Manual Turbo Intercooler estate MPG...what to realistically

[AllHailKingVolvo]

Fingers crossed...will report back when I collect the beast!

[Laird Scooby]

Originally Posted by AllHailKingVolvo

Fingers crossed...will report back when I collect the beast!

Looking forward to that Phil!

[TonyS9]

I've been running an MPGuino on my 95 B230FT manual estate for a few years now and believe its pretty accurate.

I can state fairly categorically that you will not get 40mpg at 70mph, instant or average. You can get it at 30mph if you keep the acceleration at zero (very hard), but the engine isn't happy when you need a little power up hills in 5th.

You can get 40mpg if you use pulse and glide say 50-75mph).
For a decent run longer than 15mins, that gives the drive train a chance to heat up, you can get 30mpg average driving normally and gently, but accelerating briskly, keeping below 60mpg, slower is better.

You need to minimise large throttle openings (very inefficient over fueled) and try to keep it in closed loop O2 feedback mode, VERY light throttle or idle. Ideally you should be slowing slightly. Slight acceleration will decrease mpg by 10 or so.

Coast downhill in neutral, any hill atall. Idle will give you 3xspeed in terms of mpg. Typically 100+mpg, compared with maybe 50 ot 60mpg with the throttle open and engine drag. Don't use the slow down fuel cut (throttle closed from about 2000rpm) unless you actually need to slow down.

Any 940 automatic I've had has done <22mpg.

[360beast]

Originally Posted by TonyS9

I've been running an MPGuino on my 95 B230FT manual estate for a few years now and believe its pretty accurate.

I can state fairly categorically that you will not get 40mpg at 70mph, instant or average. You can get it at 30mph if you keep the acceleration at zero (very hard), but the engine isn't happy when you need a little power up hills in 5th.

You can get 40mpg if you use pulse and glide say 50-75mph).
For a decent run longer than 15mins, that gives the drive train a chance to heat up, you can get 30mpg average driving normally and gently, but accelerating briskly, keeping below 60mpg, slower is better.

You need to minimise large throttle openings (very inefficient over fueled) and try to keep it in closed loop O2 feedback mode, VERY light throttle or idle. Ideally you should be slowing slightly. Slight acceleration will decrease mpg by 10 or so.

Coast downhill in neutral, any hill atall. Idle will give you 3xspeed in terms of mpg. Typically 100+mpg, compared with maybe 50 ot 60mpg with the throttle open and engine drag. Don't use the slow down fuel cut (throttle closed from about 2000rpm) unless you actually need to slow down.

Any 940 automatic I've had has done <22mpg.

I drove 250 miles in one go without stopping doing 70-85mph with my boot fully loaded, two adults in the car and going up massive hills, it worked out to 34mpg!

Mine is a 940 automatic and it has never been as low as 22mpg so I would think you have had problems with yours if it was that low. This week I have had to deal with lots of traffic and road works and I have averaged 24mpg using an online calculator.

Also in a manual you say down hill at idle is better than leaving it in gear with no acceleration is better? Surely not as in gear the wheels are driving the engine, on my fabia if I went downhill in neutral the mpg readout would be about 80+mpg where as in gear it would go to infinite.

[aardvarkash10]

Originally Posted by 360beast

I drove 250 miles in one go without stopping doing 70-85mph with my boot fully loaded, two adults in the car and going up massive hills, it worked out to 34mpg!

Hmmmn. That's about 12km/l. Which is a little less than what Snork (a V50 2.4i auto) gets on a longish trip at 100 kph tops on the cruise control.

Without calling your claim fanciful, I am coloured "surprised" .

Factory claim is around 28mpg . Experience tells me that this is "hopeful, under best conditions". In real-world urban combined cycle I'd expect low 20's.

[AllHailKingVolvo]

Really interesting stuff all, thankyou!

My 940 LPT was surprisingly decent on fuel, working it out pump-to-pump it was averaging 32mpg combined, 38 on a long run and 24ish around town. I do a lot of motorway driving and tend to be light footed.

Me and the Mrs' two auto B200F 745s were terrible on fuel, averaging 19mpg. I think the combination of lack of power and the parasitic power loss of the auto boxes just killed the economy. I loved them but they really felt laboured on anything but flat terrain.

My manual 744 with B200F isn't too bad on fuel-I average 28-29 after de-catting it and properly going through the engine and making it run right. It's currently prone to overfuelling as the CTS is on the way out (got one one the way) so economy is a little under par over the last week, but normal service will be resumed in due course.

My 744 is my daily since my C220CDI expired, but I plan to share duties between the TI and the 744 in the future, all being well. If the two can be somewhere near mid/high 20s on average, that's fine.

[Laird Scooby]

Originally Posted by aardvarkash10

Hmmmn. That's about 12km/l. Which is a little less than what Snork (a V50 2.4i auto) gets on a longish trip at 100 kph tops on the cruise control.

Without calling your claim fanciful, I am coloured "surprised" .

Factory claim is around 28mpg . Experience tells me that this is "hopeful, under best conditions". In real-world urban combined cycle I'd expect low 20's.

Sadly that site quotes the fuel tank of the 945 as being 75L Ash - i believe the official Volvo figure is 60L on 7x5/9x5 models.

Checking a few other cars i know the fuel tank capacity of, those are wrong as well.

It doesn't bode well for them quoting correct mpg figures!

Digging a bit deeper, they quote the fuel tank capacity of the saloon as also being 75L, if memory serves correctly, with the additional fuel tank behind the back seat, total capacity is 82L (but i would need to check this) but as far as i remember, the extra tank was only available on 7/964 models as an option.

Interestingly they also suggest the PRV V6 was fitted to the 940 :

https://www.auto-data.net/en/volvo-9...-v6-170hp-9292

There were a few 960s with the PRV V6 at the start of the run but they were rare when new and none had a DOHC arrangement!

What i'm suggesting here is that site hasn't got everything right, i know on my last 745 (B230E K-Jetronic auto), i did a long run towing an empty car trailer and returned about 35mpg, the return journey with 1490kg of car on the trailer got about half that, overall i averaged 25mpg for the round trip. Turned out the trailer alone was 660kg so technically i was over the weight limit but still very good economy.

My line of thought here is if i can get 35mpg out of a B230E with an unladen trailer then i don't see why Luke can't get 34mpg out of a laden car with a more sophisticated electronic injection system on a similar journey.

[aardvarkash10]

my experience of fuel consumption estimates by owners is that they invariably estimate low. I was involved in some strictly controlled economy testing in NZ at one point - it was an eye-opener to see how rapidly consumption rose with road speed. Typically, fuel consumption increases by 35-40% with an increase from 90kph to 120kph. That makes sense given the physics.

Steady state and low cruise speed - 90 to 95kph - the 940 would do ok. At 130kph, not so much.

Hey ho. Fuel remains the cheapest part of car ownership. It doesn't, in the big scheme, make a lot of difference if you burn 9 or 13 litres to cover 100km.

[360beast]

Originally Posted by aardvarkash10

Hmmmn. That's about 12km/l. Which is a little less than what Snork (a V50 2.4i auto) gets on a longish trip at 100 kph tops on the cruise control.

Without calling your claim fanciful, I am coloured "surprised" .

Factory claim is around 28mpg . Experience tells me that this is "hopeful, under best conditions". In real-world urban combined cycle I'd expect low 20's.

Call it what you like but the fact remains it can be done. I'm not going to gain anything from lying so why would I?

Being a saloon probably helps a bit with aerodynamics and being a low pressure turbo also helps. 70mph is bang on 2500rpm in mine and I can be very gentle to get there and I read the road ahead a lot so I don't have to slow down or speed up suddenly either.

Everyone says "you won't see 30mpg put of a 360" well in my 1984 360 GLE carb I managed 39mpg on a journey to Bicester and back, again calculated fill up to fill up.

[Laird Scooby]

Originally Posted by 360beast

Everyone says "you won't see 30mpg put of a 360" well in my 1984 360 GLE carb I managed 39mpg on a journey to Bicester and back, again calculated fill up to fill up.

I had two 360GLTs, one was 30+ years ago as a company car which spent its time loaded to the gunwales and being driven hard.
Second was mine, 20 years ago, very rarely loaded but still driven hard.

To get the mpg to drop below 30mpg on either i had to be seriously brutal. Usually it was around 31-32mpg from both, despite the 100k mile difference in age.