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Triumph TR6 - Turbo-charging

I'd like to keep the basic engine but add a supercharger to boost the output. Super-charging goes back a long ways and seems the perfect way to keep the 6 but goose it good. From what I've read, the low 8.5 compression ratio of the later model Tr6's is a good place to apply it. I'm looking for direction on what to do to beef up the old 6 to take it.

If you modify the engine with turbocharging modifications you will loose your shirt when you sell the car.

It the financial hit is OK then have at it - there is a pile of information available on the internet with the usual search methods.

I'm also interested in increasing the cylinder pressures of the old "six banger" and have recently completed construction of my "Megasquirt" fuel injection computer and have a good design including intercooling and water injection systems.

I recently changed my mind on the whole thing and am planning on staying with my current TR6 config which I really enjoy driving. I went with the old "carb-cam-exhaust" route and it wakes up the engine and I really like the car that way.

I decided that to go fast and go to the track, the purchase of a different marque is in order.

You will eventually come to the understanding that a Triumph TR6 is not a fast car but it really is one of the classic all time great sports cars for the the "sum of it's parts" behaviour. We love the TR6, but not because it is particularly quick and beleive me when I say, you'll be disapointed in trying to go fast in a TR6.

By comparison, you could purchase the lotus 32 valve aluminum double overhead cam 405 horse ZR1 corvette for about 35 grand and have one of the three fastest cars in the entire world at the time of mfg. And you will spend that to make your TR6 go half as fast.

Merry Christmas

John Parfitt

3 non-members posting...

I had saved to my favorites a real slick turbo TR6, I think the fellow lived in Colorado, used the fuel injection mentioned above, upgraded brakes to Toyota disc, put a TR4 surrey top on. I have since deleted the link, but I'm sure it's in the fairly recent archives (available to members).

Anyway, if you need motivation and good tips on pumping up the 6, I recommend you find his pages.

I agree with being able to buy a faster car for less money, and there are quite a few posts here proposing a V8 engine swap would be more bang for the buck. But it's your car, have fun!


I've chatted with the fellow in Colorado, and he is thrilled with his turbo'd TR6 as is Dick Taylor in California. Dick has over 200k on his car as 130k+ on his turbo conversion with no problems. He has an adjustable wastegate so that he can turn up his boost as he wants for more hp. I am going for the supercharger route. I think that if we enjoy our cars, and maybe consider not modifying them past the point of no return, then why not? I like the style and speed. If bang for the buck is what you are looking for, the Mini Cooper "S" is surprisingly quick. Won't outrun the ZO6 but will scare him up to 50mph or so.
Gene Holtzclaw

I know very little about Turbo/Super charging, but found the article by Jonathan Peck at:
to be of interest. If the link does not work, Google "The A.B.C. of Shorrock Supercharging"
Doug Baker


I am considering supercharging my 74. Listed below are a couple of sites of guys that have done this. I to believe the late model 6's are perfect candidates for "boost".
Please keep me advised of your progress and I will do the same.

Mitch self at:

Sal at: (all continuous)

Good Luck
John Korsak

I've installed Sal's kit on my 71 TR6. In addition to the supercharger I installed an MSD ignition with the pertronix and Jim S's roller rockers. I'm pleased with the results. I'm still in the "tweaking" process to obtain the best results.
I was looking for a way to increase the power but still be streetable and most importantly pass the vehicle emission testing to get license plates. I've got that a consistant idle even when hot and is even more fun to drive.
I've seen too many triple weber set ups failing emission testing and owners either swapping plates or just rarely using their cars.
The old proverb, "there's no substitute for cubic inches" still applies. We're dealing with a 2.5 liter six.
John Reynolds

It is not my intent to offend, however, John Parfitt, Bragg Creek wrote:

"You will eventually come to the understanding that a Triumph TR6 is not a fast carÖ. By comparison, you could purchase the lotus 32 valve aluminum double overhead cam 405 horse ZR1 corvette for about 35 grand and have one of the three fastest cars in the entire world at the time of mfg. And you will spend that to make your TR6 go half as fast."

Let me see, I've spent about 2 grand to get over 200 HP from a stock TR6 engine. Maybe not half as fast as a Corvette but faster than most would want to go!

We would all agree that a Spitfire was less than a high performance vehicle. This September I saw a 400 HP spitfire (dyno results at the rear axle) that cost a fraction of what a Corvette costs. It was fitted with an intercooled Garrett T04 turbocharged RX7 engine. The Spitfire weighs 2000 pounds, the Corvette weighs 3200 pounds! You do the math.

Itís easy to sit in your arm chair and say that it canít be done, but some of us would rather get in the garage and do it.

More on my car at
Lee Janssen

"Itís easy to sit in your arm chair and say that it canít be done, but some of us would rather get in the garage and do it."

I find that a rather boorish statement that makes me wonder if you're that type an individual.

Mr. Parfitt's post was that he did intend to do some sort of boost modification, but changed his mind. I'd go with the V-8 upgrade if that type of power appealed to me - MUCH less complicated and less likely to leave you stranded on a drive. But to each his own - eh?

Brent B

Brent B, Memphis, TN USA wrote
ďĎItís easy to sit in your arm chair and say that it canít be done, but some of us would rather get in the garage and do it.í

I find that a rather boorish statement that makes me wonder if you're that type an individual.Ē

Let me see in the past Iíve run dual HD8s, a Lucas mechanical PI system and Iím currently running a turbo on a nearly stock engine. I guess I donít have a clue about TR6s; and your experience isÖ?

Regardless you appear to have missed the point that horsepower does not require vast financial resources. John Parfitt is wrong in assuming that it takes $18k to generate 200 HP. I have nothing against superchargers, turbochargers or V8s but all of these configurations are significantly less expensive than John Parfitt states. I bet you could obtain 200 HP for under $500 without much problem; shall we start with your car ;)

When you perform extensive modifications the expense is time! Oh yeah it takes a lot of time to finally get the engineering right. Iíd talked to others that have performed engine swaps and they agree that it usually takes three times to get the finished product correct. But the satisfaction is having a really fun and exciting car to drive and isnít that what it is all about?

Sitting in my armchair dreaming of more power...
Lee Janssen da Man! Cool web-site, pretty flower pics too! (I'm not even into flora). Hey, if I could cobble together the financing would you consider installing a rocket engine in my old '73? Maybe a hydroponic garden in the back if you have time ;)
I've never considered going to the lake with my windsurfing gear strapped to the tr6 but if you can stick a kayak in yours...
Keep up the astonishing work!
c.a.e. emenhiser

Ahh, Lee, you ARE that type of individual! Ha, ha.

I'm quite happy with the rebuild I did 2 years ago on my '73 engine. I delivered a stripped block, the machine shop did the crank & pistons, I put it all back together, GP2 cam, degreed it, ect, - no sweat. The head's been milled, so compression is 9.5:1. I went to triple Z-S carbs, and with handling modifications I have a quick, reliable car that I won't hesitate to drive 300 miles. It' probably in the 140 hp range.

And I get the point of the posts completely. The TR6 is NOT designed as a high speed road vehicle. I don't think it's much fun to drive over 110 mph (No flames from track racers, please - those are different animals).

No one said "you don't have a clue" about about modifying a TR6. Why the "chip on your shoulder"? What you've done is certainly a one-of-a-kind effort. Somewhat like Mr. Cobbold's (sorry if spelling's wrong) supercharging, or any one of the unique V-8 mods. Point is, that's not for most. My engineering background says my car's more reliable than yours, though.

The arm chair comment was not necessary if you didn't intend to offend. EVERYONE with a TR6 spends time in the garage! While they may not be putting in a fuel injected turbo with supplimental water addition, the efforts are always to get performance.

Brent B

Hi, john from Tempe
can you share more about you supercharging experience?
I'm inclining to try this route.
'74 stock
Paddy Kan

Brent B, Memphis, TN USA, continues to try and bash me by writing

"Ahh, Lee, you ARE that type of individual! Ha, ha.
I delivered a stripped block, the machine shop did the crank & pistons, I put it all back together, GP2 cam, degreed it, ect, - no sweat... It' probably in the 140 hp range."

You still miss the point! This thread is titled "turbo-charging" if you want to put me down fine, but limit your comments to the topic. Based on my research there are not a whole lot of turbo TR6s out there. If you are one of those individuals then Iíll be the first to welcome your comments and listen to all of the lessons that you have to teach me.

On the other hand if you think that a large number of us haven't rebuilt an engine to the specifications quoted then you are nuts! In addition unless you have run your car on a dyno or used a G-tech to determine the actual horsepower then your performance claims are baseless.

Information is scarce, everyone has an opinion Ė which are you providing?

Lee Janssen

Tsk tsk... c'mon now girls........

I've been off the board for a few weeks and what's on when I get back - geez!

You two should kiss and make up - we can ALL learn from the benefit of other's experience - that's why this board is so bloody good.

Now if Professor Steve P still has any of those apples left, maybe they could be shared around.......

Roger H


Well in my absence over the Christmas holidays I see there has indeed been a frank and lively discussion taking place.... a very passionate group indeed.

The point I was trying to make was not about horsepower but rather whole package or behaviour of the car itself.

I just think the TR6 frame flexes too much and the suspension geometry is not well suited to achieving a fast car.

I know you can get some good power numbers out of the TR6 though.

I think Mr. Jansen exemplifies the true breed of a poor engineering student; able to create exotic horsepower with junkyard parts. Mind you Mr. Jansen has about 4 degree's in electrical engineering and builds space shuttles in his spare time.....

Anyhow - I love the old TR's but I'll buy the vette for the "go fast package".


John Parfitt
John Parfitt

I believe that I owe John Parfitt, an apology. He stated

ďI decided that to go fast and go to the track, the purchase of a different marque is in order.Ē

When I read it originally I missed the word ďtrackĒ.

I could not agree more with John, the days where one could competitively race a TR6 have been over for many a year. I also think he underestimated the cost required to make the TR6 competitive from a racing perspective.

I agree that from a cost and fun perspective an individual would be much better off working with a modern car like a Corvette. Or better yet a shifter go-cart that Grassroots Motorsports indicates can whip up on a Corvette in both straights and slaloms.

Sorry again for my ignorance

Lee Janssen

Request for information!

I would like to collect names, photos, links and whatever other information that is available on turbo charging Triumphs so that I post the information on a web page that will help interested individuals and avoid the re-hash of old issues.

Iím interested in both stock and re-engined applications so if you know of someone, who knows someone who has a turbo Triumph please let me know any and all details and Iíll try and put the information together.

Thanks for the Help

Lee Janssen

At Triumphest 04 at Lake Tahoe, I met Dick Taylor, and saw his turbocharged TR6. Very nicely done. I asked if he ever frequented this BBS, and he said most of his time is spent on the 6-Pack website. He has done some very well prepared articles for the 6-Pack magazine, and I think he would probably have more answers than you have questions! If you can't find a way to get in touch, I believe Rick Orthen is still a 6-Pack member, and he might get contact info for you. I would, but I let my membership lapse, as the 6-Pack is not very strong on the west coast.

Good luck....Rod
Rod Nichols

You can also lurk at the 6-Pack list here

and get Dick Taylor's e-mail from his responses.

Brent B

Lee -

No offense taken - really!

I have a great deal of respect for anyone that can install a home grown pressurized induction system on a vintage engine because it takes such an extensive depth of knowlege in many areas and systems.

There are so many major topics involved that one needs to grasp all the areas such as fuel injection, turbo charging, intercooling, ignition control and implementation and tuning methods.

The average joe mechanic doesn't have a clue how to aquire, assemble, test much less implement a Megasquirt computer for example.

Really the whole thing amounts to the quest for understanding and then the proof is the end result of a vintage engine with a home grown bunch of technology bolted on.

You have to love the subject matter and really I don't. I think I'd rather have an aluminum 500 hp small block and fly around a track instead of pouring over the user manual of the Megasquirt.

Best of luck


John Parfitt

Hi, Guys,

Dick Taylor is:

a. One of the nicest guys you'll ever meet

b. one of the most knowledgable TR6 experts you'll ever meet.

Well worth popping over to the 6-pack list for.
Dan Masters

Supercharging for me is much more about accleration and torque than outright speed. In a word: grunt.
Yes I accept reliability is a consideration particularly when building a one-off and going for real boost. But the MGB owners seem to be getting much joy from their off-the-shelf Moss kit, and a modest 6 psi boost.
For anyone thinking of supercharging- first read the books. Its not rocket science!
My article is on web page of someone called Jason, here:

and also on the TR register's Technicalities CD.
I kept it simple with an SU, not PI, no intercooling and mechanical boost retard.
The VIS TR6 kit used an Eaton blower and 6psi boosSimilar in concept to the MGB kit. Thta would be good starting point for a project. ( respell before sending)

P H Cobbold

Hey, Peter. Good to hear from you! I'd have probably tried it if I hadn't cut the head down to give 9.5:1. Like I said, maybe after I blow this one up.

Brent B

I think the compression is not a problem as long as timing/boost is adjusted enough for the difference. I can't wait to get mine done except a lovely e-type got in my eye(and my wallet).
Gene Holtzclaw

Gene, I reckon around 6psi would be max that a 9.5 head would take, given decent octane fuel and care with the timing. I melted pistons when the mixture leaned-out in a long bend. So I fitted a 8.5 head to hopefully run at 9psi reliably...
Brent, You could try for 6psi with your present 9.5 head, then raise blower gearing to give higher boost if you later fit a lower CR head.

And I recommend keeping a spare set of pistons to hand, and maybe dangling a melted one from the rear-view mirror, just as a reminder that detonation is always the enemy!

P H Cobbold

Peter, thanks as usual. It was your help that got me as far as I am on my s/c project. I have no intension of raising compression although my set-up is capable of 12lbs of boost(I think). I have bought a blow off valve that I intend to start out at 2psi and work up from there. Not only did the Jag crunch my budget, my fears of a proper ECM stalled me. I think I may be back on track very soon though. BTW, I am much futher along than those pics.
Gene Holtzclaw

Hi folks, I've been trying to avoid computer immersion this winter and I've missed this thread that I would love to contribute to. (What follows is rather long and a bit preachy, I apologize in advance if it is in any way offensive to you.)
I have a supercharged '75 that is an absolute blast to drive,whether on an open road around Mt. Rainier here in Washington state,USA or taking a drive to return a DVD to the local store. As Peter Cobbold said it's all about "grunt" - the feeling of power is intoxicating.
For an interested observer, it's natural to think that what a supercharged or turbo-charged car is "about" is making it "fast", but frankly, it's not that at all. I don't have any interest in racing a TR6 (no, this is not a slam against those who want to!)
I also don't want to show Honda Civic punks what a classic TR6 "can do". On the dyno my car makes approximately 185 horsepower at the crank --but frankly, in a drag race it's really not that fast- but believe me , it "feels" fast as all get out. What I want is to drive a car that exhilarates me, and supercharging is a huge boost of adrenaline ! What's also fun is that if I'm not into driving fast the car can be lugged along at low rpm just like a stock TR6. At a breakfast outing in the country I guy ran up to me as I parked the car --"Is that a V8 ? " No. "Oh,it sounds so goood" !
The smile just wouldn't go away.
Now that's "worth" all the tea in China.
I didn't rebuild the whole car so that I could sell it - I'm excited to work on the car as well as drive it. It's the reason most of us buy a TR6 in the first place : we're interested in the "journey", not so much about getting "there". If it costs me money and lots of work to have a hell of a good time in life - is it too expensive ? I, personally, could care less about being in a car club and I don't have emblems on my bumpers - but hey, that's just not "me". If it lights your fire to compare paint codes and vehicle numbers - go for it!
Corky Bell in his book "Supercharged! Design, Testing and Installation of Supercharger Systems",2001,Bentley Publishing describes all aspects of the choices involved -- and he does it with flair and good humor. It's a fantastic read and I recommend it to all enthusiasts who want to learn about forced induction.
Those of you who commented before me are all fantastic people, I wish we could all sit back together with a glass of your favorite beverage raise the bonnet, get a good look, and just talk Triumphs!
Have a great year.
David Johnston


Did you design and/or fabricate your own supercharger system or purchase a kit or combination?

Supercharger kits seem to be rare as hen's teeth...

If I ever get finished working on my Legend I might have time to dust of the TR and start getting ready for the driving season out here in the foothills!

John P.
John Parfitt

John, I used the installation kit made by Sal in New York City. Purchased the M62 Roots type supercharger from Magnuson Products and the carb from Joe Curto also in NYC. A couple of pictures of the engine bay are in the BBS photo's section. It's been a tremendous amount of fun.
David Johnston

This thread was discussed between 28/12/2004 and 31/01/2005

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