# how to boost R1 carbs? with rotrex supercharger



## rakriste (May 3, 2003)

Hello.

I got an Audi 80 quattro with a golf mk2 16v engine. it runs on E85 (bioetanol) with R1 Carbs. runs great, but its time to get some more power out of it.

I have fitted a rotrex supercharger on the engine, but have not connected the air into the carbs yet.

Any important thing to know about before I "kill" them?

currant look... 









alt.1








alt.2


----------



## NAVI51 (Aug 18, 2008)

I wanna see how this ends, very interesting project :thumbup:


----------



## rakriste (May 3, 2003)

I hve searched on the r1 forums and found out all I needed to know about.

this is how close we are to fireing here up again. give us a week


----------



## Dave926 (Mar 30, 2005)

awhile back i was fiddling with my r1 carbs and after visiting the r1 forums i thought of boost. There are tons of those bikes with turbos and all it seems they do is just drill out the main jet.

Good luck with your build


----------



## i4turbo (Oct 26, 2006)

EVERYTHING YOU NEED TO KNOW

http://www.turbo-bike.net/


----------



## Dave926 (Mar 30, 2005)

why not use a stock upper portion of a stock 16v manifold and just cut it down.


----------



## rakriste (May 3, 2003)

i4turbo said:


> EVERYTHING YOU NEED TO KNOW
> 
> http://www.turbo-bike.net/


thanks




Dave926 said:


> why not use a stock upper portion of a stock 16v manifold and just cut it down.



we tried, but the runners are not matching the carbs well enough. carb 1 and 2 are close to each other, but 3 and 4 are further away.
I welded up the the new manifold yesterday so that part is done


----------



## Dave926 (Mar 30, 2005)

Good point. I used a stock intake mani cut up for my setup when i was playing with that, and let me tell you that was a bitch


----------



## slayer00 (Oct 31, 2006)

Any updates


----------



## Mr Roo (Aug 8, 2006)

What downpipe or header are you using? I have heard of the fox guys using a passenger side header from a
v8 audi to go 16v, but they are getting hard to find.


----------



## slayer00 (Oct 31, 2006)

Mr Roo said:


> What downpipe or header are you using? I have heard of the fox guys using a passenger side header from a
> v8 audi to go 16v, but they are getting hard to find.


You just use the manifold from a 16v 80 or coupe. I have a 16v ACE from a b4 coupe that im going to use in a b4 80 quattro


----------



## MKIGTITDI (Aug 25, 2007)

Hey ive talked with a guy thats done this with a coralla on the grassroots motorsports forum and he used rx-1 carbs(identical to r-1 carbs just sidedraft version) You need to reference your bowl vents and slide vents to the boost from your plenum. you also need a fuel bypass regulator that refferences boost and will match your fuel pressure increase pound for pound with the boost pressure. He also said contrary to belief with our motors you end up downsizing the carbs but im leaving mine the same till i have wideband and can verify. look at my thread in my signiture and feel free to ask any questions if you have any. Also you cant run more than 12 psi with the stock hats without going to billet hats, slide springs and t's(your refference to your bowls and slides). also a good place with tons of info is this forum. I got tons of info from here. You have to reference the rx-1 carbs on this forum. the pics of the turbod carbs in my thread i got from this forum and the grassroots like i said earlier. Best of luck i hope to do finish my set up soon! :beer:
http://www.ty4stroke.com/viewforum.php?f=24&sid=82a5720c04138899ff24761b90773944


----------



## hinshu (May 29, 2001)

^^ that's tits!

In for more


----------



## Rocco R16V (Oct 7, 2008)

Very cool! do you have any pics of the charger mount by itself?


----------



## rakriste (May 3, 2003)

I have made some changes here. I ran the engine with 1.1bar boost, but it did'nt work well enough. 
I had some problems with gearchanges, it sounds like automatic since the compressor are forging boost without stops like a turbo dumps airflow. 

therefor we are welding in a G60 throttlebody to give us this dump of air mechanicly when we let the pedal of. 

I have ran this enginge for 2 seasons with carbs and 50%50% 98 gasolin and e85 
Sadly something happen a few weeks ago, we lost oilopressure and the engine is historie.. now we have upgraded to 2l 6A..


----------



## dr770 (Dec 31, 2011)

The most important and missing part is i think you have to use a proportional pressure regulator. you can route the float vents to the plenum but as soon as your boost pressure reaches to your fuel pressure no more fuel can go in your float chamber. so i have checked turbo bikes they are all using a pressure regulator with an input from the boosted plenum. standart pressure of a motorcycle carb is about 2-3 psi so higher boost pressure will force the fuel back to pump . Belive me find the regulator first.http://www.outlawdragbike.com/showthread.php?546-Plenum-Building 
you can find everything you need here step by step please check it out. be careful about the compression ratio.


----------



## rakriste (May 3, 2003)

I use a malpassi carb-turbo fuel pressure regulator which is the same as you talking about. 
fuel are not one of the problems we had, just that compressor and turbo work differently and therefor need a openvalve on idle just like a orginal G60


----------



## Issam Abed (Feb 12, 2004)

rakriste said:


> Any important thing to know about before I "kill" them?
> 
> currant look...


You should try and get a reverse rotating water pump impellar if you plan to run it like that. Also Rotrex / HKS superchargers need minimum 300* belt wrap.


----------



## jsvr6nsd (Jan 9, 2007)

What needs to be done to the R1 carbs to run e85? I am looking at running a high compression motor to reap the benifits of e85. Should be somewhere around 13.5:1.


----------



## bmwquick (May 17, 2010)

So I'm planning on doing on R1 carb turbo setup on my 9A once I get it running well with just the carbs. I've done research on other turbo bikes and basically you need to do everything mk1gti said, except that the float bowls should be referenced to boost via a pitot tube, not just hooked to the manifold. 

I found someone on the datsun forums who just setup an r1 turbo so I asked a few q's. He drilled jets, shimmed needles, and referenced boost to the bowls and diaphrams. he didn't use a boost referenced regulator, then again he also doesn't have a wideband lol. Here's the thread: http://community.ratsun.net/topic/7862-r1-carbs-lots-of-pics/page__st__440 

Does anybody have any more info on properly boosting bike carbs? I'd like to know how the drivability is.


----------



## spudly13 (Jun 21, 2012)

bmwquick said:


> So I'm planning on doing on R1 carb turbo setup on my 9A once I get it running well with just the carbs. I've done research on other turbo bikes and basically you need to do everything mk1gti said, except that the float bowls should be referenced to boost via a pitot tube, not just hooked to the manifold.
> 
> I found someone on the datsun forums who just setup an r1 turbo so I asked a few q's. He drilled jets, shimmed needles, and referenced boost to the bowls and diaphrams. he didn't use a boost referenced regulator, then again he also doesn't have a wideband lol. Here's the thread: http://community.ratsun.net/topic/7862-r1-carbs-lots-of-pics/page__st__440
> 
> Does anybody have any more info on properly boosting bike carbs? I'd like to know how the drivability is.


 Correction, didnt have a wideband yet, and hadnt needed the regulator...yet. all on the car now. its a workin progress


----------



## spudly13 (Jun 21, 2012)

you can check out the full build here, 

http://community.ratsun.net/topic/42212-12-bagged-and-boosted-71-4dr-510/page__st__160


----------



## bmwquick (May 17, 2010)

Awsome you got on here!! I'll have to go through your thread and figure out how to set mine up.:laugh: I'm planning on dailing mine in NA and then adding the turbo. I've already ordered a Mallory 4309 regulator in anticipation for boost.


----------

