Adding ram-air to the TRX?

[phuk72]

Cobba,

yes, it's a K&N replacement for the standard filter, NOT pods. Didn't think of that interpretation.

I thought that the air box was important in providing the carburettors with a regular, consistent supply of air. Just using pods under the tank would result in all sorts of turbulent airflow affecting the carbies. But even the air box benefits from a consistent supply of air, which is where a ram intake would help (well that's my theory!)

bazzee

lifting the front of the tank with some washers makes a big difference to airflow - as does modding the airbox snorkel

[Kayla]

lifting the front of the tank with some washers makes a big difference to airflow - as does modding the airbox snorkel

This, and get rid of the foam.

Sounds nicer too

[phuk72]

lifting the front of the tank with some washers makes a big difference to airflow - as does modding the airbox snorkel

This, and get rid of the foam.

Sounds nicer too

wot she said ^^^

[cobbadiggabuddyblooo]

Had exactly the same set up when I bought my TRX, air box,std mtr and staintunes with no restrictor in place.. I put it on the dyno at after adding another 25,000km so at almost 80,000km it came in at 70.1 h/p at the r/wheel.. Who ever had it before me tho had placed larger main jets in it and after contacting staintune I found the pipes where designed to run on std jetting.. Also the neddles where replaced and bingo.. 76.74 h/p.. 59.86ft-lbs torque. That was just with a std air cartridge that I had blown clean so it wasn't until a few mths after that that i also replaced that with a K&N cartridge myself and straight away noticed the bottom end response.. Never really noticed any probem as mentioned with that dreaded flat spot as a few of you on here now I have read have suffered... Maybe due to the contant open throttle the only problem I found was the speed never came round fast enough...lol thats why i invested in some FCR's and larger pipes... but it's a never ending battle ..it seems...now the suspension upgrade to suit the extra power so now morepower again to push the boundry ....

[DOBBO]

Isnt ram air like a defacto turbo. When these bikes get up to very high speeds, air channeled in creates positive pressure more fuel is added and hey presto you have boost. Idont think the trx would go fast enough to get any benifet from ram air effect.

[Quan-Time]

Turbo.. thats a fairly loose way of describing it.
Carbies work on a venturi effect. Ram air to the extent of POSITIVE pressure, IE: more pressure than atmosphere, im going to go out on a limb here and say "your bike will not run". Because there is positive air pressure in the carb, no venturi would take place. Its like turbo on a carby, it just flat out doesnt work. UNLESS you have a positive pressure to your balance pipes to put the fuel under the same pressure that is on the outside. You can turbo a carby with this method.

So i suspect ram air would help, but only to an extent. Soon as you make it too efficient, you would most likely loose power, or lean the bike right out.

[Kayla]

Turbo.. thats a fairly loose way of describing it.
Carbies work on a venturi effect. Ram air to the extent of POSITIVE pressure, IE: more pressure than atmosphere, im going to go out on a limb here and say "your bike will not run". Because there is positive air pressure in the carb, no venturi would take place. Its like turbo on a carby, it just flat out doesnt work. UNLESS you have a positive pressure to your balance pipes to put the fuel under the same pressure that is on the outside. You can turbo a carby with this method.

So i suspect ram air would help, but only to an extent. Soon as you make it too efficient, you would most likely loose power, or lean the bike right out.

I think that enclosing the carbs' breathers in the airbox would work and you'd have to make sure the fuel tank breather was routed into the airbox too. I think there was a race kit for the FZR400RR that used this method, running on FCRs.

Here's a v. trick FZR running FCRs and ram air. It looks like a sheet of foam or neoprene sealing against the carb inlets and underside of the tank.

http://cgi.ebay.co.uk/Yamaha-FZR400-rrs ... 7003r35169

From what I can work out from the pics, it looks like the carbs are outside of the airbox with positive pressure inside the airbox forcing air through the carb throats. Surely this would produce a venturi and if the fuel bowls were vented to the airbox the jetting would work?

[steve speed]

when will we see your bike running quan time ?? i cant wait

[trxster]

I've been running with raised tank, "(5mm at front),all foam under the tank removed, and a series of 6mm holes drilled in the top of the snorkel", no flat spots at all, it has definietly been worth it. The K&N filter would be settling down any turbulance before having an effect on the performance. It has worked

[DOBBO]

I was trying to keep it simple by using turbo and boost as examples. Do these bikes with real ram air systems have fuel injection?

[Kayla]

I was trying to keep it simple by using turbo and boost as examples. Do these bikes with real ram air systems have fuel injection?

No. The early Suzuki GSX-R 600 and 750 'SRAD'* models were carbed (so was the WSB bike) and the early R6. Don't forget the Kwak ZX-7R either and there are loads of other, earlier carbed bikes that ran some kind of 'ram air' system. Like I mentioned before, Yamaha released a race kit for the (carbed) FZR400RR that included a ram air box. GP bikes (125s, 250s and the old 500s) use ram air and they're carbed. I'd imagine it's a lot simpler to set up an injected bike as you've got pressure sensors and all kinds of electrickery going on, but where's the fun in that? Eh? Eh? Maybe I like the misery.*

* Suzuki Ram Air Direct
** To paraphrase Mrs Doyle from Father Ted.

[cobbadiggabuddyblooo]

yer it's a bit like mivrowave cooking..where the fun in that put a plastic bag in the oven and press 2 minutes ding... instead of a pinch of this abit of that and wait 5 minutes then add this while beating but only when clockwise...you know. otherwise it won't taste like how mum a made it

[Quan-Time]

@ stevespeed
I wanna have the TR1X finished by xmas, BUT ive learnt that i cant get the results i want from my current throttle setup. Im seriously thinking of custom fabricating some oval shaped ITBs to get the exact properties i want. And honestly, making your own ITBs is no small task. I can do it, its just a "time" issue. Wait and see how i go. Ill probably go ahead with what i can, and have a few more things going on in the background. Pull it off the road (again) some time next year, and put some more bits on it. Depends what work i have over xmas. Shutdown work is gonna be weird this year, i dont expect to get much, so i might have a month off, which would be SWEET for some personal work time.
-------
OK.. im gonna have another shot at this
As i said previously, carbies work venturi, which is a pressure differential. As long as you have MORE pressure on the fuel side, your sweet. It doesnt have to be much. As for "pressurised" air boxes. Under normal road conditions, its inherently hard (to the point of being almost impossible) to have more than atmosphere (1bar / 14.7psi" in there. When i get my ass in gear, ill take a quick video today with a quick mod and post it up. it MIGHT interest a few of you... *cough*

Your "plenum" is your storage of, which is ready to be sucked (or forced) into your engine. Its also "usually" concidered to have fuel suspended in it. Think of a carby V8 car. Carby, manifold, cyl-head. The manifold stores a certain volume. This must be matched to the volume of your engine. Motorbikes go in a different direction. We use the airbox as the plenum. I cant remember the formula off hand, but its something like 1:1 @ 5252rpm, 2.25x the size for every cc there after. Theres some proper "formula", but thats the general idea of it. All this means is, if you have a 5litre V8, which has max power @ 6000rpm, you want approx 5.8litre of volume. This is for a huge race application, NOT a street car, normal street car use, you look at around 75% of engine size.. s0 3.8ish litres.

Now about the airbox pressurisation thing. If an airbox is normally 9.5psi, while atmosphere is 14.7psi, and you increase it to 13.0psi, your airbox is technically concidered "pressurised". Yes its lower than atmosphere, BUT its higher that "normal" conditions. Its also able to run carbies fine.
Your VE (volumetric efficiency) is now increased. Your velo might slightly decrease, but CFM would certainly be up. Yet something you can tune (partly) around. You need 1.98cfm to produce ~1hp. So if you can stuff that in, compress it, go kaboom "easier", your power will go up. The piston DOES loose energy thru work / effort. You will get some weird side effects sometimes.. Dips in power curves, different fuel usage, obviously different jetting requirements, etc..

Homework time. Figure out air requirements for a stock TRX at 1000rpm, 5000rpm and 8000rpm. This could take a bit, but a good example will be shown

[steve speed]

i did my homework sir ,, but the dog eat it , sorry

[Quan-Time]

OK.. steve, go get your dunce hat, sit in the corner please.

Rest of you rowdy mob.. I put my MAP sensor (manifold air pressure) into the airbox instead of behind the butterfly. You can see its lower than atmosphere. Its surprisingly constant, it actually fairly stable, i was a bit surprised some what.
As i bring the revs up, on the far right hand side, the vertical bar is my TPS. So you can see what my throttle is doing.
On the actual 3d map. You can obviously see which direction RPM goes, and where the static dot is, thats full vacuum. top of the grid is "atmosphere". When i roll the throttle harder, you can see how it tends to "dip" a little bit rather than being directly linear. This is going slightly more into vacuum than in idle.

Please remember that the bike is stationary, and not under load or moving. This is just an example of how things work. Also not that is NOT my normal ignition map.
Oh.. yer, that map is ignition. vacuum / pressure effects where your state of spark should be. ANything else, just ask.

OK, steve, please come back now. And clean the chalkboard while your at it.
*snigger*