ram air

[roasty_duck]

so looking at trying a few things out and squeezing a little more out my vtr, ram air is next on the list, ive ordered some flexi hose to bodge into the rad vent holes on the front to see if it makes any difference.

what other modifications do you think may help.

i have many needles and jets so no dramas fiddling with those.

go up in mains once i fit ram air?

[Wicky]

Extruded Tupperware boxes can be used to enter the exclusive Club 18-30 (the amount of extra horsies the ram air mod can give) be prepared to find a dyno with fans to mimic +100mph head wind for when setting up the jetting.



Alternatively contact Moriwaki / Roger Ditchfield with your shopping list along with your lottery winnings.



or simply buy an SP1/2

[Stephan]

It is like to have top running shoes for runner with broken leg. There is some sequence in tuning if you want more power.

stock is around 100 bhp

1. Exhaust
2. Air filter, other airbox mods
3. Lot of fiddling with jetting to get it right

This is the point where almost everybody ends up and lucky guys can have around 110 bhp. If you are kind of obsessed with this bike, then,

4. high comp pistons
5. performance cams
6. head porting
7. Alternatively more airbox tuning
8. Of course lot of fiddling to get it even run

This is stage 1. If your engine is not busted completely (depends on what was done right and what was missed), you are on 115-125 bhp. Lucky guys have engine running more than just few miles without serious issue.

Now time for the big boys, where I am losing the knowledge

9. More aggresive cams
10. Ram air and carbs modificatons
11. Lot of all other things ...

And have bike called stage 2 or 3 with 130-150 bhp.

IMHO, there is no point to do extensive airbox mods or ram air on bike with stock engine. And never seen the proof showing it.

[tony.mon]

I agree with Stephan. but on the other hand you have to start somewhere...

I have posted all of my experiments with airboxes in the forum, the standard airbox is small but seem to work well.
To me the limiting factor is the snorkel- if you measure the cross-sectional area it is smaller than the intake stack area, and without ram-air it won't flow enough air unless forced air is used. The design is such that the air is drawn in from behind the oil cooler and right on top of a hot engine- not exactly ideal.
So without ram air adding pressure to the intake air, just siting the air intake to the nose of the bike and enlarging the channel area will help, I think.

Next, the box itself. You can enlarge the box (I have one for sale at the moment) but you have to be careful that the extra volume isn't merely pockets or boxes where air movement isn't easy- my solution was to remove the corner triangular filter sections and fabricate external corners which gives over 10% more volume. Then you have to decide what to do about filtering the air going into the top of the carbs above the diaphragm- a simple foam wrapped around the stubs on the carbs did well enough for me.

For true ram air, the effect is more noticeable at higher speed than lower speed, obviously. This means that the mixture is likely to lean out at higher speeds. Yoiu will need to jet accordingly, and possibly jet for your "normal" running speeds- track use or street use- on a dyno with suitable blowers.
Alternatively, do as I did, and fit Lambda sensors in the two downpipes, and you can then monitor the air/fuel mixture real-time, as you ride. Did I say that I also had one of those set-ups for sale?
A Flo-commander is good, as it lets you effectively trial different main jet sizes in seconds rather than having to pull the carbs each time, yes, got one of those, too. It's great for the main jet circuit but a second one for the pilot circuit one makes it even better.
And yes, all of this will only make a difference with stacks (also for sale) preferably high-comps, cams and some head work (Hmmm. Now I come to think of it, I also have a pair of heads with oversize inlet valves up for sale on Ebay at the moment).

It's all or nothing, my friend- but I'd certainly recommend giving it a go- when you get it right, the bike is transformed.

[NZSpokes]

Or you can just sell up and buy a Busa if you need that much power. Its far easier.

[Watty]

It is like to have top running shoes for runner with broken leg. There is some sequence in tuning if you want more power.

stock is around 100 bhp

1. Exhaust
2. Air filter, other airbox mods
3. Lot of fiddling with jetting to get it right

This is the point where almost everybody ends up and lucky guys can have around 110 bhp. If you are kind of obsessed with this bike, then,

4. high comp pistons
5. performance cams
6. head porting
7. Alternatively more airbox tuning
8. Of course lot of fiddling to get it even run

This is stage 1. If your engine is not busted completely (depends on what was done right and what was missed), you are on 115-125 bhp. Lucky guys have engine running more than just few miles without serious issue.

Now time for the big boys, where I am losing the knowledge

9. More aggresive cams
10. Ram air and carbs modificatons
11. Lot of all other things ...

And have bike called stage 2 or 3 with 130-150 bhp.

IMHO, there is no point to do extensive airbox mods or ram air on bike with stock engine. And never seen the proof showing it.

Or just buy a more powerful bike

[tony.mon]

Of course buying a more powerful bike is easier.
You've missed the point entirely

[Watty]

Of course buying a more powerful bike is easier.
You've missed the point entirely

Ah yes! Give yourself some aggro with a capital A!

[mik_str]

Ram air will be of little to no use unless you are travelling a quite high speeds. This may be useful if running down a long straight on the track, but on the street will be of very little use (unless your plans include finding ways to lose your driver's license). There are numerous other, less expensive and complex, and more importantly more effective, ways to gain power for real-world use.

[CruxGNZ]

There are numerous other, less expensive and complex, and more importantly more effective, ways to gain power for real-world use.

Yes there is. Roasty Duck, search for "F.I.L. mod"

[Stephan]

Or just buy a more powerful bike

Question of money worth the effort and result was not raised, so I didn't tell. As well as importancy of other mods.

Anyway whole motorbike riding is just silly thing how to spend lot of money and put yourself to danger, there are just many ways how to achieve it

[Dendrob]

To me the limiting factor is the snorkel- if you measure the cross-sectional area it is smaller than the intake stack area, and without ram-air it won't flow enough air unless forced air is used. The design is such that the air is drawn in from behind the oil cooler and right on top of a hot engine- not exactly ideal.
So without ram air adding pressure to the intake air, just siting the air intake to the nose of the bike and enlarging the channel area will help, I think.



.

Do you mean both carb intake stack areas added together? Why does the "snorkel" area have to equal both stacks added? Won't only one cylinder be drawing air at any given time?

I agree with Tony and Stephan in that, although it is easier to buy factory stuff, it misses the point. If it floats yer boat, go for it. Sometimes the tougher the challenge the more the desire to succeed. Could end in tears tho

[roasty_duck]

today i did bodge fit some tubing direct to the snorkel for some cooler air and a larger volume of it, it seems to be a bit more responsive and the intake noise

not taken it up to much speed yet to see how it really does fair.

i could buy a faster bike but then i wont have a fun vtr.

i could spend ££££ on proper kit and upgrades for a little more power but wheres the fun in that.

[8541Hawk]

I'm another one who will say it is not worth the effort to get it to work.
With that I can pass on one jetting tip. One of the things they did on the ram air nike was plug the air bleed and run smaller main jets. This was done because the changing pressure in the airbox played havoc with the CV carbs.

[Dendrob]

Extruded Tupperware boxes can be used to enter the exclusive Club 18-30 (the amount of extra horsies the ram air mod can give) be prepared to find a dyno with fans to mimic +100mph head wind for when setting up the jetting.

You're saying 18 to 30 can be had from ram air alone? In other words from the extra air pressure alone? Takes some believing.

Ram air seems to throw up an interesting paradox. The extra air pressure generated from speed gives you more power. But how do you get to that speed in the first place?