Other Reverse Jetting

D

DEXTER

Location
Some place but here!
I've been out of the scene for awhile but its still the same stuff. We used reverse jetting because thats what it took to get our carbs (Buchshot, Novi's) to run their best. The way the signal in the carb worked it just needed to let the fuel flow, so reverse jetting worked on those carb setups. Jetting specs--Whatever makes it work best.
 
Billybo455

Billybo455

Location
Central FL
masterblaster said:
So..adjust initial jetting,timing..then adjust water injection to dry pfp pipe direct from pump ..then go back adjust jetting,and timing to work with new power curve on pipe. then new prop,nozzle for new bottom power curse..then tweak jetting,timing once more for new optimal prop......? just hypothesis
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very good. it sucks because every change you make directly effects something else. make changes in the pump it changes the load on the motor. make changes to the motor it effects the pump slightly... so you do bounce back and forth a few times. but getting the motor right first should be the priority. i haven't caused a motor to blow up from a fuel issue yet and i'd like to keep it that way haha. water injection doesn't always work. oh and who uses a powerfactor anymore :)
 
dcptr

dcptr

Location
Australia
I've been consulting wax for the last couple days getting this setup running and all I can say is WOW.
The guy really knows his :):):):)! There ain't many guys out there that will give you the time of day to help out like he has. My ski feels like it has doubled power by following his methodology and I'm having to relearn how to ride my ski again because it behaves so much differently now!
 
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W

waxhead

wannabe backflipper
Location
gold coast
SN760 said:
Use to use e.g.t.'s to tune ski's - exhaust manifold I have on my ski now is drilled and tapped for the probes.
Giving the Epic a try - friend of mine has loaned it to me. Ran MSD total loss for about 2 years, decided to go back to a charging system and sold the Total Loss ( mistake). If I can get the Epic to work it will give me a good comparison of running 22 degrees advance (msd inhancer) verses 32 degrees (epic). If there is a noticeable difference then I most likely will buy the epic or get a flame.
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There will be a noteable difference. Make sure you richen up the bottom end when you do the timing as well to get the good gains
 
Watty

Watty

Random Performance
Location
Australia
I must be doing something wrong. I give the engine the fuel it wants. Sometimes jetting ends up reversed, even, or conventional, but I usually tune each ski on it's own setup. I don't think I've ever intentionally reversed the jets as a starting point. I'm not saying it's not a good idea, but simply tuning an engine the way it should be tuned will usually result in more consistent results for the average punter rather than chasing issues with something that is intentionally reversed jetted because they were told it would be 'heaps batter'. A lot of tuning I do is sorting out issues with jetting that was suggested by someone else in reverse config. Most guys don't understand enough about tuning to sort out a carb issue as it is, let alone something that is reverse jetted.

I'm all for any jetting that works, and works well. I'm still quite surprised at some of the jetting I see that works really well, reversed or not.
 
dcptr

dcptr

Location
Australia
Agreed- it Definately is not for everyone to mess with- in fact, same with programming ignitions.
So if your not a rocket scientist, tony stark, come from a racing background (mechanical-wise) or haven't spent years tuning with the experience behind you, I wouldn't recommend doing it.
Once people start messing with this kind of :):):):), you've got to be prepared to take all responsibility of your actions and not blame someone else who tried giving advise.
Not all jetting specs will work on every engine with even the same specs, mods etc- machining tolorances, clearances etc effect everything enough to throw off different setups. Example- piston to wall clearance, the type of hone that was done and the pressure that was used to hone, squish, comp, piston to deck clearance and of course, not every port job is the same- not every piston is the same size for that matter.

You've got to be prepared for failure and have an idea of the limits you can push.

Mates don't let mates run reverse jetting
-Watty
 
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masterblaster

masterblaster

X-H2
Billybo455 said:
very good. it sucks because every change you make directly effects something else. make changes in the pump it changes the load on the motor. make changes to the motor it effects the pump slightly... so you do bounce back and forth a few times. but getting the motor right first should be the priority. i haven't caused a motor to blow up from a fuel issue yet and i'd like to keep it that way haha. water injection doesn't always work. oh and who uses a powerfactor anymore :)
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It is pretty interesting how one change effects others so much,almost all parameters have to be tweaked a bit.. you guys are deff onto something with what your doing,Im with you... think outside the box,elsewise the same thing is in the box everyday and nothing gets radically improved..props on that..what do yall call the pipe now? lol
 
lanmine657

lanmine657

Location
fortcollins
dcptr said:
Agreed- it Definately is not for everyone to mess with- in fact, same with programming ignitions.
So if your not a rocket scientist, tony stark, come from a racing background (mechanical-wise) or haven't spent years tuning with the experience behind you, I wouldn't recommend doing it.
Once people start messing with this kind of :):):):), you've got to be prepared to take all responsibility of your actions and not blame someone else who tried giving advise.
Not all jetting specs will work on every engine with even the same specs, mods etc- machining tolorances, clearances etc effect everything enough to throw off different setups. Example- piston to wall clearance, the type of hone that was done and the pressure that was used to hone, squish, comp, piston to deck clearance and of course, not every port job is the same- not every piston is the same size for that matter.

You've got to be prepared for failure and have an idea of the limits you can push.

Mates don't let mates run reverse jetting
-Watty
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+1
 
Billybo455

Billybo455

Location
Central FL
can't give you guys everything! you know i tried my hardest to keep the hood closed on the white ski, but people would just walk by and open it up (checking to make sure it had fuel) is what they said. haha. you'll see one at worlds this year.
 
Philip Clemmons

Philip Clemmons

Owner, P&P Performance
Location
Richmond, Va
Billybo455 said:
can't give you guys everything! you know i tried my hardest to keep the hood closed on the white ski, but people would just walk by and open it up (checking to make sure it had fuel) is what they said. haha. you'll see one at worlds this year.
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People........lol. Got a good idea who you're talking about. Lol.
 
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