Anyone on here done it?
Maybe an M45 geared up to give around 6psi.
Blowing through a set of bike carbs
Can the float bowl be pressurized via the breather vent?
Will the slider operate as normal?
As the pressure will be linear will fuelling be setup as per usual?
What boost will bike carbs handle?
I have a red top and filter king, would that be sufficient?
Any info would be great!
Cheers
[Edited on 13/12/10 by Craigorypeck]
some interested reading here
Ray
quote:
Originally posted by rayward
some interested reading here
Ray
I remember a friend of mine tried this with a stromberg carb years ago and it was a fail!!
The Stromberg carb has a rubber diaphram like a bike carb and we run into all sorts of dramas, we believe due to that.
We gave up in the end with set up, and we replaced it with an SU, wasnt a problem from then on. If you used an SU, you can get one from a MG turbo and
bolt it straight on.
I was thinking that would be the case regarding the slider...
A set of turbo 45 dells would be a good option. Expensive and hard to find!
I'll have a look at the MG option maybe.. Is that a draw thru setup?
Thanks
Might be easier to setup with bike TB's and a boost referenced fuel pressure regulator. A lot less jiggery pokery than carbs would be. Though you
would need to fit a suitable ECU...
Cheers, Ted
The MG Metro SU is a blow through. You will need to get a rising rate fuel pressure reg and a high pressure pump, all available of the shelf, easy to
calibrate and reliable. No ECU no trickery....and cheap!!
If you where to take the option of Webers or Dellortos, you will need to modify them as most of them are not suited to blow through.
You could use a 2 inch SU from a Jag, and use this as a suck through. I have calibrated this setup on a Pre war supercharged Bentley. went really
well. Over 250 BHP at the tyres at 1800RPM.
As this is a supercharged engine, this might be the way to go?
If at all possible I'd like to keep the ecu and wiring to a minimum.
I have a megajolt for 3D ignition, thats as far as I'd like to go.
I think for turbo motors an injected ecu is prob a must but as a supercharger is linear, fuelling should be easily done on a carb??
A kit can be got from dellorto.co.uk to convert regular DHLA's into turbo models, spindle bearings that seal and a top cover with a float bowl
pressure connection.
Are choke sizes as important when being force fed??
I have a set of DHLA 40s with 34mm chokes, these would be restrictive on my engine if I was to run N/A, but would they work ok being blown on?
Is a blow off valve necessary on a charger?
Cheers
[Edited on 13/12/10 by Craigorypeck]
I would like to convery my XR2 turbo (currently turbo technics converted, using the standard weber 32/34DFT) to turbo-bike carbs. Surely it cant be
that impossible as there are many turbo'd bikes about?
Renault 5 turbo carbs are popular in the XR2 circles for a cheap turbo option, but I want something different.
here is a supercharged pinto with bike
carbs
Surely it is alos possible with a zetec
The trouble with other peoples work is you cant see what the end result was like? Did it run but had calibration issues like we had with the
Stromberg? Our car ran, but the mixture was all over the place and the consumption was very poor.
A renault 5 carb is a blow through carb, thats why it is popular on XR2's and the like.
You can use Dellortos or weber 40/45's, but you have to make sure you have blow through modified ones, otherwise it wont work.
If you had a large SU as a suck through, you shouldnt need anything special apsrt from making a manifold up.
rolling road results from pinto
his results look pretty impressive to me from a pinto
quote:
Originally posted by FASTdan
I would like to convery my XR2 turbo (currently turbo technics converted, using the standard weber 32/34DFT) to turbo-bike carbs. Surely it cant be that impossible as there are many turbo'd bikes about?
quote:
Originally posted by MikeRJ
If you are going to all the hassle of changing out the original carb you'd be a lot better off with converting to fuel injection as well. Setting up bike carbs properly on a normally aspirated engine is bad enough, but add boost correction into the equation and it will be a PITA.
[Edited on 14/12/10 by MikeRJ]
more interesting reading
pressurise carb for turbo
Dan, I'm with you as regards to avoiding fuel injection and suck through chargers !
I have both a set of ZX9R's and a set of DHLA40F, the dellortos can be converted to run blow through with these-
http://www.dellorto.co.uk/Merchandise/products_details.asp?PartNo=DHLAturbokit&CategoryID=1&PartsectionID=1
My only concern is my dells are emission spec and cant find much info on using them to blow through but I'm at least familiar with setting them
up.
Bike carbs are pretty new to me so I'll set them up to run NA and see how they run, do more research on charging them and take it from there..
Thanks for the links too!!! Good bedtime reading...
quote:
Originally posted by ianjenn
more interesting reading
pressurise carb for turbo
quote:
Originally posted by FASTdan
My experience of bike carbs on NA has been that they are dead simple to set up?
quote:
Originally posted by FASTdan
How complex it becomes with boost pressure I am not sure, but given that you can provide a boost reference to the relevant parts of the carb (floats etc) I thought it would be a decent upgrade over what I have - which itself is a NA carb boosted. Reckon it'd cost me £100 or so to convert (lots of my time of course), compared to big bucks to go EFI or the like.
The problem is that a carburettor is an inherently velocity sensitive device, for blow through forced induction applications you have to make them
pressure sensitive as well. Simply applying boost pressure to the float chamber etc gets you back to the same state that you were with a normally
aspirated set up, which isn't what you want. The mixture needs to be richened as boost pressure increases if you want you engine to last more
than 5 minutes.
Can you enlighten me a bit further?? I thought that getting the carb to work as if it was running NA but under pressure was the ideal situation, By
simply applying boost level from the air box to float bowl?
I just plan on the usual rising rate regulator. I might push the boat out and get one with an adjuster screw on the top lol.
quote:
Originally posted by FASTdan
I just plan on the usual rising rate regulator. I might push the boat out and get one with an adjuster screw on the top lol.
It won't do Bugger all at all. Without it there won't be any fuel on boost.
The system works.......it might be crude but I did 30k on that blown, shonky weber with fueling permanently monitored on a wideband (11.5-12.6afr thru
revs).98mph terminals at York so its no slouch.
I just figured bike carbs would be a nice cheap upgrade, probably never happen tho as I'm struggling to even finish the resto.
quote:
Originally posted by Craigorypeck
Can you enlighten me a bit further?? I thought that getting the carb to work as if it was running NA but under pressure was the ideal situation, By simply applying boost level from the air box to float bowl?
quote:
Originally posted by FASTdan
It won't do Bugger all at all. Without it there won't be any fuel on boost.
The system works.......it might be crude but I did 30k on that blown, shonky weber with fueling permanently monitored on a wideband (11.5-12.6afr thru revs).98mph terminals at York so its no slouch.
I just figured bike carbs would be a nice cheap upgrade, probably never happen tho as I'm struggling to even finish the resto.
I'm getting mixed up there with terminology by the sounds if it, I always understood a fpr with boost reference was a 'rising rate'. I currently run one from a metro turbo - with boost ref.
Yea, to be honest any regulator with a pipe on it that you can feed pressure to "should" be ok, though obviously some are crap and
don't work very well!
Metro one was designed for the job so should be ok.
The rising rate ones (I've only ever seen injection ones that do this) are a right pain, and not very useful! They just make it very difficult to
map an engine as the pressure moves around during mapping rather than staying constant!
quote:
Originally posted by FASTdan
I'm getting mixed up there with terminology by the sounds if it, I always understood a fpr with boost reference was a 'rising rate'. I currently run one from a metro turbo - with boost ref.
well i'm going to give it a go. I have a supercharger from a mercedes SLK, MSD 2225 fuel pump and Mallory 4309 regulator. I will make a bracket to hold in place and then make an air box with pitot tube to pressurise my bike carbs. Then it will be off for another rolling road. happy days
fair amount of turbo and supercharged info using carbs (draw through and blow through) in the forced induction section of the oldskoolsuzuki.info
site. Not into Pintos! but its only the mixture that matters (I think).
Unfortunately that side has been down for the past week. Not sure whats going on there.