i got my car dyno tuned and it didnt put out the numbers i was expecting...

internally, bone stock d15b
greddy 15g turbo kit
kenji chipped p06 ecu with vtec
2" downpipe
rc 550'z
2.5 inch exhaust all the way back
crome tuned

it put down 147 whp/ 158.2 lb ft torque on a dynojet

so basically a 40-45 whp gain, (which is REALLY shitty IMO) and a 65-70 lb ft torque gain on 7.2 psi... i wouldve thought i'd gain more hp than torque... basically more power than what i got... and considering its a honda motor, i was expecting some sort of top end power... feels like more mid range than top end

the thing is, peaks at 7.2 PSI at around 4800 RPMS... and everything past that, the psi will drop.... when i floor it, and it passes the 4800 rpm mark, u can just feel the power loss... its like the opposite of vtec engaging... what could the problem be on why psi is dropping at high rpms... boost leak ?? wouldnt think so, checked all the charge pipes... dont see or feel any air leaking... any help would be much appreciated

 

that is a decent gain on that engine....you could get a bigger downpipe and get a boost controller so that you can make more than 7psi. I'm sure you come into problems because the head isn't that efficient so you're losing power there too......

 

Go with a 2 1/2" downpipe and increase boost if you want more power. With that torque it must be really good to run on the street. Can you retard cam timing with a cam gear change? You would typically give up a little torque but gain some top end.

 

yeha like already said that dp is killing you big time, btw is your boost falling on the boost gauge?

 

small downpipe + small turbo = small HP gain

 

no boost gauge, no boost controller... i'm using the internal wastegate, usually what i do is adjust the screw to control how much boost it will hit...

back on topic, the tuner was telling me my cams are prolly max'd out which is why theres no sort of top end power... also, that its a 1.5 liter

also one more question about the boost controller... does it work this way... if i were to hit 7 psi at aroudn 4800... any higher rpm it would stay constant at 7 psi ??? i'm a NOOB

thanks for all the info guyz

 

ok get a boost gauge asap to see what your boost is at right through the power band, your cams have nothing to do with it, either does the 1.5L...your boost level should stay consistant all the way to red line unless you are running a really small turbo which yours is fine or you have a boost leak somewhere