My Vegantune is Vaguely Tuned!

[rgh0]

I think I would expect 90 to 100hp on the rolling road for a BV twink. A nominal 150HP engine should be around 110 to 120 hp at the wheels. A 170 hp engine will do about 130 hp at the wheels

Above 100 is unusual and below 90 unusual in a standard BV . But there is significant variation depending on things like tyres and tyre pressures, tie down methods and exact location on the rollers, roller wear and dyno calibration and how the test are done. Rolling roads are good for getting an engine set up right and doing back to back comparisons of different types of set up but not much good for determining actual absolute HP.

Looking at your curve a couple of comments

1. It was done in third gear so I would expect it to be a little lower with gearbox losses of maybe 3 to 5%
2. It was still going up at 6000 rpm which indicates the engine is giving good power to above standard 6500 rpm peak on an engine dyno. A rolling road has a lower peak power due to the drive train losses increasing but the engine power increase dropping off at higher revs.
3. I dont understand the torque numbers quoted as this does not line up with engine torque??? is this some sort of wheel torque measure?

cheers
Rohan

[RichardS]

Thanks Rohan

Can?t help on the torque figures as beyond my comprehension! I appreciate that there are a lot of variables with the rolling road figures.

I did have a brief word with one of the guys at Agra Engineering in Dundee who have had good feedback on the forum. They estimated ?5k to ?7k for a rebuild, obviously depending on final spec. For this sort of investment I would obviously want a significant and noticeable improvement on the current set up.

So do the rolling road figures suggest the current engine performance is a little below a standard BV engine? Perhaps on the road performance is similar if only a few bhp down on expected. But perhaps 140 to 150 bhp would be even better!

Richard

[rgh0]

Hi Richard
Yes without knowing some more about the engine and its specification and going just on the dyno results I would say it producing similar to a used standard big valve engine.

The cost to get a 150 hp engine depends a lot on the state of current components and how much rebuilding is really needed. The cost numbers quoted reflect a total rebuild and your engine may need a lot less than a total rebuild.

If the bottom end and head is sound you may only need a new set of cams and new valve spring packs and some careful reassembly and setup.

cheers
Rohan

[rgh0]

Just rereading the thread. i suspect the so called "150hp" Vegantune specification is no more that maybe a L2 style cam in a standard engine as back when Vegantune were around the high lift short duration cams were not being done for road engines as the valve springs they needed were not easily available and you had to deepen the spring pockets and only serious race builders such as Hart and Dave Bean were doing that sort of modification (and i was learning how to do it through trial and error and rebuilding / rewelding heads !)

Now a QED 420 cam or similar and suitable spring pack and a little work around the valves and valves seats can make close to 150 HP at 6500 hp with well set up carbs and a good exhaust in a 1600 cc twin cam

cheers
Rohan

[RichardS]

Thanks very much for your comments Rohan. I think I will wait and see and perhaps look at the QED 420 cams which I know come recommended as a reasonably straightforward upgrade. As the engine has only done about 15000 miles then hopefully it is in generally good shape and not too tired. To be honest the performance as it is is probably more than adequate for me these days!
As always appreciate your advice
Richard

[gav]

This is fascinating
I have one of the last Vegantune engines which I am now running with an Emerald ECU and Jenveys (I know - but it runs so smoothly).
I had it dynoed about 10 years ago when it was on webbers and it produced 150 BHP and 128 ft lb and when I had the fuel injection set up at Emerald, it produced 150/129. These figures were derived from the rolling road and are meant to represent the flywheel figures.
The head was heavily ported and the spec was for fast road rather than racing so it is very tractable.
I run it with a TTR fast road exhaust system and I think allowing it to breathe properly makes a significant difference.
I'll see if I can dig out the spec sheet over the weekend and see how they compare.
Gavin

[billwill]

As far as I am aware, George Robinson, the founder of Vegantune (and subsequently Evante Cars) was 'heavily' into race engines and ( i think) assisted Lotus racing. Team Lotus ?

I was given some information (about the history of Vegantune and their involvement with Lotus Twin Cams and later their own VTA engine), when I was drafting a website for Vegantune of Finchley (who had bought up the defunct Vegantune of Spalding).

I will try dig it out and put it into a form suitable for posting here, when I feel I have some time for it.

~~~~~

When Vegantune of Finchley also went bust, the name etc was bought by a new person who is a member of this forum, but alas has not been online here for many years and did not answer my last email/PM to him.

[nmauduit]

This is fascinating
I have one of the last Vegantune engines which I am now running with an Emerald ECU and Jenveys (I know - but it runs so smoothly).
I had it dynoed about 10 years ago when it was on webbers and it produced 150 BHP and 128 ft lb and when I had the fuel injection set up at Emerald, it produced 150/129. These figures were derived from the rolling road and are meant to represent the flywheel figures.
The head was heavily ported and the spec was for fast road rather than racing so it is very tractable.
I run it with a TTR fast road exhaust system and I think allowing it to breathe properly makes a significant difference.
I'll see if I can dig out the spec sheet over the weekend and see how they compare.
Gavin

I believe there was a whole range of preparation stages one could chose from offered by Vegantune; I don't remember where I have found the following document, but I saved it since I also have a Vegantune engine for a project:

Vegantune preparation stages

[rgh0]

Yes they were always vague on what you actually got for you money... ..

Lots of claims and a great list of spend more get more but.... what did you really get , that was always a little harder to pin down

I would love to see some real original Vegantune specs with details of porting, valves, springs, compression ratio, cam lift and duration etc...... if they were ever published

cheers
Rohan

[pauljones]

Has anyone tried or looked at the Newman cams ph5 for the twincam. Advertised specs has it at .443 lift and 280? duration. Very similar to others that have had good comments made about them.

[Craven]

It may be of interest to anyone trying to identify a Vegentune camshaft in that, the reason is not clear, they machined, looked as if tuned down in a lathe rather than ground, between the cam lobes on their modified cams.
I recall driving a series 2, ?7? fitted with a Vegantune twincam back in the 70?s, barely time to snatch the next gear before hitting the red line.

[nmauduit]

Has anyone tried or looked at the Newman cams ph5 for the twincam. Advertised specs has it at .443 lift and 280? duration. Very similar to others that have had good comments made about them.

I'm interested, too, as seriously considering this profile for my next build.
I've tried to get in touch with them several times but did not get any reply so far...

[pauljones]

Pumaspeed
Unit 6 Evans Business Centre
Monckton Road Industrial Estate
Wakefield
West Yorkshire
WF2 7AS
T: 01924 360260
E: [email protected]

Have you tried these guys?

[nmauduit]

Have you tried these guys?

no, I was still in exploratory phase so so far I've only tried to contact Newman themselves, regarding

http://www.newman-cams.com/wp-content/u ... ubishi.pdf

[pauljones]

Id be interested in the results of this vs the current tried and tested varients. I guess its getting to the limits of lift/duration for a road car.
Im certainly no expert on the matter either.