Triumph Spitfire - what could possibly go wrong?

Looks like fun to me.

Looks like that Spit' is getting screwed, double!

Lovely!

GIT UR DUN! We're anxious to see how it turns out for you.

Probably won't be in my house for a few more weeks, it's going to be shipped from Canada. But I sure am excited. Never played with a supercharger before. Figure I'll just bolt it on and as long as the engine doesn't go boom, I should be all right to at least run it to Carlisle and show off.

On draw through systems, it's important to consider what a backfire through the S/C will do.
Maybe plumb a cheap ($25 on eBay) turbo blow off valve into the plenum chamber?

Measure the two pulleys to see what the drive ratio is. It appears to be an M-45, so pumps 45 cu-in/750 cc per revolution.

So assuming you have a Spit 1500, which as a 4 stroke requires 750 cc per revolution, the boost pressure ratio is approximately just the drive ratio.

Somewhere I have a graph that Eaton published that shows parasitic HP losses vs boost, it's not linear, higher boost becomes worse as a percentage.

You can reasonably run up to about 6-7 psi boost with an M-45 on a Spitfire, after that the intake charge starts to get really hot unless you have an intercooler plumbed in, plus the HP losses reach point of diminishing returns, ie you lose more power than you make.

Figure a 30%-40% torque/HP gain at that level.

I'd start out with premium gas, until you get a feel for whether it's having detonation issues.

It's an HS4, right? Finding the proper needle could take some trial and error, maybe run it a couple flats rich until you get it sorted, particularly on a long cruise.

Please keep us updated, I'm interested because I have an ex-Mercedes M-45 (the one with electric clutch) for a future project.

Some useful info here: http://www.capa.com.au/eaton_mp45_4th.htm

How many spare diffs do you own?

Should be fun.

Ah, backfire. That will likely be a problem. Ok. Need to read up on superchargers, their care snd feeding.

The story is this all came off a long ago supercharged and running spitfire that ate itself. So, hopefully i wont find myself having to dial in things too much just to make it drive.

The engine i have in the car now is supposed to be a genuine old Triumph Tune Stage II engine. Definately ported, but if thats not a stock cam, I'll eat my hat.

I've abiult 20 spare rear ends, multiple gearboxes, and two other spare engines. But, as long as i dont launch hard from a standstill, things should hold.

And if I maximize it to the limit, I'll make as much power as a stock Miata.

JoeTR6 wrote: How many spare diffs do you own? Should be fun.

OK, so a stock 1980 Spitfire 1500 makes 53 HP.
Bump that by 40% and you get about 75 HP.
A stock 1967 Spitfire 1296 makes 75 HP.

Hmm, spare diffs are STILL a good idea.

As long as you don't lean out, and avoid knocking, and respect the redline, should be fine/fun.

Way too cool. I raced Spitfires in the early 70's. Wish I had that as a secret option back then.

Any idea where it mounts on the engine? Will you have to make mods to the bonnet? I saw a nice clean supercharger install on a MGB (think it was a rubber bumper 1500) last year at Limerock (spectator car). The guy said it took him a few years of puttering with it to get it right but now it was street able and the boost was noticeable. Post some pictures of the install.

thanks

mike h

The kits I've seen mounted the S/C exit directly onto the intake manifold via simple adaptor plate.
The extended snout places the pulley right in line with the engine pulley, uses a multi rib serpentine belt.
I don't see a mounting bracket, but the triangle shaped piece with the idler pulley may provide the tension adjustment.

Any news?

Well, the box finally arrived at my house. Getting it into the us from canads was entertaining. Superbly packaged though!

On cursory look over, it all appers there and functional. Definitely used, and im not sure i can save the pierce intale manifold, but I'll see.

Oh boy! Now I really wish I was going to Carlisle so I could see it. Glad to see that T-9 cash has finally gone to a good cause.

In reply to foxtrapper: I truly love my supercharger! It transformed my Miata more than I could have imagined. And it still looks, sounds, and drives like the 4 cylinder it is. Only better than any other I've tried.

Of course I had it easier than you. I just bought a kit, followed the how to's and it works. I suspect there will be some tinkering going on for a time with yours. But then again, years ago I often thought the tinkering on a ride was more fun than using it. HAVE FUN!

Haven't gotten into it yet, too busy and too cold. And yes, I know those are just excuses. The packing job the seller did on this is incredible though, and worthy of its own picture.

Oh yeah... can I buy your dual HS4 set-up?

In reply to foxtrapper: What could go wrong? You could smile so big your face could get stuck that way