Vulcan Engineering

[carrierdave]

Hi - not sure if anyone has seen this before?
I met up with them this week. They appear to know what they are doing and from the looks of the video and the engines within there shop they have some history with the twin cam.

Thanks

Dave

http://www.youtube.com/watch?v=FqN-3Vqqy2E

[tdafforn]

Its interesting to see EFI on a twinc. looks like the modified the inlet tract fairly exteinsively to fit it!
Tim

[curly type 26]

Hi i have used vulcan for more years than i can remember, what they dont know about Twinks isnt worth knowing, got a problem ask for Steve.

[stuartgb100]

I seem to remember Vulcan from around the very early '70's. Think they spent a lot of time on Tecalamit injection systems, back then.

Regards,
Stuart.

[msd1107]

I wonder why they posted this video.

Looking at the readout:

The first reading is 120.1 ftlbs torque @ 5730 for 131 hp.
Max torque is 128.4 ftlbs @ 6260 for 153 hp, 203.4 bmep, 13.8 bar.
Max hp is 115.5 ftlbs torque @ 7460 for 164 hp, 183 bmep, 12.5 bar.
Max rpm was 104.6 ftlbs torque @ 8010 for 159.5 hp.

It would have been useful to see readings from around 4000 to see what happened to the mid range torque.

There is only a spread of 1200 rpm between max torque and max hp, a rather narrow range. In the engines favor is that the torque does not appear to fall off badly below the torque peak, and the hp does not fall off badly after the power peak. So the useful rpm range probably extends from below 5000 to above 8000. Still a little tricky to drive.

Does any body else have dyno runs they can share to provide a comparison?

David
1968 36/7988

[SADLOTUS]

Hope this loads.... pdf

Notice the fuel is 99Ron +CVL additive, how much diference this makes I don't know.

[msd1107]

Excellent!

The CR is 10.5 on the chart, so 99 RON should be suitable. Unless they are using oxygen carrying additives, it shouldn't make any difference to the power.

Note that they used 15W40 oil and 45psi oil pressure. This is in line with the trend to use lighter weight oils and lower oil pressures to minimize losses. The oil pump just needs to circulate an adequate volume of oil. Higher pressure just increases the pumping hp.

Note the bump in the torque curve at 5500 rpm. I saw another dyno curve recently with a similar bump. This is probably the intake tract resonance point, and could be moved down the rpm curve slightly by lengthening the intake trumpets.

Let's get some more charts!

David
1968 36/7988

[alaric]

Chaps,

Really interesting video. I wish I'd taken one of mine twincam on the dyno - on the other hand I'd rather not be there.

One of the other videos listed on the youtube page was this ferrari f50 gt1 on a dyno.

http://www.youtube.com/watch?v=uQeTdkxv8-w

That's someone's job! Ridiculous!

Glad I wasn't there when QED ran my twincam on their dyno - I've got the power plot - it goes up to 7000rpm. I've attached a copy for interest. My engine's completely standard, but the bottom end is blueprinted, and the combustion chambers in the head had to be re-worked to reduce the compression ratio. The engineer was really pleased with himself, and I was really happy with the performance.

Sean.

[rgh0]

Come on Sean tell us what cams you have in it. 140hp does not come out of a "completely standard twink". Or is the QED dyno 10 to 15 hp optimistic to keep the customers happy?

cheers
Rohan

[msd1107]

Rohan,

Interesting comment. I thought that it was a very strong run.

But recently, there was a supposedly standard Sprint engine (126 hp) that dynoed at 130+ hp.

It may be that meticulous preparation is worth more than an additional 10 degrees of cam duration.

That is why these dyno curves are so interesting.

If those with strong dyno runs divulge their prepartion techniques, it can only help the universe of TC owners in having strong running engines.

David
1968 36/7988

[alaric]

Maybe that's right Rohan. It certainly kept me happy. I remain as skeptical as the next person re dyno results, but can't really comment on the calibratiion. Maybe other QED cutomers have found the same. Maybe the cams aren't standard - I did get on quite well with the guy that did the rebuild.

All the best.

Sean.

[rgh0]

Sean

I have been scratching my head about your dyno result to try to come up with a more reasonable explanation of how you get the results you did as I dont really believe the QED dyno is that optimistic.

According to Dave Bean a sprint spec engine with mild porting around the bend of the inlets and outlets can give 130 to 135 hp. If QED did not use your exhaust on the dyno but one they supplied, the twink responds well to a bigger exhaust than you can fit into an Elan. T

May be some combination of this sort of thing got the hp on the dyno to your 140hp. Regardless it sounds like you have a very healthy engine

cheers
Rohan

[hatman]

Interesting. I am very sceptical about the accuracy/reliability of dyno readings as there's effectively no way of running back-to-back checks, one against the other. I mean, who ever insists on a 'second opinion' by taking the car to another dyno just to make sure?

I had my car's Dell 'Ortos set up by a local (mini) tuning specialist a while ago then checked on his dyno. Showed that it was kicking out 129bhp (plus many more torques, as JC would say, than the factory claimed). Not bad for a well-used high-miler that then needed a full top-end overhaul a few months later. Lies, damned lies and......dyno figures.

[denicholls2]

If your dyno man is honest, he will tell you that his dyno will read differently from the one down the block. He'll also tell you whether it reads higher or lower and by about how much.

The dyno guy isn't in business to certify your horsepower. He's in business to provide a repeatable test platform that can be used to tune your engine to deliver the highest power output it is capable of.

My guess would be that the QED dyno is maybe 15 percent optimistic, which is well within the range of variability I've seen.

My own local dyno, NE Dyno in Worcester, Massachusetts, yields results that are about the same amount pessimistic according to both its manager and our observed results. Some users saw results as much as 100HP below what they'd expected based on runs at other sites (These were for expected 500+HP Esprits, Camaros, and other big block exotics. I've seen a fairly radical crossflow Renault dynoing about 25 HP down of an expected 170 but in perfect tune.

This particular dyno doesn't see many engines that make as little horsepower as our Lotus fours, and some speculated that its own tuning might put such cars at a disadvantage -- Those with smaller engines were generally more disappointed in their results than those with large ones.

I was quite pleased in this context to see over 80 HP at the wheels on my Hermes Europa in sluggish tune and with a dancing distributor.

People like to use their dyno sheets for bragging rights. They're no good for that unless the comparisons are same day, same dyno. With equal atmospheric conditions, your dyno shop's job is to give you the same result good run after good run, not to certify your absolute power and torque.

I do agree that an optimistic dyno offers a better business model.

[SADLOTUS]

Agreeing with denicholls2 above, my bike dyno man said one of the best dishonest/honest things that can give a big variable is the atmospheric pressure, if you force it one way or another on the dyno computer/settings, you can go from below sea level to half way up a mountain with corresponding results- imagine the air density at either of those and how your motor would behave. Also it's not one of those measurements (for me anyway) that on the printout I'd know was correct or not.

He also said that a really peaky delivery can be deceptive and make the bike feel more powerful than it really is.

With the bike I use the dyno as a comparison for before and after, I've only had a couple with the car, one with engine out and one at the wheels, years apart- so no comparison there then!