Cold air intake / ram air?

[80GS1000]

Are you aware of anyone who's made a cold air intake or ram air intake into a pressurized airbox on a GS engine like the SRAD and later GSXRs? The GS engine seems to put its air intake is a place that is both hot and in a still eddy of air in the back of the motor. Seems like if you made a cold air intake and/or a pressurized ram air intake with the proper design and jetting, you could make more power. Anyone heard of this or seen it done?

[LeeGS550E]

Isn't that going to fvck with your diaphrams?

[renobruce]

You're a wildman, PJ. I like you.

[80GS1000]

Thinking of starting pretty simple with a cold air intake. Colder air = denser air = more oxygen = more fuel can be added = more POWER. Right?

The design would be pretty simple to start, much like the cold air intakes you see on cars. Take a straight tube or hose, clamp it to the intake of the carb on one end, and clamp a pod air filter on the other. Make the tube is long enough to get cooler air than would be available via a standard pods setup (ie not right by the engine). Richen the jetting a bit to suit.

Kinda like this. Imagine one tube/hose and one pod filter "feeding" cooler air into each carb.



Is this a stupid idea or could this actually have some benefit?

[80GS750]

you could make a sweet setup with a large duct on each side of the bike pushing air into 2 of the carbs. kind of like a brake scoop but pushing it into the carbs. there is obvious room for it on each side.... would look badass too.

[CA180]

Wouldnt work in just two carbs, you need all 4. Uneven distribution is bad

[marz]

i was thinking

thesamebloodything.whatthehellicantputanyspacingsi n.ihatethisidontknowifitsmycomp.ortheweb.illtryagi anlatter.ferfsake!

[Mark M]

Thinking of starting pretty simple with a cold air intake. Colder air = denser air = more oxygen = more fuel can be added = more POWER. Right?

<snip>



Is this a stupid idea or could this actually have some benefit?

First off, that isn't a cold air intake, it's a hot air intake...Unless you believe the underhood temps are lower than ambient.

The general idea is to put a barrier between the carbs and the engine block, then duct in cool air to feed the carbs. It is not a stupid idea at all and should provide an improvement in slower speed running and in hot weather, along with a bit of power increase. I had an 86 GSXR750 that had the Yosh cold air kit on it and pod filters and it helped a lot with the carbs running hot.

Forget the ram air idea, it is almost worthless at street speeds and very non-trivial to sort the jetting at the same time.

Mark

[txironhead]

I thought about putting "ducts" on either side of the airbox, kinda sticking out of the side covers, but considering how finicky these bikes get if the airbox isn't sealed properly it's probably a bad idea. It would probably only work with some experimental rejetting.

However, the cold air idea is full of merit, and the reasoning that cold, dense air burns better is sound.

How exactly does the Yosh cold air kit work? I'm already running pods and a Stage 3 jet kit. Any pics?

I've already decided that one of these days I'm going to find a GS1000 or 1100 and go all-out with a Megasquirt fuel injection, crank trigger and ignition setup. That, along with an aluminum monoshock swingarm and lightening everything that I can should make for an interesting scoot. It, too, would probably benefit from a cold air intake system.

[jknappsax]

Cold air into the filterbox

I was thinking along the same lines, but a small scoop on each side both feeding into the filterbox, rather than ducting to individual pods. It should have similar characteristics to running with the stock filterbox with the lid off, with the added benefit of cooler, denser air. Any thoughts?

[t3rmin]

I was thinking along the same lines, but a small scoop on each side both feeding into the filterbox, rather than ducting to individual pods. It should have similar characteristics to running with the stock filterbox with the lid off, with the added benefit of cooler, denser air. Any thoughts?

Wouldn't you just be pulling in air that just rushed over the engine fins (and thus picked up heat)? Seems like you'd want to get out of that air stream (lower or higher? or set further back?).

[txironhead]

Either way, you're still looking at rejetting the carbs. I really don't think that it would provide much more improvement than simply running pods, which increases the air intake dramatically. Unfortunately, the placement of the pods is still in the draft from the engine, so it's not cold air. Using "ram air" systems is much easier on a V-twin, such as the "hyperchargers" or snorkel intakes often seen on customs and choppers. The only way that I can see of creating a "ram air cold intake" would be to create a plenum out of tubing that fed each carb and drew air from one or both sides of the engine. This may not be a problem for those of you running rearsets, but for those of us with the stock pegs, highway bars or forward controls you run into clearance problems. I would definitely like to see pics of the Yosh cold air kit previously mentioned. Another drawback to the "plenum" type air tube is the possibility of forcing more air into the outside carbs than the inside, creating a tuning imbalance. Since it would only happen at higher speeds, tuning could be problematic unless you were very familiar with tuning high speed circuits, and even then synching the carbs could be troublesome.

[80GS1000]

I have a lot of room to spare in the subframe now that the battery and electronics have been relocated and the airbox has been removed and replaced with pods. I was thinking of tacking or bolting on some thin sheet metal onto the X shaped bracing I have supporting the monoshock mount and the subframe. The sheet metal would serve as a support for the pods and ducting, and would create a "shadow" in the hot airflow in the wake of the engine. The sheet metal would then have holes cut in it large enough to run ducting through. The pods would then clamp onto the ducting, which would then clamp onto the carb intakes on the other side.

The bracing before it was painted looked like this. I could put sheet metal in the gaps in the bracing, cut holes in the sheet metal, then run ducts through the sheet metal from the pods to the carbs. Thoughts?

[80GS1000]

Oh yeah, would it matter if the intake ducts were all the same length? Header pipe length needs to be all the same on the exhaust, wondering if it makes a difference on the intake.

[Mark M]

How exactly does the Yosh cold air kit work? I'm already running pods and a Stage 3 jet kit. Any pics?

No pics, it was long ago. The kit consisted of a heat shield that went between the carbs and the engine and ducting to let cool air from the front fairing ducts (on the 88 750's, they started with ducting to the airbox) flow into the space around the pods. The heat shield material was a vinyl/plastic sheet with quilted asbestos type insulation bonded to it. It was shaped to fit up between the frame rails, tight to the bottom of the tank, then down along the back of the block and folded towards the back wheel, over the gearbox area. It had holes in it to slide over the intake spigots and for the throttle cables. On my 86, it was only the heat shield material as there was no provision for ducting at that time.

Oh yeah, would it matter if the intake ducts were all the same length? Header pipe length needs to be all the same on the exhaust, wondering if it makes a difference on the intake.

Yes it matters. The intake is just as much a tuned system as the exhaust.

Mark