Here's one for you V8 experts..
Discussion
Probably due to the breathing apparatus. The amount of air which can be drawn into the combustion chambers will vary. Also the heads will be different so have different gas flow properties. The internals will be different such as pistons, con rods, etc which will affect the engine characteristics.
Then there is the cam which will control the flow of fuel to the engine and the exhaust away. Plus there are the associated peripherals being run off the engine.
And that is just to start with.
Then there is the cam which will control the flow of fuel to the engine and the exhaust away. Plus there are the associated peripherals being run off the engine.
And that is just to start with.
Was about to say that a carb'd V8 can have individual carb's for each of the 8 inlet ports, whereas the injected RV8 has all 8 cylinders drawing from the mixture supplied via one plenum. I expect this is why the racing V8's have a bank of 4 x twin throttles. on top of the block. Also the AJP V8 has 8 separate throttles. Rich...
I think Carbs vs fuel injection is missing the point.
In theory - injection is approx 10% or > better that carbs...
The RV8 engine in a very old design (1950's) and the head just does not flow as much air as a small block chevy .. which has very good air flow ..
People have tried to make better heads for the RV8..
(Wildcat)
www.espritv8.net/id34.htm
But they are not reliable .. need exhaust changes etc... and their flow rates are just a copy of .. guess what the Small Block chevy..
In theory - injection is approx 10% or > better that carbs...
The RV8 engine in a very old design (1950's) and the head just does not flow as much air as a small block chevy .. which has very good air flow ..
People have tried to make better heads for the RV8..
(Wildcat)
www.espritv8.net/id34.htm
But they are not reliable .. need exhaust changes etc... and their flow rates are just a copy of .. guess what the Small Block chevy..
rev-erand you seem to know your stuff. In your exp do you think my plan will improve the problem I have regarding <2000rpm running and if so will the power be reduced. I've had it on very good advice that it will improve both. I'm not knocking injection systems per se but just feel that the setup on the old Rover lump isn't one of the best matches
So conceivably swapping out the whole induction system, say swapping it for a Holley 600 + duel plane manifold would net me a wedge more power(at the expense of fuel consumption..) and then swapping up for some wildcat heads potentially even more.
Apache – you planning on putting the quad webber 600 on the Griff???
Apache – you planning on putting the quad webber 600 on the Griff???
Tower View have done several Quad Webber conversions using John Eales manifolds etc. Might be worth talking to them before spending a lot of dosh. These have been in cars that have had new engines fitted but don't run cats. Concensus is that you get a smooth uncomplicated engine but not the real power that a DTA or similar injection system can give. Other issue is that the bonnet will require mods so that it doesn't block the air intakes/filters. Bit like the problem the Tuscan racers had and solved by cutting holes in it.
>> Edited by shpub on Friday 5th December 11:28
>> Edited by shpub on Friday 5th December 11:28
I reckon it's the carbs that are pants, all of them. I like Holley's for simplicity of function not to mention reasonable pricing but for maximum power and torque gains you need the sophistication of injection. You can still tune individual cylinders for fueling and timing if you buy the right system.
The rover stuff wasn't designed for flowing large volumes of air into a 5.0 engine. The rover is undervalved as standard so going to 5.0 really stuffs it unless you spend a lot of dosh. It's also hard to increase the exhaust port area due to the header bolt spacing. It can be done but again it costs dearly. That's a really big handicap for little flow gain. The wildcat heads are a big improvement from what I heard but I thought they were based on Buick Grand National heads, the alloy 5 or 6 bolt jobbies. The buick head had factory support for racing and does flow a lot of air. I was considering going down the buick grand nat route but decided against it on the grounds of development costs.
Moving on to your chevy, do you know that it makes 400 ponies at the crank for certain? The rovers saving grace has to be it's weight.
The rover stuff wasn't designed for flowing large volumes of air into a 5.0 engine. The rover is undervalved as standard so going to 5.0 really stuffs it unless you spend a lot of dosh. It's also hard to increase the exhaust port area due to the header bolt spacing. It can be done but again it costs dearly. That's a really big handicap for little flow gain. The wildcat heads are a big improvement from what I heard but I thought they were based on Buick Grand National heads, the alloy 5 or 6 bolt jobbies. The buick head had factory support for racing and does flow a lot of air. I was considering going down the buick grand nat route but decided against it on the grounds of development costs.
Moving on to your chevy, do you know that it makes 400 ponies at the crank for certain? The rovers saving grace has to be it's weight.
shpub said:
Tower View have done several Quad Webber conversions using John Eales manifolds etc. Might be worth talking to them before spending a lot of dosh. These have been in cars that have had new engines fitted but don't run cats. Concensus is that you get a smooth uncomplicated engine but not the real power that a DTA or similar injection system can give. Other issue is that the bonnet will require mods so that it doesn't block the air intakes/filters. Bit like the problem the Tuscan racers had and solved by cutting holes in it.
>> Edited by shpub on Friday 5th December 11:28
Thanks Steve, just had a quick word with someone on the phone. He says they are currently running a 5.2 with these fitted, it runs really smoothly and has more grunt. The only fly in the ointment seems to be that there is very little room for the filter with the bonnet closed. Really looking forward to it now and just think of all the crap you get rid of, airflow meter, ecu, lambdas(already out of the loop in my case)throt pot, wiring. Mind you I've wasted a lot of dosh trying to make all that work properly
>> Edited by Apache on Friday 5th December 12:53
Apache said:
rev-erand you seem to know your stuff. In your exp do you think my plan will improve the problem I have regarding <2000rpm running and if so will the power be reduced. I've had it on very good advice that it will improve both. I'm not knocking injection systems per se but just feel that the setup on the old Rover lump isn't one of the best matches
Apache - I'm not sure why you should have these problems..
You have a 404 (mech) which is not to wild (I'm thinking of fitting the same to my engine).. also ACT carbon plenum (single/twin .. I think ?) and Mark Adams re-mapped ecu.. so more air flow pottential but not massively so..
Other than a lack of mid range torque ... you probably need to drop a gear ...
I guess you have not gone to larger injectors..
I think seriously you should be talking with Mark Adams..
Enlarged plenum std injectors and Mark Adams and V8 Developments have exhausted all their collective investigations. The problem began last summer very slightly, the mods were supposed to eradicate it but seemed to aggrevate things, it's like a shunting at very lo throttle settings and it varies in intensity from not at all to bloody irritating. I know from emails from other owners that this is far from uncommon in 500 Griffs. One suggestion is that as the vacuum in the plenum becomes negligable the ecu jumps around the map a bit. All I know is that the injection system has developed a bug that is nothing to do with injectors, plugs, leads, airflow meter, throttle pot or wiring, cannot be found by diagnostics or with a laptop and the best brains in the business can't figure it out. (I'm going to slave in another ECU for peace of mind but am not convinced this is the cause of the problem) Hence my wish to bin it all in favour of 4 carbs
Agree that solid lifters will be harsher to drive than hydraulic, but a think Pete's is in a league of its own , i had the same cam in my previous 5.0L and it wasn't that bad, although this is all a bit subjective.
On the carb front i would recommend fitting an engine bay fire extinguisher.
Separating the inlet tracts will make for a much smoother idle etc, but i have the feeling that the plenum system isn't the cause, the 500 is prone to "shunting" but this was due to the early cam, hence later cars with "soft cam" were better.
Tim
On the carb front i would recommend fitting an engine bay fire extinguisher.
Separating the inlet tracts will make for a much smoother idle etc, but i have the feeling that the plenum system isn't the cause, the 500 is prone to "shunting" but this was due to the early cam, hence later cars with "soft cam" were better.
Tim
I have solid lifters and a TVR Power 435 cam and it's as smooth a baby's bottom right from 1,000 rpm upwards. Rich...Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff