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26-01-2013, 11:34 PM | #21 | |
Junior Member
Join Date: Nov 2011
Location: Blue Mountains NSW
Car: '98 1.8 Astina, Honda v-twin Magna
Posts: 42
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Quote:
My son and youngest daughter are both learner drivers ATM, with my daughter booked for her driving test in two weeks time. I haven't taught them anything except standard driving techniques and wouldn't want them to attempt any of my unorthodox techniques without a few years driving under their belts first, because some of these are potentially dangerous in that they add extra complexity in an emergency situation. My thought was, that I should show the same concern for the younger ones on this site as I would my own children. Maybe I've over reacted a bit ... sorry, it's a dad thing. As for the A/C question, I only rarely use the A/C. It's not normally that hot in the mountains and on the motorway, with the controls set for recirculation, the A/C compressor seems to be off more than it's on. I have been known to turn it off while climbing long hills though. I agree that urban fuel consumption is going to be much harder hit, stop start traffic with A/C is tough on the engine and electrical system. One possible way around that, is an A/C controller like this one from Jaycar http://www.jaycar.com.au/productView...UBCATID=965#11 There's a favourable review of it on Autospeed from a few years ago. |
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27-01-2013, 08:13 AM | #22 |
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Car: AZ-1, Astina Hardtop Turbo, BJ Protege, Beetle
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Quite an interesting thread I'm impressed you've got it into the 5s!
I remember being happy if i got 12L/100km.. LOL I would think a bit of lowering and smoothing out the underside of the car would help - the back of the Astina isn't the smoothest thing in the world. The front at least has plenty of plastic undertrays to help in that regard.
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27-01-2013, 12:47 PM | #23 | |
Junior Member
Join Date: Nov 2011
Location: Blue Mountains NSW
Car: '98 1.8 Astina, Honda v-twin Magna
Posts: 42
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Quote:
Yes, I could drive slower and get similar results, but I've already dropped as much speed as I want to on my commute. I don't have any hard data on the BA hatch aerodynamics. I guess I should do some tuft testing first, but I can make some guesses as a starting point. The nose isn't too bad, it could use fog light covers, ducting between a reduced grill opening and the radiator and a small front lip to the same height as the bottom of the radiator. Under the car could use a tray from the lip, all the way back. I'd like to try a diffuser at the back, but the rear muffler sits too low to get the required angles, I think. The sides are marred by the huge wheel wells. Lowering would help, but I may look at closing the gap between arch and tyre as well. Wheel offset is important as well as the wheel style, I may try moons on the wheels I have. Full wheel covers (spats) at the rear work great, but I don't know if I could make them look OK. Which leaves the rear, the most important area for reducing aero drag. While I love the look of the rear, I suspect it's not very good for minimizing the wake. This is where tuft testing will be invaluable. A full boat tail would work ... but they're just so ugly. While track aero has a slightly different focus, I'd love to get opinions from anyone in the racing fraternity. |
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27-01-2013, 02:51 PM | #24 |
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If you lower it, with the front slightly more than the rear, you'll get much better results. The amount of air under these things when stock height makes it like a parachute.
Also light wheels will help. Spoke design is negligible. |
27-01-2013, 03:24 PM | #25 |
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Join Date: Dec 2002
Location: Location: Vic
Car: Mazda '95 Astina I4, '86 B2K and '10 3 MZR-CD
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Type R skirts may help with the rear wheels and a ZXi splitter on the front.
All Mazda bits that you can't buy through Mazda Aust Just my 2c with A/C. Turning it off only works if you keep the windows up. The old piston style pumps found from the mid 80's back were real horsepower vampires but the compresser in the Astina is much more efficient. If you have a BG (or a BA with working climate control) then leave it on eco unless it gets really hot.
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28-01-2013, 04:39 PM | #26 | |
Junior Member
Join Date: Nov 2011
Location: Blue Mountains NSW
Car: '98 1.8 Astina, Honda v-twin Magna
Posts: 42
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Quote:
As I understand it, light wheels will help in urban traffic (or on the track) but not so much at steady highway speeds. Your remark on spoke design surprised me, so I looked up the documents where I'd read about it some time back. It seems to be one of those differences of focus that I mentioned. Partial (annular) blanking of the wheel face does reduce the coefficient of drag (good), but it also increases the coefficient of lift (bad). I can understand that anything increasing lift on the track is a no-no, but for "normal" road use it's probably not that critical? |
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06-02-2013, 08:01 PM | #27 |
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Join Date: Jan 2013
Location: Wagga NSW
Car: '98 Astina BA 1.8
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My first tank since owning the astina I've only got 11l/100.
I did just discover that the timing was at around 6-7degrees instead of 10... So I'm hoping that improves things. Also just did the GB and engine oil. Bit hard to know what to hit next if it doesn't improve, having no idea of the service history and only wanting to spend the least amount necessary to keep the thing maintained, but efficient. |
06-02-2013, 08:08 PM | #28 |
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you want to improve fuel efficiency? run the lightest motor oil possible... there are MX-5 guys running 5W20 or 0W20 synthetic in the BP here in the US, in the hot southern part of the country.... unpredictable oil consumption at times but no appreciable motor wear or damage from analyses reports... to be on the safe side, a 0W30 synthetic will work wonderfully with this engine
use synthetic gear oil run higher tyre pressures, use harder rubber compounds use lighter wheels with less open faces as said fit ground effects and lower the car to reduce coefficient of lift fit air diffusers under the car to reduce coefficient of lift, air turbulence, and drag remove the passenger side mirror if that is allowed... or both if allowed remove boot lid spoiler (you did that) remove or put away the aerial if you decide not to run aircon, you must keep the windows up having the windows down negates the advantages
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07-02-2013, 10:48 PM | #29 | |
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Location: Blue Mountains NSW
Car: '98 1.8 Astina, Honda v-twin Magna
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Quote:
I'm running a bit heavier synthetic engine oil at present, but with cooler weather approaching, I'll try the lighter stuff at the next oil change. What's a good weight of synthetic gearbox oil? I'm still running mineral oil at present. Should I stick with 75W-90 as the book recommends? |
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07-02-2013, 11:10 PM | #30 | |
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Location: Salisbury - Inner City
Car: 1997 BA Hardtop - Had a 2003 BJii J48 Sport20, and 2x bg SOHC astina hatches
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Quote:
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28-03-2013, 04:20 PM | #32 | |
Junior Member
Join Date: Nov 2011
Location: Blue Mountains NSW
Car: '98 1.8 Astina, Honda v-twin Magna
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Quote:
The standard assembly is much quieter of course, take that as a plus or minus to suit your mood. I believe I can feel a positive difference in torque at low rpm. I can take off from a dead stop while facing up hill easier than before and crawling past road works at 40kph in top gear seems easier. If most of your driving is stop start traffic, this could be a help. Unfortunately, it’s not normally a big part of my commute. OK, it’s all about the fuel economy for me, so how’d it do? Because I don’t have OBD2, I can’t use a fancy gauge to track real-time fuel economy. That means I really have to try it over a few more tanks before being sure, it’s too close to call at present. This tank averaged out to 5.27 l/100km (863km for 45.51l of fuel). That’s good, but not so far from my average that it's cut and dried. One down side of getting better fuel economy is that it's taking longer to get through a full tank (and it's made worse by having my Datsun back on the road now ). I'll update this thread again as circumstances dictate. Pete. |
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28-03-2013, 06:47 PM | #33 |
AstinaGT Regular
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two different standards for transmision and engine oil,
a 75w90 transmission fluid is roughly around a 10w50 engine oil in viscosity.
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21-04-2013, 11:09 PM | #34 |
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Join Date: Jan 2010
Location: Canberra
Car: 323 Astina BA 1.8L
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Impressive figures pete. The best fuel economy i've returned on my stock '96 1.8 BA is 6.5 L/100km (canberra to gosford). Have you tried running additional ignition advance? You said you run high tyre pressures, what exactly are you calling high? I'm also interested in your injector kill switch - is it automatic or must you manually operate it? I've heard newer cars completely cut injector activity when lifting off the throttle, but suspected this wasn't the case with the Astina.
Last edited by Assiduous; 21-04-2013 at 11:09 PM. Reason: grammar |
22-04-2013, 06:45 AM | #35 |
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Cannot say for Astinas before May 96, but post May 96 Astinas do drop duty cycle on injectors on decelleration and zero position on the throttle body.
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26-10-2013, 07:03 PM | #36 | |
Junior Member
Join Date: Nov 2011
Location: Blue Mountains NSW
Car: '98 1.8 Astina, Honda v-twin Magna
Posts: 42
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Quote:
No, I haven't played with the timing on the Astina, although I have on other cars I've owned. I'm a bit reluctant to fiddle with it when it's going so well. When I say higher tyre pressure, I mean somewhere between the 32/30psi on the door sticker and the 44psi max moulded on the tyre wall. While higher tyre pressures help rolling resistance, it degrades ride comfort, so I usually split the difference. The injector kill switch is totally manual. It's mounted on the gear stick so I can shift into neutral and kill the engine at the same time. Pete. |
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29-12-2014, 07:21 AM | #37 |
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Car: '98 1.8 Astina, Honda v-twin Magna
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Hi All
It's way past time to update this thread. To start, a couple of comments in relation to past posts. Switching from a pod filter to the standard air box didn't give me any gain if fuel economy. I've left the standard air box installed so I can use standard filter elements that “maybe” filter out rubbish better, although I've removed the tubing from the bottom, so it's sucking warm air again. Clean_Cookie asked about any exhaust mods, I've recently gotten under both mine and another BA and yes, the exhaust on mine is larger than standard and stamped PowerFlow. Apart from sounding good, I don't know that bigger is any better considering I rarely go over 3500 rpm anyway. There's more random, unconnected stuff to follow that I'll spread over a couple of posts. Stay safe over the holiday period. Pete. |
30-12-2014, 09:03 AM | #38 |
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So what's happened in the last year and a bit?
I had a fibreglass front lip for most of the year, but removed it after whacking it on steep driveways and while parking too many times. It looked good, but I didn't notice any effect on economy, anything I gained from less air under the car was probably countered by the extra down force. That's it on my Fuelly photo. I may make a plain flat rubber one as I get spare time. Replacing worn out tyres gave a noticeable drop in fuel economy. I went from Pirelli P5 to Zetum Solus of the same size (195/60 R15). Apparently this is quite normal, rolling resistance decreases with tread depth, apart from any differences in tread pattern and compound of the replacement tyres. Pete. |
31-12-2014, 05:36 PM | #39 |
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Join Date: Nov 2011
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Car: '98 1.8 Astina, Honda v-twin Magna
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I was rear-ended while stopped at traffic lights by an uninsured idiot a few months back.
Rather than go through my insurance, I bought a complete, registered BA for parts, for less than the excess on my policy. It's the same series and colour as mine, so I've swapped the needed parts over, am installing it's fancy stereo in my daughter's car and have most of the car as spare parts if required. It's only serious faults are faded paint on the roof, a few odd electrical gremlins and a very tired engine, although I drove it home 150km without issue. I may even fit the tow bar from it to my car. I don't expect to use it often, but it'll save me using my wife's wagon to pull the trailer with light loads. |
14-03-2016, 07:25 AM | #40 |
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Join Date: Jan 2010
Location: Canberra
Car: 323 Astina BA 1.8L
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Returned my best figure recently on a Canberra to Sydney return trip - 6.27 L/100km. The key change was a new set of tyres. I was previously running Michelin Energy XM1. Those have been replaced with a Bridgestone Ecopia EP100 (buy 3 get 4th free). The diameter on the Bridgestones must be larger as the speedo is now very accurate. This probably also accounts for my improved economy. The car remains bone stock.
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