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Thread: MPG??? B chassis

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Posts: 41-50 of 139
2011-05-05 03:44:25
#41
Originally Posted by SE-Rtainlyb13
I check everytime as well on the b13. I regularly get 31-33mpg on a 176k bolt-on DE. 80%hwy 20% city. It is all about how you drive, NOT neccessarily how fast you go.I've been experimenting since I got the car with driving techniques and how it affects mileage. I drove like a grandma 55mph hwy (painful I know) and shifted at 3k. I drove regularly at 70mph and shift at 3.5k with a few redlines. What I found best is to drive somewhere in between. The sweetspot on my car is 60-62mph and shift at 3.25k and I regularly see at least 32.5mpg and as high as 35.85mpg. I have heard that 55mph is the best, but I think that is not true for the SR20 based on where it makes torque. You want to maintain throttle position, not speed. And you want to do this just where the engine makes just enough adequate torque to keep the momentum without the rpm's climbing too high. Under 2.5k on the throttle, you are lugging the engine (even for this torquey engine) and so uphills really kill mpg. Also, you want to have momentum going into an uphill and then maintain throttle (not speed) with that momentum. Yes you will lose speed, but this is the cost. That's the tricky part. To achieve the best mpgs it honestly takes concentration lol. More fun to redline at that point. I'll let the 1.6L do the hypermiling lol.


Great post, this is exactly what my research has been finding too.

Originally Posted by SE-Rtainlyb13

Other things to do is coasting in nuetral when you can. Predict when a light turns red up ahead and go into nuetral if you know the light will be red when you get there.


Nooooo, you had such an awesome post. Oh well I guess old habbits die hard. On modern manual cars, aka most fuel injected cars, when you are decelerating he ECU cuts the fuel off completely. Reason is, the wheels spin the transmission, which spins the flywheel, which spins the crank, which keeps the pistons moving, which keeps the engine running, even though there is no fuel going in.

Now Automatics didn't have this feature for a while, since it's harder to force the auto trans to stay in gear instead of downshifting. But from what I was told, modern day auto's should have the fuel cut on decel too.

Originally Posted by SE-Rtainlyb13
Also, fold in mirrors on the hwy, have 40psi in the rear tires (watch treadwear), and use the blower on cold (not a/c or windows down) when your hot. And just for the heck of it, wax the car haha. I'd love to see what I could do with the VE with bolt-ons. I'd say 40mpg is definitely possible. Sorry for the rant but I want to share my experiences.

Dave


Careful with the mirrors, check local laws first. I usually have my tires at 35-38psi, haven't seen any significant differences.

Originally Posted by Shawn
Fair enough. Makes perfect sense.

Not that I am going to actually do it, but I cannot fault that logic.


Not here to change anyone's opinion, just trying to educate with facts .
2011-05-05 04:12:10
#42
I generally see 26-29 MPG on my car. 204,000 miles, original USDM low port in my 1995 200SX SE-R.

I am happy with it. Your numbers see low.
2011-05-05 06:03:13
#43
i was getting 27-30mpg before i broke it. Hoestly i think a flywheel helps and coasting in neutral when going down hill.
2011-05-05 18:02:58
#44
Originally Posted by Vadim

Nooooo, you had such an awesome post. Oh well I guess old habbits die hard. On modern manual cars, aka most fuel injected cars, when you are decelerating he ECU cuts the fuel off completely. Reason is, the wheels spin the transmission, which spins the flywheel, which spins the crank, which keeps the pistons moving, which keeps the engine running, even though there is no fuel going in.

Now Automatics didn't have this feature for a while, since it's harder to force the auto trans to stay in gear instead of downshifting. But from what I was told, modern day auto's should have the fuel cut on decel too.


Interesting. I've heard this stated elsewhere too, although I've heard it debated both ways. I'll have to try this on my next tank. A big reason I use nuetral is to save wearand tear on the tranny. I'd rather do brakes more frequently than a tranny. Yes I know these trannies were meant to downshift, but I do it anyways. Another thing that I do is blip the throttle on downshifts to make good transitions. This is obviously not ideal for max mpg. So I feel my driving style wouldn't make for better mpg. Who knows until I try it. Thanks

Another thing to point out is letting off on the gas while in gear slows down the car more than coasting in nuetral (duh). This is great for coming to a stop, but not on a continous drive (i.e. downhills followed by uphills/level roads) because you'd have to give it more throttle to get it back up to speed after coasting.
Last edited by SE-Rtainlyb13 on 2011-05-05 at 18-07-19.
2011-05-05 18:19:36
#45
Originally Posted by SE-Rtainlyb13
Interesting. I've heard this stated elsewhere too, although I've heard it debated both ways. I'll have to try this on my next tank.


If you have a Wideband, it will go extremely lean or show ---, that's when you know your engine is working for free . My scan gauge also reads a very high MPG figure at that point too.

Originally Posted by SE-Rtainlyb13

A big reason I use nuetral is to save wearand tear on the tranny. I'd rather do brakes more frequently than a tranny. Yes I know these trannies were meant to downshift, but I do it anyways. Another thing that I do is blip the throttle on downshifts to make good transitions. This is obviously not ideal for max mpg. So I feel my driving style wouldn't make for better mpg. Who knows until I try it. Thanks


The thing is, you waste energy when you brake. Momentum turns into heat. So to be a complete hypermiler baller, you have to never use the brakes .

But yes, brake pads are cheaper then the transmission. Rev matching helps a ton to save the life of both the trans and the clutch.


Originally Posted by SE-Rtainlyb13

Another thing to point out is letting off on the gas while in gear slows down the car more than coasting in nuetral (duh). This is great for coming to a stop, but not on a continous drive (i.e. downhills followed by uphills/level roads) because you'd have to give it more throttle to get it back up to speed after coasting.


It does indeed. Since 99% of my daily driving is city, I use this to my advantage when creeping down to a stop light . But I also am a religious cruise control user. So coasting in neutral is almost out of my diet .
2011-05-05 18:58:04
#46
When you cruise downhill in gear your ecu recognizes that as the decel point and basicly almost shuts off fuel completely. You will actually use more fuel coasting downhill in neautral than keeping it in gear and off the throttle completely. This has been a proven fact.
2011-05-06 22:29:52
#47
I didn't read the whole thread, I skipped around

My b14 with a ve swap, gets 29-35 mpg all highway, tuned for 87 octane (premium gets same mpg), pathfinder maf, vvl @5000 rpm, k&n w/pop charger, cat back exhaust, no emissions except for cat, I use castrol syntec 10w- 30

I drive 58 miles each way to work 7 days a week, and 62 miles each way to school 2-3 days a week, gas is costing me about $200+ a week, I change my oil at about 4000 miles which is about every 3-4 weeks
2011-05-06 22:37:58
#48
I get about 20 mpg with about 70% of it highway miles lol if I drive all city I get about 19mpg.
My car just rolled to the 130k mark and I usually shift at about 2k if i'm driving slow or 4k if i'm driving normal
2011-05-07 02:11:01
#49
low 20's in city 23 highway, Never ever over 25mpg even at 99% highway from Wi to NV
(110k auto 1995 200sx SER)
2011-05-07 02:41:13
#50
01 p11 190k all stock

325-350 per tank city/highway

425 per tank all highway
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