Disco Headers.

[StangGT5]

If you're concerned about packaging, the Rimmer Bros headers sit just above the bottom of the frame on my RRC. That should be the same for a D1 I believe. The Hedmanns were the ones I was thinking of. They have served a lot of people but don't seem as compact as the RB headers. To my knowledge they are not stainless either. After a jet coating the price probably evens out. Your biggest issue would be converters. My RRC is exempt, so that wasn't an issue.

Some shorty headers would be a great option though. Let us know if Doug can make a set. The P38's stock manifolds are essentially short headers, but the frame is wider. I might try making a spare set fit a disco at some point.

Name and location?

Sent in a PM

 

[special ed]

I took a original SG 3 link to my water jet guy to get copied and threw him an exhaust manifold to copy the flanges. I would love some shorty ram style headers for the race truck so thats what im shooting for, My muffler guy makes some nice 1 off headers for the local tuners and hot rodders. Not sure its a project i will ever get to but its a thought and i have the flanges cut at least.

Doug Thorley is just down the road from me. If they need anything i can take a car or manifold to them...

 

[DiscoClay]

Do you still have the G-code or CAD file your waterjet buddy used? I suppose this may be floating around the interwebs somewhere.

 

[DiscoClay]

I'd like to find a set of tr-y's, maybe those TVR/Triump ones could be made to fit. They sound nice, but they flatten the torque out.. improving bottom end.

 

[special ed]

Do you still have the G-code or CAD file your waterjet buddy used? I suppose this may be floating around the interwebs somewhere.

I was looking at them this weekend and i think they are a little thin at the sides. I need to match them to a head and see if they need a little more meat on them. I just threw him a manifold to copy while he was doing a bunch of other stuff.

 

[DiscoClay]

I think it would be interesting to make an "adapter plate" for the stock iron manifolds. The irons are well known for shrinking (forward<-->aft measure, e.g. flange end-end) and causing leaks and some power loss. It seems an adapter plate might work to re-align the ports and lengthen them slightly. Though for the money and effort.. shorties or tri-y's would likely be a much better option.. I suppose it all depends on your smog rules.

 

[DiscoClay]

These guys make flanges for the Buick: https://www.hellsgatehotrods.com/shop/buick-215-exhaust-flange/

 

[DiscoClay]

It makes me wonder.. how far off a small block ford tri-y would be... I mean, I know it needs a flange adapter but..that's doable. a 260-289 is not moving much more air than a 3.9...

 

[StangGT5]

It makes me wonder.. how far off a small block ford tri-y would be... I mean, I know it needs a flange adapter but..that's doable. a 260-289 is not moving much more air than a 3.9...

View attachment 65696

I'm curious as well. The Buick and Ford small blocks have a somewhat similar layout. I have 351W and 302 heads, headers, and manifolds laying around I could compare flange separation to.

As for air flow, the exhaust ports on stock Rover heads are incredibly small. E7 Ford heads (EFI trucks for decades) aren't much better.

The primaries and collectors on the stainless headers I bought from RB are tiny by American standards. They still made a very noticeable difference with the RPi 4.6. Stock 4.6s benefit from head work, so headers couldn't hurt. As noted previously, P38s come with shorties from the factory so they wouldn't benefit as much as the log manifold Rovers.

 

[DiscoClay]

I just noticed that, indeed, the stock cast manifolds (at least on the starboard side) are clearly a tri-y configuration. That, my friends, is a properly ordered two-into-one-into-two-into-one:

Land Rover Exhaust Manifolds

Looking for Land Rover exhaust manifolds? Atlantic British has plenty of quality Rover exhaust parts to keep your vehicle performance high!

www.roverparts.com

 

[DiscoClay]

I just checked (it's been a few decades since I was a SBF guy) and the small block ford has the same effective (physical) firing order as the Disco motor. The numbering is different (as ford does the 1234/5678 up the cylinders..rather than odd side/ even side). So.. a set of small diameter tr-y's for a 289/302 could be adapted without tooooo much fuss. The Ford exhaust spacing is 4.38 inches:
[note those cute little aluminum spacers for Cleveland headers... something similar could be done for Rover<-->SBF





According to this site [https://victorylibrary.com/mopar/bore-center-c.htm] the cylinder spacing (which should be the ~same measurement) for the Rover is 4.24 inches:




That's "only" 0.14 inches (barely over an 1/8th inch... 9/64th's to be precise). I bet I can bang that into compliance fairly easily. If the angle of the ports relative to the head/block is not far off.

Thoughts?

 

[DiscoClay]

I am thinking a long tube tri-y in a "4Y/quad-y" config could be quiet nice, help the low end torque a smidge and make it sound somewhat flat-plane'y.

Using a 1.5" primary tube SBF set as the base, cut the flanges and make single tube adapters. Conveniently, the holes are offset quite a bit; the Ford small block flange uses 3/9 mount holes. Though it I go this far, I'd probably just trim the stock flanges away and TIG new single hold flanges onto them.

 

[DiscoClay]

Hah, funny enough, check out these GT40 SBF headers:


They have a conveniently wide mounting flange.. You could almost drill them out to fit... and because they are individually flanged (my preference), the 1/8th shorter flange distance could be easily managed. Now...how to make these 180º headers fit in a D1....

[https://www.ebay.co.uk/itm/193500449998]

 

[Greg_M]

That is some kind of beautiful.

 

[StangGT5]

Here's a P38 header on my spare. The collectors are too far away from the block for a Disco but, if someone took 1/2-1" out of the pipes at the flange and pie cut them to angle the collectors closer, they could be a cheap way to start on some shorties. Swapping the collector flange for a v-band would probably save a little room too.

 

[4Runner]

The other part of the problem is the Y pipe from the factory. This was the Y pipe from my D1.

 

[DiscoClay]

I've been looking at the P38 pipes for a while. They seem to be 3-2-1 manifolds rather than tri-y's, if I have the firing order correct. It seems kinda odd why they'd order the primaries on the even-numbered side (starboard) the way they did. If I did the math and ordering correctly, then a tri-y would need secondaries to meet in this order:

1-7 [primary Y]
pairs with
4-6 [primary Y]

and
2-8 [primary Y]
pairs with
3-5 [primary Y]

Then pair those two secondary Y pipes into a final single exhaust pipe.. and you will have a very european, 180º sounding rover. I am not suggesting those two secondary pipes are easy to cross over but I am thinking they could be extended long enough to get the job down under the tranny/transfercase where the stock Y-pipe crosses over anyways. I am sure the length ratio of the primary to the secondary to the final tailpipe will need to be matched.

 

[DiscoClay]

The other part of the problem is the Y pipe from the factory. This was the Y pipe from my D1.

Yeah, that looks like they were just pissing horsepower down the drain. "We've got a whopping ~4 liters to play with! We can afford a few corners to cut"

 

[StangGT5]

I don't think there are any headers that bolt to the factory exhaust. I assumed any install will require you to know a good exhaust shop.

As your picture illustrates, the factory manifold and flange leave a lot to be desired. Despite being engineered when LR knew V8s are mandatory in North America, the Discovery and Discovery 2 frames do a good job of making the little pushrod V8 look relative cramped. I think LR was willing to throwaway some power for cost and packaging savings. As I noted before, the factory exhaust ports are incredibly small. That's a bottleneck before the exhaust flanges haha.

 

[salvvia]

Keep fire alive