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Having a sort-out in the garage the other day, I uncovered a Toyota CT-26 turbo that I'd put aside for strapping to the side of my V8. Since the V8 project is now canned due to lack of time, money and a reliable engine to start with, my attention turned to putting it on my existing lump in a draw-thru set-up. Slightly less time- and money-consuming, and I can plan it and try it out without crippling my car for too long. Thing is, with a draw-thru the seals on the turbocharger need to be of the carbon type, not a dynamic seal, otherwise oil will be drawn into the combustion chamber when the throttle is closed. Blue smoke and engine death would ensue eventually. I've dredged the net for info on these turbos but can't find much. So... anyone know if the CT26 from a Toyota Supra has dynamic or carbon seals? If it isn't suitable for a draw-thru set-up I'll have to think about a blow-thru, but this means somehow sealing the carb or getting hold of a suitable carb (more £££). I can't do fuel injection (even though I have a Megasquirt kit and all the parts ) as it's a poxy 5-port head. It's a long shot and a bit of a techy question, but I thought I'd try. Any pointers gratefully received
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No help I'm afraid but I never knew that about the seals
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according to what i've read, draw through is not a good idea. you don't have to have the carb in a box upto about 10psi I think. you need to do away with the float chamber atmospheric vent and feed it with boost pressure basically. I'm guessing, but does your merc have an oversized stromberg made by bing or zenith or some such? if so, get an adapter plate and a montego turbo carb on there stat! and home needle tuning FTW! of course the real answer would be someone really knew the what they were on about
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There were at least 3 CT26 Variants. The one used on the ST165 Celica GT4, single entry, small turbo, then there was the big single entry from the the Mk3 Supra, then there were the 2 twin entries from the St185 and ST205 models, efectively splits the exhaust into two lots of two cylinders. That is supposed to stop lag. Import ones use ceramic turbines which don't big boost.
I would say use a turbo carb and blow through. Maybe try to find a carb from a turbo esprit if a Montego or Metro one isn't big enough.
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Why not go for single point injection. It'd be the best of both worlds, probably cost less than port injection and any power losses would be more than made up for by the turbo.
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Thanks for the replies! Bodieanddoyle - The Merc has a Stromberg 175, so an SU HIF44 from a Metro Turbo should be about right as that's 1 3/4in too. As well as the float chamber, there's also an issue with the butterfly shaft that needs to be sealed (so I've read anyway). I am considering a carb swap - I missed out on a Dellorto DHLA 40 that went for £26! Meatballturbo - I fished the turbo out of the boot of a Lancia Dedra in the scrappy , so I'm not 100% sure what car it's off! It's a single entry one though, so in all likelyhood it's off a Supra. RevDickDeluxe - Hmm, single point injection sounds good. Can Megasquirt run this? Or will I need to find a car in the scrappers I can transplant the whole lot off? The only ones I can think of is a late Mini and a Skoda Favorit. I'm sure there are more though. I'd prefer to run a blow-thru, as then I can use the intercooler I have. I'm only looking to run low boost as it's a fairly high CR engine.
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Megasquirt will run it no problem. some peugeot 405's ran a 2 litre with single point injection but if your going for a turbo you might want something off a bigger engine. Maybe a holley tbi unit for a v8 might do the job but it could be overkill. Ask over on the megasquirt forum, someone on there is bound to know.
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If you have a recirc valve in the inlet tract you needn't worry about the seals. The problem comes when the turbo is 'sucking against' a closed throttle, thats when oil is drawn into the compressor side of the turdblowa. A lot of modern petrol turbos have such a valve already in the comp side, but i'm sure you can get an aftermarket one, its the same as is required when using a supercharger. Its to prevent a big vaccuum getting built up upsteram of the comp wheel when the throttle is closed.
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1974 Lancia Beta Saloon 1975 Mazda 929 Coupé 1986 Mazda 929 Wagon 1979 Mazda 929 Hardtop 1982 Fiat Argenta 2.0 iniezione elettronica 1977 Toyota Carina TA14 1989 Subaru 1800 Wagon 1982 Hyundai Pony 1200TL 2-dr 1985 Hyundai Pony 1200 GL 1986 Maserati 425 Biturbo 1992 Rover 214 SEi 5-dr 2000 Rover 45 V6 Club 1994 Peugeot 205 'Junior' Diesel 1988 Volvo 760 Turbodiesel Saloon 1992 Talbot Express Autosleeper Rambler 2003 Renault Laguna SPEARS OR REAPERS
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If you have a recirc valve in the inlet tract you needn't worry about the seals. The problem comes when the turbo is 'sucking against' a closed throttle, thats when oil is drawn into the compressor side of the turdblowa. Would a vent to atmosphere BOV have the same effect?
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The lurker formerly known as Cappuccinocruiser.. or wedgedout..
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I don't think so cos a BOV is downstream of the comp wheel and is relieveng a pressure build up. Whats needed here is a 'negative' pressure relief upstream of the comp wheel.
I'm not sure how the turbo set up will be arranged, will the throttle be downstream of the compressor or upstream?
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1974 Lancia Beta Saloon 1975 Mazda 929 Coupé 1986 Mazda 929 Wagon 1979 Mazda 929 Hardtop 1982 Fiat Argenta 2.0 iniezione elettronica 1977 Toyota Carina TA14 1989 Subaru 1800 Wagon 1982 Hyundai Pony 1200TL 2-dr 1985 Hyundai Pony 1200 GL 1986 Maserati 425 Biturbo 1992 Rover 214 SEi 5-dr 2000 Rover 45 V6 Club 1994 Peugeot 205 'Junior' Diesel 1988 Volvo 760 Turbodiesel Saloon 1992 Talbot Express Autosleeper Rambler 2003 Renault Laguna SPEARS OR REAPERS
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I don't think so cos a BOV is downstream of the comp wheel and is relieveng a pressure build up. Whats needed here is a 'negative' pressure relief upstream of the comp wheel. I'm not sure how the turbo set up will be arranged, will the throttle be downstream of the compressor or upstream? on mine... Basicly it'll sit between a metering head and a throttle body on a K Jet Car. if that makes sense..
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The lurker formerly known as Cappuccinocruiser.. or wedgedout..
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Meteringhead/airbox.. ------>> TurboBlower --------->> ThrottleBody
That make any sense?
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The lurker formerly known as Cappuccinocruiser.. or wedgedout..
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If you have a recirc valve in the inlet tract you needn't worry about the seals. The problem comes when the turbo is 'sucking against' a closed throttle, thats when oil is drawn into the compressor side of the turdblowa. A lot of modern petrol turbos have such a valve already in the comp side, but i'm sure you can get an aftermarket one, its the same as is required when using a supercharger. Its to prevent a big vaccuum getting built up upsteram of the comp wheel when the throttle is closed. Ah, cheers bo11ox! The set-up I'm planning will be: Carb ------> Turbo ------> Engine So I'd assume that a recirc valve between the carb and the compressor will relieve the vacuum when the throttle closes? Pipe it back to the airbox... I may yet draw up plans for a blow-through if I can get my hands on the bits I need cheap enough. Purely in the planning stage at the moment/
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don't do that!!!! The valve wont open as the vacuum will hold it shut, if it did open then the air/fuel mix would go super lean, you wold also loose any form of engine braking. I say blow though carb, especially with the 5 port set up, megasquirt will also be a pain to set up compared to the carb. A turbo SU has been proven to 240bhp+ you will need a pressure regulator anf high pressure pump, a return fuel line aswell. Do it, itll be fun J
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don't do that!!!! The valve wont open as the vacuum will hold it shut, if it did open then the air/fuel mix would go super lean, you wold also loose any form of engine braking. I say blow though carb, especially with the 5 port set up, megasquirt will also be a pain to set up compared to the carb. A turbo SU has been proven to 240bhp+ you will need a pressure regulator anf high pressure pump, a return fuel line aswell. Do it, itll be fun J Hmm, I'm leaning towards a blow through set up, I just don't want to over complicate things as I know what I'm like! I'll start off with a fairly simple idea and get over enthusiastic until I bite off more than I can chew and nothing gets done! The blow thru does seem like a more straightforward option though. The only extra parts I need is a suitable carb, a rising rate pressure reg and a pump. If I'm running 6psi of boost I'm reckoning on something that can deliver 10psi, possibly more if I want to crank up the boost
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