Gas mileage and different chips...

[SteveN]

One of the touted advantages of the BBPower chip is to increase gas mileage.

Several posts with other chips indicate mileage their mileage decreased while most BB chip owners indicated mileage increased.

Question 1:

What type of gas mileage do you get when you have a Laser exhaust and a Laser chip?

Question 2:

How can the BBPower chip increase gas mileage while at the same time increasing performance; shouldn't these two be mutually exclusive?

[motoman]

Originally posted by SteveN:
Question 2:

How can the BBPower chip increase gas mileage while at the same time increasing performance; shouldn't these two be mutually exclusive?

Hey, that's what Andy Granatelli and STP used to claim in the 60's/70's!

[ecolonna]

I put in a Wunderlich chip back in June before my trip to Cabo. I was expected better mileage and originally thought that I was getting it. After riding with the chip for several months I am pretty much even with where I have always been, maybe even a little less...

[roger albert]

No, not at all mutually exclusive, when you add govt. regulations into the mix, and are no longer considering mere physics, thermodynamics, chemical stoich etc.

First, I don't claim to know the whole story, but have picked up a bit. Here's part of what I _do_ know. You have to look into how testing is done. For instance, a bike might be tuned rich in one region, to lower combustion temperature and Nox emissions, at the expense of economy and other emissions, and in extreme cases, power (rare, since that would in most every case, push the HC emissions too high). It's important to realize that exhaust emissions can't be looked at as some monolithic aggregate substance. Things that lower HC can raise NOx or CO2 or visa versa. There are at least those 3 major emissions subcategories to play off one another, plus, economy and temperatures/durability. Anyway, a chip can lean such a rich region of the operating curve out.

Similarly, there are steady state noise tests that are more easily passed when, in addition to exhaust tuning, a bit of spark retard and/or mixture leaning can soften power and noise at the specific rpm and load range the tests are carried out at. To reduce the impact of the soft spot (often noticeable as a dip in the torque curve) the mixture can be run somewhat richer on each side to provide a bit of masking. If the programmer richens a bit during the dip, but leans the 'masking' region out on each side, then there can be a net increase in power and reduction in richness/fuel-consumption.

clear as mud?

Anyway, the point is, even at a given rpm/load combo, you can sometimes improve both power and economy. When you start looking at all of the operating points, then there are a lot of individual points that can be tweaked, with no one of them providing a a simultaneous improvement in both, but still offering an overall/net benefit.

That having been said, a chip can only do so much. It can ignore/skirt manmade laws, but not physical/chemical ones.

hope that helps
roger

[EZ-RIDER]

Roger I agree with you but the point Steve and myself feel is how can you increase gas
mileage by say 6 to 7 miles a gallon and still put out the claimed 98 horse power at the rear wheel like BB claims

TOM

[SteveN]

My gas mileage went up by about 4-5 mpg when I installed the BB chip. Bernie told me I could expect a 5-8% mpg increase and I got the upper end of that. Last tank running hard with stage 4 and 5 gave 46.5 mpg!

I haven't eased my riding style at all, in fact in search of optimal tuning I've been running many more full throttle roll-ons, etc. Mileage is one area I have no complaint.

It's the performance increase other's talk about that I don't think I'm seeing/feeling. I get little difference between stages 2-5 with my bike. It runs smooth at all stages with a small performance increase (acceleration) at 4 and 5. The rev limit is definitely increased but other than that, no great boost that others have mentioned say between 2 and 3.

Over stock chip setting there is a definite boost in performance as seen in 1/4 mile times, but between stages with all other mods constant, the most is about .15s in the quarter mile from stage 1 and stage 4.

Maybe I'm expecting too much, but that still doesn't answer the big difference between EX-RIDER's Vanderlinde and my Laser/BB.

NOTE: This mpg increase is after an full, open exhaust and the SJ performance filter and snorkel in COMBINATION with the chip.

[This message has been edited by SteveN (edited 09-07-2001).]