Supercharged VFR

Hello,I've got an old 1986 750 FG,I saw the article on supercharging was wondering if its possible to do this with a second hand turbocharger from a car(me being from the UK and skint)can anyone tell what revs it needs to run at,I see he's running his at 1:1 from the crank,it seems to me you could easily run a modified turbo at 4:1 at least,also what pressure you need and also wether you can run it into the airbox before the carbs.I'm also interested in nitrous but thats a future thing,soz,tried to put a pic up,but facebooks playing silly buggers and it wont let me copy my photos at the mo.Cheers!

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GavinS, on 19 December 2010 - 07:16 PM, said:

Hello,I've got an old 1986 750 FG,I saw the article on supercharging was wondering if its possible to do this with a second hand turbocharger from a car(me being from the UK and skint)can anyone tell what revs it needs to run at,I see he's running his at 1:1 from the crank,it seems to me you could easily run a modified turbo at 4:1 at least,also what pressure you need and also wether you can run it into the airbox before the carbs.I'm also interested in nitrous but thats a future thing,.Cheers!

Hers the pic.

Look up Torocharger.
Problem solved.

Welcome to VFRD from the other side of the pond! :beer:

You can turbocharge any internal combustion engine. However you need tuning. Just sticking a turbo on it will blow up. You would really need everything Toro offers in his kit. The airbox for example has to be able to handle the pressure. It would take much Carb tuning and possible at the expense of a con rod.

You cant just stick a turbo on and run it. The engine is not meant for boost. The rods and pistons cant take much boost. Real SC, turbo engines are built top to bottom. The intenals are heavier as well. Ever drive a car with a broken turbo? It wont HP is cut to 1/4 normal.

Welcome to VFRD.

Gavin, check this out from one of our members! :fing02:

http://www.vfrdiscus...ercharger-kits/

Given this some thought myself(turbocharging, not supercharging) on an older VFR. Was thinking of going to one single large carb for ease of tuning with stock internals to achieve 135-150hp.

GavinS, on 19 December 2010 - 07:16 PM, said:

Hello,I've got an old 1986 750 FG,I saw the article on supercharging was wondering if its possible to do this with a second hand turbocharger from a car(me being from the UK and skint)can anyone tell what revs it needs to run at,I see he's running his at 1:1 from the crank,it seems to me you could easily run a modified turbo at 4:1 at least,also what pressure you need and also wether you can run it into the airbox before the carbs.I'm also interested in nitrous but thats a future thing,soz,tried to put a pic up,but facebooks playing silly buggers and it wont let me copy my photos at the mo.Cheers!


Gavin, I know what you are trying to do, and it won't be easy. First off, without knowing what size turbo you have, it's impossible to say what speed it needs to be run at. You have to look at the compressor map for the specific turbo you have to figure out the operating range and final power output. Then, assuming the turbo is actually a good match for your engine, you have to figure out how to drive the thing and keep the bearings sealed.

The Rotrex I use in my kits has in internal step-up ratio of 12.67:1, and even though I underdrive it by 13%, the impeller still spins to 130,000 rpm at redline -- unless you are using a monster turbo, you will have to step up the ratio much more than 4:1. I'd say to shoot for 5psi peak initially and see how it goes, but even with your old 750, it should be able to handle 7-8psi peak (if everything is in proper working order, and detonation is avoided, that is). I have no idea, though, if the stock clutch and transmission can handle the additional load.

The carbs will have to be prepped for boost (that is, the bowls must be pressurized and you have to ensure everything is sealed), you'll have to redo the jetting, and your fuel pump will have to cope with the additional fuel demands. It's a major project, but anything can be accomplished with enough time and money. In my opinion, it would be easier to adapt the turbo to the bike as a turbo rather than converting it to a supercharger, but it's your project, so do what you want to do -- just be prepared for a lot of work either way.

What you'll need to start.
Single carb - as Sebspeed said, easy to tune, or keep the multi carbs and have some fun. plumbing and tuning gets real interesting.
Tubing - to build a collector for the turbo and intake plumbing
A small turbo - think T25 or smaller
Blow off valve - Since you're carbed you don't need to wast time with the plumbing for a CBV.
Oil feed and return lines
water feed and return lines - if the turbo is equipped with water cooling
Larger Oil cooler

A boat load of patience, good tuning, and fabrication skills

Anyone can slap a turbo on something but getting it to run right is the key, Keep the boost low to start and spend a lot of time a your local dino center to get it dialed in.

Cheers,
CG

V-4's are notoriously hard to turbo, given the disparate exhaust exits for the 4 cylinders.