crack rotor housing
09-14-13, 08:51 AM
#30
Old [Sch|F]ool
but i could envision the rotor tapping the trochoid surface could put enough pressure on the housing to crack it while not causing such extensive damage. or there simply was so much pressure from a detonation cycle that the housing deformed before the rotor/seals gave up(weak aluminum casting or flawed/dirty aluminum mix).
I do wonder what the rotor gear and its roll pins and the stationary gear look like. Including the pin that holds the stationary gear located to the side housing.
I also wonder what the clearances to the pinch are, when measured against a good rotor housing. I've only ever had one engine where the rotor got close to the pinch, but it was my current S4 rotor/S3 housings engine, every engine I'd built with the same series parts looked fine.
09-15-13, 11:55 AM
#32
10 degrees of split usually works but it is a bit extreme, most people run 12-15 split under hard boost and 0-5 split or even negative split under cruising conditions.
but with the microtech i have seen the onboard map sensors not filter rough signals which causes the ECU to read boost flutter and overcompensate for it, leaning out AFRs by up to 2 full points which aren't readily noticed on slower reading wideband gauges. the microtech also fails at logging most wideband outputs, so seeing those lean spikes is sometimes quite tricky.
if you do see the boost reading fluttering 2-3psi you can easily correct it by putting a filter/restrictor in the MAP hose about 3" up from the ECU. this issue did kill one engine before i could catch it.
but with the microtech i have seen the onboard map sensors not filter rough signals which causes the ECU to read boost flutter and overcompensate for it, leaning out AFRs by up to 2 full points which aren't readily noticed on slower reading wideband gauges. the microtech also fails at logging most wideband outputs, so seeing those lean spikes is sometimes quite tricky.
if you do see the boost reading fluttering 2-3psi you can easily correct it by putting a filter/restrictor in the MAP hose about 3" up from the ECU. this issue did kill one engine before i could catch it.
Last edited by RotaryEvolution; 09-15-13 at 11:58 AM.
09-15-13, 01:22 PM
#33
Old [Sch|F]ool
I put the restrictor as close to the engine as practical, it damps out the pulses more at the expense of a little bit of transition lag.
Where is the pressure being measured? I always thought that measuring vacuum at the runner like Mazda did it was ridiculous and a recipe for poor measurement. I always went off of a vacuum nipple in the plenum chamber. On an N/A, going off of the plenum chamber is often good enough to not need a restrictor at all.
Where is the pressure being measured? I always thought that measuring vacuum at the runner like Mazda did it was ridiculous and a recipe for poor measurement. I always went off of a vacuum nipple in the plenum chamber. On an N/A, going off of the plenum chamber is often good enough to not need a restrictor at all.
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NathanBoutin (02-18-24)
09-15-13, 01:40 PM
#34
the more upstream the better, but even at the plenum i still have seen a few cars which had a bit of resonance that still needed a restrictor. it also depends on the ECU and how much of a filter they put into the programming, with the microtech i have noticed this buffer to be a little bit unreliably setup.
the FC MAP port was very low and close to the intake port but the MAP sensor was only used for timing and the tune was conservative. the FD which used fuel based off the MAP sensor moved it up near the throttle plates. the FC configuration had much to be desired.
the FC MAP port was very low and close to the intake port but the MAP sensor was only used for timing and the tune was conservative. the FD which used fuel based off the MAP sensor moved it up near the throttle plates. the FC configuration had much to be desired.
Last edited by RotaryEvolution; 09-15-13 at 01:43 PM.
09-18-13, 12:43 PM
#37
Rotary evolution.
Want to no your thoughts/experience running rotary without trailing. So far mine is good.
Please YouTube rotary breakthrough. It's some guys idea on modifying the rotor housing. Makes so much sense I'm building an engine similar to his design. But won't have it ready until late next year$$.
And I have perfected Holley tuning. People don't seem to care but I passed Delaware emissions. Hi an low idle test. 115HC .59CO
Want to no your thoughts/experience running rotary without trailing. So far mine is good.
Please YouTube rotary breakthrough. It's some guys idea on modifying the rotor housing. Makes so much sense I'm building an engine similar to his design. But won't have it ready until late next year$$.
And I have perfected Holley tuning. People don't seem to care but I passed Delaware emissions. Hi an low idle test. 115HC .59CO
09-18-13, 12:48 PM
#38
leading only has been done, by a number of people. you will lose some performance but you will run less chance of detonation from split or trailing ignition issues. i setup a carbed turbo REPU with leading only and it worked fine.
i don't know what to think of the video, it seems like a good idea but it also covers the ignition and could cause other problems. meh to the modified rotor, too much work for almost no benefit, mazda already experimented with the tub designs and eventually ditched it altogether for a uniform tub.
i don't know what to think of the video, it seems like a good idea but it also covers the ignition and could cause other problems. meh to the modified rotor, too much work for almost no benefit, mazda already experimented with the tub designs and eventually ditched it altogether for a uniform tub.
Last edited by RotaryEvolution; 09-18-13 at 12:51 PM.
09-18-13, 06:31 PM
#39
I somewhat agree with the rotor. It does look like Mazda addressed this with the renesis engine. The rotors appear to have a tapered chamber so there must be some truth to this. I think the spark plugs would address emissions problems more then anything. I believe the msd discharge helps me recover lost performance from not using trailing.
My goal is best car for the street.
My goal is best car for the street.
09-18-13, 07:36 PM
#40
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I somewhat agree with the rotor. It does look like Mazda addressed this with the renesis engine. The rotors appear to have a tapered chamber so there must be some truth to this. I think the spark plugs would address emissions problems more then anything. I believe the msd discharge helps me recover lost performance from not using trailing.
My goal is best car for the street.
My goal is best car for the street.
that being said there have been a lot of advances in combustion simulation, and the SKY Aktiv engines all have really odd pistons, so i wouldn't be surprised if the new engine had a special shape to the combustion recess.
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