Sun visor air dam drag

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29 Apr 2014 17:33 #21 by Joseph Baz
Joseph Baz replied the topic: Sun visor air dam drag
Why do people even mention aerodynamics when talking about an OKA....well after all the windscreen slops back maybe 15 degrees....hahaha
cheers,Joe

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29 Apr 2014 22:25 #22 by OKADOC
OKADOC replied the topic: Sun visor air dam drag
Ladies and gentleman please fasten seat belts and prepare for take off at multiplex, your crew today is captain Hal in his Sidewinder entry and Capt Darren in his Exocet entry going all out in the Nil Fecies A Main finale. TH was forced out of the event due to wing sheer.My money is on the Haffie in this one. Be there or be square folks. Life's to straight without Oka's.

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30 Apr 2014 18:20 #23 by Hal Harvey
Hal Harvey replied the topic: Sun visor air dam drag
A perfect evening for it, but I had to pull the pin on that plan this morning anyway. Health-wise I had the night from hell last night, and am stuffed full enough of opiate-based painkillers that there's no way I would be driving around the block, let alone be at the Motorplex exploring the limits. Maybe next week.

Principal advisor to the Minister for Tourism, Liza Harvey MLA
... OKA 260 ... "I'm not leaving any sooner than I have to!"
www.byles.net/OLDportal/members-vehicles-public/5-oka-260

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30 Apr 2014 18:43 #24 by Joseph Baz
Joseph Baz replied the topic: Sun visor air dam drag
Well Hal,health is first take care of yourself,I know that you have the fastest brick in WA.
Cheers,Joe
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30 Apr 2014 19:39 #25 by DarrenWebster303
DarrenWebster303 replied the topic: Sun visor air dam drag
Next week, or one of the many after that Hal. You know being an ex-drag
racer, I cant wait to here how you felt when you do get to turn on to the strip from the staging lanes for the first time in an Oka. You do also know that its going to be an west v east thing as soon as you run a number, Im going to have to see what my garden shed will run! As Joe said, health first my friend. (note: I don't consider 160Kph+ in an Oka healthy!!)
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30 Apr 2014 19:56 #26 by DarrenWebster303
DarrenWebster303 replied the topic: Sun visor air dam drag
Oh Doc, You could be a bit of a dark horse in the field too, along with a few of these cummins rockets...... Must price that twin cp3 fuel pump set up....

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30 Apr 2014 19:59 #27 by Ewart and Vivian Halford
Ewart and Vivian Halford replied the topic: Sun visor air dam drag
G' day Hal, yes get your health right and then hit the track. Can't weight to see the results and hear the story.
Cheers

Ewart oka 365
0428911147
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01 May 2014 23:00 #28 by Hal Harvey
Hal Harvey replied the topic: Sun visor air dam drag

DarrenWebster303 wrote: ...as soon as you run a number, Im going to have to see what my garden shed will run! As Joe said, health first my friend. (note: I don't consider 160Kph+ in an Oka healthy!!)


Haha, "garden shed" is so on the money! And I was actually figuring on a finish line speed of around 140km/h, which should be exciting enough - we'll see. In due course. I've been trialling on a short bit of private road that I have available - and I really do have traction issues - will definitely be launching with the rear locker on, front locker off, in 4-H with the hubs locked in. Darren I was figuring on about 30psi (will be using 265/70R 19.5 initially) - how does that sound to you? Any other tips? I was holding on the line at 2000rpm for the launch.

Principal advisor to the Minister for Tourism, Liza Harvey MLA
... OKA 260 ... "I'm not leaving any sooner than I have to!"
www.byles.net/OLDportal/members-vehicles-public/5-oka-260

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02 May 2014 05:51 #29 by Peter and Sandra OKA 374
Peter and Sandra OKA 374 replied the topic: Sun visor air dam drag
This is so wrong but great!!!
What is the sweet spot on the Duramax where the power and torque curves cross?
How far does it drop the revs when you take off as the torque converter takes up?
Trying to keep it on or above the sweet spot at launch would be the go wouldn't it? Been over 30 years since I've done any dragging.

OKA 374 LT Van, converted to camper/motorhome,
400ah Lithiums, 1100w solar, diesel cooking heating and HWS,
Cummins 6BT, Allison 6 speed auto, Nissan transfer.

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02 May 2014 08:41 - 07 May 2014 07:50 #30 by outyonda
outyonda replied the topic: Sun visor air dam drag
When we were young & silly, were not young anymore!!

Sat night at Scarbourgh was the night!!
the bottom car park, beach sand at far end.
I'm shore you could relate to that Hal


A few little kerbs shouldn't slow an OKA much.

OKAs 091, 093, 094, 113, 346x6 & 405
Last Edit: 07 May 2014 07:50 by outyonda.

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02 May 2014 09:04 #31 by outyonda
outyonda replied the topic: Sun visor air dam drag
Darren I was figuring on about 30psi (will be using 265/70R 19.5 initially) - how does that sound to you? Any other tips? I was holding on the line at 2000rpm for the launch.[/quote]

tyre compound might be A traction issue??

265/70 19.5 are A truck tyre, hard & tough.
Drag tyres are soft & pliable.

#405 has 305 19.5 snow & mud, A softer tyre,
I'm pulling them off to sell after seeding,
you are welcome to "test drive" them Hal

Brett

OKAs 091, 093, 094, 113, 346x6 & 405

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02 May 2014 17:37 #32 by DarrenWebster303
DarrenWebster303 replied the topic: Sun visor air dam drag
I think 28 -30 would be a good starting point. Where ever you start to see a little tyre deformation. Make sure it feels ok at reasonable speed. Go slightly slower than the green one in Vic & that should be fine.:)))

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02 May 2014 18:03 #33 by DarrenWebster303
DarrenWebster303 replied the topic: Sun visor air dam drag
Pete, when its on tune 5 I just let the Allison TCM worry about the shift points as Im usually a bit busy steering!

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03 May 2014 10:42 #34 by OKADOC
OKADOC replied the topic: Sun visor air dam drag
Hi all, my best ones about 200 hp behind you guys can't see that bridging the gap with the power to weight ratio after I've finished their diet but would be great for the evolution of the OKA to see 6ft flames breathing from the stacks and a huge thunder rattling down the strip in a new 4x4 class dragster, yep Who wants to temper enthusiasm with commom sense anyway, boring. Growing old is mandatory and growing ups optional, there's an exciting culture evolving and keeping the Oka dream alive.
On that note Hal have you been a good boy and eating 1 whole paw paw including skin everyday cause a friend John who owns the local Cellabrations liquor shop in Newman has been battling liver cancer for 2orso years now and after I told him about my experiences he has been doing the above for a month now and his wife Anita who runs the store cornered me recently bubbling with hope and excitement and thanking thanking me for sharing my knowledge as his liver tumor has substantial shrunk in the last month, the first time since he was besieged by the pathogen, he is in Perth for two weeks chemo as I write.Everyone, this is not an isolated incident, take note and google paw paw leaves and act if necessary as it will most likely help preserve your life, and no I don't have shares in the paw paw world.
Gentleman start your engines.
Regards to all from Doc And Lyn Davey

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05 May 2014 13:10 - 05 May 2014 13:22 #35 by Hal Harvey
Hal Harvey replied the topic: Sun visor air dam drag

Peter and Sandra James OKA 374 wrote: This is so wrong but great!!!
What is the sweet spot on the Duramax where the power and torque curves cross?
How far does it drop the revs when you take off as the torque converter takes up?


See if this helps at all:



I haven't had mine on a dyno but you'd think 2500-3000 is the right vicinity. Relatively high. The chart shows emissions-regulated motors - Darren and I have dirty motors with tune dials, that should be good for about 25% more horsepower with the tune dial on the highest setting (5); don't know about torque.

So I tried again this afternoon with lower pressure and 4WD, and it made a world of difference of course. Got traction. It didn't drop revs at all by the tachometer - straight from a 2000rpm hold up past 3000, shift, and then I'm running out of my little bit of road. But no wheelspin, just a proper launch. Looking good, except the weather forecast for this Wednesday isn't. And by the sound of it I'll need a new rear ring & pinion by the end of this, but you have to do these things, hey.

Principal advisor to the Minister for Tourism, Liza Harvey MLA
... OKA 260 ... "I'm not leaving any sooner than I have to!"
www.byles.net/OLDportal/members-vehicles-public/5-oka-260
Last Edit: 05 May 2014 13:22 by Hal Harvey.
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07 May 2014 07:56 #36 by outyonda
outyonda replied the topic: Sun visor air dam drag
4WD will suck Horse power??

Have you tried the traditional "burnout" first
get the tyres tacky, more grip!

OKAs 091, 093, 094, 113, 346x6 & 405

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07 May 2014 10:28 #37 by Hal Harvey
Hal Harvey replied the topic: Sun visor air dam drag
4WD will suck horsepower but, theoretically at least, with the Nissan transfer case I can shove it back into 2WD at any speed - so leaving the Allison to its own wisdom, I'll be able to do that one gearshift once I'm beyond the wheelspin stage. This recommendation all comes from Heath in Qld, who fabricates the adaptor plates and has drag raced essentially the same driveline many times, albeit with more ponies and a lot less weight.

There's a couple of things against burn outs - the rubber on these tyres is so hard I'd really have to fry them to get then sticky, like 100km/h for 5-10 seconds, and while that would be spectacular it is also likely to be unnecessary; the bitumen at the start of the Motorplex strip is so infused with VHT traction spray that you can actually hear a car's tyres doing a pluck-pluck-pluck sound as it is pushed over it. Very sticky.

And the other thing is that these 265 tyres are borrowed from Brian Carr, and he'd probably like them back with some rubber on them. I needed a set of more-legal tyres for a recent licensing examination, and the engineer made a point of (rightly) disapproving of my 14-y.o. 285s (prior to the examination date, so I had time to change them). Brian's were much newer and served the purpose. And yes I did ask him if I could leave them on for the drags! There is/should be a gearing advantage with the smaller diameter tyres over my normal 38.5" 355s; though Heath reckoned go with whichever is lightest, which is actually the 355s. But I thought I'll save them for another night and would then be able to compare the two. If I haven't broken too much in the meantime.

Principal advisor to the Minister for Tourism, Liza Harvey MLA
... OKA 260 ... "I'm not leaving any sooner than I have to!"
www.byles.net/OLDportal/members-vehicles-public/5-oka-260

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08 May 2014 06:01 - 08 May 2014 06:02 #38 by dandjcr
dandjcr replied the topic: Sun visor air dam drag
In the interests of completing the picture, I've annotated Hal's Duramax power/torque chart with comparative data for the Perkins 1000 series engine from 2001. And that was a more powerful and torquey engine than Oka actually used.


David and Janet Ribbans - Oka 148
Oka148 profile here.
Visit our technical and travel blogs: here.
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Last Edit: 08 May 2014 06:02 by dandjcr.
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08 May 2014 06:21 #39 by Outback Jack
Outback Jack replied the topic: Sun visor air dam drag
Ouch

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08 May 2014 16:25 #40 by DarrenWebster303
DarrenWebster303 replied the topic: Sun visor air dam drag
Oh David, that is so graphic. When you consider that Hal & I have better exhaust & intercoolers than std Chev & thats a good Perkins version, the graph is actually wider apart on the base tune.

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