Hi.. recently bought a 300 V8 Disco... Only mods are freeflow exhaust and a tornado chip,

Can anyone give me a guide as to good and relatively cheap mods/improvements to give it a little more oomph so to speak?
Read bits about timing advance/cams/tubular manifolds etc but rarely seem to see same advice on other websites,
So thought here is prob the better place as it will be advice from people who have done these things and personally know the gains to be had etc.

Not after a rocket ship etc but would just like to make the most of what i have and done mind putting a little bit of money in but i dont really want to be doing engine work,

Cheers

heads are the main bottle neck on the RV8

best heads are merlin F85s but they also cost alot.

for a cam I'd look to a RC87 (evenden engineering) or RP4 from RPI


Ross

start with the basics the tornado chip will achive nothing without doing the mechanicals of the engine first
cam piper 270i new followers and valve train and rocker arms and preload the rocker arms
free flow heads polish and port will make a difference
free flow air filter too

i have 250 bhp and 22 to the gallon from mild heads but you can go wild and get near 280 anymore than that you will need a 4.6 to start with

Cheers for the replies... to be honest i realy dont want to take the heads off, not after big gains, just really want to make the most of what is there with maybe an odd bolt on bit here and there, cam sounds ok,
Is the things i hear about the timing being very 'safe' std and needs advancing? does it help?
What benifits from manifolds?
Or are you guys basically saying cam/manifold etc are pointless with std heads?

I have another car i have built (sierra cossie) for going fast so the disco will never be fast really,

Cheers for all the help i'm new to these v8 things..

Lee

PS... i am trying not to get too 'involved' with this v8 moding cos i do tend to get sucked into the wanting more and more saga too easily and if i dont control myself i'll soon be looking at twin turbo LS2 engines ha ha

manifolds help depending on the style you have - single branch are good for low down power but suck higher up so replacing these is a good idea. the twin branch ones are ok up to a point and if all you do is add a cam you are probably not worth replacing.

if you fit a piper 270 you'll have to do a little bit of work on the valve guides to accomodate the increased lift. you will loose low down torque with that type of cam.
you'd expect to get about 195-200hp with a RC87 cam with an otherwise standard 3.9.

LeeC said:

Cheers for the replies... to be honest i realy dont want to take the heads off, not after big gains, just really want to make the most of what is there with maybe an odd bolt on bit here and there, cam sounds ok,
Is the things i hear about the timing being very 'safe' std and needs advancing? does it help?
What benifits from manifolds?
Or are you guys basically saying cam/manifold etc are pointless with std heads?

I have another car i have built (sierra cossie) for going fast so the disco will never be fast really,

Cheers for all the help i'm new to these v8 things..

Lee

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The piper 270 is a direct replacement I think you refeere to the 285 which needs pocket pistons but can still run with standard guides
None of these cams require double valve springs either

If my mamomry serves me right you a cam with over 0.46" needs bulleted guides and DVS (double valve springs) or minimum high performance springs - this is due to springs becoming coil bound - spring coils touching as they are too close togeather.

In terms of tuning its all about the heads on a RV8 imagine a hose pipe with a circlip around it you can put more water in, and make either ends as big as possible, but untill you remove circlip the flow will be the flow. (unless you increase the pressure - read super or turbo)..

The heads on the RV8 are super crap they are your circlip you can pretty much do anything to the exhaust cams etc and it will not do much.

Thing is your heads, not due to flow, will be the most restrictive to power. Give you some idea; I recently brought a standard RV8 with standard heads and the project turned into a tuscan challenge engine, but along the way I rebuilt the heads and I had them flow checked they lost pressure bad. Whats happening here is coke and ****e has built up on valves and guides prevents then closing properly result = loss in compression and leakage.....

To do it properly guides valves and machine face will cost you about £250. If its done 160K miles figure on 20 - 30% of your power lost from this.

Oh also Rev limits on RV8 are defined by firslty valve springs, then hydraulic valves then con-rods first is about 5.5K rpm Valve spring then rest after about 6.4Krpm.

so my point is go with heads and cam you release a serious amount and also another 20% of revs....

Nice - will cost you about £750 quid to do, but worth it....

M

will the HP22 take it?

how many miles has she done?

pornstarmax said:

how many miles has she done?

Click to expand...

160k........

vougese39 said:

The piper 270 is a direct replacement I think you refeere to the 285 which needs pocket pistons but can still run with standard guides
None of these cams require double valve springs either

Click to expand...

nope refering to the 270 and I would advise the use of double springs to avoid coil bounce etc

not an issue spoke to piper when investigating using their cams and also spoke to Roy burrell ex v8 builder for jeengineering also said unless it was the doing major lift which the 270 is not it would be fine and so far most people use the engine i have built for everyday cars looking at mpg gain not out and out power.

the 5.2 iam building for myself is having double springs three angle seats and fully max flow heads and inlet and exhaust maniolfd with blend matched ports which will be required and a rare rally spec piper cam with a 303 duration greater than the 285 and will also be having pocketed pistons too just for safe measure again not designed to rev past 5k as with the ecu system it is all about grunt for mpg