EFI/Individual throttle bodies on old renaults

R

ReidarUF

Member
Fellow Frogger
Joined
Nov 5, 2011
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Location
Norway
It seams like a lot of you have converted to electronic ignition of some sort. Some have even ditched the distributor for a modern coilpack and megajolt.

Why not just convert to EFI?
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First I have to confess that not much have been done to my -64 R8 the last two years. Two small children(2 and soon to be 5 years)and moving to an oldish house in a rather rough state, not to mention the old barn and the ruin of boat house.
The lathe and mill are in bits and the welding machines on storage. But my head are bursting and the pile of parts are getting bigger....

I used to have a Peugeot 106 16v that I converted to gsxr throttle bodies and Vipec(NZ brand) mapable engine management. It gained about 20bhp and it was a lot of fun.
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I plan to do the same to my R8. The original 1108cc engine is a five port and the gearbox have an input shaft like a knitting pin so I have a C2J engine from a late R5 TS and complete rear assembly from a late R10 1300 waiting to get in, hopefully for the summer.

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The C2J have the inlet ports nicely spaced with about 45mm centre distance. To make the runners of the inlet as straight as possible I need to find paired throttle bodies with the same centre distance. Jenway make throttle bodies the same style as the weber DCNF carburettors withch have 48mm centre distance but they are quite expensive. Also I'd like them closer. Some of the Japaneese HD clones have nice dual throttle bodies but most of them have the inhectors in the inlet close to the cylinders. Witch means I would have to weld injector bungs in the inlet.
So theese days I look for throttle bodies from everything from old american cars to snowmobiles, outboard engines and jet skies...
 
all very sound in my view.

I have sidedraughts in place on each toy & shan't bother to change this but if starting from scratch . . . .
 
For some reason I prefer reusing original parts to new shiny tuning parts. Also the separate idf/ida ones can not be spaced tight enough to match the inlet ports.

I think the best candidate by now is from the Kawasaki Vulcan VN900. They are 36mm and quite tightly spaced.
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Goodness that is tight. You could nearly mount that to the cylinder head :p

But surely a suitable inlet runner will allow you have as much room as you may need?
 
I found another unlikely but maybe good candidate. This time from a Yamaha 115bhk outboard engine. I don't know their size but the engine is a 1,8L straight four so they shouldnt be to far off.
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Theese seem to turn out slightly more expensive than the Vulcan ones. Both lack holes for injectors witch means they have to be incorporated somewhere from the inlet tract to just before the cylinder head.
 
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ReidarUF,
What are the diameter of the chokes ????

Thanks,
Ray
 
The ones from the VN900 Vulcan are 36mm. The Vulcan is a V-twin so two sets are needed.
For the outboard ones I dont know. Ive asked two of those offering them on ebay but they dont know(?). Normally that info can be googled but I havent had any luck this far.
 
That boat engine looks interesting.

https://www.yamaha-motor.com.au/pro...our-stroke-115---350hp/inline-4-cylinder/f115

and I suppose a boat engine is tuned for toque more then rpm, ah it states the recommended rpm range is 5500-6000.

I'm trying to find a spare parts catalogue / parts finder that might list more details of those chokes for you. I'll keep googling. A quick ebay search reveals a set of four for well under $150 au.

https://www.ebay.com/p/2000-Yamaha-F115-HP-Throttle-Body-68v-13751-00-00/1342965574?iid=352160843097
 
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Hi bowie.
That link I guess is from the latest model. I think they have changed from itb to a more normal plenum inlet.

The part number for the throttle body where the TPS is attached(as opposed to the one with the cable) is
68V-13752-01-00

It gets a lot of hits with parts catalogues with nice drawings etc but no dimmensions.
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ah fair enough. Yes I was hoping to run into the part reference for the throttle plate itself. But I agree with you, boat engines aren't net friendly like motorbike ones :p
 
I asked one of the sellers who had the autbord ones on sale about the measures: "Butterfiles measure 1 7/8 and the center between openings measures 2 1/8"
So they are far to big and not mathing the inlet ports at all.

Anyway I have just placed an order for two sets of Vulcan 900 ones together with the part of the air filter box where the velocity stacks are. It was quite cheap before the owerseas postage was added....
 
After more than a week the bodies finally left USA today. The plan no is to build a model and to cast it in aluminium. Witch involves building a furnace etc...
 
Yeeeeeeess!!!

Think of all the cool extra bits you could forge!
 
I have to laugh at the irony of you putting bike parts on a car. Sounds like a nice plan.

Years ago I had an Italian bike which the manufacturer chose to put a car carbie onto - lets just say things didn't go well.....too much vino in the planning stage.

Cheers

Justin
 
I received the bodies today.
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They were supposed to be 36mm but the exit about 20mm from the butterfly is only 34mm. Still big enough for my use. The inlet opening is 38mm so a slight taper. The lengt of the bodies is just under 90mm. And the most important part the centre distance is 47mm. So nearly a perfekt match to the inlet ports.

The inlet ports on the C2J head are rectangular with rounded corners. If I should port them to a round(or eliptic as there will be an angle) they would turn out to be about 35mm. Slightly on the big side maybe?

Anyway I think I will make a model with paralell runners without taper. Then I can use round stock for the model of the core and slightly bigger half stock for the two halves of the inlet model.

The flange for the throttle bodies will be straight but the one in the head side should have 10-15 degrees angle. Making this on the model will make it hard to get the model out of the sand mold so I might just make the flange really thick and machine it afterwards.
The initial plan was to make a really long inlet but as the throttles are a bit smaller than I thought they might end up as short as 100mm. Thoughts on ideal inlet lenght are welcome...

I also bought the air boxes from the vulcans as they had nice velocity stacks.
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Hi ReidarUF:)
Good looking things and probably a good unit for your engine, and lots of other smaller engines too.
However I am puzzled by the second butterflies. They look like a choke in a carby !! Not usually necessary on EFI. What are they for in the original bike application ?
Jaahn
 
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