When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
hello everyone, last week my brother and I dynoed his camarobut we notice the hp graph after 5000 stayed flat... and couldnt make it go up.
mods: stock ls1 bottom end, 243 heads, t6 gt45 turbo, 60lbs injectors, 45mm turbosmart wastegate, 273xer cam, bbk intake, 4l80e , circle d converter, walbro 255 (edited post), even on the street it feels like it gets stuck.... with the supercharger it didnt have that problem, there are no knocks, no boost leaks and afr was a little lean at wot 12.1 but nothing else, boost @8.5 psi
and with a lot less timing and boost it would keep doing the same... boost @5.7 psi
Last edited by andresz28; Apr 24, 2016 at 12:18 PM.
#1 put both the torque and power graphs together into 1 graph
#2 do not scale them differently, it makes looking at it difficult
#3 include the A/F graph below the hp/tq graphs so we can see it
#4 always use smooth: 0 for diagnosis of dyno output graphs
#5 the torque is falling off after a peak, as if you had a stock cam/head on a stock engine. Either raise boost, or help the engine breath to bring it back up, as it passes that point.
#6 i see you have run files in the 50's. did you make 50 passes on a dyno in the same day?
if there was a #7 it would be:
#7: Generally, Do not make more than 10 or 12 passes on a dyno in a single day/event. If you needed more tuning you should have done it before you got there.
#1 put both the torque and power graphs together into 1 graph
#2 do not scale them differently, it makes looking at it difficult
#3 include the A/F graph below the hp/tq graphs so we can see it
#4 always use smooth: 0 for diagnosis of dyno output graphs
#5 the torque is falling off after a peak, as if you had a stock cam/head on a stock engine. Either raise boost, or help the engine breath to bring it back up, as it passes that point.
#6 i see you have run files in the 50's. did you make 50 passes on a dyno in the same day?
if there was a #7 it would be:
#7: Generally, Do not make more than 10 or 12 passes on a dyno in a single day/event. If you needed more tuning you should have done it before you got there.
we had some troubles with the dyno not logging the a/f but with the recordings from our wideband, the afr was steady 11.8 until 5200 wich started to lean out to 12.1
heads are 243s and cam is a comp cam 273xer , with the vortech supercharger it made 516 whp without that flat graph and with the same fuel pump
there are 50+ passes, because they stored them all since it was NA in the 2012, we only were there for an hour
so its got some cam. Not sure what the head flows (I am not an LS guru) but when you have the head/cam for a flat torque curve to redline, and you arn't getting one, and you ALSO happen to have a turbocharger, you must now investigate the dynamics of the exhaust system/turbine. Perhaps your exhaust route is restrictive.
Aside from exhaust gas pressure problems, you could be losing boost pressure. More boost as the RPM rises will "fix" the issue if the compressor has anything left in it, but it will compound an exhaust restriction problem (you might get too hot, make sure to have an EGT gauge). You really want to watch the EGT for setups with convoluted/ugly exhaust routing, homemade situations.
My engine ran out of fuel pump (single 255) at about 5psi. I know your AFR weren't reading excessively lean but you may wanna get more pump before doing anything else.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.
weird dyno graph 
