Full-Race R14 -> 2010 Modified Tuner Shootout
Apr 27, 2010, 07:34 PM
#35
Here is the dynochart from my latest round of testing with my RB26 (this was done in 4wd, on UMS's awd dynapacks, previous testing was done in 2wd mode)
this compares the S300P 0.80 a/r to the S300SX w/ 88mm compressor 1.00 a/r
orange: 0.80 a/r S300P, custom machined housing - 17.5psi tapering to 16psi
green: 0.80 a/r S300P, custom machined housing - 20.5psi tapering to 17.5psi
VS
pink:S300SX 88-75 1.00 a/r 19psi
blue: S300SX 88-75 1.00 a/r 19psi (same as above) with slight cam gear adjustment (advanced to +3 intake from +2, and added a little fuel during spoolup)
you can see the considerable gains in area-under-the-curve that i was able to acheive with this new turbo, and very small loss up top - well worth the tradeoff.
now that im all done, considering the amount of work I went through for this and time and expense required to make this S300P work, i think the 83-75 would have provided virtually the same powerband, and fit better as well as be easier to install.
^^this is a customer's twinscroll 83-75 1.00 a/r on our twinscroll subaru kit. I would kill to get that powerband with my RB26..
this compares the S300P 0.80 a/r to the S300SX w/ 88mm compressor 1.00 a/r
orange: 0.80 a/r S300P, custom machined housing - 17.5psi tapering to 16psi
green: 0.80 a/r S300P, custom machined housing - 20.5psi tapering to 17.5psi
VS
pink:S300SX 88-75 1.00 a/r 19psi
blue: S300SX 88-75 1.00 a/r 19psi (same as above) with slight cam gear adjustment (advanced to +3 intake from +2, and added a little fuel during spoolup)
you can see the considerable gains in area-under-the-curve that i was able to acheive with this new turbo, and very small loss up top - well worth the tradeoff.
now that im all done, considering the amount of work I went through for this and time and expense required to make this S300P work, i think the 83-75 would have provided virtually the same powerband, and fit better as well as be easier to install.
^^this is a customer's twinscroll 83-75 1.00 a/r on our twinscroll subaru kit. I would kill to get that powerband with my RB26..
Apr 30, 2010, 08:48 AM
#36
here are some pics of the ATESSA test-jig i built. It is going to a very bright electrical engineer friend of mine who has experience with his own tq split ECU for time attack subarus. The GST subaru runs his system with great results.
cant wait to see what he comes up with - using onboard G sensor built onto his circuit board
cant wait to see what he comes up with - using onboard G sensor built onto his circuit board
May 13, 2010, 08:35 AM
#41
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Hey Geoff, looking good there 
great fab work as usual..
how much does this weigh? how the balance?
also, did they let you run with that battery? or did you have to make a box for it?
great fab work as usual..how much does this weigh? how the balance?
also, did they let you run with that battery? or did you have to make a box for it?
May 13, 2010, 09:10 AM
#42
Torque split adjustable electronically in real-time, or mechanically by swapping out the center diff e.g. with one with different clutch plate ramp angles? How is this done? Again, how is this done? Mechanically e.g. by disconnecting front driveshaft, or can this be done in real-time?
- How did you decide between e.g. 8" main spring vs. 6" main spring + 2" helper spring?
- Are you using a helper spring or a tender spring, and if you will be using a tender spring, what rates will you be using?
- And what rate main springs?
- How did you decide between e.g. 8" main spring vs. 6" main spring + 2" helper spring?
- Are you using a helper spring or a tender spring, and if you will be using a tender spring, what rates will you be using?
- And what rate main springs?
the way i control the fixed torque split is with a simple adjustable pressure regulator, and typically run it at 75psi-100psi in the xfer case. The downside is sometimes there is too little tq split, and other times there is too much torque split. So now I am having a custom g sensor based tq split controller being built so i can choose the bias ie less split or more split and the system is still active. to run it on the 2wd dyno, i would just want to make sure there is 0psi in the transfer case. thats how the hks and other jdm drag skylines are able to do rwd burnouts, then turn on awd for the race.
spring lengths are determined by shock travel x 2 -- if you have a 4" travel shock you want 8" long springs. for the tender, the only one to use it the shortes eibach 2.25" long 0175, its the perfect tender. I made the mistake of getting the longer ones first, but sent them back and got these and they were perfect.
front rate is 1000lb, rear is 850. i could have gone slightly stiffer - and with the motons its incredible how not harsh the susp is
cenk / garage GT - the battery was put in a box for the event, but this car is very heavy becuase its still full street car with heat, stereo, interior etc. ful gas tank and full fluids, with driver and laptop computer 3400. 1100lbs on each front tire. i want my race car i am building to be 2800 total, 850lbs on each front tire (gotta move the motor back at least 8 inches to do this)
Last edited by Geoff Raicer; May 13, 2010 at 09:12 AM.
May 13, 2010, 09:26 AM
#43
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socalrally -- tq split on these cars is simply pressure on the 4wd clutch. if there is 0psi on the clutch, the car is 100% rwd. if there is 230psi on the clutch the car is 50%FWD 50%RWD.
the way i control the fixed torque split is with a simple adjustable pressure regulator, and typically run it at 75psi-100psi in the xfer case. The downside is sometimes there is too little tq split, and other times there is too much torque split. So now I am having a custom g sensor based tq split controller being built so i can choose the bias ie less split or more split and the system is still active. to run it on the 2wd dyno, i would just want to make sure there is 0psi in the transfer case. thats how the hks and other jdm drag skylines are able to do rwd burnouts, then turn on awd for the race.
spring lengths are determined by shock travel x 2 -- if you have a 4" travel shock you want 8" long springs. for the tender, the only one to use it the shortes eibach 2.25" long 0175, its the perfect tender. I made the mistake of getting the longer ones first, but sent them back and got these and they were perfect.
front rate is 1000lb, rear is 850. i could have gone slightly stiffer - and with the motons its incredible how not harsh the susp is
cenk / garage GT - the battery was put in a box for the event, but this car is very heavy becuase its still full street car with heat, stereo, interior etc. ful gas tank and full fluids, with driver and laptop computer 3400. 1100lbs on each front tire. i want my race car i am building to be 2800 total, 850lbs on each front tire (gotta move the motor back at least 8 inches to do this)
the way i control the fixed torque split is with a simple adjustable pressure regulator, and typically run it at 75psi-100psi in the xfer case. The downside is sometimes there is too little tq split, and other times there is too much torque split. So now I am having a custom g sensor based tq split controller being built so i can choose the bias ie less split or more split and the system is still active. to run it on the 2wd dyno, i would just want to make sure there is 0psi in the transfer case. thats how the hks and other jdm drag skylines are able to do rwd burnouts, then turn on awd for the race.
spring lengths are determined by shock travel x 2 -- if you have a 4" travel shock you want 8" long springs. for the tender, the only one to use it the shortes eibach 2.25" long 0175, its the perfect tender. I made the mistake of getting the longer ones first, but sent them back and got these and they were perfect.
front rate is 1000lb, rear is 850. i could have gone slightly stiffer - and with the motons its incredible how not harsh the susp is
cenk / garage GT - the battery was put in a box for the event, but this car is very heavy becuase its still full street car with heat, stereo, interior etc. ful gas tank and full fluids, with driver and laptop computer 3400. 1100lbs on each front tire. i want my race car i am building to be 2800 total, 850lbs on each front tire (gotta move the motor back at least 8 inches to do this)
May 13, 2010, 09:45 AM
#44
yes i completely agree, this chassis and the jza80 are tough to balance due to the big heavy iron 6 cyl engine up front.. moving it back and using as much lightweight in the nose as possible is key. the front frame will be redone on 0.049 4130 to save weight
