i have a t3 .42/.48, stock d16y8, i'm debating on how much psi to run, i have a 7lb spring, but i might buy a boost controller and boost up to 10psi .. i'm lookin for like 200 whp. but i was just looking in a thread on here w/ sohc times and i'm scratchin my head right now. why are these psi to hp ratios so out of whack?

why is this one so high on just 6.5 psi and the bottom two are so much different?
Racing:
14.2 @ 100
Setup:
90 hatch
d16a6
drag mani
t3 .42/.48
dsm 450's
turboedit
6.5 lbs
spearco intercooler
homemade piping
Dyno:
185 hp/155tw on a dynojet



Racing:
N/A
Setup:
D16y7 stock
T3 .42/.48
9.5psi
Uberdata
450cc
Dyno:
171.7whp 176.0wtq

Racing:
N/A
Setup:
D16y8 stock
T3 .42/.48
9psi
AFC hack
RC440s
Dyno:
186.6whp 170.1wtq

what the hell could be the difference??

 

i would say tuning would be the biggest difference...that depending on what kind of weather they dyno'd in..every dyno is different to. there are many things.

 

so tuning plays a part in how much whp you get out of your psi?? to me i just dont understand how 6.5 psi can create more hp than 9.5 psi on the same turbo .. it just doenst make sense

now this sort of screws things up for me b/c i wanted to run about 7 or 10 psi, i'm looking for 200 whp .. but i'm only going to be doing a street tune, so i can't even use these cars as a benchmark .. i just dont get it

 

were the bottom 2 running an intercooler at all? you didn't list anything in the setup for those 2 but that will affect the hp too if they don't have one. the condition of the engine, turbo, etc. too.

 

There's things like slight boost creep, more efficient FMIC, and better head. You also ran the Y8 head on the AFC hack, which sucks for making power, and the Y7 head just sucks regardless. Someone had a HX40 on a Y7 at 23psi, and it only made around 273whp IIRC.

 

well it says on that top one that the guy is running an intercooler at 6.5 psi .. the other too .. i'm assuming they have intercoolers..

i guess the d16y7 can be thrown out. but i would say that 9.5 psi making 186 whp is believable, but i just can't understand how that guy is running 6.5lbs of boost and making 185 on the same exact turbo and engine

 

You dont have all the specs on the setups, the manifold's could have been different. Also unsure of what size DP and exhaust they had and if they even had an exhaust or just ran open DP and also the length and position of the dumptube if they might have converted to external WG. I had a stock Y7 mini me with a stock Y8 haed and made with that exact same turbo 193WHP @ 10psi with a log manifold with a 2.5" DP with a full 2.5" exhaust.

 

doesn't the size of all the piping only allow for a higher spool up time? shouldnt 6.5 psi be equal to 6.5 psi on two exact same turbos reguardless of manifold, downpipe, dumptube? its still only adding 6.5 extra psi into the engine

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pjr710 &raquo;</TD></TR><TR><TD CLASS="quote">doesn't the size of all the piping only allow for a higher spool up time? shouldnt 6.5 psi be equal to 6.5 psi on two exact same turbos reguardless of manifold, downpipe, dumptube? its still only adding 6.5 extra psi into the engine</TD></TR></TABLE>

Its about effecientcy also.If one is out flowing the other, wether its the manifold or heads, no matter the boost level (granted they are the same) one os going to make more power.

And one might be old, or it was hot out, there are just too many variables to pin point, just use the info to get a ball park feel.

 

x2

I was typing and glanced down at the post... you took my exact word...efficiency.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pjr710 &raquo;</TD></TR><TR><TD CLASS="quote">shouldnt 6.5 psi be equal to 6.5 psi on two exact same turbos reguardless of manifold, downpipe, dumptube? its still only adding 6.5 extra psi into the engine</TD></TR></TABLE>

Yes, 6.5psi will always be 6.5psi but the amount of power it produces can be completly different. you could have a T3/T4 57trim with a .63ar on a D16 and

Setup A has:
-log manifold
-no dumptube, wastegate opens directly under hood
-2.5" DP with 2.5" exhaust

Setup B has:
-ramhorn manifold
-dumptube routed under the oil pan
-3" DP with 3" exhaust

Setup B could produce 50+WHP at the same PSI level as setup A, all from what was mentioned above. Efficiency.


**remember** don't always pay attention to psi, also look at WHP. No two setups will be exactly the same.

 

got ya.. that makes a little more sense

 

If your goal is 200hp why do you care how much boost it takes to get there (as long as it's in the efficiency range of the turbo (which it will be)).

What I'm saying is...you say you want to make 200 hp at 8-10 psi but if it takes 14 psi to get there why would you care as long as you have an upgraded map sensor??

And to stay on topic..like the others said there are a lot of factors contributing to the amount of power a set up can make. These things can be compression ratios of the pistons, intake manifolds, cams, pressure loss through the intercooler etc. etc...

The main difference between all the power levels would be the dyno used. Everyone's dynos read a little differently depending on a bunch of different things. The true test would be the track times and even those wouldn't be conclusive since not all tracks are the same.

 

well i'm probably gettin a street tune, so i'm not gunna know how the psi is gunna effect my hp, so i wanted to see if i could get an idea of what psi=hp on my size turbo