slingshot2000
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| posted on 4/4/12 at 11:14 PM |
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Forced Induction Carbs question
I need some help anwsering a question that 'google' has not been able to answer. . . . . .
Did the early Lotus Esprit Turbos blow through a Dellorto carburettor (DHLA) set up ?
If they did, was there any thing special about them ? (The carbs, that is ).
If so, would these carbs be suitable for a Zetec/supercharger installation ? ? ? ?
Regards
Jon
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owelly
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| posted on 5/4/12 at 12:01 AM |
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I'm not familiar with the Lotus Dellorto application but as a rule, carbs used for forced induction have to have a way of equalising the
pressure in the float bowl, with the boost pressure. This can be a simple balance pipe onto the float chamber via the breather or a tapping, and an
uprated gasket or seal on the top of the float bowl.. Also extra sealing on the butterfly spindles. I also recall folks using a 'normal'
carbs and putting it all in a sealed box fed with the boosted air.
ETA... http://www.lotusespritturbo.com/Garrett_AiResearch_T3_Turbo_Charger.htm
and...
http://www.gt6.ca/josh/supercharged.html
You can see the float chamber balance pipes on this one.
[Edited on 5/4/12 by owelly]
[Edited on 5/4/12 by owelly]
http://www.ppcmag.co.uk
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Canada EH!
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| posted on 5/4/12 at 12:16 AM |
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Don't know about Dellorto's, but 50's Studabaker Hawks had a belt driven supercharger and the 4 barrel carb was in a pressurized
housing. The carb didn't know it was in a high pressure enviroment.
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FASTdan
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| posted on 5/4/12 at 06:55 AM |
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I think the dellorto's had a slightly different designation to indicate they were a turbo model (unless I am thinking of webers). There were
definitely some turbo specific 'twin 40's'.
As mentioned you just need to ensure the float chambers see the same pressure as the top side of the carb - I have an XR2 turbo technics, that is
literally just a box bolted on top of a standard weber carb. Yes the spindles leak boost (and must have done from the factory) but its such a crude
set-up there's no detriment (no sensors to misread etc) aside from the turbo working that bit harder (minimal in the scheme of things).
I plan to swap the above for bike carbs in the near future and see how they fair.
NEW danST WEBSITE NOW LIVE! Bike carbs, throttle bodies and more......
http://www.danstengineering.co.uk/
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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ss1turbo
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| posted on 4/6/12 at 02:17 PM |
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You've got a few choices - and I think i've looked at them all (also having a TT converted CVH - or did have).
Dellorto do downdraught and sidedraught turbo-proof carbs (rubber gaskets, sealed spindles and no vents to atmosphere for the float chamber) - DRLA
and DHLA (Lotus Esprit for the sidedraughts and the donwdraughts are a conversion for an Alfasud - these are used by VW Aircooled guys a lot, so still
supported). Esprit ones are 45's though, so might be a bit big on anything sub-2 litre; Alfa carbs are 40's.
Weber did (at least) one - a version of the DFT for the early Lancia Delta HF Turbo 1600. Rocking horse manure (been looking for 15+ years for one)
and rebuild kits stopped being available a long time ago.
Solex did the 32DIS for the Renault 5 and I think a larger one for (I think) the Fuego - the 32DIS is only good for about 140bhp and the other one is
again rocking horse muck.
One you can get hold of easy is the SU from the Metro turbo; Maestro and Montego one has a load of electronic gubbins attached, so go for the Metro
one and re-jet/re-spring to suit.
As you'd expect, there are ones in the USA (Carter, I think, and maybe a Holley) that are sealed-for-turbo, but normally in the 500cfm+ range,
so you need a medium to large V8 for that.
Long live RWD...
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steve m
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| posted on 4/6/12 at 02:33 PM |
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This is so weird as only last night i looked into turbocharging my xflow, and have not discounted using one twin 40 webber, as i have a siamese port
manofold for a xlow, and running a pressurised system
My main problem was how to plumb the turbo oil feed into a xflow engine
steve
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ss1turbo
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| posted on 4/6/12 at 02:37 PM |
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quote:
Originally posted by steve m
This is so weird as only last night i looked into turbocharging my xflow, and have not discounted using one twin 40 webber, as i have a siamese port
manofold for a xlow, and running a pressurised system
My main problem was how to plumb the turbo oil feed into a xflow engine
steve
Thats the easy bit - tap-off the oil pressure switch. Add drain into the sump (above the oil level....) and as straight a path from the turbo core as
you can get it, same size as the outlet pipe from the turbo.
Long live RWD...
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