How to Accelerate?

[pumafeet10]

This is something that i have posted about a few times and find my self very conflicted. I have seen the advice from Wayne to accel slowly and then once up to speed and your are ready to Fas the to pulse at higher lod to get back to your target speed. The higher lod during pulsing i don't have a problem with.

I have a 2000 Honda civic hatchback that is almost gutted on the interior i have a carbon kevlar hood so my weight is def below average civics, and its 5spd, my tires are at 70psi and lastly the car has a full lower grille block which is on the inside of the grille which im not sure is causing problems or not? Right now according to my scangauge I am doing 60.3 MPG for the tank which is awesome, but for some reason i feel like I can do better.

So how should we accelerate, what rpm,lod and Tps ? For me i try to do about 65-76 lod but that is only like 25-30 at most on Tps , thats when I pulse after fas'ing.
What about when we are coming from a stop or just getting up to your speed where you want to start fas'ing?

Not sure if I am leaving something about but I drive slowly up to speed and its working but have seen some people with different results contray to what i am doing???

so whats the concensus??? Let the Great Debate Begin

David

[SVOboy]

Here's my take with the old set up on the crx: crxMPG - Gas mileage never looked so good » Acceleration and Fuel Economy Tested

I guess my results disagree with wayne's...but according to a lot of people he's god so we should ignore everything else!

[bbjsw10]

That is a very interesting read SVOboy. I figured slow and steady was the way to go, but Jack rabbit while EOC won out. I need to try this some time, makes sense more time to coast with a fast pulse up and long coast down.

[SVOboy]

I plan on redoing the test with the new engine in, that's about two years old, but I was pretty meticulous so I trust the results.

[bbjsw10]

Originally Posted by pumafeet10

, my tires are at 70psi

What kind of tires are those, semi retreads. 70psi that is crazy. Must be good tires to hold that kinda pressure.

[pumafeet10]

SVOboy, it was your post that i had read and had seen a few other people have the same results. which keeps me thinking but also the frugal person i am i don't want to go out and waste gas.

I am wondering if from the more rapid acceleration what my values on my scangauge should be, as in should i accelerate at 75 on the tps or with say 75 on lod? i know its different for everyone and one prob is i don't drive my car really at all during the week since i try to bkie everywhere i go locally.


My tires...well from people such as wayne and others one here and cleanmpg.com and from my research 70psi really isn't that crazy, especially from the research i had done on what it really takes to blow up a tire.

If you want better mileage, longer tread life, and a better handling car keep your tires psi high. Start at max sidewall psi and go up in small increments till about 70 some people have done more but thats where im at right now.

[SVOboy]

If you have a SG, just do a little testing! I doubt you'll ever find the ideal, but at least get a good idea and stick with it.

[azraelswrd]

Whoa, 60mpg in a Civ? Nice! But I am a bit concerned with the 70psi tires as well. I mean, that puts the HYPER in hypermiling.

(I drive an automatic so I'm not sure how much you may get out of the followin...)

As for accelerating I was doing slow-n-go since driver's ed but I (finally) realized I was getting killed on the FE just to make my gears shift (I'm in an automatic). First heard about BSFC maps here and was intrigued. Got into the habit of accelerating around 70-75 load once I had my scangauge and I have noticed some differences especially in immediate MPG. The same stretch of road that I usually got 36-37mpg on, I started to see 39-40mpg once I did some load pedalling. Slow and go is good in general, but if you have the tools to see how far (and how hard) to gas, I say go for it.

Once I get to my ideal gear, my preferred settings are:

TPS: 15-16
RPM: < 2000
MPH: 40-50

At highway speeds, this has been my better configuration:

TPS: 16-17
RPM: < 2500
MPH: 50-55

[bbjsw10]

Originally Posted by pumafeet10

My tires...well from people such as wayne and others one here and cleanmpg.com and from my research 70psi really isn't that crazy,

I am not doubting you, but my brothers valve stems blew apart at the seams at 60psi. Just be safe no life is worth 1-2 mpg. Just my .02 not trying to be a tool.

[SVOboy]

Originally Posted by bbjsw10

I am not doubting you, but my brothers valve stems blew apart at the seams at 60psi. Just be safe no life is worth 1-2 mpg. Just my .02 not trying to be a tool.

I'll agree...exceeding the maximum by over 50% is pretty foolish. You wouldn't climb a 100 pound rated ladder to clean your gutters, would you?

[pumafeet10]

i totally hear what you are saying but tires aren't rated for psi, manufactures put numbers on them to get certain parameters filled such as ride quality, noise and grip , which for me i want the least amount of energy wasted in my driveline and my tires to last as long as possible, heck i could have them at 30 psi like when my gf had some horrible perellis on her focus and the pieces of junk balloned the sidewall which were at manufactures reccomended specs.

so if something is proven to be wrong then i will stop but like our driving techniques someone told us all of these rules on how to drive when we were younger and find out now that most are not true , who am i not to try new things that have so far proven themselves completely true! I can see how somethings might be crazy but isn't that how most things are discovered or revolutionized? I am trying to think out of the box from the wasteful notions of my generations and generations past.

[SVOboy]

Well, just hope you don't hit a pothole. Bicycle tires are certainly different, but the same "suggested max inflation" things still come into play, and I've seen too many tires explode in races to take the same chance out on the road. Besides, by darin's coast down test, there's not even much difference in the rolling resistance.

I understand your point about questioning traditional wisdom, but when things like safety are concerned it's best to know first, and act second. Wayne will be in a world of sadness when someone hyperinflates, has a blowout, and then blames him for his completely uneducated recommendations. Unless he's secretly and engineer and knows more than the rest of us.

[Daox]

Back on topic.

I aim to always (regardless of speed) accelerate at around 80% load and keep rpms under 3000. With variations (rpm especially) from engine to engine, it is the most efficient way to accelerate, period. TPS doesn't really have much to do with it other than it effects load. One TPS reading will not work for everyone and will vary quite a large amount depending on many things. Load is the key.

I think there are benefit of accelerating slower. It allows you to not over-accelerate since you have more time to think and see what is going on. It also lowers average speed which will lead to small gains.

[jonr]

Moderate to brisk acceleration is most efficient. It operates the engine at its best BSFC (ie, maximum work for the least fuel).

[pumafeet10]

Daox- your thoughts about slower acceleration are the ones i have been thinking that are contrary to accelerating briskly, and keeping the engine of best bsfc is what would make sense as well

[wagonman76]

Id have to say a scangauge or mpguino would really be the best way to tell. It really depends on the car, and the driving conditions. On my car, unless I really punch it, I get the same or better mpg with brisk acceration as with just spinning fluid at really slow acceleration (which I used to do before the mpguino). So getting up to speed faster is better since I get the same mpg for less distance.

[MazdaMatt]

I'm new to all this driving tech stuff, but brisk accel quite often leads to me using the brakes. I guess it just takes practice to judge correctly.

[pumafeet10]

For me its not too much of an issue worrying about lights unless im in a completely unknown area which sometimes you really can't help but for the most part you can see it coming. Also when getting up to speed fsater will also mean that i can start fas'ing sooner and for longer periods of time which i think will really help along with keeping my target speed lower.

[thebrad]

I use 30% TPS as my staple for acceleration, I was going to try 5% increases on following tanks but that never happened panned out because I stopped driving as much, so I just stick with 30% for acceleration and 13-15% for freeway cruising at 50-55mph.

[Vince-HX]

A tuner informed me that honda's dont go into open loop unless throttle is over 90% and rpms are high enough.

I accel @ 0-1 in vacuum (about 75%) and always pulse from 1500-2000 rpm. This has given me high 60's in city driving.