I drove my fd3s hard off the line today.. seems all well on 1st and 2nd gear at 7000 rpm shifts, but on 3rd gear after releasing my clutch theres a major hesitation as my fd seems to lose a lot of power and theres 2 loud "CLANK" "CLANK" sounds.. so I let go of the pedal and then reapplied it right after the problem seems to be fine.. Whats wrong with my car it seems fine now but dunno whats wrong?? help please.. My car is almost stock as only the exhaust are 3.5 in HKS straight exhaust but the twin turbos are set to .5 bar on the 1st and .9 on the second

Thanks in advance everyone

 

nobody knows whats wrong?? now I'm in deep Sh@t.. haha

 

Do you mean you're running the stock sequentials, running .5 bar below 4500 and .9 bar above 4500? What ECU are you using and what boost is it set up for?

Has your wastegate been ported? If not, what does your boost gauge read when the engine cuts out?

 

Yeah I'm running stock twin turbos.. my ecu is an Apex'i Power FC.. My wastegate hasn't been touched.. and what do you mean about the boost gauge when engine cuts out.. any suggestions??

 

"almost stock as only the exhaust are 3.5 in HKS straight exhaust"

If this means you only replaced your muffler, ignore the wastegate question. On the other hand, if this means you replaced both the catalytic converter and muffler with straight piping, you should look into porting your wastegate.

Having a PFC gives you the opportunity to tune for higher levels of boost. However, you need an upgraded fuel system to safely run .9 bar boost. What fuel system mods do you have? On a stock fuel system the max you should run is .7 bar.

Dave

 

the previous owner replaced the exhaust with a straight 3.5 inch pipe and I just changed the muffler to an HKS.. and I think the cats gone as well.. and my fuel system is stock.. what should I do to my fuel system and would it effect my mpg?? or should I just adjust boost to .7 max?? anyway thanks for the tip dave.. right now I'm trying to custom fabricate a Blitz supersonic cold air intake to fit my rx7 twin turbos.. that should give my car better breathing as well

 

Start by dialing down your boost to .7 max. You may have the ability to go higher, depending on how much fuel you're getting and the map on the PFC, but that's for later. Right now you need a safe boost level and .7 bar is good. Hopefully

Better breathing = even more problems. Adding fuel is not the answer.

The first problem is boost control. Your PFC might be sufficient control, but take care that at 4500 your boost does not exceed the number you have it set for. Any spikes in boost are dangerous. As you open up the flow in the engine/exhaust you will eventually find the limitations of using the PFC with stock solenoids. If you get the aftermarket solenoid for the PFC you will be fine.

The second problem is boost creep. No cats means the exhaust flows faster than air can flow thru the wastegate. You need to remove your turbos and port the stock wastegate to a larger size.

There is plenty of information out there under the terms "boost creep" and "boost spike"

Dave

 

so I should get an aftermarket solenoid, port my wastegate and adjust the boost to .7 okay will get back to you after I did it.. and what do mean by better breathing = more problems?? should I install a cold air intake system??

 

better breathing = more air, which means you need to provide more fuel.
You need to provide enough fuel for the amount of air your getting to avoid going bang.

 

That's only half the story. Better breathing = exceeding the stock boost control system. Adding fuel without upgrading the boost controller and porting the wastegate is not fixing the problem.

Dave

 

let me get this right.. If I installed a cold air intake.. I need to port my wastegate, and add more fuel?? right?? and what else should I do.. I still want my car to be reliable

 

Take a look at your injector duty cycles and make sure they aren't exceeding 90%. Do a search on rewiring the fuel pump this will give a good near 2 volt increase in voltage to the pump. Which is about 30 percent more flow. Which might be enough for your mods, but you might still want an upgraded pump. The stock intercooler really isn't enough for higher then stock boost. It's actually pretty much useless for even stock boost. But at least the pressures in the chamber are lower. High intake temperatures increase the chances of detonation.