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Frame off resto underway - Dial-up beware

With the .75 OD gear + 3% converter slip on my 33'3 (32" true height) I get 1864 rpm at 65, according to the 62-65-dieselpage.com right in the sweetspot for the 6.5 TD.

3.73 give nearly 2000rpm which according to anecdotal evidence and published data moves the fuel use up enough to make a measurable difference.

This K5 will spend 95% of its life on either blacktop or dirt roads so I'd like to match the power band to the gear sets as closely as I can. That said however, I dont want to do it at the expense of driveline durability because chances are when I am in the rough stuff I will be travelling solo and hundreds of miles from civilisation. I wont be going out of my way to beat this rig, but when your snorkel deep in a croc infested river you need to be able to punch the skinny pedal without fear of breakage.

It would be a no brainer if the 14FF wasnt so damn heavy! and came with 3.5's. Oh yeah the 9" has loads of options for an disc rear with E-brake, the 14 has one and it doesnt get rave reviews. I need an E-brake that will postively preform well enough to lock the wheels on any incline, the rego authority here checks the E-brake operation quite closely.
 
Nine inch it is then, Something else that just came to mind would be a rear D60 but I have no idea what gearing options are avalible for it.... Just throwing it out there. You seem to research all of your components well so I have no doubt that a proplerly built 9" will serve you well.

Its a very interesting project you have and I have enjoyed reading this thread. Thanks for the updates and pics
 
Its a small world! I spent a few years as a kid in East Killara on Wentworth Ave and Noosa is a beautiful place to live, wish I was up there. I'm in Canberra on the northside.

This is pic is from the beach directly north of Noosa, its about 40km long and you can camp on it. Its about a 15min drive and ferried river crossing from Noosa. Ex truck & ex GF.




Once the K5 is done this will be one of the first stops, this area is too good for words and I wish I had better digital pics to show it off. Last trip I only shot with an SLR.

Jas
 
At 2000 rpm you will not notice any measureable difference in fuel consumption versus 1864 rpm. Even spinning at 2600 rpm my 6.2 Jimmy on heavy 39.5" TSL's averages 16.3 mpg highway. 2100rpm and lower will net as high as 24-25 mpg depending on speed...

My current combo should net me 21-22 mpg even on the 39.5's. (1778 rpm at 100 km/h) and better yet on 37" radials ( ~1900 rpm at 100 km/h)

I'd go with 3.73's and call it good. To achieve a 1000 km range (effective range, not theoretical) you need 22 mpg (US gallon)

Rene
 
Thats the Cherry Venture that wrecked there a few decades ago, popular tourist spot.

Rene,
Your probably right with the slight increase in rpms and 3.73's does give some leeway to run 35's without affecting the cruise performance. Having never run a TD 6.2/6.5 I'm relying on the best info I can source and the diesel page guys seem adament 1850 is the 'magic' number.

To enable a decent fuel range I will replace the 24 gallon tank with a 31 and fab 20 gal sub unit, this should, theoretically give 1000k's off road. I'm basing this on fuel consumption figures from 6.5's on similiar trips which got between 13 & 15mpg. Its a small control group though, only two vehicles and I know nothing other than they had 6.5's fitted. I am assuming, dangerous I know, they were fully loaded touring rigs, either fullsize Nissans or Toy's. The averages were taken over 3500k's, would you agree with this?

Jas
 
Well I agree 1850 is the 'magic' number, but there are other variables involved which make it not so cut and dry. Equally important is actual cruise speed because these things are the aerodynamic equivalant of a brick. The 6.5 TD won't net you the same fuel mileage as the NA 6.2, and even the 6.2 TD will do a bit worse. The 6.5 TD and 6.2 TD will both have increased fuel rates, so when you are 'on it' it'll be using more fuel (but making a bunch more power too)

More power = more fuel. All the anecdotal fuel mileage claims I've seen show the 6.5TD and turbo'd 6.2's do a bit worse for fuel mileage.

The 6.2/700R-4 rigs seem to do very well even running well above the 'magic' 1850 cruise rpm. It seems the 700R-4 doesn't eat that much power compared to the TH400 and the 4L80e.

Lastly, when figuring the tire diameter as it applies to final rpms measure the tire's circumference to get it's true diameter. When you're measuring a tire's true height mounted on the truck the loaded radius of the lower half of the tire will make them seem shorter than they are. Circumference will give you the tires true height. Example; my 39.5's measure average about 38.25" on the truck, but their circumference is 123". Their true height is 39.17".

You will likely be much closer to your magic number than you first thought.

You should probably see a worst case fuel mileage of 18 mpg at cruise, but much more likely to see 20 mpg. This is using the US gallon.

The only diesel rigs I've heard of getting less than 15 mpg freeway were 'burbs with 4.10's and the TH400 (tires anywhere from stock to 35's)

Rene
 
Aussie Great information I would like to add it all to my K5 information data base. Do you have your photos on a server like photobucket I could go and save. Also when you get done I would like to get as much info as you can give me about the GMH conversions. You are doing a great job keep it up mate. Raises a tinnie an tosses a slab at ya!
 
not trying to hijack, but i just recently bought a 84k5 w/ 6.5td, t400, and 14bff/d44 combo w/4.10 gears i run 37.5 SSR's wat kinda milage should i get

it seems to get way better milage than my old 76 k5 w/ 400sb, t350, 3.08's and 33 mtr's
 
Nice build. I would consider 3.73's, and 35" tires. Also, I'm pretty sure 3.42's and 3.23's were available in the 14FF, though they may prove difficult to find.
 
AussieK5 said:
snip......
With the .75 OD gear + 3% converter slip on my 33'3 (32" true height) I get 1864 rpm at 65, according to the 62-65-dieselpage.com right in the sweetspot for the 6.5 TD.
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Shouldn't be slipping in OD as it should have a lock-up converter. Though I doubt that 3% will offset you clear down to 3.73's.

Interesting build up.
 
If you pay for shipping I have a set of 3.73's I'll give you for a 14bff.. There just taking up space in the garage.. They came out of a 78 G30 Van, and have no chipped teeth.

By the way, awesome job on the Blazer, I like the pics..
 
lastly, when figuring the tire diameter as it applies to final rpms measure the tire's circumference to get it's true diameter. When you're measuring a tire's true height mounted on the truck the loaded radius of the lower half of the tire will make them seem shorter than they are. Circumference will give you the tires true height. Example; my 39.5's measure average about 38.25" on the truck, but their circumference is 123". Their true height is 39.17".

You will likely be much closer to your magic number than you first thought.
Click to expand...

We are on the same track here my true height was measured with the tyres off the truck and inflated to 35psi. They are brand new MT Baja MTX with a manufacturers spec of 33x12.5R15LT. If you take into account tread depth by the time these tyres wear out they will be 31's.:eek1:

The diesel page mileage poll definitely shows the TD's chewing more fuel than the NA's, although the volumetric efficiency is higher when under boost, its lower off boost for a TD over the NA (turbo inlet/outlet restriction, etc ). All things being equal I dont expect to get anything better than 21mpg at a 65mph cruise speed.

The diesel page guys did a few dyno pulls with a 6.5 NA checking the Brake Specific Fuel Consumption (BSFC) through the torque band and found the lowest fuel consumption coincided with the peak torque band. Their engine was an new economy 6.5 and it delivered its best results at 1800. They also pointed out drag, overloading and tyre pressures all need to be optmised also. I dont think I've infringed on their copyright for this article as I've not copied any text or gone into to many specifics..

The crux of the matter here is R&P availability against unsprung weight reactions. 14FF Vs 9". After grafting in coils I want it to ride like a 2006 model or as close as is reasonably practical to it. 14FF is my top choice, but its weight is a drawback.

I'm going to dust off some eng manuals from my 2nd year at uni and crunch some numbers. I was an indifferent student in Vibration classes and am wishing right now I had got a bit more excited about it when I had the chance. Any Vibe engineers on this forum??:whistle: lol ..I need to go over it again anyway, I'll post up any useful data for examination in COG. It may take some time.

I would like to add it all to my K5 information data base. Do you have your photos on a server like photobucket I could go and save. Also when you get done I would like to get as much info as you can give me about the GMH conversions. You are doing a great job keep it up mate. Raises a tinnie an tosses a slab at ya!
Click to expand...

No wukas bloke (thats means ok :D), the pics are all with Imageshack ATM but wait a little while, I may get off my backside and throw the build on to a page soon. Sort off like a DK5, Downunder K5, actually more like a DCK5-30 page. :wink1:

Shouldn't be slipping in OD as it should have a lock-up converter
Click to expand...

Full manual non lock-up is the weapon of choice.

If you pay for shipping I have a set of 3.73's I'll give you for a 14bff.. There just taking up space in the garage.. They came out of a 78 G30 Van, and have no chipped teeth.
Click to expand...

That is a very generous offer and I may take you up on it once my seizure of indecision passes and I make my mind on which damn diffs to run.:thumb:
 
Another choice may be a SF 14 bolt. Large 33 spline shafts, 9.5" ring gear and I think 3.42's were available...plus it can be had in 6 lug. Weight is also less by about 100 lbs IIRC. The only downside is that it is a 'C' clip diff, but that isn't that big a deal. For the size tires you're planning on a SF 14 would about live forever under your truck.

rene
 
Damn, you must get pissed at the crowds on those beaches eh?:D

Well if you ever did run into any of the Nettletons in East Killara, that was some of my cousins. Yep, it's a small world but I wouldn't want to paint it!:D
 
how about some fresh pics? I need to be inspired. going to wrench on the woods truck tomorrow. If it stops raining.
 
what happened to the original transfercase out of your k5 jason?....


*no parts wanted here please...Rene*
 
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Heres a pictorial update.


Finishing off the firewall repairs


All welding on the tub is done


C/K trucks always rust out here so I opened the area up to stop dirt and moisture geeting a toe hold on mine.


I shot a thin coat of stone chip/deadner on the firewall.


Three coats of the same stuff on the underbody.


After the stone chip went on I covered it with a low gloss 2K polyurethane industrial paint.


I got the sh$ts with my gravity fed gun when using it so I made a stand. Soooo much easier to deal with now.


Action shot! Actually I forgot the camera was resting on the Blazer to take this pic (timer) and I shot it with primer on my first pass :doah:


Pre, prep and more prep, 1001 small things to sort prior to the wash primer going on. The truck came in and out for sand blasting developing rust etc countless times the past week. The weather has been crap lately and Ive had to go over the whole body constantly chasing surface rust. The blaster that did the tub previously really didnt do such a crash hot job as he missed enough to cause me a lot of work.:mad:


Some primer ...finally.




Today I'll prep to go on the doors and front panels for blasting and finish of the roofline.

Jas
 
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