is a bike can too restrictive?

[dubber91]

i have a 13b NA in a beetle......i have a bike can fitted from a triumph 1000. Is this likely to be too restrictive? the issue is that the exhaust needs to be short- theres not a lot of room. Its backfiring loudly and (although comical) its not too nice for daily use.
What do you recommend? could it be causing the backfiring? I know the exhaust gasket needs doing too....

Steve

[Bobfish]

Ideally rotaries need to overfuel, because they blow up at the first sign of detonation. If you had the engine tuned by a reputable tuner, this could be the source of your backfiring. (they would have tuned it rich)

What systems does it use? Carb? EFI? or aftermarket management? Do you know what your A/f ratios are? is the engine tuned at all or standard? ported? what plugs are you using and what coils?

Rotaries do need good exhaust flow, but not so much for NA application.  For a rotary you should use an exhaust thats recommended for a 2 litre or so engine, so the one you have may be too restrictive.

Ebay do some reasonable looking chrome jap style slash cut cans, try one of those - they are only £35.

By the way, awesome conversion - get some pics up!

[dubber91]

its the standard 13b injection system. It hadnt been tuned, so could be the prob. I may try one of the cans on ebay then!

Steve

[MikeLMR]

somthing with ceramic wool would be best as anything else won\'t really stand up to the heat of the exhaust, especially with it being so close to the ports. I would have thought one straight through can would be far too loud for use on the street ?
 A lotus 7 style kit car I saw with a rotary had two full length silencers in the usual position and the exhaust doubled back through them to try and keep the noise down.

Turbocharged rotaries need a lot less silencing and don\'t really need the same thought putting into the exhaust design as the turbo is quite an effective silencer.

[dubber91]

ok.....well i figure i can do one of two things.....wait til this exhaust has the guts burnt out of it and then deal with the noise.......but hopefully there wont be a gret deal of backfiring.....

Steve

[Jono FD3]

Or the other option would be to put a small turbo on it  :yes  :3gears-lh

[travellinbob]

Hmm I kinda like the turbo idea!  Seriously do you not have the exhaust running up under the car and then back out so that it is about 2/3rds the lenght of a normal one, or does it just come straight off the exhaust ports and then head rearwards to atmosphere? Maybe a supertrapp might help. they arnt the best but have been known to shut up a rotor if need be? Also loads of thermal exhaust bandaging.
 cheers, michael.

[oldone]

All my rotary beetles had a common setup,size of pipe depended on the motor mods....i.e. 2.5 " headers which collected at the rear axle,from there a single pipe up and to the top of the gearbox,one silencer lay flat on the top of gearbox,down the other side and into a silencer,then a short tailpiece,normaly a 3".
The sound of the exhaust note depended on the choice of silencers,and YES,plenty tape on the pipes.

[dubber91]

that i certainly have, its wrapped in exhaust tape.. The exhaust litterally comes from the exhaust, down a bit, then off to the right...like this


im havin fun today....billy nomates cant seem to remove the flywheel. Im gonna have to go socialise with some people to see if they\'ll come stand on the engine for me!

[travellinbob]

Mate that is a nice bug! But no wonder you are getting flames and backfiring! Look at the ehat marks on the silencer. He, he, he..More pics please.
 cheers, michael.

[dubber91]

yeah so there she is....what she did look like.....shes just come off the road to redo a load of the work. Shame i cant afford to pay for all the nice bits it needs, but its my only mode of transport...

[dubber91]

ive just designed and made an intake system flipping it around around 120 degrees and going through the bulkhead ant up to a duct in the rear window. hopefully with some neat packaging i should be able to turn the backshelf into a professional looking area with ECU, Air flow meter, airbox and somr other bits.

Steve

[oldone]

Hey bud......you should leave that Bug at mine for a week or so I can sort it out for you....give you a courtesy(sp) car to use.........o yes and leave some pounds... :rollin

[dubber91]

haha i\'d love too! also depend how many pounds i gotta leave! whatcha reckon needs doin? ive got the new clutch and the engine\'s out.....

Steveo

[dubber91]

you havent got any of those uno turbo fans have ya?

 :3gears-rh