V12 Air intake trumpet replacement

My old air intake trumpets where cracked and brittle and they are no longer available new.
So with another XJS enthusiast we decided that it would look good if we reproduce them from aluminum. End result came out quite nice. Here’s how the trumpets look now:


Sweeeet. Did you consider cutting the trumpet back about halfway and fabbing a slightly larger horn for the end?

Yes :slight_smile: But for now I left it as is. I will be installing new exhaust from “simply performance” without intermediate boxes so I want to hear the new tone first. Then if I decide that I want more noise I might make larger trumpets and cut the tubes slightly. One problem is that on the left side there might be some clearance issues with radiator hose.

My intermediate silencer replacement pipes came from aj6 engineering & sound like this:




Currently working on a small batch of intake trumpets to replace originals that most of the time are cracked or otherwise damaged.

Also planning on making second batch of slightly bigger diameter trumpets but haven’t decided yet how much bigger should I go… any recommendations?

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How are these things attached?

Just press fit for now.

They look great! I’m looking at using the same Simply Performance exhaust, would be very interested in your feed back of the results. Also not maybe half but a 3/4 length wider diameter trumpet might be interesting sound without going too loud. Maybe you could do custom lengths to order.

Bywater once assured us that the OEM trumpets are not restrictive for the stock V12. So, my inclination would be to design trumpets for the people whose V12 have been breathed on a little bit. Like, calculate the size trumpet that’d be sized for, say, 350 hp, and fab that. Provide instructions on exactly how far back to cut the intake to install the trumpet. Lots of people with stock engines would probably buy it and be happy with it, especially if it allowed just a tad more sound than the OEM trumpets.

I cut my trumpets off love the sound

I cut my snorkels back to reach an I.D. of 48mm. I found motorcycle trumpets that are 48mm. O.D. The result (for me) was an annoying induction noise when cruising. The addition of silicone curved hoses removed the noise, except at WOT, when it sounds good. Also placed intakes away from the blast of hot air coming through the radiator.

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The alternative to shortened trumpets is the rerouting of the intake to outside the hot environs of the engine bay. Either a home brew effort utilising the headlamp area, or copying the XJR-S or 6.0L factory positioning at the top of the radiator. I think the jury is still out on exactly how much more power you get through doing this, it may depend on your ECU being able to adjust. If the noise from shortened trumpets is bothersome then I think the factory routing would be a better option.

I fitted 6lt covers and KN on my mildly breathed on 84 give a bit more clearance at the front and sounds good.

I did the mod by cutting off trumpets and JBwelding 3" pvc elec conduit. I don’t get more power, but i do feel my throttle response is much faster when going to WOT. Its also very loud at WOT, a real Jag roar. I painted them black, only issue - doesn’t look as nice as other mods on this thread. I’m sure James Love would not approve. :wink:

I also did the mod of cutting out behind headlights and fitting in air intake tubing. No noticeable difference driving or WOT or even at idle. But it did take away the nice loud roar sound (or maybe only those in front of car can hear?). So i removed tubing, but i believe now there’s some nice cool air flow through the headlights to intakes while driving. I also left air temp sensor on tubing input, thinking the air there may be a tad cooler than air cleaner, so tricking ecu to run slightly richer at idle and driving. I did unscientific measure, only about 10F diff.

About the noise: As I’ve related elsewhere, one and all can easily experience that noise. Just remove your air filter covers and tie the filters in place with wire or string. Take it for a drive. That’s the loudest it can possibly be; any other configuration including shortened snorkels or a cold air intake scheme will dampen some or all of that sound. But a quick test will tell you if it’s the kind of sound you like or whether it would drive you nuts.

Hi, sorry to revive an old thread with this. I am currently building a coffee table from an HE V12 and am rounding up the last few bits. My intake trumpets are, like all of them, crumbling and disintegrating. I saw your post and had the thought that I could most likely have a local fab shop manufacture a couple for me, but I would rather put the money into your hands if you are willing to make a couple more. Please let me know, I am located in the US, thanks.

Hi, I have them in stock, shipping to us is not a problem. My trumpets are the same size as originals and Im asking 70eur for a set including shipping to US. Payment through PayPal, just send me your PayPal email and I’ll send you the invoice through PayPal