Bad dyno day...

[redpotatoes]

Went on the dyno (dynapack) yesterday to get my car tuned, ends up at 156hp with 186tq at 7psi. I am missing about 50 hp and tq. Got a T28 setup(will be listing all the mods when I get the real numbers). Car was running like it had a block exhaust line.

Flow was not at all going out correctly. I got a 3" downpipe, 2.5 inch hi flow cat (Magnaflow) with a 2.5" 5zigen fireball catback system. At first we though the restriction could have been caused by the cat-back tip of the exhaust (canister) because it reduce at the end. We unbolted it to see and gain was barely noticeable but some gain. So I have something that blocks the flow between the head and tip of exhaust.

Turbo has been rebuilt, downpipe, elbow and manifold were brand new and nothing was blocking anywhere.

Anyways, at least the car is now tuned to drive around safely.

I replaced the catalytic converter by my 3" test pipe and went for a drive. Not a lot of changes except that I over boosted (warning was set to 10 and hit 12.4psi).

I was told that an indication that I might have solved my issue is that I would see more boost. My tuner retarded the timing so much to prevent any issue until I fix the problem, that could be a factor of why I don't feel that much improvement.

I looked in my catalytic converter and I see light through it, just a small light. Maybe it's solved and I don't know until I get back for more tuning. I don't want to go spend money for nothing on the dyno and end up having the same issue.

Could my 5zigen fireball catback (60.5mm) reduce the power that much since it's was made for N/A and it's not 3"? I am out of ideas and would really appreciate some help.

Here is my complete setup:

KA24DE 1995 (180 on all cylinder)
370cc injectors (Deatsch Werks rebuilt and tested)
N60 Maf
T28 BB (rebuilt)
Bottom mount manifold Unknown Brand with heat wrap
Turbo elbow Unknown Brand
Custom 3" downpipe
Magnaflow Hi-Flow cat 2.5" (during dyno) / 3" testpipe
5 zigen fireball cat back ~2.5" (60.5mm)
Custom 2.5" Intercooler piping
FMIC 28x6x2.5
OEM Nissan gaskets
NTK 02 sensor new
BKR6E spark plugs re gapped (tuner re gapped them)
OEM Fuel filter
Walbro 255 fuel pump
JGS Vacuum block
Greddy BOV type rs
Greddy Profec-b spec II boost controller
S13 ECU
248x248 91 exhaust cams
Unorthodox Pulley
Fidanza flywheel
South Bend clutch stage 2
Optima redtop battery

[97KATURBOSILVIA]

sounds like the cat converter was your problem. Ive seen clogged converters not only rob power but will actually limit rpm. How reliable is your tuner not doubting him but was dyno calibrated correctly etc. GL

[redpotatoes]

My tuner is reliable, is work speaks for itself. He is specialized in Nissan. Well I am hoping the catalytic converter is the problem other than that, I really have no clue. I guess I can only be sure once I get back on the dyno but I don't want to end up having the same issue a second time and waste my money...

[whereda40at]

we could not figure out what was wrong with my moms 2000 rodeo and after taking it to isuzu under warrenty they said that it was a clogged cat. the rpms would go up on there own and they fall down real fast and almost stall. sometimes it would stall. put a test pipe on and see how that does.
check for boost leaks anywhere too. very common problem to alot of things.

[Sileighty_85]

Yeah that is pretty low but on 370cc you cant boost too much, on my SR i was leaning out on 370cc after 11 psi

[redpotatoes]

370cc should make me break 200hp at least. Like I said, I did put my test pipe on, not feeling any change but I guess I have to go back for tuning to really know if it was the case. Hi flow cat looks in decent shape inside, I can see threw it, not clearly but a little light...Now I am very confused and discouraged...

One thing that can make me think cat was clog to some point is that I did ran my 370cc for a short time (less than 3km and engine running at idle in the garage). I was running way too rich and might have affected the cat. Thats why I put them out and only placed them in when I was at my tuner's place.

[98s14inaz]

Does my reading comprehension suck or is there a complete lack of ecu tuning? All I saw listed was an "s13 ecu" and "retarded timing". Are you using an safc? Standalone? Ecu tune by JWT, Enthalpy, bikirom, etc? If you lack any or all of these things that explains the power loss. You should have at least broke 200whp on a healthy ka-t like that with out breaking a sweat.

[redpotatoes]

My S14 ECU was removed and replaced with a S13 ECU(rewired) which a eprom is added once the tuning is completed. Not sure what exactly he is using but for sure is putting a PC board on my ECU and it's connected to is PC/Dyno. After that he is burning the setting to the eprom. He is also using a wideband. He is no beginner and knows what he does.

[clark]

yo, get rid of the OEM fuel filter. get a Z32 fuel filter. this probably won't fix your problem, but it's a start.

what are your impressions when driving it? does it suck you back into the seat decently?

[redpotatoes]

It does hold me back on my seat more than N/A thats for sure but still don't get the potential that it's suppose to be. Feels like I do have a potato stuck somewhere that holds it down. Next step, I will remove my 5zigen catback and have a look at it. There might be something inside that is wrong...

[98s14inaz]

It sounds like your timing is too retarded. Almost like you are knocking and it is pulling timing. IMHO.

[mifesto]

your catback is fine for the power you are pushing/aiming for. 3 incher will give you more elbow room for future improvements but its definetly not a huge limiting factor for you at this stage.

with the test pipe in now, go back to the tuner and ask for a retune w/ timing adjustment.

[redpotatoes]

Just did a test with the hi flow cat with a hair dryer. Flow at the entry is definitely not the same has the exit of the cat even if I can see light through it.

[redpotatoes]

I did another test drive and I put the boost to 15psi (just for one test run), I was not able to get more than 11. Took another appointment with my tuner / dyno to see if my cat was the problem. I hope it was the issue. Possible that my cams are doing that? I am freaking lost and don't understand a thing...

[redpotatoes]

Hi-flow cat was removed and test pipe was put in, I also change my cams to OEM 232/232 and went back on the dyno, still the same issue I do not make more than ~150whp and at ~4500rpm hp and tq falls flat dead. Seems like it doesn't like timing, thats what my tuner said. Only thing we could think of is that the timing on the cams are off...

[Ca_Silvia]

posting the dyno sheets could help alot man ecspecially the AFR sheet