4.6 and 5.0 power differences - discuss
Discussion
Okay so i'm bored at work lol
put i've been pondering this one, TVR's figures are thus if i'm not mistaken
4.6 = 285bhp
5.0 = 340bhp (earlier one)
okay i know TVR's figures ore optimistic and thats not really the point of this thread.
Bascially i'm wondering what mods were made to the 5.0 that weren't made to the 4.6? as its quite a large power increase(even for TVR) when on the face of things your only talking about ~450cc
One of the things i'd noticed is the griff 500 (at least) specifies that you run 98ron fuel wereas my 450 has no such(documented) requirement.
is one the main factors in the seemingly huge power increase of 400cc that the 5.0 has been mapped to take advantage of higher octane fuel by having the ingnition timing advanced?
put i've been pondering this one, TVR's figures are thus if i'm not mistaken
4.6 = 285bhp
5.0 = 340bhp (earlier one)
okay i know TVR's figures ore optimistic and thats not really the point of this thread.
Bascially i'm wondering what mods were made to the 5.0 that weren't made to the 4.6? as its quite a large power increase(even for TVR) when on the face of things your only talking about ~450cc
One of the things i'd noticed is the griff 500 (at least) specifies that you run 98ron fuel wereas my 450 has no such(documented) requirement.
is one the main factors in the seemingly huge power increase of 400cc that the 5.0 has been mapped to take advantage of higher octane fuel by having the ingnition timing advanced?
I'm sure someone will correct me if I'm wrong here (?Steve..). 
Don't want to sound picky but, from what i remember of what I've read a). the 450 I'snt the 4.6 its actually 4441cc (with an 80mm (TVR) rather than 82mm (landrover)stroke crank. b). In the literature on my 450 AND on the sticker by the fuel filler it DOES specify 98 octane fuel...
Otherwise I think you are right about things in that the power gains come from a combination of compression ratio, ignition / fuel mapping and presumably valve timing / lift.
Don't want to sound picky but, from what i remember of what I've read a). the 450 I'snt the 4.6 its actually 4441cc (with an 80mm (TVR) rather than 82mm (landrover)stroke crank. b). In the literature on my 450 AND on the sticker by the fuel filler it DOES specify 98 octane fuel... Otherwise I think you are right about things in that the power gains come from a combination of compression ratio, ignition / fuel mapping and presumably valve timing / lift.
Hi Alan, i always thought the 450 was a 4.6 motor, maybe not then? we'll wait for steves confirmation of that 
interesting about your sticker maybe mines gone missing? although all the chims i've seen the fuel caps on haven't had this sticker? prehaps it only applies to the later cars...
interesting about your sticker maybe mines gone missing? although all the chims i've seen the fuel caps on haven't had this sticker? prehaps it only applies to the later cars...
There is definitly a sticker on my '98 450 stating that it should be run on the higher octane fuel. Seems to run OK on standard though when I can't get the higher octane stuff.
Ignoring the official figure for a minute, what can you realistically expect to get out of the 5 and 4.5 in standard spec? Just as a ball park. Is the difference as big as in the official figures?
Ignoring the official figure for a minute, what can you realistically expect to get out of the 5 and 4.5 in standard spec? Just as a ball park. Is the difference as big as in the official figures?
There is a thread around that states that the differences....hang on, bloody phone...
oh yeah, the thread states the differences are between the engine builds it goes roughly along the lines of:
4.0 External mods to Land rover engine
5.0 internal and exteranl mods, new crank and pistons (for stroke capacity), almost fully ballanced.
I think a 4.5 was somewhere in the middle.
Not sure about 4.6 though. Was it a special like the 5.2/5.3s?
TVRPower will know all the answers (if they don't then no one knows!)
oh yeah, the thread states the differences are between the engine builds it goes roughly along the lines of:
4.0 External mods to Land rover engine
5.0 internal and exteranl mods, new crank and pistons (for stroke capacity), almost fully ballanced.
I think a 4.5 was somewhere in the middle.
Not sure about 4.6 though. Was it a special like the 5.2/5.3s?
TVRPower will know all the answers (if they don't then no one knows!)
DustyC said:
4.0 External mods to Land rover engine
5.0 internal and exteranl mods, new crank and pistons (for stroke capacity), almost fully ballanced.
I think a 4.5 was somewhere in the middle.
Not sure about 4.6 though. Was it a special like the 5.2/5.3s?
TVRPower will know all the answers (if they don't then no one knows!)
My understanding was that the 4,5 is essentially the same in terms of internals spec and mods as the 5l (e.g: vernier timing gear etc, which isnt on the 4l)Can't remember if the 4l has a cross bolted bottom end or not (the 4.5 and 5l certainly do) So that the difference between the 4.5 and 5l is really down to the longer stroke crank (and the appropriate con-rods and pistons), plus diffrent cam. The 4,6 engine was purely a landrover unit and never used by TVR as such. HOpe i'm not confabulating now...
Nano2nd said:
okay the plot thickens, just checked the TVR site and the quoted capacity for the 450 is 4546cc
I havent got it to hand but i'm pretty sure the bible refers to 4441 cc for the 4.5. Stuck at work now so cant look it up - damn , hope I'm not making a prat of myself now
(Help... Steve...)tahiti450 said:
The 4,6 engine was purely a landrover unit and never used by TVR as such. HOpe i'm not confabulating now...
Apart when specially requested.
Quite a few were shocked when the 98 black "Dr Griffen, Holby City" Griff 4.6 came up for sale in the PH classifieds.
If you are a Holby City/Griff enthusiast, see if you can notice any differences when its next on.
I believe the 500 has big valve heads so it will breath better (if it had decent trumpets fitted 
) and fewer piston rings which reduces friction and lightens the whirly bits so it potentially revs better (at the cost of worse oil consumption). The standard Rover 4.6 is actually 4.55 liters (ish) and my guess is the TVR 450 is identical or very similar capacity.
) and fewer piston rings which reduces friction and lightens the whirly bits so it potentially revs better (at the cost of worse oil consumption). The standard Rover 4.6 is actually 4.55 liters (ish) and my guess is the TVR 450 is identical or very similar capacity.greenv8s said:
I believe the 500 has big valve heads so it will breath better (if it had decent trumpets fitted
Can someone PLEASE go and look in the bible and resolve this (I won't be able to for another couple of hours and this is driving me mad 
). I think you'll find the heads on the 4.5 and 5l are the same inc valve sizes (the later ones at least). 
Nano2nd said:
just a thought were not getting confused with the earlier griff BV 4.5? as i'm sure thats different to the chim 450...
Absolutely. The 450 fitted to big Wedges BV Griff and the Tuscan racer was the 4441cc which reportedly used a Pontiac crank and produced 324TVRBHP. The later 450 in Chimps etc is basically a serpentine LR unit tuned (a lot?)by TVR rated at 285. The 285 is not a bad TVRBHP figure - add on the extra cc to 5 litre and it gives you 310 TVRBHP, then factor in that the 500 has fancy BV heads (worth at least 10 BHP?) and you're there. If you believe that the earlier engines really had extra BHP...
I'm not going to say any more 'till i've consulted the good book. Post you later. okay so capacity aside for a minute, were saying the 5.0 had larger valve heads, does this mean the 4.5 heads weren't modified or just flowed and ported rather than havin increased valve sizes?
we also think that the cam is slighter hotter and the map is a little closer to the edge hence pinking seems to affect the 5.0 more than the other engines...
we also think that the cam is slighter hotter and the map is a little closer to the edge hence pinking seems to affect the 5.0 more than the other engines...
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