Thanks devil. Finally starting to get somewhere.
U all have a great holiday/merry xmas
Carbed 2 stroke turbo guy's !!!
- Thread starter gus bohne
- Start date
Thanks devil. Finally starting to get somewhere.
U all have a great holiday/merry xmas
B
bin sledin
New member
ya i have the fuel pressure gage hooked up to my regulator and i will runn it on a stand to see if it risses . now that i think about it i did have hobbs hooked up as well as the pressure regulator plumbed into my charge box. i cant imagine how painfull it was to tune with that old system
B
bin sledin
New member
thanks for the break line tip Devil i will do that before i go out for a rip how do i get a set of Gus ,s reeds for my rmk shift 600 does he make them for my machine
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Just PM him. His # has been posted here a couple times too. Not sure what he has.
T
Team Voodoo
Active member
I believe the exhaust pipe builds pressure before the air box eliminating a lean spot. I would think this would also be the same after a wide open pull also eliminating another lean spot after a sudden throttle lift the pressure in the pipe will stick around a little longer giving extra fuel.
I don't run egt or A/F. I never look at guages so why have them.
Along with what Voodoo said, pipe pressure also is higher than boost by a couple psi.
Since I have chased electrons around most of my life, I am a guage nerd and have them all.....LOL. I used Gus's technique for the fuel pressure. And of course I have a fuel pressure guage on the bars.
I set the reg for 2-3psi at idle by the time I have engagement pressure is up to 5psi at 7psi boost my fuel is hovering around 14psi. Either the exhaust backpressure in my system is high (7psi at wot) or the reg is not truely linear. I figured my pipe backpressure would be about 5psi above intake, but looks like 7psi?????????
PS: Merry Christmas everyone!
3 psi start plus 7 psi boost = 10 psi fuel pressure if you were using just intake side pressure. You forgot to add in the start pressure to your equation Tony.
your pressure of 14 shows a plus 4 from the exhaust side additional backpressure.. so your ex side bias is plus 4 psi, not 7.
you still got plenty of room. 7 high for your use. that'll happen with your set up around 26 + psi
Happy holidays
The advantage to'' leading'' fuel supply before the demand,,, rather than follow or just keeping up is almost moot to describe ,, am I right ?
It allows a lower idle pressure which will help some with high floats from be fooled into leaning the jetting in response to a slow weapage induced rich spot at low speeds or on let off in the tightstuff.
gus
your pressure of 14 shows a plus 4 from the exhaust side additional backpressure.. so your ex side bias is plus 4 psi, not 7.
you still got plenty of room. 7 high for your use. that'll happen with your set up around 26 + psi
Happy holidays
The advantage to'' leading'' fuel supply before the demand,,, rather than follow or just keeping up is almost moot to describe ,, am I right ?
It allows a lower idle pressure which will help some with high floats from be fooled into leaning the jetting in response to a slow weapage induced rich spot at low speeds or on let off in the tightstuff.
gus
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T
Team Voodoo
Active member
Meth
Would there be a benefit installing methanol injecton to lower charge temp or would the intercooler be sufficient for higher boost efficiency? My plan is to reach 15 psi of boost. Instead of using the bulky pump and and huge draw on batt I was planning on building a meth pressure cartrige using a boost reference seleniod for activation. I realize this would not be for trail use I only run 2000 feet.
Would there be a benefit installing methanol injecton to lower charge temp or would the intercooler be sufficient for higher boost efficiency? My plan is to reach 15 psi of boost. Instead of using the bulky pump and and huge draw on batt I was planning on building a meth pressure cartrige using a boost reference seleniod for activation. I realize this would not be for trail use I only run 2000 feet.
Meth injection on a 2 stroke doesn't sound like a good idea to me. Thinking crank rusting because of the water it is ingesting. Maybe it wouldn't be a problem, me thinks it would.
I need some help again. I am runnin a aero 53 on a 02 700 rmk. Just the motor and all installed back in today. Fired it up to do some tuning. Checked all lines for leaks and nada. Fuel pressure was good, and making the right boost on the stand. Dropped it down of the stand took off for a rip and she pulled hard for about 400 ft. Let off to turn around, hammered on it and it fell on its face. Actually dropped a cylinder before I got it back into the shop. I checked over everything again and seemed to be good. Wonderin if it is simply just too rich. Cleaned it all out and fired it up, let it warm and hammered on it to get a 02 reading=14.5 which I know is way rich. Runnin 420 mains with a homemade dial a jets. Didn't have any problems last year here but could it really be that simple? What else should I look for? We have 24in of fresh snow and I would like to tune tomorrow if possible. Elevation is 0-3000ft and today 32 degrees. Thanks ahead of time fellas.
Hey Papa,
If I'm reading all the other posts on O2 correctly and base on my observations with mine. I think you are lean. Seems that you should be down around 12 to 1(on a turbo two stroke) for a safe mixture.
Hope this helps.
Hey Gus,
I knew there was sump'n I was missin......and I used to be a whiz at math, now I'm just a whiz.......LOL
If I'm reading all the other posts on O2 correctly and base on my observations with mine. I think you are lean. Seems that you should be down around 12 to 1(on a turbo two stroke) for a safe mixture.
Hope this helps.
Hey Gus,
I knew there was sump'n I was missin......and I used to be a whiz at math, now I'm just a whiz.......LOL
yeah it is a lean reading when it is runnin crisp but it was burping and puking so bad that it wasn't opening up allowing for a correct wot reading. Gonna drop a few jet sizes in the morning and go from there.
Blocking open my exhaust valves made a huge difference. Boosting real low, like 5000r's. Still a bit fat on the low end. Not sure if I will ever quit monkeying with this thing.
Didn't notice any negative from blocking the exhaust valves open. The low was as good as it was before.
Didn't notice any negative from blocking the exhaust valves open. The low was as good as it was before.
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oepn the air screws , if its still there or you go lean before it goes away,,,, its not on the pilot circut..
if it does go away then you got it and now u understand the potato in the pipe issue of valves on turbos..
Gus
if it does go away then you got it and now u understand the potato in the pipe issue of valves on turbos..
Gus
Yea, would have adjusted them out on the hill but I couldn't find my screwdriver that would fit.
How did you block the valves open? The idea of making boost at 5g's sure sounds appealing. Is it something simple you can do that is easily reversible?
Thanks
wes
I had some 1/2" washers that had oversized holes (.562) that were just the right size od. Pulled the springs, put the washers between the housing and bellow, over the valve. Hard to explain where, but if you take it apart its obvious where you need the spacer. The washers are just used as a spacer because they were the perfect size and sitting right there.
Yes its super simple to change it back. I could do it on the mountain in about 5 minutes.
Do it, all they are doing is hampering the turbo. I don't know any difference at all in the low end, before boost.
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