hi,
anyone have experiance of twin charging engines?
looking to add a supercharger to my currently turbo engine setup, only wanting to run it up to 4k
a quick web search shows rotrex units that seem to be up to this job and are small and light which is also a plus
any feedback or threads or placing to be doinf research about this
thanks
The Graham Bell book on forced induction talks about various implementations of this in a seemingly intelligent fashion.
Sell both your kidneys and arms and legs and find yourself a Lancia Delta S4..sorted!
David [ Flak Monkey ] used a rotrex on his 7 type car he maybe able to help with info
On a bike engine I am guessing? seems pretty costly for the low end power, in what situation do you need power below 4k?
Dave
quote:
Originally posted by dave_424
On a bike engine I am guessing? seems pretty costly for the low end power, in what situation do you need power below 4k?
Dave
quote:
Originally posted by beaver34
quote:
Originally posted by dave_424
On a bike engine I am guessing? seems pretty costly for the low end power, in what situation do you need power below 4k?
Dave
no a 1.6 turbo car engine
quote:
Originally posted by dave_424
quote:
Originally posted by beaver34
quote:
Originally posted by dave_424
On a bike engine I am guessing? seems pretty costly for the low end power, in what situation do you need power below 4k?
Dave
no a 1.6 turbo car engine
ah...sequential turbo possibe? Exhaust gasses flow through the smaller turbo then when a certain boost is reached an external wastegate opens and routes the exhaust flow through the larger turbo.
Like this
http://3.7mustang.com/vb/attachments/f41/144048d1270657152-compound-turbo-sequential-turbo-anyone-her_finder_du-rodesbanen.jpg
Dave
Put an eaton blower in front of the turbo , Merc m45 with integral bypass that can be pwm controlled to open it up seems the simplest solution ,
rotrex won't give you the same grunt low down .
I've done a twin charged build and IMO it wasn't worth the effort . Intercooling after the supercharger without having a long path from the
throttle body to inlet is a hard one to crack and I ended up running water meth in summer to keep things under control , you also need a mass air
meter to give a true reading of what's going in as inlet temps can spike as the charger can't do any useful work bug add heat once the turbo
spools . Fortunately I didn't put a ton of cash into the build and sold the charger kit to an autograss guy .
If you aren't getting much grunt below 4k maybe your turbo sizing needs a re think ?
Wouldn't you be better off with a better matched turbo?
What power are you aiming for?
If you had a 1000hp straight six, I could see your predicament
quote:
Originally posted by indykid
Wouldn't you be better off with a better matched turbo?
What power are you aiming for?
If you had a 1000hp straight six, I could see your predicament
Nitrous could give you the grunt and will help you spool your turbo sooner, 350hp from a 1.6 I would expect a big turbo lag, what turbo do you have?
quote:
Originally posted by dave_424
Nitrous could give you the grunt and will help you spool your turbo sooner, 350hp from a 1.6 I would expect a big turbo lag, what turbo do you have?
Have you looked at what VW did with some of their TSI engines? They used supercharging and turbo to get their small engines to deliver decent power.
170 PS from a 1.4?
Although there were rumours that the system was unusually complex and virtually impossible to maintain even for their own mechanics...
quote:
Originally posted by beaver34
no, i was thinking supercharger that worked only untill 4k then the turbo takes over
quote:
Originally posted by jeffw
quote:
Originally posted by beaver34
no, i was thinking supercharger that worked only untill 4k then the turbo takes over
Rotrex will keep going until the redline. You'll need a supercharger with a clutch which cuts out at the RPM you want...
There is a supercharged and turbocharged engine in a buggy in this video and you can see the engine on an engine dyno, there is a valve between the
supercharger and the turbo inlet that opens to atmosphere at a certain RPM/boost level so the supercharger does the low end and then once the turbo
has spooled, the valve opens which stops any parasitic power loss from the supercharger and lets the turbo have a nice unrestricted inlet.
https://www.youtube.com/watch?v=DcI3dYm6BQk
Try Torque of the Devil tuning in Uxbridge as a while back someone there had a twin charged (super & turbo) Fiesta.
alternatively research the new Borg Warner turbos and the billet wheel Garrett GTX series turbos. For a given size, they quote spool in terms of
800-1500rpm lower than a conventional technology turbo 
they aint cheap, but they are just bolt on replacements for your current, rather than a shed-load of work, effort and fabrication followed by
inevitable snagging of a pioneering setup
Any option to increase your air pump I.e engine to better match your turbo as its a bit on the large size for a 1600 cc engine ?
quote:
Originally posted by froggy
Any option to increase your air pump I.e engine to better match your turbo as its a bit on the large size for a 1600 cc engine ?
I enjoyed doing my twin charge build but it did involve a lot of trial and error before getting it to work
http://youtu.be/KzxKP2E2Nrg
Pulling uphill in top at 2000 rpm it gets to 1 bar at 2300 rpm and 1.6 bar at 3000rpm but I couldn't hold my phone and pilot it once the big
Holset comes on song .
I went through 2 chargers , 4 different manifold and cooler layouts before getting a set up that worked well .
Google ronin lotus for all the info you need on compound charging
Twin charging is a regular solution on high performance marine diesels. I have built several boats in which we installed these engines. There was a flap valve which fed induction air to the manifold from which ever charger was producing the higher boost. The supercharger was driven through an electric clutch which disconnected at 3000 rpm and prevented over revving of the supercharger which was quite highly geared from the crank. The system worked very well and the flap valve ensured a smooth switch over, which was imperceptible through the power band.