I have been modding and tuning Vettes for a long time, but am new to modding Harleys so I'm seeking advice here from more experienced folks.

I have already purchased straight pipes with a small baffle and a PC III tuner with a fuel map from Fuel Moto that seems spot on to me.

Looking at the stock air cleaner, I can't imagine it is a restriction based on my experience...it seems it would flow plenty of air for a 88 ci engine that only turns 5200 rpm. Thus, it seems I'd be wasting money on a stage 1 air cleaner.

But I would like a more experienced opinions and a dyno sheet if possible for a stage 1 air cleaner on a TC 88.

Any thoughts/help is much appreciated.

 

You can't just look at the raw surface area of the air filter. You have to look at any SHROUDING of the air filter as well.

Simple car example: On the 2003 and 2004 supercharged Mustang SVOs, replacing the air cleaner system with an aftermarket one added about 30 rwhp, despite the fact that the actual filter was not significantly larger in surface area.

On my last bike before the HD Breakout, a Honda VTX 1800R, I already had an aftermarket Forcewinder air filter with a congifuation virtually identical to the Harley Heavy Breather, and a LARGE filter. It worked well. However, a dyno tuner and I tried an experiment: we replaced the filter with an even larger one. The bike picked up 2 more rwhp (over 2%). When we re-fitted the normal filter, we lost the 2 rwhp. Put it back on and regained it.

Harleys respond VERY well to improved air intake and exhaust, because Harley has to do really restrictive stuff to make them quiet enough to pass noise regulations despite their ancient engine architecture. A stage 1 kit on a Harley (a decent one, not a cheap one) adds anywhere between 13 to 18% more power. No kidding.

I wouldn't skimp on the air intake. It might be a very foolish place to save money.

Jim G

 

Joe.... Are you sure it's the stock air cleaner? It's usually one of the first things someone changes out. The stock backing is a massive plastic piece that is quite restrictive. That said. Your HP numbers will between 65-70 and TQ maybe 75-80.

 

Hi Ace,

Yes it's stock, big plastic thing. But it has a large cutout on the bottom to let in air.

I could just remove the cover for open filter and test cover and no cover on the ¼ mile I suppose....

 

I suspect you could throw on the Arlen Ness Big Sucker Stage 1 and have Fuel Moto send you another map. Pretty common setup so I'm sure they'd have it and they're supposed to have great customer service. I think you'll be pleasantly surprised with the additional air flow.

 

adding a HP/ AC only will not increase the TQ or HP that could be noticed..

 

I suspected that is the case. On a Vette reducing inlet air temp gives drastic gains in power by adding back up to 12 degrees of timing that the stock tune pulls starting at only 86 degrees.

That's obviously not the case with our bikes that come with CAI. In fact the stock base plate draws air from the front of the bike vs the stage 1 which draws from the hot cylinders but I guess that little bit doesn't matter.

 

Not sure about just the air filter but when I did the stage one on my bike I noticed a lot more torque.

 

Sounds like a Hoover Vacuum and drops oil is what I do not like. Take a look at how small the actual area is at the butterfly. Filter does not need to be very large but a larger size allow for more dirt collection. Also remember that the vacuum created when the piston goes down is filled by atmospheric pressure. Sure at rpms above 4K or so, it may add a few HP but who runs a Harley in this range? If so, then it probably will add a few. Looks cool on certain bikes. On a big cruiser that is actually used for that, it's a silly option that hitting a big splash of water could do damage. Rain does not seem to hurt mine however. I personally think the Hoover vac sound just gives the impression and more HP and torque.

 

Having put open exhaust on my bike, I can tell you the open pipe with a small baffle opened airflow a lot...the bike was way too lean. Just checked my Fuel Moto map, it adds around 10-20% fueling in certain ranges which makes sense to me. It felt peppier when I bought the tuner from Fuel Moto, without it and the straight pipes, the bike was way down on power as it was too lean.

I think the add'l power from a "Stage 1" comes from the mufflers and more so from the tune. But that is my hypothesis...I'd like to be proven wrong.

Ripsaw the first part of your post almost makes me want to buy it....lol I do love and miss the sound of Quadrajet secondaries opening up, that moan is music to my ears. If my bike would sound like that I'd buy it! LOL

I also don't like dripping oil, one thing I like about the stock backplate is that it draws a vacuum on the heads to suck out combustion byproducts. I like to run a PCV system on my vehicles to help keep the oil free of combustion byproducts and the engine cleaner.

Still looking for someone who's done a back to back dyno on just the Stage 1 air cleaner......anyone??