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Triumph TR6 - Supercharging - now there's an idea!!

Following up on P H's comments on thread 'Flywheel lightening' I was wondering as to whether there is much info / experience about on this subject - I'm not interested in doing it - only curious.
Roger H

I personnally don't, but I believe quite a few of our Brit companions have done this, since PI is easier to supercharge than the carbs. Maybe they can help.

There are many books on the subject and a wealth of expertise in the vintage (prewar) and dragster communities. Because blowers incur a 40% cubic capacity penalty in determining racing class thay have not had a following amongst classic racers. But that penalty says it all- supercharging is a highly effctive way of getting more torque and power, and a cost-effective route too. With modern blowers becoming available (Eaton especially) the need to refurbish an old Wade or Marshall or GMC or Shorrock etc etc, is overcome.
The easiest way to fit a blower is in draw-through mode using an SU carb, although you do loose the possibility of intercooling, but this is no probelm for road use where bursts of full throttle are used only occasionally (you soon run out of road).
I am aware of only two TR6s that have been supercharged, and both used a single 2" SU. Getting the Lucas PI to meter fuel sensing both manifold depression and boost might be possible by using the choke enrichment lever togehter with a diaphragm actuator to sense the boost, but as yet no-one had done it to my knowledge.
I wrote an article on my supercharged TR6 for TRAction a few year back and its been put on the web here:

P H Cobbold

Correction: "I am aware of only two TR6s that heve been supercharged **in the UK**"
In USA ther must be 20 or so as Vintage Induction Systems sold a neat kit until a couple of years ago, based on an Eaton blower fitted to a custom inlet manifold.

Narinc built a blown racer:

And here are the URLs for Eaton and Magnuson ( famous name in USA circles):

And here's a DIY Canadian blown **B:

P H Cobbold

Maybe it was that article that made me associate it with you guys. Anyway, it show that the Brits know what to do, even if they don't do it often. Thanks.

The supercharged 2.5 has great merits yet after seeing a turbo 2.5 and hearing the cost to do it,(cheap), and then finding out the owner has put over 125,000 miles on this rebuild, well what am I waiting for?
w Holtzclaw

Arkay in Hawthorne, California fitted a LHD TR6 with a Rajay turbo and draw-through Weber carb. There's a photo in Alan Allard's book but it dates from early 1970's. Turbos are not an easy option on RHDrive cars because the steering column gets in the way of the turbo/exhaust plumbing.
Matching a turbo to the engine is also not as easy as a blower.(Compressor matching maps are not easy to interpret). Avoiding turbo lag is one problem. The other is handling excessive boost or over-running the turbo. But if you can get the details of that turbo-charged TR6 it would avoid re-inventing the wheel so to speak. I agree that it could be cheaper, but probably not by much.
Reliability would not be in doubt with a modern blower either; Eatons are fitted to Mercs and Jags and are good for 100,000 miles.
Frankly I doubt a turbo will give 1psi boost at 1000rpm- that really has to be experienced. It makes the TR6 engine feel like a V8; lots of low down grunt and smooth with it.
P H Cobbold

In summer 1997 issue of the TR6 SixPack magazine there is a long article by Nick Formica 33 Birch Hill Drive, New Britan CT 060521 about his use of an Eaton supercharger with home made mounts and linkage. Seemed very happy with the results.
Dick Porter
Dick Porter

I remember that article (its somewhere in the loft). After reading it I rang him up and his enthusiasm was clear if a little boistrous. Only later did I realise I had phoned on 4 July.
I wonder if he still has it?
P H Cobbold

This thread was discussed between 23/01/2003 and 28/01/2003

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This thread is from the archive. The Live Triumph TR6 BBS is active now.