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Supercharging A Triumph Gt6


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I've just found a couple of things on the net about using a M45 Eaton supercharger on a Triumph Spitfire. Just wondering really if anyone had had any experience doing this? I really like the sound of superchargers and it would make my GT6 a little more unique but its whether it would be worth doing. The engine is a standard 2 litre straight 6 but its off the road at the moment and ready for a bit of work to be done!

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Presumably you found Josh Bowlers information?

 

http://www.justdrive.ca/gt6/josh/supercharged.html

 

Worked well that. More to it than meets the eye I think as Josh thought about it long and hard before putting it on the car.

 

Steve Downing in the US also put one on a 2.5L 6 in his autocross Spit6. That was a nice job too producing lots of grunt. He had a Toyota gearbox and special rear end IIRC.

 

See http://sideways-technologies.co.uk/forums/index.php/topic/11-eaton-m45/

 

Also Moss do a supercharger conversion for the US spec TR6 so there are quite a few of them about.

 

Bear in mind that there isn't alot of spare strength in the GT6 driveline........

 

Nick

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The problem with Eaton S/C is they are crap and drink horsepower and therefore fuel.

You can get more power N/A than you can with a S/C,but people think the opposite.

 

The fact is, you get a brief surge low down (as you might well with a well thought out high lift cam), then ZILCH top end as it can take as much as 50bhp to drive one of those things.

If you don't believe me check out the stuff on Jaguar XJR conversions, where they manifestly failed to beat the power output of a good N/A plant, and were leagues away from the Turbo technics Chasseur cars even.

 

XJR always drank huge amounts of fuel (about 50% penalty), which mostly goes into heating air up, so you will get a charge temperature exceeding 100C every time.

That will destroy any Triumph cast piston if you want to wind up the boost a bit.

 

I worked on Golf G60, they & G40 had problems all of their own...again DRANK petrol like no tomorrow.

 

All the yankee s/c conversions are comparing apples with oranges.

Anything which makes more than the original 100bhp (if you are lucky) is considered "performance".

That doesn't mean it's any good.

 

Being as you can buy a multiple throttle body fuel injection piece of kit, SCRAP for one of those cars, I've never understood the attraction of S/C.

Turbo YES, it's been done, but then you have to cope with the huge heat source on the RH side of the car.

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Twenty years ago, this appeared in a long dead classics magazine, Jalopy.

Read, enjoy, and learn!

________________________________________________________________

 

TURBODGING

 

Inspired by the Blue Peter spirit of adventure,

R. A. Franklin added boost to his Triumph GT6, and lived to tell the tale…..

 

Why do people like me become bod­gers? I’ve just accepted it. Perhaps it’s be­cause I knew from the mo­ment1 started bending the pieces of my Meccano set that it was my destiny. Sel­lotape and cardboard often found their way into my childhood creations. It was as if I was in a frenzy to get the thing to work, and any­thing would do so long as it sewed the immediate pur­pose. Not only that, there was the satisfaction of mak­ing the kit do more than it was intended for.

Strangely enough, I ended up as a Chartered En­gineer, specializing in con­trol systems. The Bodger is still there though, lurking in the background, waiting to be unleashed at weekends. Any bodging exercise of mine has the following rules:

1) It must be safe

2) It must work

3) It doesn’t have to look good

4) It must be the most cost-effective method of achieving the goal

 

Take rust, for example. What causes rust? Oxygen, comes the deafening reply. So what’s the best way of stopping a car rusting? Yes, immerse it in a bath of sticky oil. Or better still; don’t make it out of steel. Either is preferable to the ghastly and futile process followed by the wash-your-car on­ Sunday brigade. You know, AAAAARGGGHH, I’VE GOT A BUBBLE ON MY WING, dare I burst it, per­haps it hasn’t gone all the way through. Oh no, I knew this would happen, I should have had it steam cleaned like it said in the local paper. Should I bite the bullet and burst it? That means I’ll have to chip the lovely paint off, the lovely paint that I have lavished all these Sun­day mornings on. There must be at least fifty thou of Turtle Wax on this paint, do I really have to? And then what? Rust eater? Horrid black patches followed by disgusting touch-up paint. But I’m definitely not going to look inside the wing. What if there’s more rust? Perhaps I’ll get the hose though, and give it a really good clean. .Then I’ll feel bet­ter, at least. Perhaps if I just use a hypodermic and inject some Jenolyte it’ll get better by itself? Perhaps.

No, my friend, it will not get better. It will get much, much worse. Your car has cancer. Terminal, malignant and abso-btoody-lutely in­curable. You have not been a Good Owner. You have given it Turtle Wax when you should have given it Waxoyl, but you’ll still be out there every Sunday, hopelessly sloshing more detergent-loaded water into its cavities, supplementing the corrosive mixture lurk­ing in the mud plastered into all the little places that your Hyd~o-Turbo-Blasto­Matic plastic nozzle that you bought down the local market from a chap who said it converted mains pressure to 2000 millibar, can’t dislodge. Sorry.

My old Triumph GT6 was a trifle rusty when I got it. It was also a trifle rusty when I sold it six years later. But that car was not rust­ing when I sold it, just rusty. Waxoyl, see?

 

But O, what bodgery I did enjoy with that car. The original 2-litre straight six put out a careful 95bhp. Hardly Boys Own stuff. So, I thought, why not turbo-charge it? I managed to se­cure a turbo of approximately the right dimensions (oh, all right, a bit on the big side...) but it was a turbo, and all I had to do was fit it! Right, Sleeves rolled up. Cut three inch ex­haust stubs off that old tu­bular manifold. Weld them to a two-inch square tube collector, bugger the gas-flowed corner, we’ll have a dead end after the turbo flange and the gas can find its own path.

Next: compression ratio. Easy. One eighth-inch plate spacer, with metal gasket each side - 6.5 to 1, or there­abouts. Oil feed: straight from the main oil galley. Can’t bodge this, turbos need about half a gallon a minute, at l0psi. That means a specially built pressure regulator capable of handling hot oil, and a drain to the sump, downhill all the way.

 

Ignition needs an extra spring, on the other side of the vacuum advance dia­phragm, to back off the tim­ing under boost. 8psi of boost will need about 6-8 degrees of retardation. If you know the boost and the size of the diaphragm, you can figure out the force sup­plied by the diaphragm. Knowing the movement of the diaphragm required to achieve the retardation you’re after, and knowing Hookes Law as all bodgers should... I’m sure you can work out the rest (We’re way ahead of you. Ed)

Boost control: no prob­lem. Radiator cap and neck with extra exhaust ports as a blow-off valve, brazed to the air cleaner body. A trifle noisy on the overrun, but real safe. No possibility of over-revving the turbo, which is not recommended. The blade tip velocity at full boost is around 1000 ft/sec­ond, a bit faster than the bul­let from a Browning 9mm automatic. You definitely want those blades to stay in that snail-shaped thing.

Fuel: tricky. Blow-through carburettors. Press­urised float chambers.

Blown seals on throttle spindles. Many, many dif­ferent needles. You need to add boost pressure to the lower side of the diaphragm of the fuel pump (see diag­ram), and add an air seal to the diaphragm rod. Very tricky. But it was all worth it for that one ride when the right amount of fuel went in at the right ignition timing for l0psi of boost, leaving the gum-chewing, earring-wearing Capri 3-Litre crea­ture in a black rage, bouncing up and down in his seat, making a dent in his firewall where the throttle pedal goes.

 

I did try suck-through carburation. Briefly. After all, no true bodger would be put off by the prospect of a leak in a pressurised system full of petrol/air mixture at stoichiometric ratios or thereabouts, would he? Naaah. Or by the prospect of having to install another (completely leak proof) but­terfly valve downstream of the turbo in order not to sub­ject the turbo oil seals to full engine vacuum? Er, naah. No, what put me off was the way that the fuel puddles merrily in the bottom of the compressor casing on idle, and virtually puts the fire out when it is eventually whisked into the engine in a huge gush when you open the throttle. Not to mentionthe dense clouds of black smoke enveloping the poor bloke behind you. Or the supernovae from the rear of the car as the blow-off valve (now vented to the exhaust pipe, well downstream but still hot enough to ignite the mixture) lifted on gear changes and overrun.

 

But as you all know, you quickly get used to in­creased performance. Like, the following day. So when the TR6 engine complete with fuel-injection was spotted, it was duly ac­quired and slotted in. Now the turbocharger was the right size. And fuelling was a matter of playing with springs and fuel-enrich­ment devices and rolling roads. Boost was up to 20psi. This was war. I had declared war on the car. It pinked. I added water injection. This was pure joy. A plastic water container (stif­fish) pressurized by boostair through a one-way (yes, screen wash) valve. Squirt­ing a jet of water through a 0.050 jet straight at the eye of the turbo impeller. It stopped pinking.

It then blew head gas­kets. I added 0-rings to the head and took away the head gaskets. We saw flash readings of 270bhp at the back wheels.

It munched differential pinions. I bought an XJ6 back axle, and was about to fit that, when the noise in my left ear became intoler­able. I sold it. She stopped.

 

But the bodging goes on. Now with a Scimitar (not an SS1, a proper one). The body does what it should, that is, keep wind and rain out. The paint, which is non-func­tional on this car, does what all paint wants to do, íe change colour and fall off I don’t mind, I won’t have to Turtle Wax it. The chassis has been completely fixed; all the bits that were too thin (from lack of Iron) have been replaced with new bits. And yes, it has been smothered in Waxoyl, in­side and out. The Ford V6 engine and auto box was treated as it should have been, ie. removed, ham­mered into manageable pieces and given to a pas­sing traveler.

Bodging was halted whilst the suspension bushes were replaced as a matter of course whilst they were get-attable. And the brakes were Properly Done, including replacing the pitted and scored discs, sorely tempted though I was to reface them with a big abrasive wheel. You have to arrive at the T-junc­tion at the bottom of a steep hill just the one time with smoke billowing from the wheel arches, both feet on the brake pedal and the steering wheel bent nearly double, to appreciate the full horror of brake fade... that’s after having the fill­ings rattled out of your head from the vibration due to thin, heat-distorted discs.

Never again. Oh God, never again...

Oh yes, and a Rover V8 was slipped in. Kind of. But that’s another story.

 

From Jalopy, February 1994

’

Edited by JohnD
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I did have a brief discussion about forced induction on a Triumph 6 pot with my mate Dennis (who knows a thing or two about superchargers).

 

His observation was that it was always preferable to start with an inherently strong engine...... which pretty much ended the discussion!

 

Nick

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Why?

The GT6 engine is strong.

If you put some decent pistons in there, the turbo-nitrous one had no difficulty churning out 380bhp with complete reliability and over 1bar of boost.

 

Here's a bit of background, (because I don't like vane type s/c motors).

Twin screw Swedish Lysholm YES, vane NO.

 

You'll never get an Eaton s/c to get anywhere near 1bar, before it chokes, so see the real power figures you expect to get.

They won't be any better than the G60 below.

Turbo charging done well is a zillion times more thermally efficient than any s/c system, and can have close to zero lag (especially with a good shot of Nitrous).

 

The G60 I did, (which are considered quite efficient s/c) was struggling to get over 0.9bar at full revs, despite the much improved intercooler ducting, remapped chip and larger pulley.

That got it to a genuine 180bhp from a 1.8L 2V head.

It was very close to max s/c speed of if I remember right about 12000rpm* at 2:1 pulley/pulley ratio.

It must also be said, the 2V Golf head does actually flow pretty respectably well, and burns OK.

 

When I stuck the 60-80bhp theoretic shot of nitrous on it, it always gives more power than planned on a force induction motor, (because of the charge temp drop from about 100C to as low as -20C).

That gives a huge increase in power, and reduction in detonation at the same time.

We reckoned it was making 280bhp in the end, which made it unuseable in anything under 3rd gear.

It was a bit mad for a FWD car.

 

The problem with nitrous is, you only get 4mins from a full fill of a bottle, and it costs serious money to fill (if you can find anyone at all to fill it, these elf and safety retard filled days!).

It must be about 50 quid a fill now or more.

 

The Jag XJR in view of the size of the motor, and the size needed for the S/C was unable to do more than 315bhp from 4.0L and guzzled fuel.

On the occasions Broddie Britain played with the S/C system on the Aston Martin DB7 (replacing the 3.2L engine with the 4.0L), he simply couldn't get it to make even 100bhp/L.

It did make a shed load of torque, and the Aston Engineering race car struggled up to 400+ but with huge detonation issues (he told me).

In view of the fact, those figures can easily be between with a N/A well modified engine of smaller capacity using half the fuel, it does beg the question.

Why bother with super charging?

 

The end of the line is ALWAYS respect maximum rotor/vane speed & maximum charge temp.

(it gets close to the speed of sound at the vane/wall interface).

 

The thing you must NEVER do, is approach too close to the s/c rev limit*, because bits of your s/c will end up straight in the engine, which is instant DEATH.

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Yes, I'd agree that the 2L is the strongest and could handle some boost. But Dennis was taking the view that if you are going supercharge then you want ALL the beans, whereas I was thinking about 5psi, most likely from a smallish turbo. He's also a Lysholm man and no fan of Eaton. There's a guy in the unit next door who drag-races a very special motorbike. The latest version of this is based on a Kawasaki 600 (I think) with a Lysholm on it nearly as big as the engine, chargecooled by laminova in the inlet plenum and with staged injection run by a fairly high-end DTA ECU. Runs E85 and makes I think he said 174 bhp from 6psi which is the first stage of development. Plan is 12psi and about 220 - 230 bhp - the limit for a used ebay bottom end apparently! Not bad from 600ccs...... Whether he'll still be able to hang on at 220 bhp is the subject of some debate!

 

Nick

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  • 2 weeks later...

First of all thanks to everyone for adding their input, it's more than appreciated!

 

The idea was never something I was intending to jump on straight away but in enough time I may come back around to it when I am able to.

 

My GT6 (or Steve as I lovingly refer to him) needs a little more attention before I can get him back on the road, managed to fire him back into life but then have been otherwise occupied removing a dynamo from a splitscreen camper for the past few days. First time Ive worked on one and may be my last...there's a lot less room to work on one than my 6! If there are any good links people would be willing to share on dropping a camper engine out please flood me with them. It may sound a little much but the engine will eventually be removed anyway for other work to be done on the bus.

 

I will eventually be putting some photos up whenever the uploader allows me to!

 

Thanks again for all your help :thanks:

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Ive heard that it's pretty easy to do...these guys make it look pretty easy

 

I appreciate its a bug not a van but I assume there wont be a massive difference between the two...

 

And yes Steve, I think at some point in his 41 year life he's had a bit of a knock to the front nearside. Along with that, the bonnet had been replaced at some point (probably from the knock) with a typically terrible fitting fibreglass bonnet (recently picked up a complete steel one for a bargain!) and so to sum up some rambling his 'face' kind of looked like he'd had a bit of a stroke... One day I looked at the car and 6 Stroke Steve popped in my head and so 'Steve' or '6' is what he's been fondly referred as from then on.

 

Have you got a name for yours?

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I'm ashamed to admit that was an Australian show. Grant Denyer, the host, is a better than average driver, almost made it to V8 Supercars full time. He did drive at Bathurst as a co-driver. Just occurred to me that you may be in Oz and know all this already.

 

My memory must have failed me, they didn't take the box out, I do remember that it wasn't a particularly difficult task.

 

Good luck.

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IIRC there are no engine mounts at all - it just hangs off the the bellhousing. So removal involves a couple of pipes, a few wires and the bell housing bolts. A BIG trolley jack helps alot.

 

When I was a student living in Hampton (not recently!) there was a fella over the road with a Beetle problem and he used to get the engine out of that in about 10 mins and then wheel it up the garden path to his shed. Time to put it back used to vary depending on whether he'd lined the clutch up properly or not......

 

Nick

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Nah I'm a UK dweller, I think the six might get a little warm down under!

 

Wouldn't worry about it, 4th gear is no longer selectable on the bus so thats going to be replaced in the next few weeks I hope so it will be removed anyway

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IIRC there are no engine mounts at all - it just hangs off the the bellhousing. So removal involves a couple of pipes, a few wires and the bell housing bolts. A BIG trolley jack helps alot. When I was a student living in Hampton (not recently!) there was a fella over the road with a Beetle problem and he used to get the engine out of that in about 10 mins and then wheel it up the garden path to his shed. Time to put it back used to vary depending on whether he'd lined the clutch up properly or not...... Nick

 

That is brilliant! The image in my head is rather comical :P

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slight drift,

 

hi samski,nice to see i'm not the only sucker for punishment,we have a splittie too.66 vintage.

 

get yourself one of these

 

http://www.ebay.co.uk/itm/New-1500lb-680Kg-Hydraulic-Motorcycle-Motor-Bike-Quad-Lift-ATV-Jack-workshop-/251200195105?pt=UK_Lifting_Moving_Equipment&hash=item3a7cb2ca21#ht_2261wt_1199

 

a bit more pricey than a trolley jack but if you regularly remove your engine(or even just a couple of times)just jack up,undo bolts and pull out.you'll wonder how you lived without it.balancing an engine on a normal jack even a lightweight vdub one can cause serious injury if it falls off. :pinch:

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VW engine easy to take out?

Saw Citroen 2CVs racing a while ago. One blew its engine in practice.

Front of car off was a few bolts.

Undo the engine bolts and two men just picked it up out of the car and walked off with it!

They had a spare in the back of the van and replacement was as easy.

Problem solved, plenty of time for lunch!

 

For demo see:

(It's a long video, about stripping a wrecked 2CV. The engine comes out Take 4 at 8 minutes)

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