR's is the trick.