Dyno Run After Tune..little Bit Disapointed

[SS#eater]

ok just had the 1st dyno run since i have owned the car

mods are

internaly stock rb25

greddy copy plenum

555nismo injectors

z32

water meth 375ml/m nozzle

fmic

gt3076 turbo

splitfire coils

boost bleed valve (turbosmart) not happy with

split dump...

gutted cat...

ok the car turned 281 rwkw at 20psi The mafia put 2 degrees more timing in and no gains so i got a restriction.....maybe

exhaust is 3inch right through bar the cat its gutted but is 2.5 inch in out...so i hope thats soe of the problem

next is cooler pipeing from turbo to cooler is 2.5 inch from coolr to manifold is 3 inch so im gunna go 3 inch from the turbo to the cooler then to the manifold...

next thing came to mind was air flow meter....maxing out...?? shouldnt be...

what you think here are the graphs.....

afrs need a tidy up few spots to fix.

ebc needed......

i was hopeing for more but its crazy to drive ...

what you guys think.....

[STATUS]

Curve is pretty wavy i reckon the timing curve needs "smoothing" or bit better interpolation. AFM is fine as it wont effect power (only tuning resolution, mapping points will flatline at 5v) Cooler Piping wont make a diff i run 2.5" on cars well over 300. Could just be rear housing looking at graph it tops out way early... what size is it?

Edited March 9, 2009 by URAS

[SS#eater]

.82 rear

[SS#eater]

the mafia runs same setup he has .6 something rear and is making 314kw..i got the larger housing....so i should blitz it...

tired motor maybe...

[R31Nismoid]

Curve is pretty wavy i reckon the timing curve needs "smoothing" or bit better interpolation.

same thing i was gonna say exactly

curve needs work

[wolverine]

as you state the cat looks a no-brainer for replacement.

3" pipe to 2.5" to 3" is not going to give you the best result.

[SS#eater]

will do the cat and do the cooler pipeing get some tuning time on the dyno... to dam hard on the road plus its unsafe......see what it pulls..

[paulr33]

id say its a fundamental issue you have

the restriciton sounds pretty bad given you are stuffing 20psi into it on a 3076 compressor wheel

i would be looking at the copy plenum you have, they are known baddies

the exhaust restrisction probably isnt a big big issue, sure every bit helps, but not that much difference i wouldnt think ?

cooler piping is a waste of time

theres no way it would restrict it

if its the same size as the compressor outlet then its fine

only if it was smaller in diameter, would it be an issue

[R31Nismoid]

the mafia runs same setup he has .6 something rear and is making 314kw..i got the larger housing....so i should blitz it...

tired motor maybe...

he is using methanol injection or whatever too

key factor

[TiTAN]

They are both using Water meth injection ash.

[R31Nismoid]

oh shit - missed that part

[SS#eater]

ahh crap i had wondered about the copy plenum.......it looked great inside and ports matched up pretty well to the gasket had to tidy a little bit up with die grinder.....dammit

another r33 made 290kw same setup no water meth standard manifold (inlet)

mafia 314kw stock manifold....water meth

i made 281 water meth greddy copy....

dosent look good at all.....

fark fark fark......

[SS#eater]

has anybody heard or made 300kw with a copy greddy????

[wolverine]

if the cat has 2.5" inlet and outlets then you are losing around 30% of your cross sectional area.

i would change the cat before i did anything else. it is the cheapest and easiest thing to change and it is clearly a restriction relative to the rest of the exhaust.

[allthewaytotheskyline]

if the cat has 2.5" inlet and outlets then you are losing around 30% of your cross sectional area.

i would change the cat before i did anything else. it is the cheapest and easiest thing to change and it is clearly a restriction relative to the rest of the exhaust.

so even though its gutted it is still a restriction?

what if it were something close to 3" say 2,75"???

[wolverine]

2.75" there is a difference of about 16% in cross sectional area compared to 3"

is it a significant restriction?? i guess it depends on power levels.

getting the same diameter of pipe all the way through removes a known/likely source of turbulence and restriction for not too much money. it just makes sense to me to do the cheapest and easiest things first.

[cactus]

Surely intake plenum wouldnt make that much difference even if it were slightly out. I run one, have made 387rwhp @ 18psi through a built auto with mine before and I had to do a lot of cleaning to the ports to get it to match right... I didnt think it would impact that much??

[Strik3r]

definitely look at the exhaust before you look at anything else.. if your cat is a 2.5" entry that could be holding you back big time.. I doubt that plennum is a restriction at that power level. Its a 2 minute test. Drop the exhaust after the dump pipe and put it on the dyno. if you have good power, you know you've got a restriction.

Other questions that come to mind - what fuel system are you running (pump, pressure reg). fluctuating fuel pressure could make it difficult to control the AFR's which would explain why they are a bit jumpy.. However at no point is it running overly rich, so i dont think your losing power because of the AFR's...

[SS#eater]

fuel system is bosch 044, standard fuel reg....

doing cat tonight.....wont be able to dyno again till next week.....

thansk for everyone help too!

i doubt its the plenum

should i be replacing the bov?

maybe leaking under high boost....all little contributing faults....

[SLAPS]

cooler piping is a waste of time

theres no way it would restrict it

if its the same size as the compressor outlet then its fine

only if it was smaller in diameter, would it be an issue

2" cooler piping made 300rwkw on PULP @ 17psi with cams, std exhaust manifold, std inlet.

Pressure drop was fairly high and with more boost top end boost simply tails off.

The dyno curve was also rather spikey and wavey, something the 100mm fmic with 2.5" piping fixes.