On its own it might have limited gains, but gains it will. As part of other mods it can make a difference. But most power gains from the exhaust are by fitting long tube headers. This does make a difference. And a free flowing exhaust will only help.
Do you have a link to Suport this?
I think you’ll struggle. You might have to get them made up tbh.
Mot inspection manual. Easily available to download. If a car is listed in the appendices, it gets a cat test and needs to have a cat. Unfortunately, it is not straightforward to read. It says to look at the flow charts in 7.3c but you can only tell which section you are reading (ABC) from the chapter contents page. It could easily prove confusing to the average grease monkey which @wammers is not.
I think you’ll struggle. You might have to get them made up tbh.
The trouble is you need what the Americans would call a long tube header. In the U.K. we normally just refer to them as tubular manifolds.
But there is a huge difference in what they do. On a naturally aspirated engine you want to promote a thing called exhaust scavenging. This is essentially where the exhaust from one cylinder helps suck more air into the cylinder with the inlet valve currently open.
This increases the charge density. This is so much more important than flow rate in most cases.
However as you can surmise. It’s quite a timing issue to get the right exhaust outlet primary to pass the right cylinder just when the inlet valve is open.
There are normally three different types of tubular header:
-shorties which are not much bigger than stock manifolds just made up from tubular section often a 3 into 2 into 1 step
-mid length which have much longer primaries
-long tube which have much longer primaries again.
The rule goes. The longer the primary the lower the rpm you’ll promote exhaust scavenging.
As the RV8 is a low revving engine you’ll see no real scavenging with shorty headers. Although because they flow well they are ideal for forced induction setups. Where it is all about flow rates.
Long tubes are what you need. They match the Rev range of most road going engines and especially OHV V8’s perfectly.
I have some on my 3.9 RV8 powered TR7 V8. They are essentially what the Works rally cars used to run. I think they have 2.75 or 3” collectors and run from the engine past the bell housing to the gearbox. And they work very very well. Running these and some other mods my previous cammed 3.5 made 230bhp flywheel est on the rolling road.
Just to give you an idea what a long tube header looks like:
The cost / gain ratio is higher than tuning
think janspeed claim 15bhp for theirs. If the RPeyes of this world are to be believed, the p38 runs lean so £750 to mark Adams might be prudent before bolting on induction and exhaust mods.
no it doesn't
280 HP will cost over 3 grand on a p38
The 4.6 was rated at 225hp and then 214hp for the latter Thor’s Land Rover got taken to court in the USA and lost.
Not if you are ignorant to facts and reason, no. For everyone living in reality it’s a very simple yes
More torque will give you more HP.
Not if you are ignorant to facts and reason, no. For everyone living in reality it’s a very simple yes
Over £3000 in parts. Don't sh1te on about better internals. Not many engines with such a weak margin of safety as the rover v8
Yes, I know it is an old thread, but had a 2 pennorth to add. Another trick, instead of mole grips, would be to bench vice and then weld a bar or a chunky nut / bolt to the broken stud (s). It gives you a lot more grip and the welding heat will also help trying to free it off. That is an old trick for UJM 4 cylinder engines where the oil filter was mounted on the front crankcase below the centre cylinders and got all the road crud and corrosion, plus usually only being a 10 or 12 mm head. Quick grind clean, then weld on a 17mm nut using the centre hole to plug weld. Bolt comes out easy as afterwards.
