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Triumph TR6 - Moss Supercharger Kit

I have seen the Moss Supercharger kit and it looks well made and thought out. A friend and I were out chasing parts last Friday and went into the backshop of one of our local sources to see another friend's "new" racer. After we looked over that average driver's racer, I turned around and there it was, sitting on a work bench, a TR6 supercharget kit out of the box. I did not pick things up and do any handling as it looked to be set for installation in a customer car (quick way to get disinvited from ever going into the backshop again is to mess with stuff on a money paying customer car). However, it looked to be well made and complete to minimize that "and you need to get these too" scenes.

Very, very nice, and considering the cost and considering what it cost to build a hot TR6 motor through the conventional means, very reasonable to boot. Given the effort, expense and nature of the modifications to the TR6 motor it's too late to even give it any thought for that car. Which then of course begs the question of could I get away with sliding one of those in the list when it is time to do the TR250, would it cost dearly in non-fiscal means or would I never live to tell the tale.........

I agree that the setup is well manufactured, however, it is a compromise between good engineering and building something that can be sold in the marketplace. The lack of an intercooler and reliance on a carburetor limits the capability of the system. I recommend that anyone installing one of these units also install a pyrometer to make sure that the exhaust gas temperatures do not get high enough to start melting the pistons.

I have a little experience in this field. For more information go to

Lee Janssen


That is pretty much it, this kit is not intended for an all out balls to the wall kind of car. It is intended for those with what amounts to a stock motor that is in good shape as a bolt on significant jump in power. For an all out BTTW car, there are definitely things to do differently, but Moss needs a kit that can be sold to a reasonable handful of individuals as opposed that much, much smaller handful for whom too much of everything is just enough, but would only be interested in a bolt on kit. My experience is that the people that would want to go all out are going to have decent fabrication skills and access to equipment to make the one off bits that they need as opposed to "just bolting something on."

As for the the EGT monitoring, yes, it would be nice thing to consider. But given the level of boost and as long as you don't go mucking about with the kit (to send the car off in that BTTW direction) it is not an absolute necessity in my eyes.

In the mean time, I'll stick to my normally aspirated retro grouch motor.....but you never know what the future may hold.

Ha - that's a new one. A "Gouch" motor... Got to love it.
Brent B

Yuk - make that "Grouch".
Brent B

When providing boost EGT is important for the following reasons:

1) There was a very wide range of compression ratios over the TR6 production run.
2) There is no easy way to determine if the carb is ever running lean.
3) Unless you have always owned the car it is difficult to know what some DPO has done.
4) Without an intercooler additional heat is being introduced into the engine.

EGT is simply cheap insurance against melted pistons.
My experience is that you can generate temperatures in excess of 1500 degree F by running as little as 3 pounds of boost (sea level equivalent) with a stoichiometric mixture.

Everyone has an opinion, far fewer have facts. You decide which is more precious.
Lee Janssen

Lee, here's opinion,(not like you guys haven't heard this before) Pull the old Grouch and drop in a V8.
No big expense, lots of reliability, 300 hp easy.

Mind you, the sound of a well tuned straight six
is something that cannot be surpassed
Christopher Trace

I wouldn't consider most of this to be rocket science and having played with a number of cars over the years ranging from street cars to some rather beastly racers, experience yields results (some good, some not so good) and that in turn helps to form opinions. As a result of that experience, I familiar with use of exhuast gas temperature monitoring used in conjuction with cylinder head temp monitoring for signs of detonation and the different types of sensors that can be used for those tasks, cooling compressed inlet charges and the dreaded stuck wastegate. The main thing to keep in mind is that every design and every act involves some level of compromise. My primary point was that given the intended market and the limitations of the kit in terms of boost, I think Moss has a decent kit out there.

On the last points raised, there were really only two nominal compression ratios from the factory for the NA market TR6 and one is rather low in keeping with the era and the earlier high one is not really that high. I agree that it is rather difficult to determine if an individual cylinder is running lean in real time, but even that can be masked to the EGT sensor by dilution of exhaust from the other cylinders. The big problem with carbs and TBI systems on a boosted motor is that they are not the most efficient when it comes to ensuring that each individual cylinder gets an even amount of fuel due to the limitations of the inlet system but a low boost system renders that somewhat moot. Knowing what the DPO did? That can be a scary thought, but I would like to think that anyone willing to plunk out the brass for the kit would make sure they did this on a solid engine and that they would either verify or pay someone else to verify the compression at the very least to ensure that they were not going to have too high of a compression ratio. As for the compressed air feeding the intake charge being hotter, anyone that managed to stay awake through high school chemistry should remember the impact of Charles' and Boyle's law and the relationship between pressure, volume and temperature for a given mass of gas. Besides, even the turbo-tr6 website refers to the intercooler as "this item is total overkill but it looks cool." Not that I have a problem with the cool factor per se, I've been known to do things for the exact same reason, but that doesn't make them necessities or even something the more rational person might do.

One thing that I am somewhat curious on though is the mention of pyrometers. When I think pyrometers, I think emissivity and the electromagnetic spectrum. My experience says that would nominally be more of a surface consideration as opposed to gas flows, not to mention the issue with materials that may be too reflective to measure accurately and then tying the works into the exhaust stream. RTDs are nice for temperature measurement but too fragile in my mind to be used in a harsh vibrating environment. For my money, it's hard to beat a good old Type K thermocouple in applications such as these.

Truth be known, I really think Chris' approach is rather reasonable for those want a dumpster full of horsepower and a TR6 in the same package. Even among the most die hard of purists I think we all know that deep down in our hearts there are times when we might think about his car or Dan's and go "WOW! I could'a had a V8."


Let me address you rant objectively:

1) Sure a V8 or V6 would be vastly superior to a Moss supercharger kit, much cheaper, more power, more reliable.

2) I agree that a Type K thermocouple is good to have Ė this is the same as an EGT gauge.

3) The ideal gas law is not the issue, for forced induction you need high gas density.
A blower is only about 50 percent efficient, the extra mechanical energy goes into heating the air, not into increasing the gas density. This heat is a killer to engine components.

My point is:
If you add a Moss supercharger you would be wise to install a EGT gauge (that uses a Type K thermocouple) to make sure you donít melt your pistons or burn your valves.

Flame me - what do I care I run with an EGT, do you?

I didn't see any "flaming" done in Steve's discussion. Looks like some valid points with some "tongue and cheeck" thrown in.

Your points are fine too!

HP Henry Patterson

I only see one person doing the flaming and it is not Steve. I also do not see Steve "ranting".
Lee, everyone has an opinion and is free to say what they wish. Mostly we see opinions backed up with experience on this BBS. This is demonstrated in both your posts.
I think this is the first time I have seen the word flame (or flaming) used in this BBS since I have been on it and that has been since 1998.
Rick Crawford

Ha ha - you get all kinds on a forum. My fav's have been:
1) The grump the grouses when a thread goes off topic,
2) the egotist looking for strokes that can't write a post without a challange but whines like a child when it's addressed, and
3) adds for testosterone suppliments.


Brent B

Good manners
will open doors
that the best
education cannot.

- Clarence Thomas
Roger H

Hardly a "rant". I thought it was rather an eloquent and erudite explanation about something I know nothing about and if the truth be known I still don't understand.
But who the hell cares, bolt the thing on and have fun melting the pistons!

Steve I for one thoroughly enjoy your contributions to this BBS.

Rant on.

Cheers. Neil.P.
N.T. Peniston

Lee, Steve, from what I have read from you guys over the years shows that you are both extemely knowledgeable and a great asset to this board, period!

Lee, I honestly don't think Steve was flaming you.

Civility is one of the greatest things about this board
and is sorely lacking in alot of other disscusion groups, lets keep it alive here gentlemen.
Christopher Trace

This thread was discussed between 25/10/2006 and 01/11/2006

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