Ka24det tuning issues

[nrchia]

Hi everyone,

I'm Nick and have been a pretty heavy lurker of this forum for about a decade. I got my car tuned about 4 years ago and was very disappointed with the outcome. my current setup is a t3/t04e 50 trim .63ar stage 3 wheel and I'm running the jgs log manifold and 2.5 inch jgs downpipe. when i got the car tuned my tuner said he was running into detonation issues and could not raise the boost past 12psi. the attached graphs also show a dip in the midrange. The tuner said that it may be an issue with the apexi NOIR exhaust causing too much restriction because of the giant mufflers. he was also concerned about the 2.5 inch downpipe which the wastegate is recirculated into. Im just wondering if any of you have seen anything like this before with the Ka24 and what my next steps should be before I dish out another $4-500 for a tune.

Relevant Mods:
JGS log manifold
turbonetics t3/t04e 50trim .63A/R stage 3
2.5 inch jgs "uppipe?"
isr downpipe
apexi Noir exhaust
tial 38mm wastegate
megasquirt pnp2
stage 3+ spec clutch
stock cams
front mount intercooler
built bottom end
850cc sidefeed injectors
walbro 255
93 octane

http://i.imgur.com/HLtAzRG.jpg

[Silv1401]

Fwiw I'm pushing 1.1bar on almost the same setup, with 550cc injectors, tuned on a pfc, with no issues.

Sent from my SM-N986U1 using Tapatalk

[brndck]

get a bigger downpipe for starters.
what injectors and what fuel are you using?

[inferno s14]

use better gas?
or fuel delivery issues?
detonation means temps are high in your cylinder causing hot spots. might need to work on timing and fuel, but reality is the answers to your problems are shown in your logging sessions.

[Kingtal0n]

1. that ecu is very difficult to setup. Its more likely you have a timing issue than anything. Did you verify the ign timing at high rpms? Under load? I don't trust that ecu or anything from MS anymore. Its probably got an inductive delay issue or similar for example.


2. engine being "built" means nobody has any clue now whats inside it now. Could very well be an issue with quench or cylinder head shape or use of valves causing the issue with poor behavior especially if any work was done to the head, or it was machined wrong, etc..

3. tuning that ECU is not simple as a typical stand alone. For example,
Injector phasing is critical to avoid spraying into an open intake valve or you face the issue you are facing. Did you verify the injector end of injection spray setting? I bet not

4. Wrong dyno used. There is no diagnostic info in that dyno graph we can use.

You SHOULD be using a Dynojet, set to smoothing = 0, with an AIR fuel curve present , Along with in-car wideband behavior data to compare with. Also we need to see mph vs torque AND rpm vs torque for max info

5. Big mistake using the stock cams. This pulls about 30-40% of the potential power out of the engine. Not good fighting stock cams on any engine. garbage

6. Need an EGT gauge off the downpipe combined with torque curve & boost pressure log from being on a dynojet to see how expanded exhaust gas volume is before determining its too small. fwiw I've made 350rwhp through an OEM 240sx exhaust system before, complete with OEM muffler and OEM sr20 downpipe neck. 240sx exhaust is identical to silvia exhaust. Silvia uses sr20det making 300rwhp OEM so the small exhaust is not an issue at that level.


My advice is get an sr20 or if you are stuck diagnosing the KA then change the computer to PFC or something with plug and play setting for crank and cam and phase so you don't have these questionable situations with timing or whatever, that will let you narrow down the issue to the engine itself so you can begin replacing it.