tr6 Pinks fast road engine

[pinky]

Hi my tr friends,

As some of you no the last 3 to 4 years I have been trying to build a fast road engine,

I kept the original engine and bought an engine of rimmers, the engine was cheap, no return, exchange, etc, I used this as a starting point, every thing was changed, machined, etc,

Apt from the pistons, they appeared to be new, big mistake the rings were the wrong size, resulting in the engine coming out, there were other problems with water and oil leaks

new pistons were bought, balanced etc

The spec of the engine is as follows

Sprint camshaft

Followers tuft drilled

balanced engine

Spitfire bearings

Flywheel 5.2 kilos

Stage 3 head

6 branch exaust

Webber carbs

123 ign

The car went on the rolling road Tuesday at sigma engineering

I thought I would share the results with you

I am really pleased with it

 

Pink

 

 

 

 

[Bill944T]

Hello Pink

 

What gear were you in to get 84.4 mph at 5595 rev/min?

 

Regards

 

Bill

[Tom Fremont]

Hi Pink,

 

Should give a stock P.I. a run for its money!

 

Do you by chance have the Weber settings? Would be good to compare notes, and see if there may be any more power to be had .

 

Cheers,

Tom

[Alec Pringle]

"What gear were you in to get 84.4 mph at 5595 rev/min?"

 

Sounds about right for direct 3rd gear on a later TR6 box and lower/wider than OE tyres.

 

Cheers

 

Alec

[Motorsport Mickey]

And a relief to see an honest rolling road report with the power and torque crossing at the appropriate revs.

 

Mick Richards

[pinky]

 

Hi bill I believe 3rd

 

I will send them to you tom

 

You need to be carefull at low speed with the throttle it dousnt like going slow

 

2500 rpm and it starts to fly

 

I believe, (been told) 141 at the wheels is a good result, and the power curve is good

 

Stock pi would manage 102 hp at the wheels, with the wind behind it

 

However is it worth it doing , probably not, that is why I kept the stock engine

 

Pink

[heckler]

Does that not show 116 at wheels & 141 & the fly wheel ?

Chris

[Alec Pringle]

Indeed it does, just a slip of Pink's fingers on the keyboard . . . . .

 

A stock CR PI engine would originally have been around the 100rwhp mark max, give or take a handful of horses and bearing in mind that the overdrive unit would eat 5 horses at full chat.

 

A stock CP PI engine would have been nearer 110, and relatively few had o/d ex-factory. The factory 'road test' cars perhaps a few extra horses, benefiting from careful assembly.

 

A blueprinted prodsports lump back in the day might have achieved around 125rwhp, 150-155bhp at the flywheel.

 

Cheers

 

Alec

[heckler]

Thanks Alec I thought it was pretty near CP figures .

Chris

[pinky]

 

 

The fig corrected power 141.7 is the important fig used to compare cars around the world

 

 

Pink

Edited August 5, 2016 by pinky

[Alec Pringle]

If you want an accurate and absolute measure of engine power and torque then an engine dynamometer, measuring output at the flywheel, will provide that.

 

A chassis dynamometer, or rolling road, is not an absolute measure - but it is the proper route to making the best of the engine as installed in the vehicle.

 

There are a significant number of variable which may be introduced by rolling road operator technique, and it is not unusual to find a 10% spread of results if a particular vehicle is tested on 4 or 5 different and reputable chassis dyno installations. There are other installations which might well offer substantially more exaggerated figures.

 

The 'corrections' and projections used to produce a flywheel output figure from a rear wheel horse power measurement are arguable at best . . . . . . . and in any event differ between dyno manufacturers, and are subject to manipulation by dyno operators . . . . .

 

The idea that figures can be accurately compared between various vehicles and chassis dynamometers is, I'm afraid, a myth.

 

What matters, Pink, is that your chap has hopefully made a good job of fine tuning your engine and extracting the most from what you have !

 

Cheers

 

Alec

[Jersey Royal]

Pink

 

So that's 116 at the wheels, thought your old motor (which you still have) gave 125 at the wheels.

 

It's all down to how it drives and feels, if your happy that's all that counts.

 

Cheers

Guy

[Alec Pringle]

If Pink refers to Sigma Engineering in Gillingham, Dorset, then it's safe to assume that the 116 figure refers to proper horses . . . .. as opposed to the aspirational ponies which some Triumph outfits seem to specialise in breeding.

 

Peter Lander was already an acknowledged and successful engine tuner when he first set up Sigma, way back when Triumph were still manufacturing TR4s . . . . his original business partner at Sigma was Neville Trickett, later responsible for designing the body of the TR8 Turbo Le Mans (and of course the Minisprint), but they parted their ways in 1965.

 

Peter is not given to flattering his customers, and in my experience he'll always focus on the torque curve and maximising driveability, as opposed to aiming for an irrelevant maximum headline power output number. No doubt Pink left Gillingham with a car performing distinctly better than when he arrived . . . . . .

 

Cheers

 

Alec