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jcslocum

UK carbs or USA Carbs

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HI all!

I have recently bought an '84 esprit that needs a bit of engine re-assembly after a timing belt break. I'm working on a list of items to bring that car back to running and driving service. It currently has Mikuni carbs mounted (odd that) but I guess they were the turbo carb for many japanese cars of the 70's and 80's. I have NO records or info on the cars past but need some help determining what carb is best. The UK uses a different carb for the Esprit Turbo and because the UK didn't have all of the useless emissions stuff are they the better option??

 

Here is a post I put up on Lotus Talk but has had no responses yet:

 

I have been working on my list of parts needed to bring the Esprit back to life. It has the strange Mikuni carbs installed at least bolted to the manifold!

IMG_0719_zpsbb5rr7of.jpg

I'm not in  much of a mind to struggle with these carbs only to discover they are crap. These appear to be from a Datsun, Toyota, Honda turbo kit from the 70's or 80's. They may be good to go and it looks like they were on and running but I'm not confident.

I see that there are a different market carbs that were offered for the Esprit. The Euro version doesn't have to "power" valve as the USA model has. Is there any reason to get the USA specific carb??

We no longer have to meet emissions controls here in the USA and I intend to strip all of whatever might be left on the car off. So, is a set of UK carbs, set up with the jets and chokes, going to be a smart choice??

Your input is very much appreciated.

Jon

 


Jon - 1984 Esprit Turbo

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I would think that Euro standard carbs would be the way to go. Don't forget the rubber mountings between the carbs and the manifold; look at the parts book to see what else you'd need...there will probably be bits you hadn't thought of!!


Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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Here are some more pics. I have never seen it in this configuration. I got it after the head work was done and reinstalled.

 

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Jon - 1984 Esprit Turbo

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 I never knew Mikuni made sidedraft carbs.....    However, they are respected manufacturer for high performance applications (bikes), so why not give them a go?   The key question is can they be blown through, which is standard Esprit setup.   After 1 minute of googling, I could see other turbo setups using these carbs, blown into via a plenum.   If It was my car I'd give them a shot.       

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I have no info on them and there is scant supporting info out there. I don't want to waste time fettling them only to learn that they won't work are are all wrong. I will ebay them and hopefully they can go to someone who needs them. 

 

I have ordered the Dell's set up to the UK/Euro spec and should have them in a week or so. This will give me a solid baseline to work from as I sort the car out. 


Jon - 1984 Esprit Turbo

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After a MOUNTAIN of work this spring and summer, see the link below for the thread on Lotus Talk:

http://www.lotustalk.com/forums/f164/recommissioning-vivian-373641/

I have moved to the point where I'm dry assembling the intake and it's various parts. It's a USA car from 1984 so it had the worst of the worst emissions control equipment when new. As you can see from the above, it was butchered over the years in many ways and I'm trying to get it back to where it should be. I have new Dellortos in hand from the UK and almost all of the other parts. I do have some issues and questions. Some things I have worked out already but some other a re a bit of a mystery.

On the USA turbo cars, the pipe from Turbo to Plenum had a flapper in it. Any idea what the thinking was behind this???

image%208_zpslq6b8swy.jpeg

I have removed it and plugged the shaft hole in the pipe. BUT there is a bunch of vacuum stuff associated with this and some other things under the hood, so I could use some help with getting it plumbed right. What my goal is, is to get the engine set up like a UK/ROW car. Does anyone have a picture of the 1984 vacuum lines sticker from the engine bay?? I have the USA version...

 

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When I bought the carbs, I didn't have the balance and boost piping. I was able to find it after buying the AN fittings and SS hose. The end fittings of the pipes are angled so wont fit on the carbs without heave modifications. The 2" plenum spacer doesn't help this at all either...

 

Any help would be great!!!

 

 

 


Jon - 1984 Esprit Turbo

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Does anyone know what the function of the "Balance Pipe" actually is? This is not fitted on early turbos (or non turbos). The other inlets on the top of the jet covers which connect to the intake pipe are only for air when the choke is active.

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I think you'll find it balances the pressure between the plenum and the fuel reservoirs, without it the highly pressurised air in the plenum would push the fuel back through the jets rather than it the fuel going through the jets and mixing with the air going into the engine.

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The balance pipe isnt connected to the plenum though. It only links the carbs and is not present on early Turbos.

The pipe which is connected to the plenum is the pipe supplying cold start air. Its closed off unless the choke is out. That makes sense because pressurised air would be needed for the choke. On non-turbo carbs there is a small vent in this position.

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There are 2 different pipes. One balances between the carbs and 1 (or 2 depending on year) from the turbo plenum.

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Edited by jcslocum

Jon - 1984 Esprit Turbo

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Thats correct, the two pipes connecting to the plenum are cold-start air when the choke is out. The one I am wondering about is the pipe which connects the 2 carbs together. 

BTW I would assume the pressure equalization of the float chambers under boost is done in exactly the same way as on a non-turbo carb because there is a vent which runs from the airbox into the carb adjacent to the main inlet tract.

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All new hoses made up this weekend using Earl's AN fitting and 3/8" SS lines. East to do and makes these very safe. I'm not worrying about fires from leaking hoses...

 

IMG_0508_zpsmfrfiu9m.jpg

 

And, they look racey!


Jon - 1984 Esprit Turbo

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First Start crawls closer....(!) It's looking good....


Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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