Hi

I have a spare 1.8, 8 valve, carburettor CA18S engine which is low miles and perfect condition (I know the full history of it and it’s been really well looked after). Sadly it only produces 90bhp which is a bit low but average for a 1980’s engine. Now before anyone starts going on about fitting another engine rather than bothering with such a sad pile of poop… I’m not remotely interested in another engine and want to keep the engine I have but just give it a bit of boost over what it already has.

So I’ve been thinking of fitting a small turbo, an intercooler & a better carb - one that can handle being pressurised & then making all the plumbing out of steel pipe and hoses. Budget for this project is, hmmm £200 - £300. There is fortunately a big scrapyard just down the road, a real one where you can help yourself.

Can anyone offer advice on things like carbs, turbo’s that would be good candidates? Can you use the turbo from a diesel car, can’t think why not tbh. Also I’m assuming I’d have to lower the compression ratio but what is an easy way to do that without expensive mods?

See lots of questions…

Cheers

I would start by finding a car that is turbo'd and taking the whole system, turbo/wastegate/intercooler/fueling etc and try to fit it to yours, at least that way you know it all works together.

A diesel turbo will probably be killed by the temps in a petrol application and the operating range will be miles off.

I'd look for something like an old Volvo low pressure system or maybe Something from a SAAB.

Not an expert on this subject by any stretch of the imagination but a couple of comments -

Nice project and I can see why you are doing it - keep us posted
Engine has a compression ration of 8.8:1 which is a good starting point
Turbo will need an oil supply so you will need to put a couple of ports in the sump
IIRC Diesel Turbos are very different to petrol ones so I'd go for a pertrol one
I'd look at a VAG 1.8 Turbo (the 150hp version should be enough and the cheapest, Passat parts are also ldess desirable for some reason)
Have a look at supercharging with a Mini E45 supercharger may also be worth lookng at - no exhaust pumbing to do
You will ned to look at ignition/fueling at the higher rev range to make sure you don't run lean and melt pistons

Just a few pointer but noth there that can't be over come.

The thing is, is that a compression ratio of 8.8:1 might seem good on paper, but due to chamber design etc. it could still ping and get detonation at low boost. Especially with no timing retard.

A cheap and easy way to lower compression is to try and find 1mm or so shorter rods.

But you might/probably will get away with low boost on standard compression.

As others have said, just go with something like a k03 from the VW 1.8t, get some exhaust bends from this place www.zx55.com, stick an intercooler on there and you are good to go.

I do know that ZX9 carbs handle boost well since it's a ram air bike, but don't know much about bigger single carbs.

mitsubishi td04 - 13c - std 940 turbo , about 6 psi boost .

cheapo intercooler from a diesel , (they run much higher pressures)

j pipe from the original exhaust manifold

feed and return pipes from the oil system , you might be able to find a sandwich plate for the oil filter which has a take off point for the oil feed . return straight to the sump , and at least twice the inside diameter of the feed pipe if not more .

SU carbs are more adaptable to turboing , or even just have a suck through carb for cheapness , about 1.5 or 1.75 should be right .

wideband lambda , file the needle and adjust spring on SU for acceleration and WOT operation .

youll need a boost referenced fuel pressure regulator too .

to lower CR , you could use two headgaskets, or by a MLS one which is much thicker . volvo turbo has 9.0:1 CR , so as long as you dont run too much boost you should be fine .

BUT , if its not mapped/tuned setup properly , no matter what you pay or buy , it will still go bang ....

get on with it

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Originally posted by Volvorsport



BUT , if its not mapped/tuned setup properly , no matter what you pay or buy , it will still go bang ....

get on with it

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Find the bits from a Bluebird turbo and bolt them on?

Low boost turbo, box in the existing carb and use a rising rate fuel regulator so will probably need another fuel pump (3-5lb + boost pressure) and a way of metering this and bolt together.

Oil from the oil pressure switch and stab a return into the sump.

Woosh, whirl then bang if it runs Lean.

Sealing the carb could be challenge unless it is nice and simple so swapping for an SU is a very I good suggestion or suck though reduces complexity.

If only I knew in my 20's what I know now, I would have shoved a turbo on every car that came through my hands!

[Edited on 16/6/14 by mark chandler]

I had a ZX Bluebird Turbo for a while - it was alright actually that would be the easy route, finding one might be harder

thanks for all the good suggestions

I think the chances of finding a decent bluebird turbo are close to nill if not less so wasn’t even going to look at that route.

Had thought of an SU, their cheap, simple things and I’m not wanting to go down the fuel injected route, which is more complexity than I can be bothered with, but was going to fit a lambda sensor so I can have a dash mounted mixture gauge to help with tuning. If I got just 20bhp more than standard I’d be plenty happy so a low boost would be fine and I don’t want to stress the engine or brake unnecessarily.

The materials used for exhaust valves and valve seats in Japanese engines if this era are fine for normal use but suffer badly if subject to extra heat.

You can't use a fuel pressure regulater on a carb as there its no fuel pressure to speak of

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Originally posted by Mr Whippy
thanks for all the good suggestions

I think the chances of finding a decent bluebird turbo are close to nill if not less so wasn’t even going to look at that route.

Had thought of an SU, their cheap, simple things and I’m not wanting to go down the fuel injected route, which is more complexity than I can be bothered with, but was going to fit a lambda sensor so I can have a dash mounted mixture gauge to help with tuning. If I got just 20bhp more than standard I’d be plenty happy so a low boost would be fine and I don’t want to stress the engine or brake unnecessarily.

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Originally posted by luke2152
You can't use a fuel pressure regulater on a carb as there its no fuel pressure to speak of

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quote:

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Originally posted by Volvorsport

quote:

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Originally posted by luke2152
You can't use a fuel pressure regulater on a carb as there its no fuel pressure to speak of

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oh yes you can, when boost is referenced into the fuel chamber it blows it back down the jet.

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quote:

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Originally posted by DIY Si

quote:

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Originally posted by Mr Whippy
thanks for all the good suggestions

I think the chances of finding a decent bluebird turbo are close to nill if not less so wasn’t even going to look at that route.

Had thought of an SU, their cheap, simple things and I’m not wanting to go down the fuel injected route, which is more complexity than I can be bothered with, but was going to fit a lambda sensor so I can have a dash mounted mixture gauge to help with tuning. If I got just 20bhp more than standard I’d be plenty happy so a low boost would be fine and I don’t want to stress the engine or brake unnecessarily.

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Get one from a Metro Turbo and you'll be fine. It's capable of what you need and easy to tune.

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