MPGs run, Aspire SE

[TominMO]

When do you suppose you slipped a tooth on your timing?
Do you suppose any of the previous runs were afffected?

No, this happened when I put the new cam on, so it only affected the one test. But it's interesting that I got as good a mileage as I did (52.4) with the cam off a tooth!

[Pu241]

When do you suppose you slipped a tooth on your timing?
Do you suppose any of the previous runs were afffected?

[TominMO]

Just took it for a run to see what's what. At 10 degrees timing with the cam sprocket lined up properly, it seems to have about as much power as with the stock cam. If I can pull some good MPG numbers too, it will def be the "best of both worlds" cam, because I know I can add more timing for more power, with only a slight loss of MPG, if any. I will go back to increasing the timing after this next run, to try to find an optimal timing for MPG.

[TominMO]

Was curious about the unexpectedly low MPG number of my last run, so I went outside and looked at the cam timing again. Yup, off a tooth. It was retarded one tooth, therefore about 7 degrees. This was masked by having the ignition timing advanced 3 degrees; and with the cam profile being different, maybe it tolerated the discrepancy more than a stock cam would have. But I don't know. Anyway, I corrected the timing and will do a run this week, possibly as early as tmw. I set the timing at 10 degrees BTDC.

[mikeyjd]

Oh wait, I have that backwards don't I?

Si

[getnpsi]

I personally think you should go up to 150 miles on computations, however the more data you get the less important if the trends follow the mods, traffic speed and weather conditions

[FestYboy]

you so Ca-razy!!!

[TominMO]

That's right, schmuck. Get with it.

Hey! Language!

[TominMO]

Oh wait, I have that backwards don't I?

That's right, schmuck. Get with it.

[TominMO]

It just occurred to me that all these tests have been done with summer gas! Maybe just switching to the winter blend will give me 10%, which I have seen in the past.

Oh wait, I have that backwards don't I?

[TominMO]

Here is a summary of all my Aspire MPG tests, so you don't have to go flipping back to find them:
Aspire SE mileage testing synopsis
(All tests done at 60 MPH except the first one)
....MPG.......Description
A. 45.0.......stock; 185/70x13 tires; 55 MPH; approx 250 miles
B. 55.0.......small front air dam, same tires; 100 miles
C. 52.7.......larger air dam, side/rear wheel skirting, 165/80x15 front tires on steelies; 155/80x13 snows on rear; 100 miles
D. 59.7.......larger air dam, side/rear wheel skirting, 185/70x13s on front, 155/80x13 snows on rear; 100 miles
E. 51.3.......larger air dam, side/rear wheel skirting, 155/80x13 snows all around; 100 miles
F. 54.0.......as above but with new 155/80x13 Kumhos @44PSI, removed wipers and mirrors; 243 miles
G. 53.3.......Kumho tires, reinstalled wipers/mirrors, removed all side skirting and added kammback; 176 miles
H. 51.2.......kammback removed, back to front airdam only, cleaned and balanced injectors; 220 miles
I. 52.4.......as above + Dickmeyer Aspire MPG cam; 241 miles

You're right mikeyjd, a 1.2 MPG difference between H and I.

Tests B through E should not be taken as seriously since they were only 100 miles; more of a chance of skewed data due to fill errors. However, except for D, all results @60 MPH fall between 51.2 and 55.0 MPG.

It just occurred to me that all these tests have been done with summer gas! Maybe just switching to the winter blend will give me 10%, which I have seen in the past.

Hopefully I will get Matt's FPR and header installed before Madness; and for the trip, I am thinking of going all-out with rear wheel skirts, kammback, wiper/mirror delete.

[mikeyjd]

There's an apples-and-oranges aspect to this too. Matt's customer reporting 7 MPG increase was driving a carby Festy; so different cam and different fuel system. Plus I regard his results as more anecdotal than mine, simply because I don't know anything about his methodology. Also, the carby system has less ability to adapt than an EFI system, which may have helped in some way; i.e., the full increase came immediately.

I would consider my tests to be Matt's practical testbed for the Aspire MPG roller cam. I don't consider the 1.4 MPG improvement to be inconclusive, just minimal; plus, it may improve with less timing, and the computer "learning" the new fuel parameters. He said I just need to drive it around for awhile, then look for results.

Good thoughts.

[TominMO]

There's an apples-and-oranges aspect to this too. Matt's customer reporting 7 MPG increase was driving a carby Festy; so different cam and different fuel system. Plus I regard his results as more anecdotal than mine, simply because I don't know anything about his methodology. Also, the carby system has less ability to adapt than an EFI system, which may have helped in some way; i.e., the full increase came immediately.

I would consider my tests to be Matt's practical testbed for the Aspire MPG roller cam. I don't consider the 1.4 MPG improvement to be inconclusive, just minimal; plus, it may improve with less timing, and the computer "learning" the new fuel parameters. He said I just need to drive it around for awhile, then look for results.

[mikeyjd]

OK, this is gonna take some explaining....

Went out early this morning and did a 241-mile MPG run @ 60 MPH, on the usual road course (I-70 in IL, east from St Louis). It took 4.6 gallons to refill, for a fuel economy of 52.4 MPG. With the stock cam under basically identical conditions, I got 51 MPG.

I had timed the ignition at 13 BTDC, and used 91 octane. I did that because Matt said there was a possibility that I would lose some power with the new cam, and I didn't want that to happen. But the system might be happier with 10 degrees, in terms of fuel mileage. So today I am going to return the ignition to 10 BTDC; I just filled it w/89 octane. My next run will be with 10 degrees, but Matt says I can safely go to 87 octane, so the next fillup will be with 87.

I called Matt and reported the results; we had a long discussion about the cam design, EFI, and how basically the system needs to get used to the new cam parameters, and that quite likely fuel mileage will go up. Also, since he will be sending me his adjustable FPR and the header, I can expect mileage to improve when I install them, and back fuel pressure off by about 10%. The header will improve flow. I am not sure what effect this will have on mileage, tho.

So initial results are inconclusive I guess. Thank you very much for your willingness to share your results with us. I look forward to following you future tests to see if there are any more notable increases. While your results (1.4mpg) is a 4% increase in economy. I was hoping for closer to the advertised 7mpg (20%). I think it's probably to early to tell what the results are, but it seems that initial reports at what % increase to expect might have been on the hopeful side.

[TominMO]

OK, this is gonna take some explaining....

Went out early this morning and did a 241-mile MPG run @ 60 MPH, on the usual road course (I-70 in IL, east from St Louis). It took 4.6 gallons to refill, for a fuel economy of 52.4 MPG. With the stock cam under basically identical conditions, I got 51 MPG.

I had timed the ignition at 13 BTDC, and used 91 octane. I did that because Matt said there was a possibility that I would lose some power with the new cam, and I didn't want that to happen. But the system might be happier with 10 degrees, in terms of fuel mileage. So today I am going to return the ignition to 10 BTDC; I just filled it w/89 octane. My next run will be with 10 degrees, but Matt says I can safely go to 87 octane, so the next fillup will be with 87.

I called Matt and reported the results; we had a long discussion about the cam design, EFI, and how basically the system needs to get used to the new cam parameters, and that quite likely fuel mileage will go up. Also, since he will be sending me his adjustable FPR and the header, I can expect mileage to improve when I install them, and back fuel pressure off by about 10%. The header will improve flow. I am not sure what effect this will have on mileage, tho.