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TR6 TR6 Dyno results

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zmayne

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Hey everyone,
Recently had my TR6's engine tested on a chassis dyno. Results were pretty good, though I'm surprised at the disarity between the horsepower and torque. As you can see, peak hp was 104.3 at 4150 rpm and peak torque was 147.8 ft-lbs at 2750 rpm. With the parasitic loss from the driveline that works out to maybe 120 hp and 165-170 lb/ft of torque at the engine, which is a loose guess.
I am very happy with the torque figure, but the horsepower figure was a bit lower than expected.
This is a freshly built motor that has not really been setup yet. Carbs are as I bought them, with the exception of different emulsion tubes. Its still running the points setup since the Crane I had installed gave me problems. I'll be going with a Pertronix soon.
Here's was the motor has so far:

.060 overbore pistons
10:1 c/r
Medium fast road cam (can't remember the specs right now)
big valves, h/d valve springs, h/d lifters
ported and polished head
cannon intake
triple Weber carbs
air horns (for dyno)
Monza header
1.75-inch exhaust with two resonators, no muffler
stock ignition and distributor
lightened stock flywheel

Future additions:
Roller rockers
Pertronix
3-inch exhaust
Mallory distributor
and more...

How do these dyno numbers look?
 

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Those numbers look great. And they were achieved with the stock ignition. What plug gap were you using? Does the Monza set up you are using have a cross over for the duals? Great numbers. Put the run on utube so we can see it and hear it.
 
For all out performance, your a/f ratio should be in the solid 13/12 range.

It's definitely falling off there after 4000rpm, did you get a chance to play with the timing?

I think with your setup, it would greatly benefit from the Mallory, assuming the coil and the wires are upgraded as well. I know mine really smoothed my car out.

By the way, you spelled disparity wrong. :smile:
 
You look a bit lean, and as Shannon said, you are falling off after 4k. Peak torque of 147 at 2800ish is pretty decent though.

jooi - What cam is in there?

If you want something for comparison, here's mine.
8.5:1 compression, fuel injected, custom cam grind.

https://www.6-pack.org/spaw/tr6hptorque.pdf

There are 2 runs on there, one with and one without the stock box. You can see that the stock exhaust is actually not bad at all.
 
Wondering where your going to put that 3" exhaust? 2.5" is supposed to be a tight squeeze through the cruciform.

Your probably going to need to spend some $$$ and time on tuning the Weber's. Unless they came off an engine the same spec as yours and within a 1000' (plus or minus) altitude differential. The dyno could be your best friend for that job.
 
Thanks everyone.
Actually, the header is not a Monza. It's a Pacesetter which goes into a single, 1.75-inch exhaust. Sorry.
The cam is the BP270 from BP Northwest, which has a duration of 270 degrees, intake lift is .410 and exhaust lift is .400.
I agree about the lean issue. I was hoping my hp curve would look more like yours Alan. Power really tapers off after just over 4,000 rpm, and I'd like the motor to have a more distinctive power curve with more power up top.
What would the leanness be caused by? Jetting in the Webers? We've played with the timing, bit just on the side of the road by turning the distributor a little to see if tht helped.
Right now my exhaust is 1.75-inches, which in retrospect seems small. Even my built 2.0-liter Alfa motor uses a 2.25-inch. Will going with a 2.5-inch free up more power?
 
1.75 is a little restrictive, it could be a little of the reason why HP drops off when the engine is trying to flow a lot of CFM. You could run it as an open header on the dyno just to see the benefits of a very "free flowing" exhaust. 3 inch will fit but just barely, but I don't think that you need to go that big with a NA engine putting out less than 250hp.

The jetting will be where you will take care of your engine running lean. As far as AFR you want to shoot for 11.5-12 maybe 12.5, but not leaner than that if you are going for power.

Love to see a video, and good luck.
 
Unfortunately no video, when I was leaving it crossed my mind I should have shot some video. It sounded pretty impressive.
 
Hello Zmayne,

I take it that there was little optimisation done on the dynamometer?

What is the layout of the exhaust manifold (header) as these engines work best with a well designed 6-3-1 system.

I would have thought that you should have more horse power although you do say the engine is new so will bed in and give a little more.

Out of interest the 1964 and 1965 Triumph 2 litre works rally cars (Triumph 2000 sedan) developed 150 bhp on triple webers, retaining the standard cast exhaust manifold. This also had the in line port configuration rather than the more efficient high inlet port configuration of the 2.5 litre engine.

So I think that with your existing set up you should be able to get quite a bit more power.

You might like to talk to some of the guys here:-https://www.tr-register.co.uk/forums/index.php?showforum=7

Quite a few race TR 6s and many use the Weber set up.

Alec
 
Okay, the leanness at the top, is the major area of concern that I would focus on. Make sure the fuel pressure is good(2 psi) and volume is good, Might want to upsize the tubing, and make sure you have NO kinks or restrictions.

Then check the float level and raise it to the upper edge of specs.

On the DCOE's the fuel enrichment circuit(like the power valve on the Holley's) is in the accelerator pump circuit. What I have done is played with the accelerator pump jet and return jet size.(if I got the terminology off, sorry, first cuppa in the am, you'll be able to figure it out with one of the good Weber books.


Remember, emulsion tubes larges affect is throttle progression.
 
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