Jump to content
SAU Community

Help With Exhaust

bundy_bowler
 Share

Recommended Posts

gotRICE? Veteran

gotRICE?

Posted
Posted (edited)
I installed a 3inch cat back the other weekend. After the install i did an ecu reset but the car still runs real sluggish.

It felt a lot more responsive with the old restrictive exhaust on.

Can someone please give me some help?

Seems clear? :)

Bit wierd, if anything it should be making a tad more boost and run better.

Edited by gotRICE?
oh to dream Contributor

oh to dream

Posted
Posted

i just installed a 3" dump pipe and cat to go with the rest of my 3" exhaust using the standard ecu. car feels a tonne smoother throughout the whole rev range and air filter is heaps noisier below 3000rpm because of the increased flow and the turbo being able to spool up sooner. you should definitely not be feeling sluggish. not sure about diagnostic though.

gotRICE? Veteran

gotRICE?

Posted
Posted
Take your car for a quick test drive and look at the factory boost meter.

it should reach full boost at about 3000rpm.

it may sound silly, but check your exhaust manifold, you may have a leak.

Should come on bit sooner than that.. mine makes 10psi by 2700.

Although with full exhaust.. not just cat back.

TALBO Grand Master

TALBO

Posted
Posted
mine doesn't make full boost, 10psi until 5,000 RPM. Is there a problem? Could 3.5" be causing back flow problems in my case?

Afaik, not a problem unless the actuator has been modded...

http://www.skylinesaustralia.com/forums/HO...ost-t42895.html

  • 2 months later...
Odium Grand Master

Odium

Posted
Posted

Strange... Turbo car likes a freeflowing exhaust after the turbo.... engine gets its backpressure from the turbo.... Big exhaust in a N/A car and you don't have enough backpressure + exhaust speeds are too low and it'll work against you. Correct? (very simplified obviously)

I bought my GTS-T with a 3.5" catback on it, got it switched to a stocky for EPA test and it felt so restricted.... bout the same low down, but high range and it struggled.

R31Nismoid Grand Master

R31Nismoid

Posted
Posted
Strange... Turbo car likes a freeflowing exhaust after the turbo.... engine gets its backpressure from the turbo.... Big exhaust in a N/A car and you don't have enough backpressure + exhaust speeds are too low and it'll work against you. Correct? (very simplified obviously)

Not correct.

Most people with N/A's put exhausts on and don't tune.

I had a twin 2.25" exhaust on a V8 years ago - loved it

mad082 Grand Master

mad082

Posted
Posted
I installed a 3inch cat back the other weekend. After the install i did an ecu reset but the car still runs real sluggish.

It felt a lot more responsive with the old restrictive exhaust on.

Can someone please give me some help?

i would check the dump pipe. when removing or installing the new exhaust you may have twisted the dump pipe a bit (possibly when trying to undo the bolts on the cat) and it may be causing the wastegate flap to foul slightly and not close properly.

mine doesn't make full boost, 10psi until 5,000 RPM. Is there a problem? Could 3.5" be causing back flow problems in my case?

definately a problem. i had a 3.5" exhaust with stock ecu and was making 12psi by under 3000rpm. may be an issue with your boost controller (i also had an issue with a boost controller causing boost to come on very late. it wasn't releasing the pressure between the controller and the wastegate when you lifted off so when you changed gears the wastegate would still be open, and on a few occasions it was open so far at 5000rpm i was only just starting to make boost)

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Duncan
      V37 Radiator removal

      By Duncan · Posted

      So, this shouldn't be such a mission, but there were a few tricks so I thought I'd post up a DIY for it. This was on a Q50 Red Sport but I doubt any other V37 model is very different (maybe just less steps for the intake heat exchanger hoses) I pulled the radiator out to flush it because the car was running hot at the track, but obviously the same steps apply for changing a radiator for any reason including an upgrade. If you are removing the radiator, you of course need to drain and refill, so have 5+ litres of blue coolant ready. You don't need to drain the intake heat exchanger to remove the radiator but depending on your plans you may need a couple of litres for that as well. You will also need something to deal with the auto transmission lines, I used 2x 8mm rubber caps on the radiator side, and a short length of 8mm pipe on the car side.....unless you can block these lines quickly you will loose AT fluid and it may be enough to hurt the transmission if you don't refill it. Other than that....lets go... "First, jack up your car". Yes really, and put it safely on stands. If you are not confident doing that you need to give this job to a mechanic
    • MBS206
      Unpeeling the Orange

      By MBS206 · Posted

      If the forester is anything like our old 2007 GTB Liberty, I could near on run ling Long's and "rate them", as no matter what, it just hung to the road, even when abusing it in a hard launch in the wet, or throwing it at corners.
    • The Bogan
      NC MX5

      By The Bogan · Posted

      LOL, all of the CAI like Craig I just need to put a hole saw through my bumper Done and dusted, the car runs, which is nice, I'll take it for a spin when the weather clears up Just need to put the bumper back on for good
    • EndZee
      R33 Gts/-t Abs Module Wiring Schematic (not Gt-r)

      By EndZee · Posted

      Brooooo Please send ABS control unit schematic Please! R33 gts25t ABS (Its two plug ecu, black and white) wire colors possible? [email protected]
    • GTSBoy
      Boost cut after swap(RB25DET NEO) R34

      By GTSBoy · Posted

      Don't even try to run it on the stock ECU if you're going to have the boost controller bring boost above ~10 psi. I've already told you that. If you use the Nistune ECU, you will need to CAREFULLY read the available documentation for Neo tuning, and read some threads on the Nistune forums, to discover the various things you have to do to prevent the ECU from going bananas when the boost is too high. The is a table associated with th boost sensor that must be modified to prevent it from shitting the bed. This is just one of the things that you will need to do to the tune in Nistune, because the Neo turbo ECU will be expecting to see a number of things (such as the TCS) that are not there, and you have to block the DTCs on those. It is totally not surprising to me that you are having the problems that you are, but the solutions to these problems have been known for >15 years. So just get it done.
×
×
  • Create New...