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A Few More Beans


RayHutch
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My Vitesse 2L engine has about 10,000 miles on it since a rebuild. I’m not sure what cams were fitted or what was done as it was 2 owners ago and the history file doesn’t have the details. I’ve recently had reconditioned Strombergs fitted and they’ve been professionally tuned. 

It goes well and sounds great - my question is, what is a cost effective way to get extra horsepower?

I’m not looking for silly boy-racer stuff just a subtle bit extra. I know a bit about achieving this from a K Series but have no experience of the straight six.

Looking forward to constructive comments.

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Ray, 

As said by anglefire, the principles are the same, right up to F1.   And like F1, the more you do, the more it costs! 

You have already had your carbs tuned - did this include a rolling road session?   Then the ignition timing could be optimised as well, as far as a stone age distributor can be optimised.  

Which brings up electronic ignition.   This may be just replacing the points by an electronic trigger, optical or Hall effect, or all the way to a crank sensor and individual coil packs (eg Megajolt) which can be "mapped".

You probably don't want to go as far as  fuel injection that can also be mapped and more closely tuned than a csrb can.

As well as optimising timing and fuelling, actual ignition can be improved.  Efficiency of combustion increases with compression. And Triumphs left the factory with a CR of 9.5 or less.    You can aim at 10.5, or even 11 and run without octane boost on V-Power or similar 98 octane fuel.    You won't get preignition, unless the fuel id allowed to grow 'stale' as it does on a few weeks.

For general text on engine improvement I suggest you look for Graham Bell, and for flowing and combustion chamber improvement, Vizard.    The latter's book on larger Triumphs is online somewhere!

Good luck, and keep us informed!

John

 

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Thanks John,

Carbs were tuned without a rolling road. Wasn't sure of the value given that there was no ECU to map. Valves were also checked. We tried a sports coil but it appeared to have little effect.

It has electronic ignition but I'm not sure which brand. It also has a nice stainless steel exhaust. Air filters are the metal pancake type. I'll check on the manifold tomorrow.

Don't understand your comment about CR 9.5 to 11.

I fitted verniers to a K series in the past and that helped a lot - not sure how this applies to this set up. Friends went for a lightened flywheel but that made tickover erratic.

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A rolling road session will enable the operator to modify the needles so you get correct fuelling across teh rev range. Unless the previous tuner was gods gift to tuning, it is almost impossible to get this right without a session on the rollers.

Example. My old 1500 engine, (modified cam and head, all balanced etc) was at 80bhp, but a session on the rollers took it to just over 90, plus it felt MUCH better to drive. Took the chap 45 minutes, he didn't faff about! He did have a play with the distributor, but could not improve it. But with yours changing advance springs may bring benefits.

As to CR (compression ratio) that needs to be increased as using high lift cams lowers the effective CR. And ideally you need it to be a little higher. My 1500 ran 10:1 CR on std fuels.

Vernier sprockets enable you to swing the cam a bit and alter cam timings, available for "our" cars but it can be done by altering the way the cam sprocket is fitted. Not sure about the benefits really if the cam timing is set correctly. OK, one way gives a little more torque, the other a bit more power, but in the middle is the best compromise.

Otherwise usual stuff as above. 6 3 1 manifold, bigger carbs can help, sidedraughts definitely will.... as will headwork, but some simple work can be done quite easily. You don't say if it is a mk1 or 2 engine. But if MK1 and using the original inlet I think there is a modification to greatly help power (check Chris Witors site for details) and changing to the bigger mk2 head studs is essential...

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The std MK2 cam is very good all-rounder, hopefully that is what was put in?

You can spend substantially on an exhaust manifold for a bit of extra power, or get similar by picking up a TR6 cast iron manifold and downpipe, and do a bit of cut/shut to get it to fit. But beyond that you are talking spending substantial sums. 

I still think a modest £150 (depending where you are) will have a session to set it up and maximise what you have. Plus you will find it will be more economical, mine was by about 10%. win-win.

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If you are using your Vitesse for road use, are running it on carbs and only want to increase the power by a small amount then I would leave the Compression Ratio, CR, at it's present 9.25. I agree with Clive's view on the existing cam.

So what to do -

Firstly the bit the goes in the engine -  Fit K & N air cleaners and heavier piston springs in the carbs. You don't need richer needles as the existing one's have a wide range of adjustment. 

Secondly the bit that come out of the engine -  Fit a sports exhaust.

Also replace the points with an electronic ignition.  

I agree with John and Clive re the a rolling road.

The above will give up to 15BHP more and the engine will also rev more freely with no loss of low end torque.

However, if you are after a lot more power then follow John's and Clive's feedback.

Dave.

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Ray,

If you don't understand what is compression ratio (CR), then we must rein back and consider your education, despite your exploits with a K-series engine.   May I humbly suggest you read my article on CR on the Technical articles forum?   http://sideways-technologies.co.uk/forums/index.php?/topic/7551-how-to-raise-the-compression-ratio-safely-and-effectively/

Vernier sprockets are useful for tuning on a K, as it has a cam BELT, and sprockets that are external, with a light plastic cover, and may be accessed and swung easily to adjust and tune, even during a rolling road session - the ideal.       The Triumph has an enclosed drive CHAIN, and access is only by partly dismantling the front of the engine.  Not very practical as a tuning move, although a vernier will let you set the timing exactly where you want it in the workshop.

Big plus to the 6-3-1 exhaust manifold Clive suggests, but it MUST have equal primaries.  (And Clive's other suggestions!)

But K&N pancakes are a BIG no-no!     Unless you enclose them in as large an air box as you can, ducted to get COLD air from the front, they will aspirate hot turbulent stuff from right next door to the exhaust.    And heavier piston springs?  They need to match the needles, and the needles need to match the intake air flow, or else they will just hold the pistons down, accelerate what air you have flowing and make it run rich.     Which might be what is needed, but who knows?

Maybe you're wishing you never asked?

John

 

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All we can say is that looking for more power involves

(a) Lots of unintended consequences. 

(b) costs far more than you imagine 

(c) if not done holistically and to completion can result in a very empty wallet and a car that doesn't go any better than when you started!

I have met my limitation with my car, and apart from some minor fettling I am not looking for more power. I think I have as much as I can without having to spend many thousands of pounds....

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11 minutes ago, clive said:

All we can say is that looking for more power involves

(a) Lots of unintended consequences. 

(b) costs far more than you imagine 

(c) if not done holistically and to completion can result in a very empty wallet and a car that doesn't go any better than when you started!

 

Add to that: usually lots of noise, becomes uncomfortable to drive in normal use or on long journeys, and becomes expensive to insure.

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4 minutes ago, Colin Lindsay said:

Add to that: usually lots of noise, becomes uncomfortable to drive in normal use or on long journeys, and becomes expensive to insure.

In fact that CAN be a consequence of poorly done modifications. But my own spitfire with over double the original BHP is comfortable for the vast majority of journeys (having done long autobahn trips at 3 figures, alpine routes plus pottering about town) is quiet, but I had to make an exhaust that is both quiet but free flowing, there is nearly 6' of exhaust box. Expensive to insure? still under £200 a year...that includes my Toledo. Yet the Sptfire still handles well on trackdays.

Yes, on speedhumps and big potholes it is bumpy, but in all honesty a std spitfire is just as bad.

 

However, the usual approach of the twin exhausts (very noisy) and hard, uncomfortable suspension that has terrible bump-steer is all indicative of people who have not thought things through. Largely as stuff is sold as being wonderful, but most people have no idea on how to use it or what works best.  And usually do not have corrective tuning/alignment done. Except the exhausts, that are just unnecessarily noisy.

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14 minutes ago, RayHutch said:

Coming to the conclusion that marginal improvement is not worth the effort and cost. Might try and find a local rolling road though ;-))

This company may be able to assist, no personal knowledge - just did a Google search for RR Berkshire:

http://novatech.info/

Worth a call to ascertain their worth............... seem classic car focused.

Good luck.

Richard.

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11 hours ago, clive said:

But my own spitfire with over double the original BHP

Courtesy of 1990s Ford technology mind 😛

Sticking with a mostly Triumph engine, after about 15 years of development my own Vitesse 2L Mk1.5 is up by about 40%.  That involves a gas flowed head, increased CR to match the more aggressive cam, 6-3-1 manifold plus bigger bore exhaust and electronic engine management.  It's not really any noisier than standard and is quite a bit better on fuel.  We'll not go into the cumulative costs and aggro though!  The Mk2 Vitesse (and GT6) engine is one of Triumphs best efforts as standard and some care is needed not to spoil it.

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1 minute ago, Nick Jones said:

Courtesy of 1990s Ford technology mind 😛

 

Fair point, but weighs the same as the Triumph engine, so handling etc is not affected by any changes there. 

I maintain a badly or ill-conceived set of modifications make the cars worse. And often setting up (rolling road and proper alignment) transforms a car in standard trim. But then some of us like to fiddle and make changes, some of which are"unpalatable" to some purists. Never mind. No point in doing things by half 😎

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1 minute ago, clive said:

I maintain a badly or ill-conceived set of modifications make the cars worse

No argument there - and definitely not putting your nicely sorted beast in that category ☺️ 

Thought it needed putting out there though as getting double the power out of any Triumph lump is very challenging, and keeping it road-usable at the same time even more so.  Anyway, you are being modest..... it's a bit more than double isn't it.....?  I ain't no purist :ph34r:

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11 hours ago, clive said:

However, the usual approach of the twin exhausts (very noisy)

I have fitted a ss manifold and twin exhaust and don’t find it noisy at all - or at least not too noisy. Cruising it doesn’t make much more noise than normal exhausts - accelerating it does make some noise - but not bad and sounds nice. 

Possibly because as well as the two silencers, one on each “handle” it also has a straight through one in the single tube - which many don’t seem to have. 

Whether it makes any difference I have no idea!  

Edited by Anglefire
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Mark, there are a variety of the twin exhausts. Some are dreadful, a few (not sure which) do a much better job, yours must be the latter. Having owned a couple over the years, I would not risk it again. In fact, the last system I was given, and used for a year on the current spitfire. But it was dreadfully noisy on motorways at 70-80, which was not good as I do a fair bit of that (not by choice, but to get places) That is when I bit the bullet and made a 2 1/4" system, with a 3 1/2" silencer as you have between the chassis rails, and then 2 4" diameter silencers with a total of 4 1/2' under the boot floor. About 92db when measured at noise tests on trackdays. So well within limits.

Nick, always good when people push the boundaries! The mk3 spit is about 120bhp I think, and that is a 1300 Triumph engine....

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ST170 (which is a zetec with a few improvements). Absolutely bombproof. Trust me, I have tried😂 And not exactly new, being over 25 years old!! In fact, it is only 12 years newer than the last spitfire engines made. Scary thought that engine design improved that much between those dates, though to be fair the Triumph engine was rather long in the tooth at that point. 

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On 13/02/2019 at 09:30, clive said:

In fact that CAN be a consequence of poorly done modifications. But my own spitfire with over double the original BHP is comfortable for the vast majority of journeys (having done long autobahn trips at 3 figures, alpine routes plus pottering about town) is quiet, but I had to make an exhaust that is both quiet but free flowing, there is nearly 6' of exhaust box. Expensive to insure? still under £200 a year...that includes my Toledo.

So we're talking about replacing the original Triumph engine with a modern? (Hits Clive an exasperated slap) It's hardly fair to compare the BHP then, or any other characteristic. I'm sure my Mondeo is more comfortable and certainly quieter than my GT6, and better suited to long journeys. It won't help the OP get more power out of a Vitesse engine, though... :)

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