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Triumph TR6 - Cold air for carbs

Hi guys

As I prepare to put the engine back in the car (really! It's only been five months since I started the job) I have been wondering about how to get cooler air to my carbs. With the exhaust manifold right underneath and heat's annoying tendency to rise it seems like some sort of cool air supply would help things out.

In the How to Imporve book there are pictures of ducting from the grill/radiator shroud to the carb area, and I know that Goodparts makes a ram air box, but I don't want to spend a fortune on this. I already have K&N filters (and a set for an early car - if anyone is interested!). I wondered about using the ducting, but then it occurred to me that simply cutting a slot or two in the radiator shroud would allow more cool air to pass to that side of the engine. Hopefully I could do this without changing the flow through the radiator too much - I don't want cool air for carbs which are feeding an overheating engine.

Has anyone tried the ducting or cutting slots, holes etc? Any other ideas? Will this make no difference anyway? Any thoughts appreciated.

A Hewitt

Alistair, a lot of guys are running their 6's quite happily with no shroud at all, and not over heating, so I would think that a hole cut in to duct air to your carbs would not be an issue.

rw loftus

Thanks Rob

I wouldn't want to go without the shroud, but as you say, a small duct shouldn't be a problem. The question now is how big does it need to be, and I suppose another question is whether I am just dreaming up ways to waste time - it's not exactly a racing car I am building here!

A Hewitt

Hi Alistair, I agree that getting cooler air to the carbs is a good idea: denser mix produces better VE thus power. Insulating/coating the manifold and drop pipe is a also important for two reasons: 1. to keep the carbs and fuel cooler 2. to hold the heat in the exhaust system for a little longer thus creating a drawing effect which aids scavaging in the cylinders... better VE ultimately. A heat deflector such as the ones made by AE engineering will help the carbs while building an adapter for a fiberboard shroud and the air cleaner will supply cooler and denser air. I see there is an adapter on EBay for a stock air cleaner to fit a 3" flex hose.... could solve some problems easily and cheaply. Regards, Rob

Rob Gibbs

Hi Guys,
I use my 6 as daily driver and also a few long trips on the highway plus one 1hr stop and go drive one the 401 stuck in traffic and gained 1 mile ! the temp gauge climed up to 1/2 to 3/4 but the car ran fine.
I have a 16o thermostat and it works fine. I don't see any advantage to running a cooler vent to my carbs.

Charlie B.

Rob-Nice adapter, must be made by another Rob in BC. I noticed that my Haynes manual (page 59) shows 2 hoses connecting to the tubes on the air cleaners. The other end of the hoses connect to a support panel, probably on the radiator shroud. I have never seen these fitted to a car or shown in any catalog.
Berry Price
BTP Price

that would be from an early model car having the two 1.5' hoses. I haven't seen one hooked up either.

Yup, that Rob guy in BC does some cool parts.

Charlie, I agree that cool air to the carbs does little to nothing re- cooling the engine. Cooler air is beneficial to VE however and any "free" gain in power seems like a good one to me.

Cheers, Rob
Rob Gibbs

Here's what's been done to my '76. The air cleaner housing is from an earlier model (69-71?)with the trumpets on the front. The other end of the hoses are connected to adapters on the radiator shroud. I'm not sure how effective it is but I like the looks of it!


DW More

I just noticed this on eBay to adapt later air cleaner housings:

DW More

Wow-Another Rob in BC producing cool TR stuff. there must be at least 3 of them. What are the odds of that happening?
BTP Price

This thread was discussed between 28/03/2008 and 30/03/2008

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