disappointing 2871r results
disappointing 2871r results
setup:
stock crank and rods
balanced rotating assy
supertech pistons
gt2871rs @ 21 psi
fmic
750 injectors
bc 264 cams
nistune
93 octane crap ethanol gas
q45 diff
i was a little disappointed. i expected more, quite a bit more. i adjusted my fuel map inbetween runs. i got it at about 12 now. i increased my timing afterwards since it was pretty conservative. imma try and go back and do a little tuning next month. we'll see what happens.
stock crank and rods
balanced rotating assy
supertech pistons
gt2871rs @ 21 psi
fmic
750 injectors
bc 264 cams
nistune
93 octane crap ethanol gas
q45 diff
i was a little disappointed. i expected more, quite a bit more. i adjusted my fuel map inbetween runs. i got it at about 12 now. i increased my timing afterwards since it was pretty conservative. imma try and go back and do a little tuning next month. we'll see what happens.
Last edited by broken40s on Sat Jul 23, 2011 11:20 pm, edited 1 time in total.
95 240, nothing special
the image is too small to read any of the numbers....
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Thinking about E-Mance? Think twice and read this:
viewtopic.php?t=45057&postdays=0&postorder=asc&start=0
WARNING: Emance is now using an alias as ECUTUNERGUY and REFLASHPROS. Spread the word.
- superDorifto
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my guess is the cams are not degreed correctly and that is causing your terrible power drop off
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if you have some, pm me
im using stock cam gears, so im sure it could benefit from some adjustable ones, but they're right on. runs too smooth for it to be off a tooth. wastegate line comes from the plenum, so if there is a boost leak, it shouldnt affect it too much, i wouldnt think, and like i said it never went below 19psi. intercooler pipes are one piece to try and alleviate multiple couplings and i checked them for leaks with water overnight when i welded them up. intake vacuum is 20 in/hg at idle. imma go back after i get paid again and do a little bit of tuning. i got andy from autovaughperformance giving me some advice on it. after the dyno, when i advanced timing it "felt" quite a bit faster, since it was a pretty conservative timing map. i'm monitoring knock with an safc2, prolly not the best tool, but its what i got. i'll post updates as i get them.
95 240, nothing special
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I would expect 330-350whp on that setup at 19 psi.
The jagged dyno plots look like possible spark blowout and or timing way too retarded. Try closing the plug gap down .005 and see if that makes it run smoother up top. If not, your timing needs adjustment. Do you know the peak timing you are getting..
Just FYI I picked up 50whp with 4 deg more timing.
So as they say "it's all in the tune"
The jagged dyno plots look like possible spark blowout and or timing way too retarded. Try closing the plug gap down .005 and see if that makes it run smoother up top. If not, your timing needs adjustment. Do you know the peak timing you are getting..
Just FYI I picked up 50whp with 4 deg more timing.
So as they say "it's all in the tune"
Last edited by NateDogg on Mon Jul 25, 2011 11:29 am, edited 1 time in total.
'91 S13
Built, balanced KA-T
Built, balanced KA-T
- redpotatoes
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The numbers seem low for that kind of boost, I am at 14.5 psi with 232/232 cams and making 305/320.
KA24DET GT2871R .86 Setup:
viewtopic.php?t=44222
viewtopic.php?t=44222
its possible you could have boost leak but not able to pick up on it due to having your waste gate ran to you plenum. you could be seeing 20psi on the gauge but your turbo is struggling to keep up, you should run a line from your charge pipe to your turbo. inefficient boost feels way different from efficient boost turbo could be work at 35psi trying to make 20psi
wtf is juice nigga i want that purple stuff
98 240sx t28
264lb/220hp
274/270lb 20g 12psi
i'm pretty sure theres no boost leak. i've checked the couplings for tears and the pipes for leaks before i installed them. plugs are gapped to .025. dyno looks horrible like its breaking up, but it actually runs smooth all the way up. the tune im running was originally for a t3/t4 setup at 15 psi that i've been manipulating, so like i keep saying i'm pretty sure its pretty conservative for my lil turbo. i'm anxious to go back to the dyno after making some adjustments. imma steal my fiancee's ipod and put the dynolicious app on it for now. i was expecting about 360 whp, but it did at least give me a baseline to see whats up and where to go from here. at least i can make adjustments myself and dont have to send off my ecu.
95 240, nothing special
Yep. Bonomoskat dyno'd his car with BC cams and stock gears and was very disappointed with the results. He then degreed the cams and picked up a whole lot of power... 50 whp and almost 70 wtq in some places. See here: viewtopic.php?t=43575all shal perrish wrote:my guess is the cams are not degreed correctly and that is causing your terrible power drop off
There was also seanc, who dyno'd his car before/after installing BC V2's and had the same exact curve... he actually lost about 4 hp and gained 4 wtq: viewtopic.php?p=180360&highlight=#180360
BC cams are well known for being way off from the cam card, even when installed in stock positions. And we're not talking about a degree or two here. We're talking about 10 degrees off. This has been confirmed several times by members of this forum.broken40s wrote:im using stock cam gears, so im sure it could benefit from some adjustable ones, but they're right on. runs too smooth for it to be off a tooth.
BC cams with stock cam gears perform no better than stock S13 cams. I've been on this forum for a while now and I've seen it time and time again.
Wiseco/Eagle, JWT S1 cams, BC valve springs, PT5857, ID1700 injectors, SR20DET ECU w/ Nismotronic, COP conversion with LS ignition coils, etc, etc...
--> YouTube channel --> my build thread
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Do you know what size gt2871 you have? Turbine AR and Compressor Trim? Smallest gt2871 vs gt2876 flows 10 less lb/min, pretty significant.
If you have the 64 AR exhaust you might want to try s13 cams in stock position or degreeing the BC's. The less overlap the better for small turbines.
If you have the 64 AR exhaust you might want to try s13 cams in stock position or degreeing the BC's. The less overlap the better for small turbines.
Current Experiment: Project Twin-Charge 2022
turbine ar is .64, and compressor trim is 52.p00t wrote:Do you know what size gt2871 you have? Turbine AR and Compressor Trim? Smallest gt2871 vs gt2876 flows 10 less lb/min, pretty significant.
i think the next mod is to get some gears and degree the BCs.p00t wrote:If you have the 64 AR exhaust you might want to try s13 cams in stock position or degreeing the BC's. The less overlap the better for small turbines.
also, i could be completely wrong, but what do you guys think about my q45 diff causing the lower numbers?
i went back to the dyno today to try and tune it a little better, and this is the best i could get with out any knock. almost 40 hp improvement.
95 240, nothing special
Much better. I would still look into degreeing those cams if I were you. It would really help to keep the power from dropping off.
Wiseco/Eagle, JWT S1 cams, BC valve springs, PT5857, ID1700 injectors, SR20DET ECU w/ Nismotronic, COP conversion with LS ignition coils, etc, etc...
--> YouTube channel --> my build thread
--> YouTube channel --> my build thread
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