|  | Home > Technical (L322) > 4.4 ajv8 vs 4.2 | 
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| Danwilderspin Member Since: 15 Jun 2016 Location: Cambridgeshire Posts: 2301      | Bump Current stable:
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|  8th May 2019 9:48pm | 
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| Dolphinboy Member Since: 07 Dec 2009 Location: Bristol Posts: 3284      | The jag 4.4 is a good engine but not so good for lpg. I would go for the 4.2 SC for its thrills and good reputation for resilience.
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|  8th May 2019 10:47pm | 
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| Danwilderspin Member Since: 15 Jun 2016 Location: Cambridgeshire Posts: 2301      | Is your 4.4 on LPG though? I think I am going to go with the 4.2 on lpg. After a lot of research the main problems seem to be running off a single hole tank (so it runs lean) and things get too hot and people don’t use valve saver. Both of which I will do. I also will get it converted myself so hoping I should get many miles before lpg issues! Current stable:
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|  9th May 2019 9:35pm | 
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| TugRR Member Since: 11 Jan 2011 Location: Bakewell Posts: 1201    | I owned a 4.4 AJV8 for 18 mths - superb, 300bhp with decent economy. Only problem I had was a MAF unit costing £150.
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|  10th May 2019 6:19pm | 
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| Dano0404 Member Since: 28 Dec 2017 Location: Uk Posts: 44    | I've got a 4.2 sc on lpg with valve saver and get 13.5 mpg with just normal running around. I'm not really heavy on the throttle either. 2007 sc | ||
|  10th May 2019 6:46pm | 
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| paulbrown22 Member Since: 23 Dec 2017 Location: London/Poole Posts: 358      | I'm not sure there's vast mpg differences between the various petrol engines, especially the 4.2 and 5.0 S/C - the real impact is how and where you drive them?
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|  10th May 2019 9:14pm | 
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| stu1 Member Since: 06 Dec 2013 Location: UK Posts: 276      | Yes, avoid stop start traffic like the plague in an SC. For comparison, we previously had the 4.4 BMW engine and the MPG compared to our 4.2 is the same. Not a direct comparison to the AJ4.4 but I would be surprised if the difference was noticeable. | ||
|  10th May 2019 9:28pm | 
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| Danwilderspin Member Since: 15 Jun 2016 Location: Cambridgeshire Posts: 2301      | Great advise guys - I’ve had the 4.4 bmw for 3 yrs on lpg and happy(ish) with those fuel bills so if I go 4.2 on lpg it will be there or there about a and 4.4aj marginally better? Current stable:
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|  11th May 2019 1:25pm | 
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| stu1 Member Since: 06 Dec 2013 Location: UK Posts: 276      | Sounds about right, but don't forget the 4.2 is super charged, so I'm guessing that at least initially your MPG won't be anywhere near the normally aspirated  | ||
|  11th May 2019 6:40pm | 
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| Danwilderspin Member Since: 15 Jun 2016 Location: Cambridgeshire Posts: 2301      | Yea tbh my wife drives the more local trips in it during the week so the s/c will barely be used and I use just on long runs so hoping it will bed In Current stable:
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|  11th May 2019 8:16pm | 
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| Danwilderspin Member Since: 15 Jun 2016 Location: Cambridgeshire Posts: 2301      | Just went to look at eBay item no eBay Item No. 123776619028 
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|  25th May 2019 11:23pm | 
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| stu1 Member Since: 06 Dec 2013 Location: UK Posts: 276      | Bad luck. 
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|  27th May 2019 9:40am | 
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