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Post by richie8664 on Feb 16, 2016 17:16:32 GMT
As I'm working through what I want to do after overhauling the v8 and installing efi, I've been considering the exhaust manifolds, which just by looking at them, are stubby & lack flowing lines and will do nothing but strangle benefits from installing efi.
Has anyone bought any off the shelf exhaust manifolds that help breathing but actually fit with the power steering box on the p5b?
I don't particularly want to have a bespoke pair of manifolds built as they won't necessarily do much else than just fit (unless someone can tell me to the contrary, of course). If someone already makes a set that work, that's the way I'd like to go. I recently watched an episode on line of that show with Mike Brewer and Ed China where they did a P5b and had a new pair of exhaust manifolds made (they said at about £1600, which is pretty steep to me) but never really said anything about whether they improved breathing. Perhaps someone in the club knows the result or bought the car and if it did improve a carburetted engine it should help the efi. By the way, I'm not looking for something ridiculously powerful. The old P5 chassis and suspension were not made for anything above the already quite scary 112 mph top speed, but I am looking to break the 30 mpg target and with efi and a 4 speed ZF autobox, I have a chance.
Most of the off the peg manifolds I've seen come out too far from the head before curving backwards and would never get past the steering box.
The curve of each stub (at least on the r/h side of the engine) will need to be much tighter to avoid fouling the st/box.
Any suggestions??
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Post by enigmas on Feb 17, 2016 1:43:28 GMT
There is nothing off the shelf as far as tubular manifolds go for a P5B. The expense of manufacture validates the high cost. You could look at/utilize some cast manifolds from a Vitesse for the passenger side. If you have the skills/equipment you can modify by'brazing', the drivers side to accommodate the steering box. Paying someone else is prohibitive, although it's only money...it really depends upon how much you want it?
The easiest path is to reduce back pressure through the total system by tailoring twin pipes from front to rear, fitting a balance pipe behind the gearbox and utilizing several straight through mufflers (cherry bombs/hotdogs).
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Post by Warwick on Feb 17, 2016 11:55:26 GMT
Could you modify a set from a Range Rover? The left one might fit.
If you can wait a week or 2 I could have a look and let you know. I have a set for my Range Rover, not yet fitted. And (unfortunately) my P5B is sitting in the shed with no manifolds fitted.
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Post by richie8664 on Feb 17, 2016 16:13:12 GMT
Yes, waiting is not a problem as I have the start of the respray process on the list first and it is unlikely I'll be ready to do the manifolds before the summer anyway.
I'm just trying to work everything out in advance of doing it.
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Post by Warwick on Feb 18, 2016 7:26:00 GMT
OK, I'll get back to you and let you know how it looks.
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Post by Dr Bob on Feb 19, 2016 14:15:46 GMT
As I'm working through what I want to do after overhauling the v8 and installing efi, I've been considering the exhaust manifolds, which just by looking at them, are stubby & lack flowing lines and will do nothing but strangle benefits from installing efi. Has anyone bought any off the shelf exhaust manifolds that help breathing but actually fit with the power steering box on the p5b? I don't particularly want to have a bespoke pair of manifolds built as they won't necessarily do much else than just fit (unless someone can tell me to the contrary, of course). If someone already makes a set that work, that's the way I'd like to go. I recently watched an episode on line of that show with Mike Brewer and Ed China where they did a P5b and had a new pair of exhaust manifolds made (they said at about £1600, which is pretty steep to me) but never really said anything about whether they improved breathing. Perhaps someone in the club knows the result or bought the car and if it did improve a carburetted engine it should help the efi. By the way, I'm not looking for something ridiculously powerful. The old P5 chassis and suspension were not made for anything above the already quite scary 112 mph top speed, but I am looking to break the 30 mpg target and with efi and a 4 speed ZF autobox, I have a chance. Most of the off the peg manifolds I've seen come out too far from the head before curving backwards and would never get past the steering box. The curve of each stub (at least on the r/h side of the engine) will need to be much tighter to avoid fouling the st/box. Any suggestions?? Asking the same question for my Coupe and have found an organisation called RPI Engineering. I am sure the forum know about these guys; they seem to be able to help here as they have a set they have designed/built and fitted to a P6 and a Morgan Plus 8 - they think that this would do the job - about £800 for the pair. I spoke to an excellent chap - the Proprietor - called Ian who really knows his stuff on V8's. They have also done some work on P5's. We seem to be in the same boat as i am rebuilding my P5 currently and will be calling on them in the summer to help on this one (although the Full 4.6ltr v8, 4 speed Zf and Jensen Axle sounds like a plan...) |
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Post by Welsh Warlock on Feb 19, 2016 14:30:12 GMT
RPI Engineering are well known in the V8 world and have varying levels of approval IYSWIM.
There are places that offer better value IMHO for most things RV8 but I don't know about the manifolds.
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Post by Warwick on Feb 20, 2016 4:51:26 GMT
Sorry Richie, No luck. I thought you might be able to get away with modifying the lower end of a pair of Range Rover extractors, as we call them down here. However, if the upper section (the header) is held up to the exhaust ports on the cylinder head, the point where the lower section (engine pipe) bolts on is right where the subframe's crossmember is.  |
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Post by richie8664 on Feb 21, 2016 9:18:16 GMT
Ok. Thanks for trying.
I don't particularly want a completely straight through system suggested by "Enigmas" as I don't want it to sound like a boy racer's ford escort and you cannot tell what the noise levels will be until it's done (and paid for). My brother had a straight through system done for his old Royale coupe (Opel Monza shape) years ago, which was ok(ish) until you got to 70-75 mph when it made a horrible, deafeningly loud drone, which was exactly the speed you didn't want to hear that sort of racket. Enigmas is right in what he says as I've discussed the issue several times with my brother who has a corvette (recently on Car SOS) but my brother's 74 corvette sounds like a racing car and that sound wouldn't go with the P5. I'd like to keep the subtle v8 burble (and my eardrums) intact and be able to have a conversation at motorway speeds.
So the search continues.....
I'd still be interested to find out if anyone knows whether the Wheeler Dealers bespoke manifolds for their P5B actually improved things, particularly as they seemed to keep the exhaust system otherwise stock, from what could be seen on the show.
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Post by flatplane8 on Mar 12, 2016 22:56:34 GMT
Hi,
I've got a P76 block in a P5b and use SD1 manifolds both sides. I fitted these as I had read that they were as good as most tubular ones. I do have a 3 litre manual steering box fitted though, which may make a difference.
Simon
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Post by enigmas on Mar 13, 2016 8:25:46 GMT
Simon although your profile page is very sparse, I gather you're an Aussie since you have a P76 engine in your P5B. Can you provide some photos and tech details of your installation.
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Post by enigmas on Mar 13, 2016 9:01:19 GMT
Richie reducing backpressure by carefully selecting the right combination of silencers/mufflers doesn't necessarily make for a noisy car. But you will have to have more than one type along various positions in the system to progressively knock down the noise not the flow of exhaust gas. I have 3 on mine as it's a split twin system and it has a lovely quiet burble.
The original cast iron P5B manifold incorporates some awkward contortions for a couple of the exhaust ports, including the area over the power steering box. The Wheeler Dealer manifold though very attractively made, (no negative connotations inferred) is not a tuned length header due to the confines of space. If it's running the stock exhaust system from the header collectors back, it may be making very little difference in engine output because it's being strangled and restricted by the original spec muffler.
Having your exhaust manfolds (either cast iron or custom tube) ceramic coated ('Jet-Hot'),improves the thermal efficiency of the exhaust gases and minimises under bonnet heat. It also preserves the manifolds from further degradation. The silver colour is particular nice IMHO as it has the look of nickel plating.
Warwicks Range Rover manifolds do look good to my eye but like all custom fitted parts require some creative fabrication to link them to the P5 exhaust system.
PS.
Spending time carfully matching the exhaust port openings of the cyl head to the cast iron manifolds is well worth the effort as any misalignment can cause serious obstructions to flow.
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Post by flatplane8 on Mar 14, 2016 7:51:11 GMT
Simon although your profile page is very sparse, I gather you're an Aussie since you have a P76 engine in your P5B. Can you provide some photos and tech details of your installation. Hi, I'm from New Zealand, but live in suffolk now. I've had my rover for over 20 years, but just brought it back from NZ to the UK last year. It has a P76 block bored out to 5 litres with a Toyota 5 speed gearbox and a few other mods including running dedicated LPG. For those of you that are aware of Simon Legge's Chevy powered P5 from Wellington NZ, he was my inspiration for getting into Rovers and is my friend ( I lived in Wellington for about ten years). I did all the mods for fun and Simon and I used to race in sprints and hill climbs in the area. I need to get the Rover on the road over here, but haven't had much time since I brought it back, but hopefully this spring. Simon |
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Post by enigmas on Mar 14, 2016 11:53:30 GMT
I was close! Interesting that you successfully managed to get the P76 engine out to 5 litres. Quite a few engine reconditioners that I've spoken too and who have an intimate knowledge of these engines aren't too keen on doing it, as it usually involves boring the block for oversize liners which can compromise it's integrity.
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Post by ray on Mar 14, 2016 12:44:11 GMT
Simon,
I need to get the Rover on the road over here, but haven't had much time since I brought it back, but hopefully this spring.
If you do will you bring it to the National Rally in August and let us look at it?
Ray
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Post by Welsh Warlock on Mar 14, 2016 17:22:13 GMT
Simon, I need to get the Rover on the road over here, but haven't had much time since I brought it back, but hopefully this spring. If you do will you bring it to the National Rally in August and let us look at it? Ray Apologies for going O/T but where and when is the National rally this year? There's no mention in the Events section. Perhaps a committee member could open a thread in there and let us know? |
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Post by Roy of the Rovers on Apr 1, 2016 9:05:13 GMT
Most of the off the peg manifolds I've seen come out too far from the head before curving backwards and would never get past the steering box. The curve of each stub (at least on the r/h side of the engine) will need to be much tighter to avoid fouling the st/box. Any suggestions?? Hi Richie, have you considered the Range Rover P38 Exhaust manifolds. I picked up a pair cheap, I haven't tried them on the car yet but I think with some adjustments to the downpipes on the original system and the exit from the manifolds they should work. As for exhaust Mine has a s/steel system all through but I've had a main pipe fabricated without silencer which will take a cherry bomb. I've done this conversion before and there no drone but you do get the slightly deeper tvr like rumble which (to me) is very pleasing to the ear. Usually if you get a bigger back box it gives the rasp'ier boy racer ford escort sound IMO. cheers Roy Anyway here's a couple of pics of the manifolds .   |
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Post by Donald on Oct 11, 2017 3:07:13 GMT
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Post by enigmas on Oct 11, 2017 6:40:23 GMT
Unfortunately it's all a tight fit especially on the DS (RHD) of a P5B. This is what I did for my P76 V8 powered MK3. Yes, there are clearance issues, so the manifolds were designed to fit around the available space, not necessarily to improve exhaust flow. They are less restrictive than the standard P5B cast manifolds but not necessarily later versions of cast manifolds for the Rover V8s. For real gains exhaust manifolds need to have tuned length primaries which often can't be accommodated on a standard car without some serious inner guard body mods. Reducing restriction through, the use of freer flowing pipes and mufflers is the easiest, most cost effective of the available options.    |
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Post by wozzer on Oct 12, 2017 17:00:31 GMT
If your fairly compitant with a welder then you can buy v8 maniflold kits from custom chrome.
What you get is rv8 flange set, loads of bends and a couple of collectors.
What you then need is patience and the ability to cut and weld the tubes together. I made a set this way and they came out really nice but did take at least a week of my free time.
Woz
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Post by Donald on Oct 13, 2017 4:33:18 GMT
I do like the look of the P38 manifolds, but yeah that d**n rh skirt and whats in there is tight.
Im getting ahead of myself anyway. I have an edelbrock manifold and am waiting on my new AVS carb and extras to get something familiar for me to mess with. I grew up with ford V8's four barrel carbs, and tho im sure the SU's are fine, the 4 barrel is familiar.
Ahead of myself.. i also picked up a camshaft last week and am looking at some nos 4.6 heads on offer.. i need to back away from the computer!
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Post by Donald on Oct 15, 2017 5:46:40 GMT
Richie reducing backpressure by carefully selecting the right combination of silencers/mufflers doesn't necessarily make for a noisy car. But you will have to have more than one type along various positions in the system to progressively knock down the noise not the flow of exhaust gas. I have 3 on mine as it's a split twin system and it has a lovely quiet burble. The original cast iron P5B manifold incorporates some awkward contortions for a couple of the exhaust ports, including the area over the power steering box. The Wheeler Dealer manifold though very attractively made, (no negative connotations inferred) is not a tuned length header due to the confines of space. If it's running the stock exhaust system from the header collectors back, it may be making very little difference in engine output because it's being strangled and restricted by the original spec muffler. Having your exhaust manfolds (either cast iron or custom tube) ceramic coated ('Jet-Hot'),improves the thermal efficiency of the exhaust gases and minimises under bonnet heat. It also preserves the manifolds from further degradation. The silver colour is particular nice IMHO as it has the look of nickel plating. Warwicks Range Rover manifolds do look good to my eye but like all custom fitted parts require some creative fabrication to link them to the P5 exhaust system. PS. Spending time carfully matching the exhaust port openings of the cyl head to the cast iron manifolds is well worth the effort as any misalignment can cause serious obstructions to flow. With your split twin exhaust, when you say split, is that after the crossmember? After your suggestions of freeing the pipes, and looking harder in my engine bay, I'd have to agree those manifolds are staying put. But looking at the exhaust system as is, passes thru that rear crossmember, to do a proper dual exhaust would want freeing that other side member hole up of the handbrake cable and fuel lines. Did you go that far? I do like symmetry! |
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Post by enigmas on Oct 15, 2017 22:51:00 GMT
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Post by Donald on Oct 29, 2017 12:43:34 GMT
Thanks mate. Looks good, sounds great!
Got my new windscreen in and half way thru the roadworth list. Hopefully get on the road by Christmas, if I can resist the urge to paint it.. really just want to drive it a spell before throwing paint on it.
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Post by Brendan69 on Nov 15, 2018 14:37:01 GMT
I know this is an old post and me being a newby member this week but there is a place up in Nottingham area ( Ilkeston area I think ) called PD Gough Exhausts who are quite famous for fabrication of specialist and bespoke systems for any car. There number is 01159 382241 and they have a great website too.
They actually built the custom approved full system with sports cats for my Aston Martin which I bought via Quicksilver Exhausts who are an approved AML supplier.
Regards,
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