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kpr last won the day on June 22 2015

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About kpr

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    Dr Dolittle of 4age

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  1. too many diffs aye. the front one will go down!
  2. going by your drawing. can you lift the rear of gearbox up and drop the pinion down so your angles are less aggressive ? the hanger will have to be moved up as well obviously. Or possibly leave the gearbox where is. run first shaft up at 2.5deg angle from the gearbox, so the flange on end of first shaft is at zero deg. then drop the diff nose down to zero deg also. which should get you pretty close doing some rough maths. all depends if you can do that in your tunnel though reason for running a very small angle on the first shaft, is because it has no 2nd uni to cancel out how the uni accelerates and decelerates the shaft when run on an angle. sub 3 deg is fine. running a zero best, but yeh, uni will wear fast since doesn't have and bearing rotation. to much angle will cause more problems that running none. as @Mof says the rear shaft angles need to be matched. ideally the less angle the better, long as it has enough angle to keep the uni's happy. the nose of the diff will want to rotate up under acceleration. but from memory you are running rose joints on the 4 link? if so wont get bugger all deflection. so set up neutral will be fine
  3. You still want to richen it up as load increases. if stay lean with too much load will run into heat and knock issues. will basically end up same as what you would use in a car. its more what the motor wants than what its in. will depend on the whole setup as to how much load is on engine at "boat cruise" . from memory the supercharged mang machine i tuned, once got up on the plane and backed off wasn't a silly amount of load on engine. so the afr could be fairly lean at that point the link map i was thinking of must be in the g3 software. g4 has vvti version. dont have it installed on this pc at the moment
  4. there is a pretty good base map in the link software, one we used would have been in the older g3 or g4 pclink. that only needed a few tweaks to get right, on a mates 1uz years ago. maybe worth a look just to get the trend of the fuel map. plus some ideas for the ignition map. compare to old mates one you found
  5. cold start idle thing probably isn't too much of an issue in jet boat, since you would be generally in the boat manning the throttle soon as its started.
  6. Map looks horrible. I would suggest disconnecting the shaft between the engine and jet unit if possible. So you can run the engine while out of water. Tune as much of map as possible free revving it and getting all the idle stuff right . Then yeah from that guess the rest of the tune. A stock engine without cams will have a fairly smooth map with highest numbers being at max torque. Once in the water, as you say will only be able to tune certain part of the map, the way the jet unit loads the motor. I would do part throttle runs. Once get that right . Repeat at higher throttle. Right up to full throttle. Then use trend from the points you tuned to guess rest of map. Need to sort the main tune before bothering with any of the compensation
  7. silly question. how much fuel do you put in on a fill from empty? my fuel gauge is janky as, when its on E a massive 20L fills it. from a quick google they are 40L tank? sucks to going to gas station every 200km. <- from that, you can feel better about your fuel economy
  8. Turns out it still had the og shocks in the struts. pulled one of them apart. found they have a stopper on shaft to limit extension travel. chopped that off and welded it back on 40mm lower. did some super janky shaft re-polish. they were leaky anyway so whats a bit more. also "machined" the little spacer plate on compression side of shocks. to effectively make bleed holes on compression side smaller. so will have who knows how much more compression dampening, along with 40mm more droop for those hectic jumps. I want to add a second shock on the rear that only starts working at last 1/3 or so travel. so its like some kinda amazing redneck hillbilly bypass shock
  9. yeh try run the sense wire directly back to battery on its own wire. see what it does
  10. @Roman Dave getting all the credit, with his following of fellow graph theorists
  11. Ive tired stuff in the past. only very significant change in afr or timing has an effect. timing is it the sweet spot, few degrees either way no change. afr; 11afr right up to near 14afr same power. done over 300 runs on this thing so know how it behaves . the biggest effect on power is oil temp. and of course if tied to dyno different which it never moved off. This plot below I went full retard and forgot i loaded the normal tune back on at end of day. soo the afr was a lot richer on the day 2 blue run. still only maybe 1kw change. oil temp makes up to 3kw change. 80 - 100c
  12. maybe thats the yo-yo bounce, like on old mates one in the vid a few pages back
  13. That intake with or without filter makes same power. so yeh just ran it as is. Looks like if got all the lengths exactly the same. (since the opening shape and diameter have an effect) the roman dave, pvc with full bell and my normal intake would all be pretty much the same power throughout. think the only reason my normal intake looks sightly better is its acting slightly shorter than the other 2 (dave +45 and the pvc w/ plastic bell)
  14. Here we go, 2 days of dyno testing and even longer editing. @Roman also made some science graphs with the dyno data. maybe he will post them up here.
  15. maybe put some oxy in instead of nitrogen. bit more travel would be nice. but some more compression damping while retaining the lack of rebound should make it fly and land like a trophy truck. Its borderline that already, so with some minor tweaks...