Mazda Rotary Club

General => General Technical => Topic started by: MikeLMR on March 02, 2003, 01:58:25 PM

Title: Tuning a rotary
Post by: MikeLMR on March 02, 2003, 01:58:25 PM
Is this a task that can be trusted to the local (very knowlegable) Rolling road outfit ?

I\'m looking at fitting a weber carb instead of the Nikki and want to know if I can get it set up locally or whether theres a black art to setting up a carb\'ed NA rotary

any ideas ?

Cheers,
             Mike
Title: Tuning a rotary
Post by: richrx on March 02, 2003, 03:20:08 PM
if i was you i\'d go down personally to book it, but while there just slip in some subtle questions to find out what they know.

I they are jap car specialists im pretty sure they would have a good knowlage, although they also could be  MAX POWER outfit, and coment \'a rotary, cool man\' and know jack ****
Title: Tuning a rotary
Post by: MikeLMR on March 02, 2003, 03:35:16 PM
I know the guy I\'m thinking of taking it to and he\'s very good with weber carbs and setting up pissed on engines and he\'s the guy behind MBE ignition systems so he should know his stuff

what I\'m more interested in is if there is a great deal of "art" in setting up an NA rotary on a carb ... I can\'t imagine its a great deal different  than tuning a carb on any other engine

I\'d be hanging around to make sure everythings done right too ;)

(never like leaving my car alone when other people are working on it  :eek: )

hopefully I should be able to get thet jet sizes pretty much correct 1st time  :confused: :eek:
Title: Tuning a rotary
Post by: richrx on March 02, 2003, 03:42:56 PM
all as i know is make sure the fuelling is high. Which is what the carb is for:confused: obviously.

i dont know about setting them up but i think if you trust him it should be ok
Title: Tuning a rotary
Post by: MikeLMR on March 03, 2003, 06:22:07 PM
bttt
Title: Tuning a rotary
Post by: richrx on March 04, 2003, 12:40:32 AM
Bttt???sorry for being a dumb ass but what does that mean
Title: Tuning a rotary
Post by: grinder on March 04, 2003, 09:52:55 AM
Back
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Title: Tuning a rotary
Post by: richrx on March 04, 2003, 02:58:26 PM
:D
Title: Tuning a rotary
Post by: MikeLMR on March 09, 2003, 11:19:18 AM
anyone got any experience of a driving a 1st gen with a single weber carb ? Seriously thinking about getting one but I want to make sure it\'ll still drive nicely afterwards :)

anyone from Oz tell me where the best place to get one is australia is ? I\'d bet even with shipping it\'ll be cheaper than here :(
Title: Tuning a rotary
Post by: Glenn Butcher on March 09, 2003, 11:25:47 AM
Hi Mike!

They are so damn rare all over the world, I use to have one on my RX-2.  Should be able to remember/find out the jet/choke sizes.  But you\'ll have to get one first ;)

You thought about fuel injection?  using a Microtech?
Title: Tuning a rotary
Post by: MikeLMR on March 09, 2003, 11:41:11 AM
I think that fuel inj would be a bit too much £££\'s (this is my second big project afterall .. still got a kit car in the garage too!)

Rotechnics advertise a dellorto set up, but dellorto\'s are out of production so I don\'t know how they can offer a brand new carb ?? + its harder to get parts for the del\'s

I\'ve got some time to find one anyway as I\'ve got to get the exhaust sorted first (hopefully via a member of this board ;) )
Title: Tuning a rotary
Post by: Carl on March 10, 2003, 08:41:35 AM
Hi MIke,
Is your engine modified or standard?
I have had some dealing with Weber carbs on race engines and can let you know the jets required for a safe starting point that won\'t cause you any problems either for road or race.
I have a side draught Mikuni 48 that is the Japanese version of the Dellorto.
Regards
Carl
Title: Tuning a rotary
Post by: Glenn Butcher on March 10, 2003, 10:03:27 AM
:wave Carl,

Good to hear from you!

I have read on another Forum that Webber are going to start making these Carbs. again.  Know anything about that?

Also there is a comany in the US that makes IDA carbs. which apparently can be adapted: http://www.geneberg.com/carburetionpg8.htm

Finally - got an email here from someone in Oz that converted from Webber to Fuel Injection, he has provided cost breakdown here:
here\'s what i spent converting mine from carb (weber) to efi:

50mm t/body, s5 turbo injectors and surge tank: $750 2nd hand.
malpassi adjustable fuel reg. : $200
goss efi fuel pump: $200
wolf 2d comp and loom: $400 2nd hand
king dragon airfilters:$90 x 2 (one for each ram tube)
install, set-up and tune: $700 (includes all those fiddly bits you forget about in a copnversion like this, ie fuel hoses/clamps/filters (efi rated stuff costs a bundle but is paramount!), connectors/plugs, wiring and mounting etc.

the car now drives similarly to a well set up weber with small chokes down low, and makes topend power like that of a weber with big chokes (mine had 44mms in it before i did the swap, and it was shithouse to get off the line cleanly to say the least but pulled like a 13 year old to redline!)

mid range power is where you will notice the biggest gains, topend will be negligible compared to a well tuned weber because the a/f ratios @ w.o.t would be fairly consistent.

oh, and don\'t forget that bonus of fuel economy over the old juice dribblers!


Might not be a bad idea?  (There is AUD$3 to £1 by the way.)
Title: Tuning a rotary
Post by: MikeLMR on March 10, 2003, 12:31:47 PM
hi, guys

thanks for the info, might have a talk with Mike Barret in Lincoln as he does EFI stuff (not somthing I\'ve really dealt with in my short experience of cars... my kit car has a pair of 40 dcoes on it and the 323 is an electro mechanical carb monstrosity similar to the Nikki on the rex)

My engine is standard for now (seems a shame to rip into a perfectly good engine for no reason)

Carl,

how do you find the Mikuni on your car ? does it pull cleanly from low rev\'s ? RotaryEmotions (Bart) from Belgium has the same carb and he seems to like it (plus the mikuni\'s are well suited to blow through turbocharging :burnout :evillaugh )

what are parts like to get hold of for the Mikuni or are Dellorto parts interchangeable ?
Title: Tuning a rotary
Post by: Carl on March 10, 2003, 06:14:41 PM
Mike,
Had the carb on a standard 12a for a while and it was quick.took it on an airfield day at Kemble which twisty but could still keep a Ferrari 355 at bay and hit around 95 mph on the short striaght which was same speed as the Ferrari!
Not sure of interchangeableness of Dellorto parts.
There was a slight hesitation at pulling away but clean all the way through the revs up to 8500.
Regards
Carl

Hi Glenn,
Interesting idea of injection there buddy.Will have to try it.
Regards
Carl