Max BOOST on pump Fuel
06-08-2006, 11:28 PM
#1
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I have ten years worth of tuning expeirence and several rotorys done succesfully that run very well. The most boost I have ever tuned is 14 PSI on pump fuel with small single turbo on 13B in 85 old school with custom manifold and stuff. car went 12.00s no dyno numbers cause dynos werent aroud then. Any way!
Guy brings me a 93 Rotory with HKS 51R turbo big HKS cooler street ported fresh motor with 1,000 K on it. Tuning went pretty easy, Started fat as usuall and leaned it till it liked it and made good power. ended up with AFR around 11.5 12.5 trhough out the curve. Made 374 HP and 299 TQ on Mustang 1750 Eddie current load Dyno pulls were clean and hard, felt and sounded good. Timing at 19 PSI was what I consider a very conservative 5 degrees. I was making some final pulls to flatten out the fuel curve before I moved to timing and on my obvious last pull at about 6k it started protesting the pull so I let off and when it came down to Idle it was stumbling, Obvious it has a single broken Apex seal on one of the rotors , Only hitting on 4 of the 6 combustion chambers. Motor has 2MM seals in it. was customer asking us to push this engine to hard on 93 octane pump fuel or could I have tuned it to lean...... What kind of timing are guys makeing this power running and what are our AFR,s
Are we pushing this motor to far on pump Fuel. The next step was to go to 25 PSI on C16 but never got that far.
TUNER X
Guy brings me a 93 Rotory with HKS 51R turbo big HKS cooler street ported fresh motor with 1,000 K on it. Tuning went pretty easy, Started fat as usuall and leaned it till it liked it and made good power. ended up with AFR around 11.5 12.5 trhough out the curve. Made 374 HP and 299 TQ on Mustang 1750 Eddie current load Dyno pulls were clean and hard, felt and sounded good. Timing at 19 PSI was what I consider a very conservative 5 degrees. I was making some final pulls to flatten out the fuel curve before I moved to timing and on my obvious last pull at about 6k it started protesting the pull so I let off and when it came down to Idle it was stumbling, Obvious it has a single broken Apex seal on one of the rotors , Only hitting on 4 of the 6 combustion chambers. Motor has 2MM seals in it. was customer asking us to push this engine to hard on 93 octane pump fuel or could I have tuned it to lean...... What kind of timing are guys makeing this power running and what are our AFR,s
Are we pushing this motor to far on pump Fuel. The next step was to go to 25 PSI on C16 but never got that far.
TUNER X
06-09-2006, 08:43 PM
#2
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Join Date: Jun 2002
Location: La Plata, Maryland
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19psi and 93 Octane... There is your problem.
If your running so much as 15psi and dyno tuning I would suggest the race fuel. I have to assume that you maxed the stock injectors out to boot. I would not run past 15psi on stock injectors. Or at least that is riding the fringe so to speak.
If your running so much as 15psi and dyno tuning I would suggest the race fuel. I have to assume that you maxed the stock injectors out to boot. I would not run past 15psi on stock injectors. Or at least that is riding the fringe so to speak.
06-10-2006, 12:58 AM
#3
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Originally Posted by Fd3BOOST' post='823377' date='Jun 9 2006, 09:43 PM
19psi and 93 Octane... There is your problem.
If your running so much as 15psi and dyno tuning I would suggest the race fuel. I have to assume that you maxed the stock injectors out to boot. I would not run past 15psi on stock injectors. Or at least that is riding the fringe so to speak.
The car never was lean. I just we feel we pushed the mechanical limits with pump fuel. The car has Haltech on it with 820 primarys and 4 Yes i mean 4 1600 secondaries. Injector MS is less than 5ms at 8k RPM and 19 PSI and I have enuf fuel to send the AFR below 10.0 I am not sure what the limits of the motors are with the big turbos these days but it just seems to me like 19 PSI on a rotary was pushing the limits but He told me the engine builder ( not sure who that is ) said it would all be good.
06-10-2006, 10:52 AM
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I never said anything about the A/F being lean. I said that pump gas and 19psi doesnt work and the engine you blew up is proof. Over 15psi you need water/meth injection or race gas. That was really the bigest point I was making. I'm no tuner but I have been around the block enough to know that you don't run that much boost without race fuel. Your engine builder either doesnt know what he is talking about or lied to you in regards to the engine being close to it's limits at 19psi. PFSuprecars (search if you don't know them) www.pfs.cc , I have seen Ray of PFS run 30psi on the stock seals more than once and the engine holds. It's all in the tunning and the fuel. You also say you pushed the mechanical limits of the pump but your running enough injectors to launch a space shuttle. Who engineered that set up? Either way the fuel delivery system doesnt sound like the problem to me. Like I said you run 19psi on pump gas and it will break. Esepecially be carefull with all these mixed 10% ethanol fuels you find at the pump lately.
Anyway you asked what we thought and now you know what I think.
Anyway you asked what we thought and now you know what I think.
06-10-2006, 12:06 PM
#6
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FD3BOOST
The prhase in the post stated pump fuel meaning gas not the fuel pump, As you see the car has enuf Injector and a -12 fuel supply with huge pump and filter. Like you said enuf fuel to launch the space shuttle. L O L . It has been a few years since I have tuned any rotory's and technology and componets change and get better. In the past we would never gone over 14 PSI on pump fuel on a Rotory but we run 19-21 PSI on several different piston engines with 93 pump fuel very safely. Like you say it is all in the tuning. When owner said 19. I questioned it and he said it should be good to go. I think there were several people involved in deciding the setup on the car but I dont know who they are. It was just brought to me to tune since that is what I do best. It is the first motor I have ever had come apart on the Dyno that was not becasue of a Direct mechanical failure not related to tuning or trying to Sqeeze to much from the engine and even though I no it is not my fault you just feel bad when you give the guy a Bill and hand him back a broke car.
The prhase in the post stated pump fuel meaning gas not the fuel pump, As you see the car has enuf Injector and a -12 fuel supply with huge pump and filter. Like you said enuf fuel to launch the space shuttle. L O L . It has been a few years since I have tuned any rotory's and technology and componets change and get better. In the past we would never gone over 14 PSI on pump fuel on a Rotory but we run 19-21 PSI on several different piston engines with 93 pump fuel very safely. Like you say it is all in the tuning. When owner said 19. I questioned it and he said it should be good to go. I think there were several people involved in deciding the setup on the car but I dont know who they are. It was just brought to me to tune since that is what I do best. It is the first motor I have ever had come apart on the Dyno that was not becasue of a Direct mechanical failure not related to tuning or trying to Sqeeze to much from the engine and even though I no it is not my fault you just feel bad when you give the guy a Bill and hand him back a broke car.
06-12-2006, 03:13 PM
#7
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Originally Posted by tunerx' post='823455' date='Jun 10 2006, 09:06 AM
FD3BOOST
The prhase in the post stated pump fuel meaning gas not the fuel pump, As you see the car has enuf Injector and a -12 fuel supply with huge pump and filter. Like you said enuf fuel to launch the space shuttle. L O L . It has been a few years since I have tuned any rotory's and technology and componets change and get better. In the past we would never gone over 14 PSI on pump fuel on a Rotory but we run 19-21 PSI on several different piston engines with 93 pump fuel very safely. Like you say it is all in the tuning. When owner said 19. I questioned it and he said it should be good to go. I think there were several people involved in deciding the setup on the car but I dont know who they are. It was just brought to me to tune since that is what I do best. It is the first motor I have ever had come apart on the Dyno that was not becasue of a Direct mechanical failure not related to tuning or trying to Sqeeze to much from the engine and even though I no it is not my fault you just feel bad when you give the guy a Bill and hand him back a broke car.
The prhase in the post stated pump fuel meaning gas not the fuel pump, As you see the car has enuf Injector and a -12 fuel supply with huge pump and filter. Like you said enuf fuel to launch the space shuttle. L O L . It has been a few years since I have tuned any rotory's and technology and componets change and get better. In the past we would never gone over 14 PSI on pump fuel on a Rotory but we run 19-21 PSI on several different piston engines with 93 pump fuel very safely. Like you say it is all in the tuning. When owner said 19. I questioned it and he said it should be good to go. I think there were several people involved in deciding the setup on the car but I dont know who they are. It was just brought to me to tune since that is what I do best. It is the first motor I have ever had come apart on the Dyno that was not becasue of a Direct mechanical failure not related to tuning or trying to Sqeeze to much from the engine and even though I no it is not my fault you just feel bad when you give the guy a Bill and hand him back a broke car.
Stock Apex seals will handle more power than that, so its not the 2mm seals... I have been running 20 psi for the last 1.5 years or so on 91 octane, with a few boost pulls tapering off to 23 psi without any real issues on a T51 FC...
But When you get to those boost levels, you have to pay attention to everything in regard to ignition quality, heat range of plugs, and quality ignition wires and layout is a must, at 20 psi, the resistance to the spark is huge, so wires tend to crossfire...I think you may have run into what I did with the 1600's as well, it makes the fuel pressure pulse like mad and makes the mixtures different from rotor to rotor, and ends up damaging the injectors..Put a big chunk of fuel safe soft rubber line in the fuel supply, works wonders for tuning and fuel puslations.. Also its not uncommon for the 1600's to differ by a large amount as well, one rotor can be at 11:1 the other at 11:7...
Once you cross the 17 psi threshold you need to be richer than what you were though especially with 9:1 rotors...
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