Fuel Injection

[North London Mike]

Mike,

 

If you had the supercharger actuated via an electric clutch (as per your a/c in the Jag), for short bursts as Peter says "Supercharging for road use - brief burst of boost - allows pistons etc to cool down at cruise" no head work needed? I suspect that off boost the power will be well down though......

 

Mike

 

Mike

 

Thanks for that........understood, however, other than some drag, normal performance (off boost) will be unaffected in the standard (5psi) set up to which Peter's 'short burst' refers.

 

But Peter thinks 10psi (upgrade) is better, best, hence my supplementary ref lower CR...........

[North London Mike]

Mikes

The extra power/torque over and above the atmospheric power curve will be roughly linear with boost. That's only very roughly, as blowers raise the temperature of the mixture more at higher boosts, which reduces the air density- meaning some of that 10psi is due to higher temperature not air.

 

re Moss kit. Never having seen the spec on the kit I dont know exactly whats on offer. I'd be surprised if the kit info doesnt mention safe boost/CR range. The Eaton M62 blower they use will certainly be capable of flowing 10psi at 5500rpm.

 

Declutching the blower is used on moderns to kill its horse power loss (maybe 1 to 2 hp) when the engine is at cruise, an economy measure. Detonation will hole a piston in very few seconds at wide open throttle so killing boost is best done by lifting off immediately its heard. Problem is, detonation can be inaudible at full chat with roof down...the first sign can be blue smoke pumping out the exhaust and catch tank. So tuning to ensure detonation is 'impossible' is safest. Start with low CR and work up? The TR6 low CR USA heads are ideal for that, but I guess TR4 had no really low CR heads? So shorter pistons?

I know off two TR3s being supercharged in UK at present - perhaps they can advise.

 

Peter

Peter

 

Thanks for the follow up, as you say, take it slowly, and maybe our TR3 brothers and share their R&D ?

[peejay4A]

The supercharger on my (relatively) modern runs all the time. The only time you know it's there is when you boot it and the glorious whine builds up and the scenery goes into Star Trek mode.

[Peter Cobbold]

Both blown TR3s I have heard about are using the old Judson (vane compressor).

Here are a couple off the web:

http://canadasbest.ca/carcrazy/vote-now.php?id=33566778

http://www.v8triumph.com/JS.htm

[ianc]

Compression ratio can be reduced by the use of one or more solid copper or steel gaskets.

 

From the re-build in the early 1990s, 4VC was running on a single copper gasket but after the water pump fell apart when the car was on full chat on a rolling road, the head (which was already high compression) warped and had to be skimmed, so then I added a second copper gasket - that was in 1995.

 

In the days of TR2, I seem to recall that there was a Low Compression kit for countries with terrible, low octane, petrol - this would have been a thicker gasket, possibly of steel, added to the usual copper/asbestos gasket.

 

Ian Cornish

[North London Mike]

From the re-build in the early 1990s, 4VC was running on a single copper gasket but after the water pump fell apart when the car was on full chat on a rolling road, the head (which was already high compression) warped and had to be skimmed, so then I added a second copper gasket - that was in 1995.

 

Ian Cornish

 

Thanks Ian

4VC. double gasket, good trick, assume to restore the original CR pre skim, good cheap way to lower the CR though

 

Back to S/C: Be interesting to see how extreme the heat build up would be in continual road use, say climbing the Stelvio

 

i.e. if the race boys need intercoolers due to high % on boost, how hard could you drive it 'on road' before you're in trouble (say in the alps)

[mike3md]

Mike,

 

Have we got time to fit to LNK before May???

 

 

Mike

[Peter Cobbold]

re cimbing Stelvio.

Heat build up might be a problem with a draw-through carb (aka 'wet blower'). Its impossible to use an intercooler, it will explode into smithereens and a ball of flame in a manifold backfire. The extra heat itself isnt going to melt pistons its the mixture detonating at the higher temp that's the risk . Even a couple of degree too hot can lead to detonation.

So before extreme hill climbing:

-add octane booster of two different types , say manganese and aniline

-fit water injection that works, not just water squirter ( eg http://www.aquamist.co.uk/ ) and maybe add some alcohol to the fluid

- fit a knock listening device for the passenger to listen to.

-boost retard the spark

- assumes you have already an oil cooler, and decent radiator

Be sensitive to any hint of rough running, and lift off immediately.

That said, the torque from a supercharged engine is perfect for the job.

Edited December 14, 2012 by Peter Cobbold

[ianc]

W O Bentley was totally against the fitting of blowers by millionaire Barnato to his engines because the engine had never been designed to be boosted. And W O was right, because reliability was compromised when the engine was blown.

 

I have had a Christmas card from the chap who acquired my Uncle's 1925 3-litre Bentley in 1998 - apart from travelling around Europe, the car has crossed Australia from West to East coasts (a few punctures), has travelled the West coast of Oz from South to North, and has just returned from South Africa, where it clocked a further 2500 miles "with no problems whatsoever". Keith did fit an electric fan and an overdrive (same as that on the 4-pot TRs, by the way) prior to the first trip to Oz, but other than that, the car is standard.

 

The 4-pot TR is exceedingly reliable, even in considerably modified form, when naturally aspirated and with the cooling system working properly, and one can keep the throttle to the floor with impunity.

 

For me, the idea of having to monitor continuously for the onset of detonation and disaster would remove the enjoyment of the driving experience. And climbing the Alpine passes would likely provoke problems because the engine would be working very hard all the time - and perhaps not a good place to blow a hole in a piston (or four)!

 

Ian Cornish

[North London Mike]

 

The 4-pot TR is exceedingly reliable, even in considerably modified form, when naturally aspirated and with the cooling system working properly, and one can keep the throttle to the floor with impunity.

 

For me, the idea of having to monitor continuously for the onset of detonation and disaster would remove the enjoyment of the driving experience. And climbing the Alpine passes would likely provoke problems because the engine would be working very hard all the time - and perhaps not a good place to blow a hole in a piston (or four)!

 

Ian Cornish

Ian

 

I would tend to agree ! The list of precautions required in order to allow a flat out S/C hill climb is enough to close this particular door. With at least six high (over 2500m) alpine passes on the schedule, better to have power that is 100% reliable and accessible and enjoy the peace of mind me thinks

 

(Maybe the late 'works' webers )

[Peter Cobbold]

The limitations of safe supercharging are well known amongst its congnoscenti. Stay within those bounds and holed pistons will not be an issue. But its very much a question of being prepared to learn oneself as expertise is thin on the ground, and mostly in the vintage racer community.

[Dean]

I put a throttle body fuel injection system on my TR4 several years ago. Really drives good with this set up. Not so much more power but no hesitation or warm up needed. Controls the mixture and timing. A short write up on our web site www.theukmotorsports.com Click on "this week in the shop" then look under "popular projects"

 

Dean

[gt6s]

I believe Revingtons can do that but its expensive and can I ask why?

Stuart.

 

 

Yes very expensive. AT ALL COSTS AVOID WEBER ECU !

Programmable only by Weber dealers.

 

Buy an ECU (I use a DTA one on my Gt6 2600 EFI) there are many user programmable ECU's out there, a set of throttle bodies, manifolds trigger wheel and sensors. Then do it yourself.

 

Why ? Because EFI is the doggies dangleys.

 

Advantages power AND econemy, tractability even on wlld cams, reliability and the SUPERB 3D ignition mapping.

 

Laurence

Edited December 16, 2012 by gt6s