turbo motorbike! video now on youtube must see!!!

[tim_blair]

haha i knew that would get your attention

anyway i have turbed my zxr400

its a 400cc 4cylinder 4stroke 16valve dohc EVO EATER which i have spent the last 3 years building and it has some serious mods, like a vz21 turbo!

my question is does anyone have any experiance with blow through setup cv carbs???

ive got it running ok but not the best

it needs to be running well enough for me to get it to the shop/ dyno and they can get it going mint from there

at the mo i can rev it up quickly all the way to red 15,000 but if i try and hold the revs it strugles to get over 8,000 (when the turbo gets going)

i have alot of info and pics on my project if anyone is interested
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[Paulio]

pics plz!

[thegreatestben]

Hardest thing would be finding a turbo that suits a bike as they pretty much don't exist for a 400cc motor. What turbo have you bespoked the bike with?

[loudstealthGT-Four]

pics plz!

+1

[RS13]

Hardest thing would be finding a turbo that suits a bike as they pretty much don't exist for a 400cc motor. What turbo have you bespoked the bike with?

Garrett don't just do the GT series turbos for cars, they go right back to a GT1241, which requires 400cc minimum up to 1200cc maximum. I'm sure there are a couple of kei-cars around 600cc that would also have a suitable turbo for a motorbike, as a budget option.

http://www.turbobygarrett.com/turbobyga ... _sheet.htm

[MR2BOY23]

There are some Chinese turbos on ebay smaller than the gt12

[RobertC]

All is told in the original post...

like a vz21 turbo!

[thegreatestben]

I've only read bits and bobs but there was mention that adding boost does funny things to the float level in the carbs. I think some of the guys on oldschool know a bit on this subject as that's where I remember glancing at some info about this sort of thing. Perhaps they can't keep enough fuel in the carbs to keep up any more. Have you done anything to the fueling system?

[fivebob]

CV carbs will be a PITA to get working with a turbo as they (try to) react to airflow/density and boost in a blow through setup just confuses them. You'd probably be better off with a slide carb. When it was popular in the eighties most bike turbo conversions used a single SU carb in either blow through or suck through configuration.

For an idea on how CV carbs work take a look at http://www.bikerenews.com/Stories_Archives/Carburetors.html

[Rookie]

^ this is BS, you have to pressurise the float bowl though.
TGB is right, the link on OS is http://oldschool.co.nz/phpbb/viewtopic.php?f=2&t=24281 listen to Bubblegoose, he knows his shit.

[Bazda]

Suck through carb.

[spencer]

^ I helped out on a turbo'd bike with suck through and methanol works sweet, but the main jet was as big as the carb could go by the time we got it rich enough

Read that thread on oldschool, I thought blow through CV's would be shit with boost but if you pressurise the bowl and diaphragm shits all good to go.

[tim_blair]

how do i put in images?

yes the turbo i have used is the one pictured above with the pepsi can
its from a suzuki cappachino a 660cc car
my bike and the cappachino flow about the same and its the smallest turbo i could get a hold of as it needs to fit behind the radiator

i have plumbed the float bowl breathers to the airbox as well as the top and bottom of the diaphragms, aparently thats all i need to do to get it running but i cannot hold the revs above 8000 it kinda trys really hard to rev up but wont hold and just falls back to 8000ish

im not going to change my setup as its 99% complete and it cost me a shit load of money and a mother $&#$% crap load of time to design and build

the fuel system is standed, tank to filter to pump to carbs, will be more than adequate as i am only running low boost

[Rookie]

For images use Imageshack or photo bucket to host them and then use the [img] tags

the fuel system is standed, tank to filter to pump to carbs, will be more than adequate as i am only running low boost

I would say this is your problem, you will need a rising rate (1:1 should do) fuel pressue regulator. What is happening is that when it is coming on boost the boost will be overcoming the fuel pressure and it won't be able to get to the float bowls. as its a carb set up the fuel pressure will be between 1~5 psi ( I'm unsure of exactly what it is for bikes), so it wouldn't take much boost to hinder the fuel supply.

[tim_blair]

hmmm i understand that, my standed pump is only 2 psi
ill try and get a bigger one and put in a pressure regulator

[thegreatestben]

Like this:

Code: Select all

[img]http://img101.imageshack.us/img101/2299/dsc00158p.jpg[/img]

[tim_blair]

doh!


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[tim_blair]

http://img138.imageshack.us/img138/9440/dsc00182ir.jpg
http://img826.imageshack.us/img826/1483/dsc00183yt.jpg
http://img138.imageshack.us/img138/9440/dsc00182ir.jpg
http://img32.imageshack.us/img32/580/dsc00178uh.jpg
http://img214.imageshack.us/img214/4798/dsc00176ev.jpg
http://img709.imageshack.us/img709/51/dsc00166op.jpg
http://img29.imageshack.us/img29/30/dsc00163cl.jpg
http://img375.imageshack.us/img375/2630/dsc00162qm.jpg
http://img641.imageshack.us/img641/4569/dsc00161ed.jpg

Admin edit - resize them, waaaaaaaaaaaaaaay too big

[whynot]

I would have thought the fuel bowl breathers would need to see positive pressure from the turbo otherwise the fuel will be getting pushed back into the bowl from the jets.

[tim_blair]