Superchargers

[Steve 13-60]

Anyone any experience with these?

https://www.ebay.co.uk/itm/314632524718?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=zvzlfdudtq2&sssrc=4429486&ssuid=7hKzZKXBQrq&var=&widget_ver=artemis&media=COPY

Nice and cheap on fleabay, tempted to play with one on the Herald, currently has a bog std 1500 in whilst the original 1300 is being rebuilt.

[JohnD]

Steve,

Suggest you go to http://supertrarged.wordpress.com/ the personal website of Prof. Peter Cobbold, who has a supercharged TR6.

John

[Nick Jones]

The “vendor” has sold just one item….. Buyer beware.

[rog1]

Check out Swallows Racing for super charging knowledge/advice.

Based in Somerset

[Mark]

Seem to remember a red mk3 Spit with fitted with a supercharger, think it was built by Josh Bowler, remember seeing it at the first Retro magazine car show years ago. There was a short video on YouTube, can't find it now.

[zetecspit]

8 hours ago, Mark said:

Seem to remember a red mk3 Spit with fitted with a supercharger, think it was built by Josh Bowler, remember seeing it at the first Retro magazine car show years ago. There was a short video on YouTube, can't find it now.

I think it broke the crank. And later it was sold to Mattius on here, who had a crash and wrote it off. I think the supercharger had gone before that though.

[Nick Jones]

It did break the crank, through the usual rear main/#4BE web iirc. Which was a pest because it was very specific 1300 FWD one for reasons of front pulley attachment. 
 

It was ridiculously torquey for a 1300. Can’t remember how much boost.  Made a fairly obnoxious noise, though I’ve only seen video.

Was some info hosted by Andre Rousseau on his GT6CA site, which appears to be defunct.

Rebuilt in it’s original NA form, which was actually pretty bloody good anyway.

[mattius]

I wasn't trusted with the supercharger, which is probably just as well!

Josh lost interest after the supercharger went i think, the rebuilt engine was still a damn nice engine.

Don't really think the Triumph cranks can really handle that much torque

[Mark]

Just seen this on YouTube. A company developing a supercharger kit for the Spitfire.

https://youtu.be/wMLEvidwPBw?si=wXVcJ4NLNVspRm9J

[JohnD]

Is that a MINI Cooper supercharger in the OP?  The BMW version? 

There always seem to be dozens for sale on eBay, which says something about MINIs reliability, or the way they are driven.

John

Edited October 20 by JohnD

[Nick Jones]

22 hours ago, mattius said:

Don't really think the Triumph cranks can really handle that much torque

I think you are basically right, though with the right prep it might have lasted longer. I broke one in the same place on my 1300 Herald (probably about 100 bhp). The metallurgist and crank specialist who looked at that for me (then work contact) said it was entirely down to poor radius machining where the journal met the web. I’ve also seen a couple break at the front where very little torque involved.

 

[Nick Jones]

 

9 hours ago, JohnD said:

Is that a MINI Cooper supercharger in the OP?  The BMW version? 

No. Cooper S is an Eaton M45. OP was an Aisin AMR500 roots type blower.

I think the one in The Hyde Motor Works video is too.

 

[mattius]

59 minutes ago, Nick Jones said:

I think you are basically right, though with the right prep it might have lasted longer. I broke one in the same place on my 1300 Herald (probably about 100 bhp). The metallurgist and crank specialist who looked at that for me (then work contact) said it was entirely down to poor radius machining where the journal met the web. I’ve also seen a couple break at the front where very little torque involved.

 

I think Bastuck used to do a billet crank for a spitfire... But once you get to that price range, your out the budget of most triumph owners.

IMHO if the crank didn't fail, the diff will eventually. I remember Josh being concerned about that when we talked.

Edited October 20 by mattius

[Escadrille Ecosse]

18 hours ago, mattius said:

IMHO if the crank didn't fail, the diff will eventually. I remember Josh being concerned about that when we talked.

With a Quaife or plate type that eliminates the weak point round the cross pin for the differential gears the diff will handle a 2.5L six doing max standing starts on race rubber.

I very much doubt even with dangerous levels of boost a 1300 will deliver that sort of torque. More likely gearbox to go first.

[PaulAA]

Reverting back to the original question, I think the AMR500 is designed for Japanese Kei cars - 660cc motors. It has a theoretical swept volume of 500cc and, if my rudimentary understanding of Allard passes muster, I believe it would have to be belted/pulleyed to turn at 3x engine speed on a Herald, no?

Paul

[Nick Jones]

3 hours ago, Escadrille Ecosse said:

With a Quaife or plate type that eliminates the weak point round the cross pin for the differential gears the diff will handle a 2.5L six doing max standing starts on race rubber.

I very much doubt even with dangerous levels of boost a 1300 will deliver that sort of torque. More likely gearbox to go first.

This. Though the standard 4.11 provided with the Mk3 the engine was in might not have lasted.

[Escadrille Ecosse]

3 minutes ago, Nick Jones said:

Though the standard 4.11 provided with the Mk3 the engine was in might not have lasted.

Yeah, a very fair point that

[Nick Jones]

3 hours ago, PaulAA said:

Reverting back to the original question, I think the AMR500 is designed for Japanese Kei cars - 660cc motors. It has a theoretical swept volume of 500cc and, if my rudimentary understanding of Allard passes muster, I believe it would have to be belted/pulleyed to turn at 3x engine speed on a Herald, no?

Paul

Don’t forget that 4 stroke engines only have half their rated displacement/rev. 
 

AMR500 is rated up to 16,000 rpm and is considered ok for up to 2L engines though the boost or engine rpm are a little restricted at that size.

[egret]

15 hours ago, Nick Jones said:

This. Though the standard 4.11 provided with the Mk3 the engine was in might not have lasted.

Sorry for the tangent, but does the above mean that higher diff ratios are harder on the internals, or is the 4.11 a weaker design/casting?  It also seems like you're saying the side gears and spider gears are the weak points and replacing with some kind of ATB/LSD component strengthens them.  Is this correct?

[PaulAA]

15 hours ago, Nick Jones said:

Don’t forget that 4 stroke engines only have half their rated displacement/rev.

Ah... my ignorance exposed

15 hours ago, Nick Jones said:

AMR500 is rated up to 16,000 rpm

Doubtless a tad uncomfortable at full chat.

[Escadrille Ecosse]

18 minutes ago, egret said:

Sorry for the tangent, but does the above mean that higher diff ratios are harder on the internals, or is the 4.11 a weaker design/casting?  It also seems like you're saying the side gears and spider gears are the weak points and replacing with some kind of ATB/LSD component strengthens them.  Is this correct?

Basically the original Mk3 (and earlier) 4.11 diff with the small flanges is weaker. The later 'large flange' diffs have stronger internals. You can of course use later Marina/Ital CWP to make a 4.11 (or 4.55) in the later 'large flange' flavour.

The holes in the diff carrier for the planet gear cross pin cause a weak spot and high torque loads can cause the carrier to break there. And generally the high separating forces of the sun/planet wear the thrust washers quite quickly too.

 

LSDs are generally beefier in this area which minimises the issues. Although you cant really avoid pinion carrier wear. But if monitored that is usually a relatively straightforward rebuild and reset of the pinion height.

High torques can also shear/twist even the big flange output shafts, although the doughnuts in the rotoflex rear end do help cusion things here better than CV joints

Edited October 22 by Escadrille Ecosse

[egret]

Perfect answer, thanks.

[Nick Jones]

9 hours ago, egret said:

Sorry for the tangent, but does the above mean that higher diff ratios are harder on the internals, or is the 4.11 a weaker design/casting?  It also seems like you're saying the side gears and spider gears are the weak points and replacing with some kind of ATB/LSD component strengthens them.  Is this correct?

It depends which 4.11. The later ones (mk3 Spit era onwards) have the same size output shafts (though not flanges) as the others and not significantly weaker.

The main weakness is the carrier itself (that carries the crown wheel and differential gears) and the cross pin. So yes, the gears themselves are reasonably strong when correctly set so an LSD/ATB centre makes a big difference. It’s the main reason I put the Blackline in the Vitesse, the torque bias effect is a bonus!

[mattius]

We found the limits of a Quaife type differential with cast differential gears in the Corvette, though it was outputting > 500 ft/lbs of torque that you will never achieve in an English lump. The pictures of that one are comical.

But you are totally correct.

Josh was running a T5 gearbox ( which I inherited ) very nice on the 1300 just first was too short, which are pretty bullet proof, so hence the concern over the diff.