velocity stack filters

[EndStar]

i have the l28 with round top SU carbs. wondering what my best options are for filters on velocity stacks that wont reduce performance.

mesh on the ouside, filter around it?

links would be very helpful! thanks!

here's by set up

_DSC4513 by Evan Serilla, on Flickr

[Dolomite]

I had filters around mine and it was terrible, one day I had a backfire and one blew off. I took the other off just to get home and it ran so much better. Screens are where its at.

[Stoffregen Motorsports]

A large filter with plenty of area is the best type of filter. It's also not a great idea to mount the filter right on the velocity stack as it disrupts the flow that was so painstakenly created by the addition of the stacks in the first place. Use ITG or equivalent foam filters for best performance.

 

I know...you see tons of guys using the velocity stack filters. Well just because someone else does it doesn't make it right.

 

It's also not a good idea to remove the backing plate. It serves multiple functions not the least of which is to block the hot air from entering the carb.

 

...and... the vent holes in SU's need to be payed close attention to. Stock L6's have them with one hole open per carburetor. If you plug the holes, that's a problem. If you have two of them open, that can also create tuning issues... not likely, but possible.

[EndStar]

A large filter with plenty of area is the best type of filter. It's also not a great idea to mount the filter right on the velocity stack as it disrupts the flow that was so painstakenly created by the addition of the stacks in the first place. Use ITG or equivalent foam filters for best performance.

 

I know...you see tons of guys using the velocity stack filters. Well just because someone else does it doesn't make it right.

 

It's also not a good idea to remove the backing plate. It serves multiple functions not the least of which is to block the hot air from entering the carb.

 

...and... the vent holes in SU's need to be payed close attention to. Stock L6's have them with one hole open per carburetor. If you plug the holes, that's a problem. If you have two of them open, that can also create tuning issues... not likely, but possible.

but which itg foam filters?

[Profile]

Which ITG filter? The biggest one that will fit on the car. In this case, bigger is better.

[Stoffregen Motorsports]

but which itg foam filters?

Sorry, I never got back to you.

 

ITG sells a blank backing plate that you would need to cut out for a single unitized filter, which I think is the best way to go, but they are large. The single SU filters are good as well, but the large backing plate acts as a sort of heat shield which can help performance.

 

The height (towards the fender well) of the filter is important too. Too short and you create air turbulence problems. Too tall and you run into the fender well and master cylinder. I would rather have it hit the master and have to massage it to fit than have it too short.

 

With those long velocity stacks, you would probably have a hard time fitting a foam filter without hitting the master cylinder. I might consider swapping to a shorter velocity stack. You won't lose any HP there. Even the stock velocity stacks, cut out of the stock backing plate, would be a good choice.