Just finished a MPG test trip on my H/C/I/E 98 TA
06-01-2008 | 12:06 AM
#1
Just finished a MPG test trip on my H/C/I/E 98 TA I had some out of town business, so I decided to use this little trip to test expressway gas mileage. 
This is the first chance I have had to drive this far since I did H/C/I/E last year. Cam is advertised 224/228 .581/.588 110lsa installed ~2 degrees advanced. My 98 TA has a stock M6, stock rear (3.42), stock tires, and the JAAM kit. The round trip was 190 miles. I filled up before and after at Shell stations allowing the pump to shut itself off at full tank detection. Unfortunately I could not use the same pump to fill up both times. I used 7.4 gallons which equals ~26mpg. 
Granted this is a smallish sample size, but I still think it fantastic, especially considering I was stuck in actual “stop and go” traffic on the expressway for 40-50 minutes. ~8 miles was in-town driving. Except for one quick WOT blast, I drove very conservatively, but did not skip gears. Average non-construction zone, expressway speed was ~74mph. I think the 30+mpg claims of some are entirely believable.
BTW, as pre-emptive strike, I say to all those who are about to consider criticizing anyone for wanting good fuel economy, STFU!
This is the first chance I have had to drive this far since I did H/C/I/E last year. Cam is advertised 224/228 .581/.588 110lsa installed ~2 degrees advanced. My 98 TA has a stock M6, stock rear (3.42), stock tires, and the JAAM kit. The round trip was 190 miles. I filled up before and after at Shell stations allowing the pump to shut itself off at full tank detection. Unfortunately I could not use the same pump to fill up both times. I used 7.4 gallons which equals ~26mpg. Granted this is a smallish sample size, but I still think it fantastic, especially considering I was stuck in actual “stop and go” traffic on the expressway for 40-50 minutes. ~8 miles was in-town driving. Except for one quick WOT blast, I drove very conservatively, but did not skip gears. Average non-construction zone, expressway speed was ~74mph. I think the 30+mpg claims of some are entirely believable. BTW, as pre-emptive strike, I say to all those who are about to consider criticizing anyone for wanting good fuel economy, STFU!
06-01-2008 | 11:45 AM
#5
I am not certain how much power I am putting down, and have no track times. I started off w/ a base tune from Wait4me. SspdDmon was kind enough to meet up with me a couple times to dial it in using EFI Live and his wideband. SspdDmon deserves a big 
for helping me out and answering all my dumb questions.
Conservative in-city driving yields mid to high teens. Lead-footing yields low teens. Hopefully I will get a chance to do more longer-distance driving w/o the stop-n-go; maybe a day trip to a car show this summer.
for helping me out and answering all my dumb questions.Conservative in-city driving yields mid to high teens. Lead-footing yields low teens. Hopefully I will get a chance to do more longer-distance driving w/o the stop-n-go; maybe a day trip to a car show this summer.
06-02-2008 | 07:57 AM
#7
sounds about right.
ive tested mine on quite a few 600mile round trips. the first 1/3 of the trip was all 45-55mph with minimal stopping. the rest was cruise control at 75-80mph.
i always run with the windows down, and usually the ttops off (found that robs about 1mpg at highway speed).
doing that same trip about 5 times, i've always gotten 25-26mpg.
and i've got a poor tune for part throttle....and a bigger cam than you.
i anticipate it going up a little when i tweak the tune.
ive tested mine on quite a few 600mile round trips. the first 1/3 of the trip was all 45-55mph with minimal stopping. the rest was cruise control at 75-80mph.
i always run with the windows down, and usually the ttops off (found that robs about 1mpg at highway speed).
doing that same trip about 5 times, i've always gotten 25-26mpg.
and i've got a poor tune for part throttle....and a bigger cam than you.
i anticipate it going up a little when i tweak the tune.
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06-02-2008 | 03:44 PM
#8
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Joined: Aug 2004
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From: United States
Sounds fun, but isn't the purpose of doing these mods to go fast? 
Maybe the parts are just being broken in. 
I'm a young and "spirited" driver. But I'm getting better about driving more conservative as I age.
Maybe the parts are just being broken in. I'm a young and "spirited" driver. But I'm getting better about driving more conservative as I age. 
06-03-2008 | 09:17 AM
#11
I run the same cam except mine is a 110+0 LSA and I get 26 on the highway and 20 around town and still put down 452 at the rear wheels...nothing wrong with good fuel economy especially since gas prices are higher than giraffe ***** ...
06-03-2008 | 10:51 AM
#14
TECH Senior Member
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Posts: 6,524
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From: Western Burbs of Detroit
Dallas to Detroit = 1200 miles. 2 tanks of gas, no bs. Boy oh boy do the ewp and ud pully improve gas mileage. Probably didn't hurt that it was all highway, very light traffic on the weekend driving experience. 75 mph w/cruise set all the way. Had a bowl of chicken breast and diet coke so I didn't have to stop to eat. Good run. 3.42 gearing dumdumdum !!
06-03-2008 | 10:53 AM
#15
I am hoping to attend a dyno day to get some numbers on the cheap. There is no way I will be putting down 452rwhp. I would be very happy with 400/400 and a very flat torque curve.
06-03-2008 | 11:22 AM
#16
Dallas to Detroit = 1200 miles. 2 tanks of gas, no bs. Boy oh boy do the ewp and ud pully improve gas mileage. Probably didn't hurt that it was all highway, very light traffic on the weekend driving experience. 75 mph w/cruise set all the way. Had a bowl of chicken breast and diet coke so I didn't have to stop to eat. Good run. 3.42 gearing dumdumdum !!
06-03-2008 | 11:33 AM
#17
Thats why I opted for the LS engine vice doing the RAMJET 502 build I was originally going to do. Performance and economy are the way to go nowadays. I'm hoping to get better milage since these Novas are usually 3k loaded with an iron head/block engine.
