Went on the dyno (dynapack) to get my car tuned, ends up at 156hp with 186tq at 7psi. Got a T28 setup. Car is running like it has restriction.
I got a 3" downpipe, 3" resonator with a 2.5" 5zigen catback system.
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. Will be going back to the dyno for the 3rd time once I get this issue fixed.
My tuner (Almasi tuning) retarded the timing to prevent any issue until I fix my problem. My S14 ECU was removed and replaced with a S13 ECU(rewired) which a eprom is added once to tuning is completed.
The HP and TQ drop completely dead at ~4500. I verified my cams timing and everything is perfectly aligned. Only thing I didn’t check is the bottom chain but compression is perfect so. I did try to play with the boost controller and the boost is not going over 9.X. I did this to see if turbo could take it. even if boost is set to 15 psi, won’t go over 9.X.
If someone can help, it would be appreciated. I posted on multiple forum and no one seem to have a clue including my tuner other than cam timing or something related,
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) / Now 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 * removed and now running 232/232
Unorthodox Pulley
Fidanza flywheel
South Bend clutch stage 2
Optima redtop battery
have u checked for clutch slippage?
No sign of clutch slipping. If there were any, my tuner would have see it with the dyno. BTW, I am still running my 4 spoke ceramic clutch with oem pressure plate. My stage 2 is not yet installed.
Post says nothing about an a/f ratio. How rich is it running ?
Are you sure the Boost Controller is hooked up right ? If the turbo wont hold more than 9psi than the waste gate is opening for some reason. either it can barely hold 9psi or somethings up.
ECU may have something to do with it. As for stopping @ 4500rpm, isnt that when a MAFS cuts out when faulty or whatever ?
well my tuner would have noticed a bad maf in is maps. Boost controller is hooked up correctly, even tried without it and results were not has it should. I will try to grap another T28 to test if it’s the turbo. ECU was removed from a functional S13
id say its the turbo… you got no powa captin…
it must not be holding the pressure…
I assume you dynoed with the cat in?
Could it be possibly clogged?
Secondly, what is the a/f?
What is your fuel pressure as well.
Any boost leaks?
1st dyno session was with the cat, cat was replaced with a 3" test pipe and did change a thing. The high cat I had was ok. Fuel pressure was ok, a/f was steady, don’t remember the number but my tuner said it was find. No boost leak.
I had a problem similar to the one you had,
expect that mine was a leaky BOV, was only leaking under boost.
Pressure test the system to 15 psi and see if it hold the boost.
One thing is for sure, for pushing power this low, either the air is not getting in the cylinder or the timing a mad retarded.
The timing was retarded for safety reason until I find my bug. During the dyno session, every time he tried to advance the timing, the car was not responding well to it, it was not pushing bigger numbers. None of my gauges indicate a boost leak. It shows steady boost.
the gauges would not a show boost leak. The wastegate regulates the boost from the exhaust gas coming out of the engine, when you have a boost leak, Your turbo will have to work even harder to produce the same boost level.
Do a pressure test, it’s the only way to check for boost leak, also pressure test for a couple of PSI higher then what you will run. (much rather have IC piping poping off while testing then on the road)
you can also check the chain on the crank to be on the safe side, just pull the valve cover and the front engine cover.
BTW: What 's your compression accross all 4?
I meant to say compression number after the tune.
You did a compression test… the next thing I would do is a boost leak test, bust out the soapy water.
Goodluck.
Perfect compression, 180 on all 4 cylinders.
really weird problem… sounds like a pretty major boost leak to me, but that should throw the A/F ratios waaaaayyy off.
i’d do a boost leak test anyway. like the old saying goes “better safe than sorry”
good luck.
I had a similiar problem with my old Talon.
Turned out the motor was fucked. The valves were bent, during compression test they would hold pressure for that split second it needed to. I had 155 across (almost perfect for a 4g63) Pulled the head. Bent.
How does the car idle? and run up to 4500?
What fuel pressure? What are you using for fuel pressure control?