13B PP Ignition breakup
#126
"Elusive, not deceptive!”
#127
Exhaust Manifold Leak
Thread Starter
I just kind op copied the FD and RX8 end mill cuts on this RX4 housing. I did not touch the wall thickness of the boss itself on purpose (i reduced it slightly as I went a bit too deep with the end mill when removing the casting around the bolt boss below the leading plug boss) but I do not think it is critical. I also removed the the fin at the trailing boss as this is also done (altough its cast in and not milled) on rx8 housings. I also copied the end mill cuts found on the FD leading to the trailing boss as you can see.
Lets see what it does. I think it will work just fine =). at 70°C thermostat would be really nice. do you know if this exists for S4 water pump houing?
Lets see what it does. I think it will work just fine =). at 70°C thermostat would be really nice. do you know if this exists for S4 water pump houing?
#129
Exhaust Manifold Leak
Thread Starter
graph of engine with MFR housings, these are flywheel numbers. I think actually we should have had a bit more peak torque. Top end after 9k the float level was too low. got some grose jet now so that should be fixed =)
#130
Exhaust Manifold Leak
Thread Starter
New housings dynoed about same power as the MFR. Seems there really is a problem somewhere restricting peak ower. torque was around 250 Nm. when the mid range was leaner.
Here some footage.
Less is more, atomisation is really nice with these venturis. but the transistion is really tricky to get right. at we run F4 emuslsion, 80 idle, 120 air and 240 main. goes really well on top end but below 6k its too rich. :
For comparison normal IDA venturi, here we have no grose jet and you can see at the end of the run the float is about empty.
Dyno overview
Qualifying, just before the end one can hear the overly rich condition when coming out of the corner.
Here some footage.
Less is more, atomisation is really nice with these venturis. but the transistion is really tricky to get right. at we run F4 emuslsion, 80 idle, 120 air and 240 main. goes really well on top end but below 6k its too rich. :
For comparison normal IDA venturi, here we have no grose jet and you can see at the end of the run the float is about empty.
Dyno overview
Qualifying, just before the end one can hear the overly rich condition when coming out of the corner.
#135
Exhaust Manifold Leak
Thread Starter
In a quest for more top end, I opened up the exh a bit sooner and installed TII exhaust sleeves instead of the tiny RX4 ones, had to increase the size of the hole from 58 to 65mm. I hit some water in one housing but welded it again, hopefully it holds.
Also Barry, the modifications to the water jacked proved not to help anything. lifting is still there. I must say altough on the last race we had a problem with the fuel pressure regulator casuing the carb to overflow. therefore we drove on just one pump instead of 2 causing the engine to run quite lean up top, which could also cause to high temp around leading spark plug..
There was also sign of rear rotor hitting the rotor housing just slightly. not damage but one can see the carbon missing from the rotor where it hit
Also Barry, the modifications to the water jacked proved not to help anything. lifting is still there. I must say altough on the last race we had a problem with the fuel pressure regulator casuing the carb to overflow. therefore we drove on just one pump instead of 2 causing the engine to run quite lean up top, which could also cause to high temp around leading spark plug..
There was also sign of rear rotor hitting the rotor housing just slightly. not damage but one can see the carbon missing from the rotor where it hit
#136
"Elusive, not deceptive!”
This is your original.
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This is what you have now.
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It may be wishful thinking but I think I see some improvement.
I think your specs are... stock water pump housing and pump. Are you running a thermostat?
How much water pressure are you seeing at the rear of the engine?
Have you seen the new RX8 impeller/pump?
[/url]
This is what you have now.
[/url]
It may be wishful thinking but I think I see some improvement.
I think your specs are... stock water pump housing and pump. Are you running a thermostat?
How much water pressure are you seeing at the rear of the engine?
Have you seen the new RX8 impeller/pump?
#137
Exhaust Manifold Leak
Thread Starter
This is your original.
[/url]
This is what you have now.
[/url]
It may be wishful thinking but I think I see some improvement.
I think your specs are... stock water pump housing and pump. Are you running a thermostat?
How much water pressure are you seeing at the rear of the engine?
Have you seen the new RX8 impeller/pump?
[/url]
This is what you have now.
[/url]
It may be wishful thinking but I think I see some improvement.
I think your specs are... stock water pump housing and pump. Are you running a thermostat?
How much water pressure are you seeing at the rear of the engine?
Have you seen the new RX8 impeller/pump?
The TII pump look most like the Mazmart RX8 pump impeller wise. (3rd one in your pic)
it looks indeed a bit better now but its still a bit there
#138
"Elusive, not deceptive!”
You are close to eliminating the temp problem around the plugs.
I would suggest that if you don't run a thermostat at least run the frame as a restrictor.
It allows the pressure in the block to go to about 45 PSI ...... raising the boiling point to about 300 degrees fahrenheit..
This is what a Boyesen design water pump impeller looks like...
I wonder who designed the new Mazda pump?
I would suggest that if you don't run a thermostat at least run the frame as a restrictor.
It allows the pressure in the block to go to about 45 PSI ...... raising the boiling point to about 300 degrees fahrenheit..
This is what a Boyesen design water pump impeller looks like...
I wonder who designed the new Mazda pump?
#139
Exhaust Manifold Leak
Thread Starter
Hi Barry, do you have maybe a performance curve of a TII or mazmart pump? I am curious to know the tradeoff in flow when you increase pressure. at I am seeing almost no pressure increase over static pressure at the temp sender location. nonetheless with the bigger exh port the engine performes much better. got now over 260 Nm of torque and 306hp at the flywheel. it has still a bit more inside but we had no more time at the dyno. midrange was too rich and top end too lean. might need to use different emulsion tubes.
#140
"Elusive, not deceptive!”
Hi Barry, do you have maybe a performance curve of a TII or mazmart pump? I am curious to know the tradeoff in flow when you increase pressure. at I am seeing almost no pressure increase over static pressure at the temp sender location. nonetheless with the bigger exh port the engine performs much better. got now over 260 Nm of torque and 306hp at the flywheel. it has still a bit more inside but we had no more time at the dyno. midrange was too rich and top end too lean. might need to use different emulsion tubes.
You should be seeing over 40 psi at the back of the engine.
#142
Exhaust Manifold Leak
Thread Starter
Still going strong. for 2016 season we remade front suspension and subframe rack and pinion steering. the engine is now unopened for 2 seasons, approx 30 hours or racing and compression is still better than we measured after the engine was freshly together. the NRS seals are doing a superb job. I think it really proves for racing these engines are ultra reliable once jetted and balanced properly with good dry sump oiling system, even after a handful of 10k+ rpm misshifts per race. the only wears parts we changed where one set of Bosch W2CS plugs. thats it.
thats sub 50 dollar of parts for 30 hours of racing. now compare this to a 300hp cosworth BDx
#143
Rotary Freak
You should enlarge the float bowl and use f2 em tubes and try some B9egv spark plugs. I make a separate float bowl that joins to carby using the float drain plug .I will do a drawing of the setup if you like .
#144
Exhaust Manifold Leak
Thread Starter
I have extended bowl, but on that run the fuel pressure/grose jet was the issue. we now run 2 seasons with 3.4mm glass ball and 250 mbar fuel pressure without issues. I adjust main jet / air corr to balance the rotors so the end up with similar egt at the end of long straights.
#145
Exhaust Manifold Leak
Thread Starter
Here some footage from the most recent race.
Car goes very well, reliable as a watch. the only thing that seems to wear in the engine are the side plates and side seals. rotor housing stay new with ceramic seals .D
Car goes very well, reliable as a watch. the only thing that seems to wear in the engine are the side plates and side seals. rotor housing stay new with ceramic seals .D
#146
"Elusive, not deceptive!”
Here some footage from the most recent race.
https://www.youtube.com/watch?v=V02hzmZModQ
Car goes very well, reliable as a watch. the only thing that seems to wear in the engine are the side plates and side seals. rotor housing stay new with ceramic seals .D
https://www.youtube.com/watch?v=V02hzmZModQ
Car goes very well, reliable as a watch. the only thing that seems to wear in the engine are the side plates and side seals. rotor housing stay new with ceramic seals .D
I have had side plate wear that I attributed to tight side clearance …. less than .003".
You might try zero clearance corner seals.
Zero Clearance Side seals
Barry
#149
Exhaust Manifold Leak
Thread Starter
Fronts are hi- spec, i think around 305 mm disc, they fit in 15'
rear are brembo calipers from an evo, and discs from a vw mk3 gti fronts, around 280mm vented. Has front and rear separate masters with an adjustable balance bar.
rear are brembo calipers from an evo, and discs from a vw mk3 gti fronts, around 280mm vented. Has front and rear separate masters with an adjustable balance bar.