mistah mofro Posted March 9, 2011 Share Posted March 9, 2011 Wellim debating on keeping my dgv's or swap them out for SU's, i hit the search button and have been browsing for hours. Looks as if the su's can out perform dgv's and have gas mileage aswell. I just would like to see what other dgv owners gas mileage is looking like, before i make my decision. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 10, 2011 Share Posted March 10, 2011 and the mileage you are currently getting is... Quote Link to comment Share on other sites More sharing options...
mistah mofro Posted March 10, 2011 Author Share Posted March 10, 2011 im not entirely sure but its not the greatest i think 14-19 mpg all around at regular crusing speed, but theres exhaust and vacuum leaks here and here so i wont be able to give accurate guess plus no tach. I seen you mentioned your friend with dgv's had to fill up more often on a road trip or did i just make that up? So i was wondering if what other people sre getting so i can get a taste of fuel economy potential. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 10, 2011 Share Posted March 10, 2011 changing carbs won't fix the underlying issues. Mileage is easily recorded when you fill up, fill the tank to the same point, record the fuel used to reach that level, divide. Composite mileage. SU's will be in the same range, or worse, or better...depending on the state of repair of the engine and it's ancillary systems. I have gotten from 17 to 27 on the SU's with my L26. All depends on what I'm doing. My commuter mileage is steady 22-24 at 70-80mph on the 60FWY each morning. I am not light footed. In town that will drop to mid 15-17. Combined 22. But get me on the interstate and block my foot to 55? 27 or more. Block it to 65, about 25/26. 75, 24/25 85, 21/23 95, 20 100, 19mpg And I have copious ledger notes to back those numbers up from 20,000+ miles of intense monitoring with a navigator/assistant who logged such details. That's interstate numbers. In town 35-50 accelerating and stopping every block, more like 14-17. I bet that's rght in line with what you are realistically doing. How long is your longest steady-state interstate trip? Quote Link to comment Share on other sites More sharing options...
xxxpatsabxxx Posted March 13, 2011 Share Posted March 13, 2011 Well, I was in the same boat as you with the dual dgv vs. SU. I did A LOT of digging and what it pretty much boils down to, is the ease of rebuilding SUs back to near perfect conditions and or tuning them to desired specifications. DGVs on the other hand are real pains when it comes to tuning and jetting to get the results you're looking for. Maybe its just my experience with a bad set of dgvs but I'm always struggling to get more out of my carbs. I tried tuning with colortune, the smell and listen test and switching jets but it's just tough work. On my trip from San Diego to Monterey Bay, I averaged 16 MPG going 65 w/ a 4 speed auto. Ive done this trip around 5 times and logged each fill up and calculated the mileage. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 13, 2011 Share Posted March 13, 2011 (edited) The 4-speed autobox has a.67 overdrive, if you are still running the 3.36 rear gear, and not something like a 4.11 you're waaaaaaaay overgeared with a non-turbo car with no bottom end torque. You might pass with better mileage if your car was a 3.0 high compression stroker N/A, but with a stock L24 or even L28 only running 65mph you are lugging the hell out of the engine, which will result in some terrible fuel economy. Point Blank: If you aren't breaking 21-22mpg when you are on the freeway with a STEADY AND CONSISTENT THROTTLE FOOT running anywhere between 2500 and 3500 rpms, there is something SERIOUSLY wrong with your fuel delivery mechanisims. I didn't break 20mpg with a Stock SU'd L26, Centerforce Lightened Flywheel, 82ZX Five Speed, and 3.7 gearset until I AVERAGED over 100mph. Under 100 mph, I STILL averaged 20+ mpg in steady-state interstate driving. And that 19mpg? That was in 103F heat blasting across Nebraska and Iowa...with the A/C on and an interior temperature of 70F! Anybody who says Z's with A/C overheat and won't cool the cabin may want to rethink their skills when it comes to diagnosing root causes...that gauge didn't budge over 190F the entire trip! Edited March 14, 2011 by Tony D Quote Link to comment Share on other sites More sharing options...
xxxpatsabxxx Posted March 14, 2011 Share Posted March 14, 2011 sorry i meant to put 3 speed auto. lol typo Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 14, 2011 Share Posted March 14, 2011 I ran an L24 with Solex/Mikuini Triple 40PHH's and a three speed autobox, running the 4.11 rearend in the car from LA to Phoenix some years back, and returned 28mpg. You are way under the curve as far as mileage goes only getting 16 on the freeway at that speed. I had a typo as well, I meant to say "2500 to 3500" --- really cruising at 50-75 it doesn't seem to make much difference in mileage running in that range. Even up to almost 4000 like with the 4.11 and Autobox! Quote Link to comment Share on other sites More sharing options...
Noddle Posted March 14, 2011 Share Posted March 14, 2011 Why not go EFI ( megasquirt ) ? my turbo L24 is getting 34.34 mile per gallon on highway cruise, sitting on about 3K @ about 68 mph. Nigel Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 14, 2011 Share Posted March 14, 2011 I have this irresistable urge to say "Imperial Gallons don't count!" right now... Quote Link to comment Share on other sites More sharing options...
CamH Posted March 14, 2011 Share Posted March 14, 2011 Since Noddle brought it up, I'd have to agree with him. I'm able to get high 20's out of my car, with a nice lean cruise on the freeway. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 14, 2011 Share Posted March 14, 2011 Since Noddle brought it up, I'd have to agree with him. I'm able to get high 20's out of my car, with a nice lean cruise on the freeway. O.K., Noddle, Me, CamH, that's three of us. It is now incontravertable internet fact to be trotted out in future arguments and debate. Personally, I feel my proclamation was enough: "Point Blank: If you aren't breaking 21-22mpg when you are on the freeway with a STEADY AND CONSISTENT THROTTLE FOOT running anywhere between 2500 and 3500 rpms, there is something SERIOUSLY wrong with your fuel delivery mechanisims." In some Southeast Asian Countries, I am a minor diety... Quote Link to comment Share on other sites More sharing options...
rayaapp2 Posted March 14, 2011 Share Posted March 14, 2011 I have this irresistable urge to say "Imperial Gallons don't count!" right now... I second that! Its not fair for comparison Nigel! Quote Link to comment Share on other sites More sharing options...
Noddle Posted March 15, 2011 Share Posted March 15, 2011 I second that! Its not fair for comparison Nigel! Ok, try this, 288.5 kilometers using 23.74 liters of fuel = 8.22 liters per 100 k so that's, 179.2656 mile, using 6.271445 gallons of fuel = 28.58 miles per gallon, so it appears that the calculator I've been using is (UK gallons) I apologize for misleading you guys. looks like I need to lean my fuel a little more to get over 30 mpg Nigel Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 15, 2011 Share Posted March 15, 2011 Curiously your numbers coincide with the Mikuini Trials I did on the way to Phoenix in 91/92! You can get over 30 with a turbo, JeffP was getting close to 32.5mpg at steady state 65mph in the old days of the 55mph speed limit. Since it's raised to 70 in most places, the speeds have risen and those numbers have not been revisited in some time. You didn't mislead us Nigel, I knew exactly what you meant! I'm odd that way furinners are always asking me "K or M--ph?" I am so used to the conversions they come as second nature. We had the same problem with Canadians, when you grow up as a 12 year old kid listening to adults without enough brains to figure out Canada used Imperial gallons talking about how there is a conspiracy in manufacturing gasoline at the Mobil Refinery in Detroit because 'that canadian gas does 4mpg better than our US gas' and realizing then that 'adult' doesn't necessarily coincide with 'smarter'... Conspiracy theory, mind you! Evil corporate conspiracy with the fuel so you buy more in the USA. (Remember this is in the state where Michael Moore was born!) When as a kid asks, 'doesn't canada use Imperial Gallons, aren't they bigger than US Gallons' and is pish-poshed as 'bean ignint' you get the idea I guess... Quote Link to comment Share on other sites More sharing options...
mistah mofro Posted March 16, 2011 Author Share Posted March 16, 2011 wow guys, this helped a whole lot...i am wanting to do l24et but i cant approach it currently rebuilding the motor and might be grabing new carbs until i habe the money (after brakes upgrades,tires,misc,etc). I guess something is wrong with my fuel delivey system considering im around the 16mpg relm at cruising, but i will be attacking this soon. Thanks again guys for all you advice and comments. Quote Link to comment Share on other sites More sharing options...
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