Turbo Project

ceebeeargh · 10-12-2004, 1:55 PM

Hi All,
I'm currently in the process of modifying a CBR 600 FN to include a variable vane turbo. I have most of the bits I need. But I'm having a dilemma with the fueling. Does anyone know what boost level I can put through the standard carbs. I would love to stick a fuel injector set up on it and map it but the budget is a little too tight to allow this. I would welcome any advice anyone has, I've seen CBR turbo's running on standard carbs 929 and 600's but I haven't had any response from the people who carried out the mods to see what changes were required for certain boost levels.
Thanks in advance for any advice anyone might have.

CeeBeeArgh

P.s It does have to be the turbo charge option not an engine swap or N/A tuning as its for my second year motorcycle degree project.

*norubit_xL* · 12-27-2006, 8:46 PM

Why not turbo a F4i??? already Injected... only reason I ask, is cuz I have one, a REALY REALLY REALLY wanna see some1 turbo it....

Repeater · 12-27-2006, 10:48 PM

I know someone has posted a thread about an f4i turbo'd. I would do a search to see what you can find. silverbullet may be able to help. he is the drag racing guru with a shop.

http://www.fireblades.org/forums/mem...llet-4948.html

thats his profile pm him. he's a nice guy and i am sure if he can help you, he will.

bacon117 · 12-28-2006, 1:08 AM

We turbo the f4i engine on our formula SAE race car. We saw decent gains below 11,000. above that, it sucks, b/c we have a restrictor.... silly sanctionaing rules

We ran about 11:1 CR to allow more boost. We ran a mild fuel map with low boost 2-5 psi, and a high boost fuel map and I think we saw close to 12 psi. fun to drive!

*norubit_xL* · 12-28-2006, 8:20 AM

My bigest want, was to see a setup acutally on the bike, wondering where the best placment for the turbo would be, what path would be best for the piping and all.... mi bike is totalled at the moment, dont really have anything to look at.... wondering if i stay low boost, 4-5 psi, i should need an intercooler..... just happy thoughts is all :-D

bacon117 · 12-28-2006, 3:21 PM

kinda hard to turbo a wrecked bike.... lol

We use 100 octane gas and we lowered the CR with the turbo. I'd be curious to see how much boost you can run with stock CR. you may want to run like 104 octane, or somthing high... Just to be safe.

*norubit_xL* · 12-28-2006, 3:24 PM

Forgive my stupidity, but I am only new to the idea of turboing the bike, or anything at that matter, what is cr, and what would higher octane benefit to being safer? Im eager to learn...

bacon117 · 12-28-2006, 3:56 PM

CR stands for compression ratio and basically means how much the piston will compress the air/fuel mixture. For example, if at bottom dead center the combustion chamber has 150cc of air (and fuel) and at top dead center it has comressed it to 12.5 cc, it has a 12:1 compression ratio (150/12.5). Stock f4i has about a 12:1 CR.

When you turbo an engine you force more air into the cylinder, and this allows the engine to inject more fuel, giving more power. However, now that you have more air to start with at bottom dead center, the piston will compress the air/fuel mixture to a much higher pressure when it is at top dead center. Gasoline has the ability to spontaneously combust, or pre-detonate, from heat and pressure. Higher octane levels help to increase the amount of heat and pressure the gasoline can handle before pre-detonating. This is why a turbo car, such as a WRX or any other high performance car requires the use of premium, to prevent detonation.

Keep in mind that one pre-detonation event could ruin your motor. It probably won't, but instead you'll hear "knocking" coming from the engine, and any prolonged use of an engine while knocking WILL destroy the engine.

It is in preventing pre-detonation that I say higher octane will keep your bike safer. In the end, the shop, or person, that tunes your torbo'd bike will tell you what octane you should run.

*norubit_xL* · 12-28-2006, 4:09 PM

oh compression ration,... duhhh.... lower compression is safer when turboing correct???? still dont understand why higher octane makes running tubo safer...

*norubit_xL* · 12-28-2006, 4:10 PM

LOL... ur post didnt show up untill after i answered my own question, hahaha.... great stuff.... well all i need is a set of headers, and the bike is back on the road, just no body.....

*norubit_xL* · 12-28-2006, 4:13 PM

so basically if i go turbo, and still want to run 89 or 93 octane, i need to use lower compression, aka shorter pistons correct??

*norubit_xL* · 12-28-2006, 4:22 PM

Aslo, I associate lower compression with less power.... how would this affect things?? Would it be better to keep 12:1 weith race fuel, or say 10:1 with road fuel.

bacon117 · 12-29-2006, 6:13 PM

Yea, if you were staying normally aspirated, lowering CR will lower power, but the turbo will MORE than make up for that loss.

Wiseco sells a lot of good pistons for the F4i, thats where we bought our lower compression pistons from.

12:1 with race fuel is beeter for power, but race gas is expensive. Its up to you.

im4u2nv81 · 01-20-2007, 3:21 PM

first and foremost I'd say your first step would be researching and learning the basic functions of an engine and how a turbo relates, the different grades of fuel and its burn quality per grade of fuel, ignition timing, compression ratio, boost, etc. That would be where I would send you first.

most bikes mount the turbo in the front of the engine...where the exhaust is. they run the pressure pipe (off the compressor housing) to a fab'd box covering the carburetors (or a reinforced airbox of some sort) to pressurize (boost) the intake system. The downpipe (exhaust pipe coming from the turbo) generally will exit on the right hand side of the bike and the wastegate dump (if not integrated into the turbine, exhaust, housing of the turbo) also exits there.

You will have to tap into an oil supply for the turbo bearing cartridge and also modify the block/pan to accept a oil return from the turbo.

Fueling will be the most important part of any forced induction system, especially so on a carburted bike. Enjoy that one.

if you run anywhere under 7psi you should be fine w/o an intercooler and I believe most bikes dont run an intercooler regardless. Past 7psi MOST turbos will start to heat the boosted air so much so that detonation will become a problem due to pre-ignition caused by the super-heated air.
Lowering compression will help quell detonation by reducing cylinder pressures and heat...also allowing you to run more boost. You can do this by either installing pistons with a lower height (dished in most cases) or by installing a thicker headgasket. Basically the idea is to raise the combustion chamber volume.

Using a variable vane turbo? Are you out of your mind? The cost of such turbo would be RIDICULOUS! Diesel engines have been using them for years, BUT... Porsche just started using them on the new 911 turbo THIS YEAR! Problem with variable vane turbos is that the super hot EGT (exhaust gas temperature) on a gasoline engine under boosted conditions just basically makes these turbos not very feasible. I would opt for a more traditional ceramic bearing or ball bearing turbo.

hope this helps.

dattaway · 01-20-2007, 3:42 PM

I've been thinking of toying with a turbo one of these days.

With the ram air setup on the 600f4, the stock carb setup should be able to accept very low levels of boost without problems. The wastegate would be at its most safe setting. Then I could somewhat safely experiment with tuning it up.

The two things I would check for would be air/fuel mixture and dentonation vibrations. The carbs are calibrated for a certain flow and could introduce too much oxygen. That's why I'd want an oxygen sensor mounted on the header to trigger an alarm or emergency shutoff so the engine won't burn. The other would be a simple detonation sensor. One could be made cheaply out of any vibration sensitive element. I hear the beginnings of detonation is easy to detect. It would be sensed by any sharp spikes from the sensor and could be wired to disable or retard the ignition system with a valve to help open the wastegate.

im4u2nv81 · 01-21-2007, 10:43 AM

Quote:

Originally Posted by dattaway

I've been thinking of toying with a turbo one of these days.

With the ram air setup on the 600f4, the stock carb setup should be able to accept very low levels of boost without problems. The wastegate would be at its most safe setting. Then I could somewhat safely experiment with tuning it up.

The two things I would check for would be air/fuel mixture and dentonation vibrations. The carbs are calibrated for a certain flow and could introduce too much oxygen. That's why I'd want an oxygen sensor mounted on the header to trigger an alarm or emergency shutoff so the engine won't burn. The other would be a simple detonation sensor. One could be made cheaply out of any vibration sensitive element. I hear the beginnings of detonation is easy to detect. It would be sensed by any sharp spikes from the sensor and could be wired to disable or retard the ignition system with a valve to help open the wastegate.

would have to do away with the ram air setup and seal the air box so your off there. A good wideband o2 sensor will do wonders in helping your tuning...but you'll have to remember to retard your timing pretty heavily as well. Are there provisions to retard the timing on your bike? Not sure a "detonation sensor" will work well on a bike due to all the vibrations coming through from the suspension and the fact that the engine is hard mounted to the frame. Might be shooting yourself in the foot there.