Welcome Guest! To enable all features please Login or Register.

Notification

Icon
Error

Login


Take the time to read our Privacy Policy.

supercoach24 Offline
#1 Posted : Monday, 15 October 2018 3:58:03 PM(UTC)
supercoach24

Rank: Member

Reputation:

Groups: Registered
Joined: 15/07/2018(UTC)
Posts: 15
Australia
Location: Adelaide

Recently took my HT GTS 253 for its first long country drive and was a little curious about my fuel consumption. I have been reading about people getting down to 10L per 100km on the highway and 25mpg.

I know you don’t buy a V8 for fuel economy (I didn't) but I wanted to see if my engine was running well or infact it is not and I need to pay some attention to the setup.

I completed a 668km (415mi) country trip, my speed varied between 100-115km/h (70-80mph), revs where between 3,000-3300rpm, temp needle sat between 180F and the first white line of H, so maybe 190F. Yes I did floor it a few times to see how she went when overtaking.

On the way up I completed 373km (231mi) and used approx. 53L (14gallons), this gives me a consumption of 14.2L/100KM (16.5mpg)

On the return trip I completed 294km (182.7mi) and used approx. 44.67L (11.8 gallons), this gives me a consumption of 15.19L/100KM (15.4mpg)

My overall fuel consumption for the whole trip was 14.62L/100KM (16.08mpg)

I have looked back at my 1969 Motor Manual magazine review on a 253 HT GTS and in their report they give a fuel consumption of 15.8mpg, with an expected range issued by GMH being between 15-17mpg. I don't know if this highway, metro miles or a combination of both.

Should I be concerned about my fuel consumption? Does it sound like I have an issue with my timing/setup/tune or is this about right for a 1969 253 V8?

What is the optimal mph/rev combo to sit on when highway cruising to get the best performance out of the engine?

I have a factory setup on my 253, running banjo 3.08 diff, 2 barrel Stromberg carby which has recently been rebuilt and tuned on the dyno, I have a different cam than the factory spec, I placed a crane came 244521, which gives the 253 a slight lope at idle, but gives a broad power band and excellent street performance & fuel efficiency. The lobe is 112 with int:206 ext: 214, int dur:268 ext dur:276, with the lift being .448 & .464. I have done about 2,500mi since he engine rebuild.

Loving my car, but just curious as to whether I have it running right or not. Thanks in advance.
wbute Online
#2 Posted : Monday, 15 October 2018 4:10:31 PM(UTC)
wbute

Rank: Member

Reputation:

Groups: Registered
Joined: 25/01/2010(UTC)
Posts: 867

Thanks: 1 times
Was thanked: 9 time(s) in 9 post(s)
My WB used to get about 18m/g. It was standard with quadrajet and electronic ignition, 3:36 diff. I didn’t drive for economy though.
HK1837 Offline
#3 Posted : Monday, 15 October 2018 5:56:38 PM(UTC)
HK1837

Rank: Veteran

Reputation:

Groups: Moderator, Registered, Veteran
Joined: 1/03/2005(UTC)
Posts: 12,900

Thanks: 1 times
Was thanked: 157 time(s) in 155 post(s)
Modern Motor August 1969, Wheels August 1969 and Sports Car road tests No.6 all got best of 22mpg from a 253 4spd HT GTS.

For HQ which are slightly lighter but bugger all Modern motor 4/72 got best of 22mpg on 253 LS (assume 3spd manual), Motor manual 11/72 got 23mpg from HQ SS (these are 3.36 rear axle) and in 1/73 got 24mpg out of another HQ SS.

Exactly what is "best" is anyone's guess - it probably is cruising economy. What you'd expect given you have changed the cam and maybe exhaust? and fuel is different today so is hard to say. I can't see one of these getting much better than low 20's though. Normally a 186 or 202 in one of these will only pull low to mid 20's.

Do you know if you have the correct vacuum advance canister and even the correct distributor and is it graphed to suit the camshaft? Is it the right carby with the right vacuum advance for the transmission?

Are you sure you have a 3.08 rear axle? Revs seem a bit high unless the tyres are tiny. A 3.08 axle manual car with an ER70H14 tyre (205/70/14) should be doing 38km/h per 1000rpm in top gear. 100-115km/h would be 2600-3000rpm.

Edited by user Monday, 15 October 2018 6:03:57 PM(UTC)  | Reason: Not specified

_______________________________________________________
If we all had the same (good) taste, who would buy all the Fords?
supercoach24 Offline
#4 Posted : Tuesday, 16 October 2018 9:59:39 AM(UTC)
supercoach24

Rank: Member

Reputation:

Groups: Registered
Joined: 15/07/2018(UTC)
Posts: 15
Australia
Location: Adelaide

I didn’t see the part where they got 22pmg, I would have to drive slower and keep the engine revs lower in order to achieve that.

Yes everything is correct for the engine as nothing has been changed since it sat in the shed for 20 years and I have just been refurbing all existing parts, in regards to the carby, it is for a manual 253 and not auto, I made sure of this when getting the carby rebuilt. Yes I am pretty sure it is the 3.08 banjo as auto got the 2.78 in the 253 and the 350 got 3.36 and I don’t have LSD. It even has factory twin exhaust system. option.

The car does smell a bit ‘fuely’ but I put that down to it being a carby engine and not fuel injected.

I was probably going too fast and giving it stick, but is there an optimal mph/rev to sit on? E.g 60mph returns better fuel economy than 70mph?

Like I said I didn’t buy it for fuel economy, but wanted to make sure I didn’t have a problem with excessive fuel consumption, as that’s not fun over fuelling the engine. So wanted to hear from other 253/308 owners who have a similar factory set up to me

I am hoping to catch up with a mate who has an identical car and set-up and compare the 2, but dont know how we will do that without going for a long trip.

Edited by user Tuesday, 16 October 2018 10:03:02 AM(UTC)  | Reason: Not specified

Sandaro Offline
#5 Posted : Tuesday, 16 October 2018 12:48:44 PM(UTC)
Sandaro

Rank: Member

Reputation:

Groups: Registered
Joined: 3/10/2015(UTC)
Posts: 108

Thanks: 1 times
Was thanked: 9 time(s) in 9 post(s)
I guess you've checked that the fuel pump isn't leaking out the small hole in the side(split in diaphragm), which could cause the smell you've noticed and add to fuel usage.

That said, there may be nothing wrong and there is I believe an eror in your conversion to MPG. We use UK gallons, not US gallons. 4.55 litres per Aussie gallon, so you're actually at about 19.5mpg.


This is about what I get from my 308 with 2.78 rear fitted
supercoach24 Offline
#6 Posted : Tuesday, 16 October 2018 4:08:18 PM(UTC)
supercoach24

Rank: Member

Reputation:

Groups: Registered
Joined: 15/07/2018(UTC)
Posts: 15
Australia
Location: Adelaide

Yes, have checked all of that and nothing obvious that can been seen e.g stain marks.

I thought the formula to work out mpg was, miles divided by gallons = mpg

e.g 231 miles divided by 14 gallons = 16.5mpg
HK1837 Offline
#7 Posted : Tuesday, 16 October 2018 4:37:56 PM(UTC)
HK1837

Rank: Veteran

Reputation:

Groups: Moderator, Registered, Veteran
Joined: 1/03/2005(UTC)
Posts: 12,900

Thanks: 1 times
Was thanked: 157 time(s) in 155 post(s)
53 litres is 11.6 gallons not 14. So 231/11.6 is about 20mpg.
_______________________________________________________
If we all had the same (good) taste, who would buy all the Fords?
Sandaro Offline
#8 Posted : Tuesday, 16 October 2018 4:41:04 PM(UTC)
Sandaro

Rank: Member

Reputation:

Groups: Registered
Joined: 3/10/2015(UTC)
Posts: 108

Thanks: 1 times
Was thanked: 9 time(s) in 9 post(s)
Yeah that's the formula, but on your way up (to use your example) you did 231 miles for 53 litres. That's actually 11.7 gallons in Australia.


So 19.7 mpg.

In US gallons you'd get the figure you worked out, but I believe the figures others have quoted from Motoring magazines would be in Aussie gallons which is what you need to compare it to.
supercoach24 Offline
#9 Posted : Tuesday, 16 October 2018 10:10:36 PM(UTC)
supercoach24

Rank: Member

Reputation:

Groups: Registered
Joined: 15/07/2018(UTC)
Posts: 15
Australia
Location: Adelaide

thanks for all your help guys, didnt realise the whole imperial us gallon thing, guess thats what happens when you didnt grow up in that era.

I have redone my figures below

Total 415mi – 668km

Total fuel used 21.97 imp gal – 99.92litres (53L + 46.92L)


on the way up it was 373km (231.7mi) and I used 53 litres at the pump on fill, which works out to be 14.2L per 100km or in the old book 19.9mpg

on the way back it was 294km (182.68mi) and approx. 46.92L used, which works out to be 15.96L per 100km in the old book 17.70mpg

Which works out to be for the whole trip 14.96 litres per 100km, old book 18.88mpg sitting on 70-80mph revs at 3300rpm, engine temp at about 190-195F

So does that seem to be ok for a 253 V8 or should I be getting better mpg than that.
HK1837 Offline
#10 Posted : Wednesday, 17 October 2018 6:16:34 AM(UTC)
HK1837

Rank: Veteran

Reputation:

Groups: Moderator, Registered, Veteran
Joined: 1/03/2005(UTC)
Posts: 12,900

Thanks: 1 times
Was thanked: 157 time(s) in 155 post(s)
I'd be happy with close to 20mpg. You might get a bit more by better tuning (like optimise dizzy advance and carby jetting) for ULP. A HEI dizzy and coil might improve it a tiny bit too if graphed right.

Funny the perceptions of economy today, people always tell me my Hilux uses too much fuel (despite them never owning one), and buy a diesel instead and pay more for it. In reality in standard form the Hilux would be similar to a 202 HT-HQ, even better at cruise (like straight roads at 100km/h), the only times you'd see worse than 14-15L/100 would be towing. But even 10-15 years ago you couldn't give away a 6cyl HK-HQ, everyone wanted the bigger, more powerful, stronger drivetrain V8 versions. And today people would rarely take a 6cyl SL/R or GTS or Sandman over a V8 one even though the 6cyl ones are collectable today. 20mpg used to be reasonable economy, from a 1.3 tonne car. Today you get 2tonne V6 Hiluxes and 2.5tonne V8 Landcruisers that do that easily and they are shunned!
_______________________________________________________
If we all had the same (good) taste, who would buy all the Fords?
commodorenut Offline
#11 Posted : Wednesday, 17 October 2018 6:22:38 AM(UTC)
commodorenut

Rank: Veteran

Reputation:

Groups: Moderator, Registered, Veteran
Joined: 2/03/2005(UTC)
Posts: 3,121

Thanks: 1 times
Was thanked: 30 time(s) in 29 post(s)
Basing it on when I drove a 253 Commodore with aircon for a few years, those numbers aren't too far what I would get on a trip up the blue mountains - highway running nut with a bit of load.
Around town it was less than 300km from a tanks - but a fill was only about 50-55L (63L tank) so that would be approx 20L/100km. The blue motors had the 4 barrel quadrajet, which let them take a lot more fuel under load than the red 253, so I think your numbers aren't too bad at all.

The other thing to consider is the fuel today is not like the fuel from 1969, or even 1999 for that matter. Octane, lead etc have all dropped, and I found - living with Holden V8s through the 90s & 2000s, that as fuel got worse with the progressive removal of lead from 1994, performance suffered (you had to back off the timing to cope) and consumption increased. The old "LRP" was woeful in them - you got far better mileage out of 95-PULP and your own upper cylinder lube (I used flashlube kits back then).

What fuel were you running on the trip?
Cheers,

Mick
_______________________________________________________________

Judge a successful man not on how he treats his peers, but on how he treats those less fortunate.
HK1837 Offline
#12 Posted : Wednesday, 17 October 2018 7:24:51 AM(UTC)
HK1837

Rank: Veteran

Reputation:

Groups: Moderator, Registered, Veteran
Joined: 1/03/2005(UTC)
Posts: 12,900

Thanks: 1 times
Was thanked: 157 time(s) in 155 post(s)
GMH used to promote the 253 as a V8 with 6cyl economy. And I guess the fact that in a Holden most 6cyl were 3.55 rear axle whereas the 3.08 (which was developed for the 253) rear axle would have been a large part of that.
_______________________________________________________
If we all had the same (good) taste, who would buy all the Fords?
supercoach24 Offline
#13 Posted : Wednesday, 17 October 2018 11:42:12 AM(UTC)
supercoach24

Rank: Member

Reputation:

Groups: Registered
Joined: 15/07/2018(UTC)
Posts: 15
Australia
Location: Adelaide

Thanks for the replies guys. If I can get 20mpg or more on a flat highway then I will be happy for the long trips. The trip I did consisted of old bumpy hilly country roads, so would have been pressing harder on the accelerator then I would on a normal freeway.

When I rebuilt the engine I changed the heads to run on unleaded. When I dyno tuned the car and carby, I did to run on premium 98. I may give Premium 95 a go and see what happens.

For country driving what is the optimal MPH/REV combo? Can I sit on 70MPH to maintain around the 110km/h speed? or Should I sit on a lower speed to maximize distance?

Edited by user Wednesday, 17 October 2018 11:43:00 AM(UTC)  | Reason: Not specified

Sandaro Offline
#14 Posted : Wednesday, 17 October 2018 12:50:07 PM(UTC)
Sandaro

Rank: Member

Reputation:

Groups: Registered
Joined: 3/10/2015(UTC)
Posts: 108

Thanks: 1 times
Was thanked: 9 time(s) in 9 post(s)
I think 80km/h used to be considered an optimal speed to sit on for fuel efficiency, but buggered if you'd find me cruising at that speed on the open highway just to save a few bucks!!
commodorenut Offline
#15 Posted : Wednesday, 17 October 2018 9:46:15 PM(UTC)
commodorenut

Rank: Veteran

Reputation:

Groups: Moderator, Registered, Veteran
Joined: 2/03/2005(UTC)
Posts: 3,121

Thanks: 1 times
Was thanked: 30 time(s) in 29 post(s)
Originally Posted by: Sandaro Go to Quoted Post
I think 80km/h used to be considered an optimal speed to sit on for fuel efficiency, but buggered if you'd find me cruising at that speed on the open highway just to save a few bucks!!
I think you're spot on.
I did a lot of km in my VS 5.0L Calais over the years. Normal cruising average was about 11-11.5L/100km on the freeway at 110km/h with a passenger & luggage.
When we did a 6-week 5700km tour that took in 3 states & Kangaroo Island, we travelled with a bunch of vintage cars, and sitting on the Goulburn Valley Hwy on 80k/h I managed 8.5L/100km for that leg, with additional passengers and luggage! But like you say, you don't really want to be cruising at 80 to penny-pinch.

Originally Posted by: supercoach24 Go to Quoted Post
When I dyno tuned the car and carby, I did to run on premium 98. I may give Premium 95 a go and see what happens.

This could be false economy. If it's tuned for 98, it may not be happy on 95, and might need the timing retarded a little - which will lose all your gain on '98.

But if it doesn't pin on 95 then you may as well give it a good run for comparison. As an example - and I know it's a completely different engine, but the fuel choices are the same - my wife's 6.0L VE gets about 10-15% better range on 95 than 91, so it's actually cheaper in $ per km to run 95 in it.
However, 98 doesn't give any better range than 95 does. I think it's probably already on the maximum timing advance on the ignition map in the PCM on 95, so there's no gain to be had from 98 without having it tuned to allow more advance.

Originally Posted by: supercoach24 Go to Quoted Post
For country driving what is the optimal MPH/REV combo? Can I sit on 70MPH to maintain around the 110km/h speed? or Should I sit on a lower speed to maximize distance?
Don't fall for the trap of lower RPM for a given speed is always better, as it can get to the point where there's too much load, and consumption increases.

To find your optimal speed will take some testing. It's far easier in modern cars with trip computers, but can still be done with notes & records and a calculator.

I had an interesting swap meet run in the aforementioned VS in the early 2000s. My father-in-law drove 1 leg of the 800km trip, and left it in drive (4L60E). It averaged 20L/100km, with 4 in the car and 1600kg trailer weight. When I took over, my leg was 16L/100km average. Only thing I did different, was at the slightest hill, I dropped it back to 3, and once over, back into D. Letting it labour in D used far more fuel.

Likewise I did a similar test in my FG with the 6-speed ZF auto. Unless the road is dead flat or downhill, I've found it uses more fuel pulling 6th gear along at low RPM, labouring, than being comfortably cruising in 5th. Even on a slight incline, watching the instantaneous fuel consumption, it drops 1-2L when changing it back to 5th.

I found in the old 1:1 top gear cars (most of my early V8 Commodores until I discovered 5-speed conversions) that 3000rpm with a 2.78:1 diff was around 110km/h and gave pretty good economy. It got worse when I swapped the 2.78 for a 3.08 as the revs increased at 110km/h, and so did the consumption. Maybe try a trip doing 70mph vs the same trip doing 60mph and see if there's a noticeable difference.

Cheers,

Mick
_______________________________________________________________

Judge a successful man not on how he treats his peers, but on how he treats those less fortunate.
castellan Offline
#16 Posted : Wednesday, 16 January 2019 4:32:57 PM(UTC)
castellan

Rank: Veteran

Reputation:

Groups: Registered
Joined: 26/02/2009(UTC)
Posts: 1,288

Thanks: 12 times
Was thanked: 11 time(s) in 10 post(s)
Originally Posted by: commodorenut Go to Quoted Post
Basing it on when I drove a 253 Commodore with aircon for a few years, those numbers aren't too far what I would get on a trip up the blue mountains - highway running nut with a bit of load.
Around town it was less than 300km from a tanks - but a fill was only about 50-55L (63L tank) so that would be approx 20L/100km. The blue motors had the 4 barrel quadrajet, which let them take a lot more fuel under load than the red 253, so I think your numbers aren't too bad at all.

The other thing to consider is the fuel today is not like the fuel from 1969, or even 1999 for that matter. Octane, lead etc have all dropped, and I found - living with Holden V8s through the 90s & 2000s, that as fuel got worse with the progressive removal of lead from 1994, performance suffered (you had to back off the timing to cope) and consumption increased. The old "LRP" was woeful in them - you got far better mileage out of 95-PULP and your own upper cylinder lube (I used flashlube kits back then).

What fuel were you running on the trip?


I thought that in Australia the Super petrol was 97 octane to the end.
There was a low lead I remember in the years near the end of Super in QLD I used it once but I did not think that the octane was lower than 97.

We just had 91 and 92 octane unleaded from 1986 I do not remember if 95 came out in 1986 as my first unleaded car was in 1992, I know they had 95 then, but how many unleaded cars needed 95 before then, as we still had 97 leaded then I am sure.
Around 1994 I think was the end of lead fuel and you had to use 95 octane with flashlub, I never had to use that stuff. but my wife's dad had a dizzy graph machine that he would reset the timing advance back a bit down low rpm mainly and see how it went from there so they could run on 95 octane without pinging. one I seen him do was a 1968 Galaxie with a 390 V8 9.5:1 I think they had, so she needed to be done. one could just retard the whole thing by timing light but I think it better to re graph.

If a car was to run on 97 Super and you go put 95 in it, all could be fine unless your compression ratio is high needing 97 but most should of been ok on 95 but people wanter to use 91-2 unleaded in there cars that used Super and that's when they ran into problems, Standard was 89 octane and if you went over say 8.3:1 I think it was with iron heads you were looking for Super unless you retard the timing a bit.
So running 91-2 octane would be 8.5:1 fine to about 8.7:1 at the max I would think.

When 98 came out there was some playing about with the fuels Shell, had one that could cause a bit of a problem with jetting bikes mainly, you had to lean it out a bit to get the best out of such and all was fine, but some bikes were better to go to BP etc for 98. but most bikes were fine on 95 octane, my dirt has 13:1 and 95 is recommended and fine, and I mainly run it on 98 and have ran 98 E10 and then it smelt different and ran a little leaner, power wise I don't think it lost any as it's a little on the rich side, so I think if anything picked up a bit more power maybe.

The First of the E10 when it first came out was crap but it got real good when Shell brought out a new improved economy type they called it and nothing but good results with E10 nowadays, I would not use anything other as power improvements can be great but there is a E10 91 octane out there at some BP that is not as good as the E10 94, I would say that any car from 2010 running on E10 94 will perform real well over the 91 unleaded crap.
But for Boats I would use unleaded.

My wife's Toyota Aurion goes like the clappers on E10 94 it's truly amazing the difference as the 91 unleaded is crap, the manufactures all are suppose to be running on 95 octane but they sell then as 91 ok, but what that does is the computer has to retard the timing back to run that crap and you loose power and economy.

NSW has been running only E10 now I think.
HK1837 Offline
#17 Posted : Thursday, 17 January 2019 6:48:29 AM(UTC)
HK1837

Rank: Veteran

Reputation:

Groups: Moderator, Registered, Veteran
Joined: 1/03/2005(UTC)
Posts: 12,900

Thanks: 1 times
Was thanked: 157 time(s) in 155 post(s)
I started using E10 back before it was even called E10 in the late 80’s to early 90’s. We had it in the Hunter Valley made by a company called Bogas. I remember I had a WB tonner with a red 6 with a Yella Terra head and 30/70 cam. It wouldn’t run on unleaded but was fine on the Bogas fuel. The fuel used to keep the carbon out of the combustion chamber, I remember pulling the head off at one stage and being shocked how clean it was.
_______________________________________________________
If we all had the same (good) taste, who would buy all the Fords?
castellan Offline
#18 Posted : Thursday, 17 January 2019 11:27:01 AM(UTC)
castellan

Rank: Veteran

Reputation:

Groups: Registered
Joined: 26/02/2009(UTC)
Posts: 1,288

Thanks: 12 times
Was thanked: 11 time(s) in 10 post(s)
Originally Posted by: HK1837 Go to Quoted Post
I started using E10 back before it was even called E10 in the late 80’s to early 90’s. We had it in the Hunter Valley made by a company called Bogas. I remember I had a WB tonner with a red 6 with a Yella Terra head and 30/70 cam. It wouldn’t run on unleaded but was fine on the Bogas fuel. The fuel used to keep the carbon out of the combustion chamber, I remember pulling the head off at one stage and being shocked how clean it was.


A mate was using the dregs off his distillery and poring it into his bike and all was fine, Honda CR500 it was, so mixing oil as well in a 2 stroke.
He drank 500ml of rum a day then and still does plus beer that he makes as well.
So he made a fair bit of dregs in what he was distilling.
He wanted me to buy a setup, and said it would pay off in 3 months, more like 3 years or more for me I would think, but he believes everyone drinks like him, I said no mick I do not drink on week days, he believes I am joking.

I have pulled off heads that had been done up with only 3weeks driving and the carbon looked like it had don 100,000miles on leaded fuel.

I remember a due that was complaining about getting a full recon engine and It blew up after 3 months or so and he took of the head and went off his rocker claiming that it was an old engine that had just been painted, but no it was a fully reconed.
Users browsing this topic
Guest
Forum Jump  
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.

Powered by YAF | YAF © 2003-2019, Yet Another Forum.NET
This page was generated in 0.450 seconds.