KA-T tuning problem

[truth211]

I have a 1992 240sx with a ka24de-t. The engine is from a 1996 240sx and I am using the s14 upper intake and the s13 lower intake. I have removed all my emissions and all un-neccessary vacuum lines. I have one vac. from the FRP to the lower intake, BOV vac. to the lower intake, AAV/AICV hose to the cold pipe, WG to the hot pipe, 370cc sr20de-t purple top injectors, stock MAF, retuned ECU for KA-T and set-up, 3" down pipe and exhaust, No cat, T25 turbo no oil restrictor, 3" in/out FMIC and electric fan set-up. Removed a/c as well. Timed at 20* BTDC on warm idle.

So here is my problem. I accelerate from first gear and shift to second gear. I stomp on the gas (WOT) and she bucks, loses a tremendous amount of power (almost feels like it dies for a second or two) and there sounds like a popping noise when that happens. It really does it through all the gears but is most noticable in second gear. Also I have the WG set at around 7-8 psi but that puppy shoots right to 15 psi in second gear. She boosts fast to 15 in second gear. Quite strange really. But I can not figure it out.

I want to be able to mash my foot to the floor and see a max of 14 psi and have no hesitation. I want it to run strong with no more issues. Any clues to how I can accomplish it? I have spent alot of time finding threads but nothing with my particular situation. Also can 370cc injectors handle 14 psi of demand? Really I only wanted to run 10 psi max. What are your suggestions?

[r3v_v3ng3]

you need to stop stomping on it. if your wastegate is set at 7-8 lbs and shooting at 15 psi, the boost is spiking.

what you need to do is STOP flooring it and find a place to tune it or else it will blow up like your previous motor. thats why it has all the symptoms because its in need of tuning. never do a WOT on a previously non boosted car if you don't know the A/F ratio

Be patient. once everything is tuned, you can floor it all you want

[sunnys14]

Please don't run a T25 to 14psi. Thats pushing the turbo so hard that its just blowing out hot air. SR's run 14psi on their cars but the turbo doesn't last for very long AND they have a tad lower compression to combat detonation. Even with a tuned ecu, it will pull timing to prevent detonation but it cant stop the turbo from blowing hot air and melting your pistons.

14psi on a T25 is damn near maxing the **** out of the injectors. If boost is creeping then your wastegate signal is cut or loose and thats what causes the car to bog and run rich at WOT.

[480sx]

Those were two great posts, you really should take heed.

In addition to all of that, you have a problem with your wastegate. Since your running a t25 im assuming your using an internal wastegate. First thing to check is your vac source and the line itself. Its probably best to run the wastegate source directly off the compressor outlet on a internal wastegate. How is yours hooked up?

The wastegate problem is your number one concern right now. Fix that before you boost.

[truth211]

In this picture you can see the vacuum line is only about 4" long. So it is about 8" from the compressor housing. I have both ends of the silicon hose clamped from leaking and I used the shortest amount of hose possible. I also made sure I used a little bit larger diameter silicon hose too. I am however using a 3" SS down pipe that comes directly off the turbo. I am actually going to install a oil restrictor too. It does well as it is but it occasionally blows smoke when I step on it. I will have that done this weekend. Great oil pressure though. I also forgot to mention I have a stock O2 sensor. In the pictures you can see how I have my set up. I also need to make note that I changed the one hose (AAV & AICV). I connected it to the cold pipe and moved the valve cover hose under the manifold and put a chrome breater tube on it. It idles nicely now. As you can see in the picture the nipple off the hot pipe is going to the WG. The vacuum hose is only 4" long and very close to the compressor housing.

[UNVMY240]

First off beautiful engine bay!!! Clean, clean, clean. The other thing is get a heat shield for your master cylinder.. Over heated brake fuild = failure/crash. Last thing get 2 more nuts for your water pump pulley.

[taco_401]

heat shield would be a smart move

[truth211]

Thanks. I have spent a long time doing this engine up. By the way thanks for the reminder. I totally did not see the nut issue. I will put two more on there. Thanks for the extra eyes. Let me ask this again. As far as the questions I had above...Do you see anything wrong with the set up? Please refer to the questions with the pics. Thanks again. Still in need of the help. Still boost creeping. On a side note it seems that when I mash the pedal down it misses. I think the plugs are fouling out due to the extra fuel. It does back fire occassionally though I also do not have a cat either but it is burning rich. I have not checked the fuel pressure yet.

[sunnys14]

It looks to me like your maf is too close to the turbo bro.

Get a longer pipe and pull it away from the turbo.

[truth211]

What would that have to do with anything? I have seen tons of turbo set ups where the MAF sensor is that close if not closer. But that really does not solve my main problem. Thanks for the props on the engine guys. I am getting the rest of the body on the car prepped for the custom paint job. I am almost finished molding the whole car. I am filling the small air hole pockets in the body filler after I have sanded. What a pain but it will look great when it's done.