TR6 Opinions: best way to get 150hp TR6?

[MTribe]

I'd like to get 150hp out of my TR6.

I already have a GP2 cam (slightly hotter than stock) and 9.5 CR.

Opinions on the best way to do this, and why?

Triple strombergs? PI system? Supercharging? Something else?

 

[poolboy]

Here's some others who've tried. Check out the dyno charts.
https://www.6-pack.org/sixpack//index.php...37&Itemid=2

 

[tdskip]

How do you plan to use the car? Let's start there since it will help determine the path...

 

[prb51]

Drop a SBC in it and detune it....JK

 

[DNK]

Buy a early PI car?

 

[Deleted member 8987]

289 Ford and remove two plug wires ought to drop you to about 150HP.

 

[vagt6]

Just wondering why 150HP is the magic number for you. For example, a TR-6 with 130-140 HP runs like a scalded cat IMO, and it can be done with period-correct parts and routine modifications such as a higher lift cam; shaved head; head porting/polishing; more carburation, headers/straight exhaust, etc. Not that hard to do, really.

Depends on how you intend to drive the car. Let us know that and we can provide better input for you. Also, if you don't have David Vizard's book on tuning these engines I suggest you read it. It's an easy read and provide the basic stuff you have to do to get good performance from these engines.

Give us a little more info, maybe.

 

[tdskip]

289 Ford and remove two plug wires ought to drop you to about 150HP.

Haaaa! LOL.

 

[MDCanaday]

Having built a few,I would suggest the tri-carb setup along with an improved ratio roller rocker set.You did not mention a header but even with the stock exhaust you should be over 150,perhaps 160ish.I have the strombergs (3) and a 9.25 to 1 comp ratio.Dont get to extreme with the ratio, 1.55 should do fine with the cam you have.The next step would be porting.....
MC(mad dog)

 

[MTribe]

I knew I came to the right place!

Here's the deal. I've been doing more rallying (the melee, etc) and the lack of capability of the car has gotten less charming with every drive. Now, I have zero pretensions of making this close to a modern car, or even more capable cars of the era. I'm just looking for a comfortable GT car that can take the twisties with aplomb versus feeling like I'm outside the envelope of the car most of the time, if that makes sense.

So I figured a good next step would be to give the car a chance at its original design power, which I think was 150 with PI.

I will check out the table above, which looks excellent. The 150 number isn't magic.. just saying that I don't want to spend a fortune and eek every last horsepower. If I could get to 180 without too much trouble, all the better.

MDCanday, I didn't want to seed the crowd too much, but I've been eyeing the triple strombergs... do those really add that much power, say to 150+? Keep in mind I already have 9.5 compression ratio if that biases people's input...

OK, let me know what you think I should do...

 

[poolboy]

With all due respect, MT, maybe you just need suspension upgrades and more practice.

 

[MTribe]

With all due respect, MT, maybe you just need suspension upgrades and more practice.

Good point and it's well taken... I'm the last one to think improving the car makes a better driver. After autox/track/lemons the past few years, though, if anything the reverse is true. The limits of the car have become that much more apparent, so I'm just interested in improving the experience of driving the car a bit.

 

[tdskip]

Here's the deal. I've been doing more rallying (the melee, etc) and the lack of capability of the car has gotten less charming with every drive. Now, I have zero pretensions of making this close to a modern car, or even more capable cars of the era. I'm just looking for a comfortable GT car that can take the twisties with aplomb versus feeling like I'm outside the envelope of the car most of the time, if that makes sense.

Hey - great to hear you are actually using her! I'll see you on one of those rallies soon. So here is the deal based on my Cal rally experience, start with the suspension.

A reasonably healthy TR6 should have more than enough power to keep up easily with the rest of the iron on those events, as Ken (aka Poolboy) said you'll be likely better off starting with the suspension. I have a friend in a well driven MGB that humbles much "faster" cars since he simply carried more speed through the turns.

I just go done rebuilding my front and rear suspension on the '74 TR6 and she is a go cart now. A bit bouncy of a ride, but I was willing to make that trade-off to get her set up for these events. (and in the interest of fair disclosure I have a <span style="font-style: italic">spare</span> TR6 that will be more stock)

A bit lower, a bit more tire contact, lighter wheels, Richard Good springs all the way around with new poly bushings and you'll be smiling.

Make sense?

 

[trfourtune]

Get the Gareth Thomas triumph tuning book!
This is indespensible for the tr6. He has a unique aproach that must be read. Use the original fuel injection. Replace the original fuel pump. Put on 6-3-1 headers and free flowing exhaust system. Use a tr5 cam grind. Build a proper air box that has much more volume.
those are the basics. Head work is always a bonus.
Rob

 

[TR3driver]

I'm surprised no one has mentioned the Moss supercharger. Bolt-on kit, and unlike wild cams & so on, supercharging makes the engine more driveable rather than less. And while anything that increases power output is going to increase strain on components, supercharging actually tends to be kinder to bearings & such, because you don't use more rpm to make more power. High rpm increases stress on rods & bearings more than high power output.
https://www.mossmotors.com/graphics/products/pdf/150-108_Bigboost.pdf

 

[poolboy]

I thought about that, but I wasn't too sure that it would mate up too well with his compression ratio. What you think ?

 

[pjsmetana]

I used to have a Jackson Racing Supercharger on my 98 Honda Prelude SH. Sure, those things make a tremendous amount of reliable power, but the sound is just plain annoying! With an open cockpit, such as a TR6, and that sort of whining sound... It would drive me nuts on a long rally. Maybe Moss' super charger isnt a roots blower, like JR was, so maybe it don't make the same noises... but if theres the chance that it would, theres no way I would get it. If you want forced induction, then a turbo is my only weapon of choice. Plus, they sound awesome.

Personally, I love natural aspiration. Yes, NA tuning comes at a cost of reliability, but theres nothing like the high RPM sing when flying low

 

[trfourtune]

the gareth aproach does not require more revs or a big cam. Gives a broad fat power band. The tr5 cam grind is a european stock cam grind. These cars made 150hp in england and europe-bone stock. North America did not get the same configuration due to the emmissions requirement at the time. All you are doing here is making the motor the way it was intended. What we got was not the same.
Rob

 

[martx-5]

I thought about that, but I wasn't too sure that it would mate up too well with his compression ratio. What you think ?

I have a Miata with an Eaton blower on it (from Moss - Jackson Racing). The compression ratio on a stock 1.6 Miata is 9.5 to 1. It's not a problem, but you'd have to retard timing about 6 deg, or do it electronically while in boost...the preferred method.

The unit that Moss sells for the TR6 is an Eaton. Basically a Roots type, but it has three lobes that have a twist to them. They are much more efficient the the traditional type Roots. They also have by-pass valving in it so it doesn't boost unless you put your foot in it.

Generally, 6 lbs. of boost will yield about a 40% increase in HP.

 

[MTribe]

Can anyone comment on the noise a supercharger makes in a TR6? Or better yet, post a video?

I do like the NA sound, and the sound of the TR6 has always been one of my favorite parts of it. But I've got an open mind on that one.