What’s wrong with your current exhaust?
Spacers…I made mine out of 1 inch ( 25 mm to,you youngsters) Chunks of broom handle drilled for the bolts. Are they still working Sam?
A man after my own heart.
I didn’t bother with rear spacers as I have found that the tips of the diffuser fins can ground out on the types of road found in the North Yorkshire hills.
John - I thought the issues of the Lotus VHPD manifold cracking around where the pipe meets the flange was “relatively” common - is that not your experience?
There’a a couple of leads for different manifolds on this thread, with the caution that it’s a little old so might be out of date:
VKG Racing:
Torque Technique
Have seen a few, out of the hundreds I have seen. Normally when the primary pipe support bracket has either broken, hasn’t been fitted or fitted with the pipe under stress. On the flip side have also seen pretty much all of the aftermarket manifolds either break in a similar place, open the slip joints, rattle, be too close to the O/S driveshaft boot, not fit at all without heating and bending, the list is quite long. As I said pick the exhaust you want from the ones out there, that you think has least/most appropriate for you compromises.
I’ve found 2 things that make the biggest difference for manifold life below
A rear lower engine mount with less compliance - after all it’s meant for a car with 118hp, 205 Pzero’s and road use in mind - we just used to press out the big bush from the mount and turn it through 90 degree and refit, instead of the voids being in the fore/aft direction, you now have rubber. Without going for something that’s mega expensive, has zero compliance and if you’re really unlucky damages the sump.
A second flexi section in the cat pipe and leave the first mount off on the subframe. This gives a lot more flex between the fairly solidly mounted rear silencer and the manifold that moves with the engine.
Thanks - useful advice.
Yes it’s all very useful. Can air be blown down the back of the bulkhead behind the manifold out then through the gap in the tray? Plenty of room now to possibly duct something from the front through the sills. Or would another area benefit from this.
I think I’ll stick with the OE manifold then, tidy it up, check the welds and coat it. Looks a JSR exhaust could be on order John my boy!
If air can get out via the lower tray the it has to be replaced by something and that would be air coming in via the right and left ducts. At least with it open at the back it keeps everything moving. There could be a chance the fast air moving under the car and past the rear opening could draw air out the gap.
I work next door to the Red Bull wind tunnel, I’ll see if I can pop the car in and get them to do a quick test at lunch.
Wow lol ok! You big name dropper 
That’s exactly what I was thinking tbh
Is that the tunnel up at twinwoods?
With your money, the right supplier will blow air anywhere you want
I’m on a budget!
Yep, it’s also the airfield where Glen Miller (ask Pesky) took off from and was never seen again.
I work on Thurleigh Airfield and can see the main gate and you lot going on your track days.
Maybe we can do a group buy for a go in the wind tunnel. :0)
I know the place, my folks only live ten minutes away.