MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Webber V.S. Supercharger

Hi Folks:

Some of you may remember me . . . I am building a 1275 powered single seat Austin based race car.

Can anyone tell me how much extra power a single Webber will give me?

Also how much more would a super charger provide if I went that way instead?

I intend to use the racer in autocross type events -- Solo II, Gymkhanas, and perhaps the odd hill climb. I am too fat, old and smart to try wheel-to-wheel.

Godspeed in Safety Fast
Jc



John Crawley

If you use a turbo spec dellorto you can also have the supercharger :-) however i've been looking for a reasoable priced one for ages & they are quite rare.
Brad (Sprite IV 1380)

Cool - you have all these events IN Alberta??????
rachmacb

John, You need to sit down and do some serious research and get a feel for engine tuning before diving in with a 'how much' question'.

Next you need to at least give us a fighting change of giving reliable answers by stating the size of the engine.

You say a single Webber and I guess you mean a single DCOE Weber though I can't guess the size. Better/bigger/both carburation by itself doesn't allow the engine to produce much more power rather its part of package of modifications.

Just fitting a supercharger MIGHT, in the right circumstances yield a better power hike than conventional tuning but not necessarily.


Daniel Thirteen-Twelve

John

Im not sure your in the correct N. hood, you may have the wrong website but welcome just the same... yes your car is a midget, but maybe not the type that we are. we are a british sports car from the 50s to late 70s era, we are not a dirt track racers like your car classificassion... see photo below

Midgets like yours are vary popular hear in the midwest on local dirt tracks, there is a great oranization called Outlaw that has really done the sport of midget racing like your car vary well but ive never known your style of midgets to do the type of racing your wanting im only aware of it as local dirt track racer ussally no more then 3/8 mile tracks

Prop




Prop

Hmm,

Okay after re-reading your post... Im a bit confused as to what your car is... sorta of a midget in both definations of the word.

you got a 1275 in a dirt track racer midget ... certianly creative, All the dirt track racer midgets Ive seen have big ol american V-8s starting at 327 cu inch

I cant say wheather or not a super charger vs a weber as we dont have enough info,

on the super charger idea....

it sounds like everything you want to do is vary short, so My thinking and only my opinion is a super small blower more for a ATV or a large go kart then the tradional car blowers...My thinking is you want lots of torque rather then hp, so you want something that will spin up fast and max out even faster is the way to go... Id go back to the main menu and scroll down to the super charger link and talk to those guys

or talk to Trevor who is on here about once a day, apperantly he has this weired idea for living ...He calls it a life, somehow it involves a Job, wife and children. Not sure what that means. LOL

Prop
Prop

LMAO Prop - at least he's got an engine that works!!!! That makes it a midget-type to me - and not just an ornament :)
rachmacb

filter out Prop
listen to Daniel

and read 2 books
-Tuning the A-series engine -by David Vizard
-The MG Midget AH sprite high perfromance manual - by our verry own mentioned above Daniel Stapleton

building an race engine is not a slap on job you need more info and a complete plan/vision for what you want
Onno Könemann

yeah ... Just ask me

I know all about having an engine vision and plan. LOL
Prop

John, a lot of the effect of either the Weber or a supercharger will be determined by the type of transmission and gearing. If you plan on running a rather low gear and really turning the engine tight then perhaps the Weber might give you some advantage on the upper end, but at lower revs the supercharger will give you much improved torque where you can really use in in an autocross or Solo type event. The two books mentioned are great references and resources.
I really like the car you're building, interesting take on a weekend racer.
Bill Young

your racer is really cool. it looks like an old fashioned roller skate but i bet it will go like sh1t of a shovel. can i make a mental suggestion and say put a suzuki gsx1300r hayabusa engine in it.now that would be fast.
roy j

OMG roy

I never even thought of that, with that car being as light as it is... it would go like stink off a skunk.

the only issue would be to much torque and send the car rolling like a twinkie every time he hit the gas in a turn...

yeah definatly a suzuki gsx1300r hayabusa engine

here is a vid of that engine in a smart car taking on a ferrari in a drag race... and the engin is the same size at the 1275...well okay 1300cc and no doulbt Ill bet 1/3 the wieght

now thats a rice cooker

Prop

http://www.youtube.com/watch?v=f5S1NAMnYKM&feature=related
Prop

here is another great video of the engne in action

http://www.youtube.com/watch?v=CdJ84nho3_k&feature=related

Prop
Prop

Ha! Here is even a better vid... this engine in a mini cooper completely feminizing a modern day MG


http://www.youtube.com/watch?v=hMzFqpsp-Ro&feature=related
Prop

Hi Guys:

My monoposto is a “Car that Never Was”. I built it as a replica of an Austin Factory racer of 1954 (to complement my TF). The trouble is that Austin never built a single-seat racer in that era . . . so it is a replica of a car that never existed.

I used materials, construction methods and parts that could have been available to Austin if they had in fact built the car. The front suspension is bug-eye Sprite with disk brakes, modified with inboard tube shocks; the trany & diff. are MG midget. The engine is a midget 1275, balanced, ported, 3-angle valve grind, ¾ cam, 9.5–1 comp. headers, etc. I hand hammered the body in metal, the frame and rear suspension are of my own creation. I have used period English parts throughout including wiring from a ’54 Austin and period leather for the upholstery. The charging system, radiator and all major components are from Sprites or MG midgets. I consider the car to be as close to a recreation of a period Austin Team Racing monoposto as I can make it.

After I had the body done I found the attached image of an Austin Racer in the Melbourne, Australia auto show of (I believe) 1949. So I am not too far out in my design.

Anyway it is just for fun in solo events to show the rice racers that there is an alternative to having big bucks and sticky tires.

I am very active on the TD/TF side of this list and thought that the best place to get advice about Webber V.S. supercharger was from guys that may have tried it on thier Spridgets. Thanks for your comments so far.

Godspeed in Safety Fast
Jc



John Crawley

Hi . . .Another picture of my car . . . the dash and the cross-remote shifter.

Jc


John Crawley

And one more of the engine . . .
jc


John Crawley

Nice work John i like it.
As your engine isn't built around forced induction & your going to need lower down power rather than max rpm i would go with a DHLA 40 to begin with.
Brad (Sprite IV 1380)

Very nice
Gary Lazarus

Very cool machine John. And I do think you're at the right place, as it does run a lot of major midget components.

Take off the little hs2's and fit a 40 or even better a 45 DCOE with say 34 or 36 venturis for torque low down and still get revs
Alex G Matla

For a big increase in low down easy power on tap, then a supercharger is the only answer.
You could always try a single 1.75" SU, that will give an increase in torque, albeit maybe not to same levels as a weber. But it could be cheaper.
Tarquin

prop if you want a mental misuse of a hayabusa engine look no further than this go-cart.http://www.youtube.com/watch?v=vlbfVRVRgHE
roy j

na sorry wipe that,just found some one else in more of a hurry to die. hayabusa engined golf cart.http://www.youtube.com/watch?v=6gBs_miaBPE
roy j

Mr Vizard reckons the bigger SU's are almost as good as the Webers, just lose out a little bit at the top end. My personal experience is with SUs so maybe I'm biased, with that engine I'd be tempted by twin 1 1/2 s on a decent manifold, or as mentioned above, a single 1 3/4. The twins are possibly the cheapest but nowhere near as cool as a supercharger :)
Rob Armstrong

Rob i have to agree with you there.


Brad (Sprite IV 1380)

how's that going Brad? I nearly got mine supercharged but went K instead :)
Rob Armstrong

I will be building up the spare 1380 next week. I've got the Turbo head back from Peter Burgess, who opened up the chambers to 25cc, which should give me 8.5:1 CR with the dished Omegas.
The block has been cleaned, checked, decked by 3 thou & painted ready for fit up.
The biggest problem at the moment is where to put the intercooler, i'm going to have to relocate the oil cooler & electric fan. I'm toying with the idea of putting two oil coolers on the inner wings as my wings are vented, that will free up enough space at the grill area for the intercooler & ducting to the coolers.
B Richards

Good info but these facts remain

A turbo/ supercharged engine has the capacity to double both torque and power whilst a carburettor mod could maybe add say 3 percent, therefore the question is a no brainer!

Regarding carburettors the Weber will always beat any SU or combination of SUs due to its design

When you accelerate with an SU the initial rate of accelleration is held back to allow the air fuel ratio time to adapt. The weber however utilises a throttle pump that allows much faster throttle response and is one of the main reasons race cars will use a weber in preference to SUs Also as has been noted above SUs tend to run out of steam at higher revs.

Finally a 45 dcoe and a 40 dcoe are the same carburettor when fitted with the same chokes. The only difference between the 2 is that the 45 can be fitted with larger chokes than the 40 although these will not be required in an A series engine!.
Bob Turbo Midget England

Hi Bob,
don't suppose you know of a DHLA-M going spare do you? I'm going to use a metro turbo su set up but would really like the dellorto.
B Richards

This thread was discussed between 08/06/2010 and 09/06/2010

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.