6 into 1 exhaust manifold

[WELLSY]

I have the Racetorations 6 into 2 into 1 manifold  and exhaust system with triple webers.  I would like to remove the s/s manifold and connect the standard twin outlet cast manifold with the single bore Racetorations system. This is due to the underbonnet heat,noise and inaccessibility of the starter motor.

Has anyone made up, or considered a single big bore downpipe from the cast manifold instead of the twin downpipe ?   This would need the grinding open the outlet of the manifold to match a large single bore flange with a new tapered downpipe made. 

I Know I will loose some HP and have the webers re-jeted but I am trying to improve the standard set up with what I have. 

Will it work ok ? Be worse than the twin  standard set up?

Simon

 

 

 

[colin3511]

Simon, a little off topic but I’d be interested in the extractor manifold if you would like to sell it. I have a spare cast manifold you could have to ‘practice’ on if necessary.

Colin

[Dave McDonald]

On 12/20/2020 at 2:16 PM, WELLSY said:

I have the Racetorations 6 into 2 into 1 manifold  and exhaust system with triple webers.  I would like to remove the s/s manifold and connect the standard twin outlet cast manifold with the single bore Racetorations system. This is due to the underbonnet heat,noise and inaccessibility of the starter motor.

Has anyone made up, or considered a single big bore downpipe from the cast manifold instead of the twin downpipe ?   This would need the grinding open the outlet of the manifold to match a large single bore flange with a new tapered downpipe made. 

I Know I will loose some HP and have the webers re-jeted but I am trying to improve the standard set up with what I have. 

Will it work ok ? Be worse than the twin  standard set up?

Simon

 

 

 

Simon,

The USA cars had a cast iron manifold with a flange for one single down pipe instead of the UK cars 2 down pipe flange. Not sure of diameter of flange hole but one of those would be easier to adapt than a 2 hole flange.

I have one for sale if you're interested.

Dave McD

[JohnC]

Perhaps get a 2 into 1 adapter from Moss? You'd need to check if it's the same diameter as the Racestorations exhaust, but they are available to connect a Phoenix exhaust to standard manifold.

[WELLSY]

Thanks for your replies everyone.

Dave , what is the diameter of the  outlet hole on the USA manifold?

If all else fails I will go for the 2 into 1 from the TRShop ,which is probably the easiest option.

Simon

[Andy Moltu]

Wrap the manifold? This will reduce under bonnet heat and noise.

A modern starter motor can be accessed without removing the manifold.

[Tom Fremont]

I have the 6-2-1 Racetorations manifold on my Webered TR250 for 100K miles now. I had it " ceramic " coated before fitting and I'm not aware of any heat related issues over the last 20 years with it. It is connected to a single pipe large bore exhaust ( by them as well ) which has a "Y" connecting the 2-piece manifold into the single pipe system. I believe it will interface as is with the dual downpipe factory manifold; this allows the single bore system aft of the manifold to fit either arrangement via the " Y ".

Tom

[sixtynine]

I had a 2 1/4 made, bolts to a stock single manifold. (which is better flowing than the double in my opinion)

 

[TRTOM2498PI]

Hi Simon,

 

Whilst not answering your question specifically, you should really be OK with the existing set-up that you have. Before you commit to a change of manifold, have you considered having Camcoat/Zirotec ceramic coat your existing exhaust manifold to reduce under bonnet temperatures  ?

I run a Tony Law 6-3-1 race manifold that wraps around the steering column on my TR6, coupled to a bespoke 2.5"single stainless steel exhaust system, and do not suffer from excess noise of temperatures, despite 5-7k miles a year and driving in many different European countries in the summer.  For the record, my exhaust manifold is mild steel and NOT ceramic coated, but I will consider that option in due course.

 

Cheers.

 

[WELLSY]

Hi Sixtynine

Interesting your views on the stock single manifold. What you have had made up is just what I am looking for ,lambda connection as well. But mine would have a tapered section from the flange reducing to  21/4" as the double manifold will be a large oval after grinding out.

Where did you have your downpipe made up?

Simon