MPG Contest, Who wants to play?? |
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MPG Contest, Who wants to play?? |
r_towle |
May 7 2008, 08:25 PM
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#1
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Custom Member Group: Members Posts: 24,624 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
I started this on another site...not alot of joiners.
The idea is to test, tune, and tweek your car, and your driving style, to get the most MPG in a 914. This is a redo of a contest that the NY region did with 356's back in the day. These guys got 70mpg with one guy getting 100mpg. Alot of it is tuning, more if it is driving style. Here are the ground rules. We have several classes. 1.7, 1.8, 2.0, 2.0/6, and modified (all the rest of you), and vendors (special class) This is for 914's Using the honor system the goal is to win the mpg goal in your class. I am in 1.7 and aiming for 40mpg this first round out.. The contest will run from Memorial Day till Labor Day...this gives us all time to change things and tune things. This is meant to be fun with the 914magazine offering t-shirts as the prize...so its not meant to be for cheating. So, if you want to join, list the following. year, motor, tire size Use GPS or highway mileage markers to verify your odometer so we are all being fair. Rich |
toon1 |
Jun 8 2008, 02:43 PM
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#2
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Senior Member Group: Members Posts: 1,849 Joined: 29-October 05 From: tracy,ca Member No.: 5,022 |
I got Dr Evil to rebuild my gear stack and we talked about taller 5th. He discouraged it (we all know- for cooling). I really thought about it and wanted it too. But ultimately I think the engine cooling must really be "at the edge" already, and extended highway time torque loading (like a long hill) would provide less cooling than is really needed- cooking the life out of the oil even faster and contributing to higher wear. I have never seen any data to support this claim. I am just rigging up a full gauge setup to monitor heat, and then I will play with gears... If we stick with stock motors, the tranny is the next thing to futz with that delivers better mileage. A taller gear will still keep the car above 3k (my goal at 75mph ish) I will test to see what the differences are with several 5th gear sizes to monitor not only MPG, but heat...I think there is alot of room for different and taller gears here...its a light weight car, and with its relatively low co-efficient of drag, it should be ok with a taller gear...its not a bus guys... If I talk with someone who actually put a taller gear in a 914 (nothing else) and has experienced heat/cooling issues on the highway, I will consider the myth subtantiated, but till then...I will have to run the test myself to see real world data...its really the only way to know for sure at this point.. My gauge setup will have CHT on all four plugs, and oil temp, and oil pressure..along with fuel pressure and amps... I am looking for a decent mileage/trip computer to use so I can keep long term track of things...right now its pen and paper... I am totally open to suggestions on this..I will attempt to try and test as many decent ideas as we come up with and share the results. Does anyone have the stock torque curve for a 1.7 (72) dJet motor? I would like to see the chart to plan the gear selection with the idea to keep it right at the peak torque with the gears...the most efficient area for shifting. Rich Although I don't have documented data, I have played around with different rpm's and wached the CHT's. I have noticed that anything under 26-2700rpm's in a taller gear will create heat. recently while driving a backroad and climbing a small hill in 5th gear and about 2600rpm's,the temp's started to climb, I downshifted to 4th(about 3k)and wached the CHT's come down by 7-10*. I repeated this a couple more times to prove to myself it wasn't a fluke. Cross winds are a killer. Case and point. on a drive yesterday, I had a TRUE crosswind. It was a bit of a tail wind BUT mostly blowing accross the car. The CHT's rose by ~8-9*'s. the road was PANCAKE FLAT. I feel that the air going across the car disrupts the low pressure area behind the back window and the engine is now fighting to pull air in. turbulant air can be easily disrupted. I am going to fabracate some scoops soon for the B pillar to force air into the engine bay to see if this stablizes the temps. JM .02 It will be interesting to see your data |
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