Knowledge of Turbocharging a 5th Gen.

I know what you're thinking, and Im not interested in the $5k supercharger kit. Also, this is using a VFR800 engine on a tube frame, not on a motorcycle, so I am not limited by space or rider interference. After doing research when I first picked up my 2000 VFR800, I saw that the max HP I was looking at with the kit was around 150. I was talking to one of the techs at ASK motorsports and he said that he beefed up the centrifugal kit and got 200hp to the ground. Said he could go higher but the cooling system was far inadequate at that point, and he would have to lower compression more and space the head out farther. I havent seen him in a while, and I got more questions for him.

Looked around some more, and saw some people saying that the transmission and clutch are not strong enough to hold even 150 for very long. Trying to figure out what actions I should take to find out what the limit would be without grenading the engine. The other mechanic at my shop rebuilds, rebores, and overhauls engines, so unless the engine really gets destroyed, it should be able to be rebuilt solidly.

I got 3 small turbo's to choose from for my bike, and we got plenty of steel and aluminum left over from other fabbing projects to build the turbo intake and exhaust manifolds on the cheap. The guy helping me build this has built several high HP vehicles, and daily drives a 950HP Supra making 38lbs and gets 30mpg. The thing has over 60,000 miles since the rebuild, and still runs strong, so I believe that Im in good hands.

The cooling system will be upgraded tremendously with a single larger radiator and fan in the front of the vehicle. Is the stock ECU with a power commander all I would need to tune it? Or would I need to look aftermarket like an AEM or MegaSquirt?

Anything else you guys want to throw at me, Im all ears.

 

Why are you stuck with a VFR motor when there are other engines with the hp you're looking for built-in, not added-on, and with trans, cooling systems, and clutches designed for it ????

Rods, bearings, gears, cranks designed for 110 hp or so, are not likely to withstand significantly more power for long.

 

Cause thats what I got. Bought a salvage bike and already made my return investment and flipped some profit on it, with more stuff to sell, and still have all the parts I need. Right now its a free engine, so figured I might as well have some fun with it. I can find another engine and bolt it up if I really wanna get some power. I like the V4 platform and sound.

Im already kinda set on this. I do appreciate whatever knowledge you can give. If it helps you, Im doing this for the experience more than the end result. Id rather try and fail and gain that experience than have someone else do it and learn nothing.

 

I'd imagine you'd need the use of a dyno, a whole new FI map, the savy to create it and the ability to add it to the system.

 

Because the stock ECU cannot allow the injectors to open up that much, or because the injectors themselves cannot pass enough fuel? Also curious if the block has problems with handling boost? Figured if the centrif supercharger kit worked on this platform...

I've used Megasquirt before, and converted an old Mercedes that was mechanical injection to electronic injection (and turbo'd it as well). That was much more fabbing than the current project is going to require. Also got a DynoJet dyno at a local tech school to tune it.

 

How's that done with the pre-6G gear driven cam drive?

 

Good point. He just stated that it was an 800, didnt say year. I got some more questions for him next time I see him, so I'll add that to the list.

 

Correct me if I'm wrong, but won't increasing the size of the combustion chamber lower compression.

 

Depending on the thickness of the pistons, you may be able to dish them to lower compression. Most have enough to do so.

 

Going that route, I could bore the walls out or shorten the rods to make more combustion chamber room.

Good stuff. Keep it comin.

 

Boring it out will do just the opposite and give you more compression. Unless you mean by boring is reshaping the combustion chamber (head) which I don't know if it can be done. Larger bore with same combustion chamber (head) is stuffing more in to the same bag. (head) I doubt you'll find a rod .010- .050 shorter that will fit your motor. You could have custom pistons made and raise the pin height (lowers piston). Then you are getting in to squish (quench) band area. To little or to much is a bad thing. Range should be about .030-.080 for squish area.

 

When that though popped into my head, I was just thinking of milling the top of the piston down. Im trying to determine what the desired ratio is, and what steps would need to be taken to achieve it.

I havent looked into it a ton, since I gotta get this thing running and get the suspension tuned before I start on the forced induction, but I wanted to get some ideas on what would be needed so that I can start looking now and find deals (if possible).

 

I would not mill the piston, best to use custom made or stay w/ un-modded stock.
the use of force induction would very much shorten the life span of a mill down piston

 

Ah, guess I was giving the stock pistons too much credit. I'll probably run low boost until I decide whats up. Figured since I'd have room for an intercooler, smoke em if you got em. Might hold off on that for a bit. I'll check with my internals supplier and see if they got anything available in the means of custom.

 

I was able to talk to a guy that did turbo his VFR, although it is not a 5th gen. Heres the email he replied with:

Unfortunately i wasnt as organized as a build thread. I would recommend talking to someone who has good technical knowledge of turbochargers (there are people that think they know about turbos), i used a T25 but my probs where lack of room. i used the net a lot, the biggest prob was knowing if what people told me would apply to my project, a good place of info was the busa sites, they done loads of turbo jobs. it took me about 3 to do all the theory.

My turbo project is no more, it went bang. due to turbo failure not melted pistons. the turbo broke up, a bit went through air intake jammed valve cracked a piston. i have two theories as to why turbo broke firstly it was a second hand one but did checkout ok, secondly i took an oil feed from the pipe between the oil pump and oil cooler and i am not sure if there is enough oil pressure ?, if oil pressure was a prob, suzuki fit an adapter to some bikes that fits between oil filter and block, you could run a feed from there.

I have some paper work i am trying to dig out.
not sure how much experience you have of turbos, if you go to Garrett website they have very good technical pages that will help, from there you will discover me saying i used a T25 turbo means nothing: you have to match the compressor size to the job your doing (i used AR48). on garrett site you can get flow charts for different spec turbos, you need some maths etc to calculate in relation to rev range, power reqd, area of plenum, distance from turbo to plenum will vary lag etc(i fitted a dump valve to reduce lag, dump valve not just for boy racers they serve a purpose).

vtech compression ratio 11.6 : 1 so no need for any engine mod, compares with busa specs.

Turbo:
once i calculated the spec i needed i went round a car scrap yard to find the one i wanted,

Fueling: i used AF ratio 14.7
after some home work on web, discovered that vfr vtech has the same fuel injectors as CBR1000RR, 12 point high pressure injectors so no need for upgrade (they may fit yours ?). fuel pressure regulator was sufficient (35psi) no need for upgrade. you may need to get some bits from a Vtech i not sure of specs on yours.
i had to go to a pet shop to buy some air pump tube and one-way air valves x 3, the guy that is selling the super charger kit has the same prob, i dont think he knows wot the prob is, the fuel pressure regulator will cut out when on boost, this is solved by the one way valves.

I need go work now, this should give you plenty to think about, happy to help as you go along.

Another:

if you have looked at garrett web site im sure you found it very interesting, assuming your reading some of there downloads i will bore you with more probs, you asked about cooling, i didnt change anything, the engine is designed by very clever people who know that the system fitted to the bike is sufficient to cool the engine under the most extreme conditions (if you run engine to cool it not optimum power).
the only mod i made to fueling was fit a power commander and i bought leo vince end cans, on the vtech ignition timing is computerized,not sure on your bike. if you can it will need retarding.
i had to modify the exhaust but on my bike it was easy as it has a collector box i took the outlet and run a single pipe to the front of bike to drive turbo then a pipe back to the end cans.
for the intake side i used original air box,i cut a whole in the front and ran a pipe from the turbo up to the air box with a dump valve fitted in the centre, due to the length and location approx 18 inches long and at the front of bike i didnt feel intercooler necessary as forward motion created cold air round induction tube.
as for rev range, i had mine start to boost at approx 4500 rpm so that i was on full boost 10 psi by the time vtech kicked in at 6700rpm, but at low revs it would drive round town as a normal bike.