0 registered members (),
265
guests, and 1
spider. |
Key:
Admin,
Global Mod,
Mod
|
|
Forums69
Topics113,633
Posts1,341,396
Members1,814
|
Most Online731 Jan 14th, 2020
|
|
|
Re: #BHP vs MPG
[Re: djmobi]
#809135
07/04/2009 13:15
07/04/2009 13:15
|
Joined: Dec 2005
Posts: 882 Banbury
djmobi
OP
Enjoying the ride
|
OP
Enjoying the ride
Joined: Dec 2005
Posts: 882
Banbury
|
I hve had a good read through the tuning guides for the 20VT and was wondering if there are certain mods you can do that effect MPG less than others or is it a case of the higher the BHP the lower the MPG???
Back Owning a Coupe
|
|
|
Re: #BHP vs MPG
[Re: djmobi]
#809136
07/04/2009 13:15
07/04/2009 13:15
|
Dan_S
Unregistered
|
Dan_S
Unregistered
|
?! i think something is missing... .
|
|
|
Re: #BHP vs MPG
[Re: ]
#809138
07/04/2009 13:16
07/04/2009 13:16
|
TurboJ
Unregistered
|
TurboJ
Unregistered
|
here comes Nigel.....
|
|
|
Re: #BHP vs MPG
[Re: ]
#809139
07/04/2009 13:16
07/04/2009 13:16
|
Dan_S
Unregistered
|
Dan_S
Unregistered
|
the basic ones like air filter and exhaust will not affect the mpg much
|
|
|
Re: #BHP vs MPG
[Re: djmobi]
#809140
07/04/2009 13:17
07/04/2009 13:17
|
JIM16vt
Unregistered
|
JIM16vt
Unregistered
|
Depends what car mate, in my diesel runaround it has to be MPG.
But in my modded quick coupe mpg is not in my head, i'm just think BHP.
Coupe isn't really a MPG car, MPG is more of a diesel thing or petrol 1.1. Deffo not acoupe anyway, all tho a standard coupe is not that bad off boost and drove sensible.
Hello mate, werlcome to the forum.
|
|
|
Re: #BHP vs MPG
[Re: OO7]
#809150
07/04/2009 13:38
07/04/2009 13:38
|
eldinho
Unregistered
|
eldinho
Unregistered
|
you should only really notice big mpg differences when you are accelerating hard, with normal driving it should be quite similar (better if you have headwork). But like J says I'll let Nigel have his moment
|
|
|
Re: #BHP vs MPG
[Re: ]
#809159
07/04/2009 14:03
07/04/2009 14:03
|
Joined: Dec 2005
Posts: 3,158 Near Reading
JohnS
I need some sleep
|
I need some sleep
Joined: Dec 2005
Posts: 3,158
Near Reading
|
If you drive it economically as long as the modifications are well thought out there will be little or no effect on MPG. Tuning the ECU will actually improve like for like steady running as more ignition advance improves the combustion of fuel.
Anything that reduces the impedance of airflow into or out of the engine will generally improve economy.
Former low boost hero - 616BHP@1.5 bar. 2.4 20VT RIP
|
|
|
Re: #BHP vs MPG
[Re: djmobi]
#809166
07/04/2009 14:10
07/04/2009 14:10
|
Squid
Unregistered
|
Squid
Unregistered
|
If there was ever a topic that was made for Nigel, this is it. He's probably composing a 2000 word essay as I write this....
|
|
|
Re: #BHP vs MPG
[Re: ]
#809181
07/04/2009 14:31
07/04/2009 14:31
|
DanielTheManual
Unregistered
|
DanielTheManual
Unregistered
|
Yes, almost certainly quoting his best tank range efforts on that 1 historic (but dull) drive
|
|
|
Re: #BHP vs MPG
[Re: ]
#809199
07/04/2009 14:54
07/04/2009 14:54
|
peanuthead
Unregistered
|
peanuthead
Unregistered
|
i am trying to work out how long it would take to recop the cost of a 400bhp coversion if i got another 10mpg as nigel gets between 35 and 42mpg and i get between 25 and 30mpg. i do 15000 miles a year so not to long lol :-)
my caluclations as a 10mpg difference i would make back about £790 a year. how much would it cost to hit 400bhp?
|
|
|
Re: #BHP vs MPG
[Re: ]
#809204
07/04/2009 14:59
07/04/2009 14:59
|
Joined: Dec 2005
Posts: 882 Banbury
djmobi
OP
Enjoying the ride
|
OP
Enjoying the ride
Joined: Dec 2005
Posts: 882
Banbury
|
Sounds like good news then.......mod as much as you want and you could even potentially improve MPG.
Back Owning a Coupe
|
|
|
Re: #BHP vs MPG
[Re: djmobi]
#809210
07/04/2009 15:05
07/04/2009 15:05
|
peanuthead
Unregistered
|
peanuthead
Unregistered
|
well the main thing is increasing the mpg on these or any car is having a decent port and polished head, decent balanced engine using low resistance parts and most of all a good map.
|
|
|
Re: #BHP vs MPG
[Re: ]
#809212
07/04/2009 15:07
07/04/2009 15:07
|
Joined: Dec 2005
Posts: 882 Banbury
djmobi
OP
Enjoying the ride
|
OP
Enjoying the ride
Joined: Dec 2005
Posts: 882
Banbury
|
If you do the air filter and exhaust do you get much of a BHP increase?
Back Owning a Coupe
|
|
|
Re: #BHP vs MPG
[Re: ]
#809222
07/04/2009 15:13
07/04/2009 15:13
|
Squid
Unregistered
|
Squid
Unregistered
|
If you are looking to modify a Coupe engine on the basis of saving money on fuel, well... That's just Once you go above 350bhp you will require a complete engine rebuild. That will cost about £1200 in forged parts alone and that's before you start on the ancilaries like bearings, gaskets, etc, etc. Then you have labour on top of that, bigger turbo, FMIC, exhaust etc. It really is an expensive and time consuming business not to be undertaken lightly. if you are on a budjet, don't do it, as there is always something else to do. The best bet is to take a look at TurboJ's 20VT tuning guide, and make a decision after reading that. Also, don't forget that if you modify a car to give it improved performance, yes, it will improve MPG if you drive it cautiously, but who is going to drive a 300+bhp coupe like an OAP? You are bound to take it out for a good thrashing every now and again, that is what the car is for! If you want to save money, buy an economical diesel run around.
|
|
|
Re: #BHP vs MPG
[Re: OO7]
#809241
07/04/2009 15:39
07/04/2009 15:39
|
JIM16vt
Unregistered
|
JIM16vt
Unregistered
|
007 it surprises me because when I modded my bravo hgt the fuel comsumption went rediculously high. I couldn't belive it. havn't noticed it yet with coupe but my project has a long way to go so i expect it will soon.
|
|
|
Re: #BHP vs MPG
[Re: OO7]
#809282
07/04/2009 16:09
07/04/2009 16:09
|
Joined: Dec 2005
Posts: 3,158 Near Reading
JohnS
I need some sleep
|
I need some sleep
Joined: Dec 2005
Posts: 3,158
Near Reading
|
Buy a 60MPG+ car and spend the savings on tuning your coupe Based on business miles that I get paid at the gov rate I realised that by running a 60MPG car instead of a 30MPG car for my 35000 business miles/year I could save a few grand a year in total car expenditure. So now I use a Audi A2 TDI for work. £35 a year to road tax, £200 to insure and does 62MPG without much effort. Takes 25,000 miles to wear out the tyres and is made from lightweight aluminium so will never rust. Helps pay the insurance and road tax on my other 4 cars that I get my fun from!!
|
|
|
Re: #BHP vs MPG
[Re: JohnS]
#809285
07/04/2009 16:15
07/04/2009 16:15
|
peanuthead
Unregistered
|
peanuthead
Unregistered
|
yeah but i only use my car to drive for pleasure not work and i do 50/50 motorway and late night b roads so i normally cruise on the motorway which would give me great mpg and then have 400bhp tp have fun with on the way home :-)
|
|
|
Re: #BHP vs MPG
[Re: ]
#809286
07/04/2009 16:16
07/04/2009 16:16
|
peanuthead
Unregistered
|
peanuthead
Unregistered
|
i never said it was the best cost effective method but atleast it would be fun as i don't just want a car i drag out the garage on a sunny day and driving a boring car most the time as whats the point,
|
|
|
Re: #BHP vs MPG
[Re: ]
#809377
07/04/2009 18:08
07/04/2009 18:08
|
Trickymex
Unregistered
|
Trickymex
Unregistered
|
rule number one of engine tuning is the more fuel and air an engine can consume the more power it will produce
Obviously there are other factors that effect fuel consumption, these are effiencys like thermal effiency, mechanical effiency, we will ignor these as they are not going to be very different from one 20vt to another 20vt although things like wheel diamiter can effect these
Ontop of this and as john has said how it was mapped can effect it also
But you will find with turbo charged engine that have larger turbos fitted they will be laggy in comparison to the standard setup, this means they will be producing boost later in the rev range than the standard setup, in some cases this can be higher than your cruising speed on the motorway
So if you sit at 70mph and 3000rpm you may, depending on your setup be producing very little boost and as such you will not require so much fuel.
So if your clever with your setup you can make a very powerfull car but also in a certain situation very economical
Ricky
|
|
|
Re: #BHP vs MPG
[Re: Flea]
#809424
07/04/2009 19:11
07/04/2009 19:11
|
Trickymex
Unregistered
|
Trickymex
Unregistered
|
Thank you Flea, I did not make that very clear and that in itself makes clear that driving style makes a massive difference to fuel consumption
|
|
|
Re: #BHP vs MPG
[Re: ]
#809489
07/04/2009 20:22
07/04/2009 20:22
|
Joined: Dec 2005
Posts: 17,367 Staffordshire
Nigel
Forum veteran
|
Forum veteran
Joined: Dec 2005
Posts: 17,367
Staffordshire
|
LOL - am I getting THAT predictable? The best mods you can do for performance AND better mpg is headwork The cylinder head is the most restrictive part of the engine and any gains here will always result in better flow (which equals better power and/or better mpg I'm running around 400bhp and I have got a best of 43mpg. However, when I got the 43mpg, I doubt that I produced more than 40bhp all day. I can get mid to high 30's mpg cruising at motorway speeds. Even my daily commute gets me 30mpg if I turn the boost down. I conservatively reckon that when I'm producing peak power, I'm probably doing 6 or 7 mpg at best. I once got 7.9mpg while on track (and that was with 300bhp) A lot depends on the mapping too - Flea currently has my car for some more tweaks and I'm hoping he'll keep it fairly lean off boost so I can get decent mpg on long motorway journeys. So - spend £1000 on a mildly-worked cylinder head and get an extra 30 - 50 miles per tank - it won't be long before its paid for itself
|
|
|
Re: #BHP vs MPG
[Re: Nigel]
#809555
07/04/2009 21:35
07/04/2009 21:35
|
TurboJ
Unregistered
|
TurboJ
Unregistered
|
it won't be long before its paid for itself Yea and the rest
|
|
|
Re: #BHP vs MPG
[Re: ]
#809783
08/04/2009 09:39
08/04/2009 09:39
|
peanuthead
Unregistered
|
peanuthead
Unregistered
|
£1000 for a modified head is a lot of money! how come its so expensive on these cars as any other head i have had port polished and larger valves and so on has worked out about £450-550 but then thats with me fitting it.
i recon that if you picked up very good hardly used secondand parts and built it up then 400bhp could be done for about £3000 if i done all the work except mapping. so it would take about 2.5 years to pay off in better fuel consumption but more relisticly you would maybe lose 2k in extra mapping and parts failing but then that would be a fun 2k.
|
|
|
Re: #BHP vs MPG
[Re: ]
#809790
08/04/2009 09:52
08/04/2009 09:52
|
Joined: Dec 2005
Posts: 12,295 Sandhurst
Begbie
Ex El Presidente
|
Ex El Presidente
I AM a Coop
Joined: Dec 2005
Posts: 12,295
Sandhurst
|
how come its so expensive on these cars as any other head i have had port polished and larger valves and so on has worked out about £450-550 but then thats with me fitting it. Do you get any flow results with the head? A properly modified head will easily cost in excess of £2000+, there is a lot of work to be done, especially when you are watching how the airflow goes through the head, matching the inlet / exhaust ratio to keep it around 75% or 85% (can't remember), lapping, grinding, modifying the seat, fitting race spec valve guides, cleaning everything
Your car is Usain Bolt with wellies
|
|
|
Re: #BHP vs MPG
[Re: Begbie]
#809802
08/04/2009 10:01
08/04/2009 10:01
|
peanuthead
Unregistered
|
peanuthead
Unregistered
|
maybe i am used to old school engines as i used to know a guy who used to work for vulcan and he done all my head work for me. and most the old school guys i used charged around £450 or a 4 pot 8 vlave £550 for a 4 pot 16v and £600 or a straight six. i am not saying it is easy work but the haed for my old 2.1 pinto that made 212bhp cost me £300 to get sorted lol. might see what these guys can do for coop heads as they are very good at what they do.
|
|
|
Re: #BHP vs MPG
[Re: ]
#809821
08/04/2009 10:13
08/04/2009 10:13
|
eldinho
Unregistered
|
eldinho
Unregistered
|
i recon that if you picked up very good hardly used secondand parts and built it up then 400bhp could be done for about £3000 if i done all the work except mapping. all I can say to that is dream on!
|
|
|
|