A question for you guys. I was posting on zcar.com about tuning SU's. It was mentioned by someone that you must have the vent hose from the bowls connected to the stock air cleaner so that the pressure balance is correct. So I asked what do people do if they have chrome air cleaners. They were not built with any kind of tube to attach the hose. He said they have to attach one. Here is my question. If that is the case has anyone here done that? I don't remember seeing it done before on cars that I have seen with chrome air cleaners.

Another questions I have is since the carb needs an airhorn and they are not supplied with the air cleaner, what have you used instead? From what I understand the ones that MSA sells are not the proper diameter. If I'm wrong please let me know. If it is the case has anyone used the airhorns from the stock air cleaner? Seems like it would be a natural fit.

Any clearification on this would be greatly appreciated.

He's correct. And most folks who have chrome air cleaners just let the vent hoses dangle and point down at the exhaust manifold.

Regading air horns, the factory ones and the full radius TWM ones work with the TWM ones having an advantage if running ITG or another type of open element air cleaner. The stock air horns have a slight advantage over the TWMs if you're running the stock air cleaner or a closed top kind of aftermarket unit (K&N).

BTW... the factory air cleaner with the OEM air horns flows better then the K&Ns without air horns, but neither are as good as the ITGs with the TWM air horns.

The hoses coming off the float bowls are vent/overflow lines. To function properly the bowls must be vented. You can run with out the hoses or as JC stated just let them hang. The only problem with either is if a needle valve fails and the float chamber over flows , fuel will be going down onto a hot exhaust/manifold. Plus the open end of the hose is open to all the dust and dirt flying around the engine bay. Gary

So what your telling me John is that the stock airhorns would work well with the K&N air cleaners. Do you know of anyone that has done this before. I was also planning to go to Home Depot and get a fitting to fit on the back of the air cleaner (inside part of the filter) to attach the vent hose to. Just seems like unfinished work if I just let it hang.

I guess my first question would be why not just use the factory airbox? How much benefit is there to ITGs or K&Ns with the appropriate airhorns? How much tuned beyond stock do you need to go before the stock airbox is a bad thing?

He's correct. And most folks who have chrome air cleaners just let the vent hoses dangle and point down at the exhaust manifold.

Regading air horns, the factory ones and the full radius TWM ones work with the TWM ones having an advantage if running ITG or another type of open element air cleaner. The stock air horns have a slight advantage over the TWMs if you're running the stock air cleaner or a closed top kind of aftermarket unit (K&N).

BTW... the factory air cleaner with the OEM air horns flows better then the K&Ns without air horns, but neither are as good as the ITGs with the TWM air horns.

Cool. Here is my ITG & TWM Air Horn set up all sold by MSA.

The separate air cleaners do look cool . So does the little filter on the valve cover. How about the fumes in the cabin from the engine. The Stock air cleaner box is a efficient unit and for a street engine but I admit it doesn't look as cool. However with a K&N filter element installed it is still difficult to improve upon. If you build a 280 engine and with a big cam you will most likely go with triples anyway. The stock air box will be a good choice for most other street engines. For 37 years we have been trying to improve these engines and some accomplishments have been made . However at a cost of drive-ability. Certainly the choice is performance or style. Some times they are at opposite ends.

Hi Arne, my concerns were not rooted in performance but more towards appearence. I was just courious as to how people handled the vent line from the float bowl when not using the stock air cleaner. I have both and I have to admit that the chrome air cleaners will look a lot nicer then my dirty old stock cleaner. I 'm just intrested in finding out if anyone has gone a step further and attached the vent line to the aftermarket cleaners instead of using nothing at all or just letting them hang down.

From what I'm told the hose must be attached to achieve proper tuning of the SU's.

OK, I can understand the cosmetic value. And like you, if it were me I'd want to fabricate nipples for the two vent hoses. But I'd also want to run the valve cover breather to one of my filters, as that little filter on the valve cover just looks silly to me. (As well as causing some hot oil smell in the car, by some reports.) So before I went to all that work, I'd probably strip and refinish the stock airbox instead. Probably cheaper, too.

When I picked up my last car, the PO made air horns out of a cut up air box plate, a real simple but effective idea. The problem was they were being run without a screen. I have since taken them off and replaced them with a factory air box, if you want them let me know. They are nothing special, just taking up room on my garage shelf. I have the ITG, TWM set up on the shelf as well, will install it when I think the engire is worth it.

i'm running k&ns with the TWM air horns.

for the bowl vents, i just drilled holes in the base of the k&n cleaner and fited a rubber nipple and attached it that way.

eventually i am going to weld in some metal nipples, but for now the current setup is ok