i have a 2000 1.8t,and i cut the resonator and muffler off (replaced with a magnaflow), in order to get that sound and performance boost, but i lost my lower end/acceleration. it sucks, anyone have an idea how to fix the problem!?

 

it's possible with the slightly reduced backpressure that the exhaust gas doesn't hit your turbo as hard at lower rpm. ur still using the stock turbo? i just picked up an 01 a4 and turbo spools around 1800-2k. when does yours start to pull?

 

This happens because exhaust takes the path with the least resistance and now more of it goes thru the wg instead of going thru the exhaust wheel. THe problem is that the ECU does not adjust for the decrease in back pressure and it does not keep the WG fully closed as the turbo is spooling up since the turbo spools too quickly. Way around this is to use an EBC but they don't work all that great for such a small turbo.

 

i thought the wastegate was operated by pressure. you could use an ebc or a less accurate mbc to keep the wastegate closed longer. small turbo won't get much help though. doesn't get spinning hard enough at the low rpm to make up for loss. the gases are going out the exhaust instead of towards the turbo because of the reduced back pressure. basically, your turbo is not spooling fast enough for the ecu to be able to compensate. an exhaust manifold would help the problem. mine as well get the bigger turbo while you're at it

 

Yes the wg is opened by pressure, but the ECU tells the N75 when to open and that is not based on pressure but more on throttle position and rpm. So basically there is no way for the ECU to compensate when you reduce the back pressure, even the MAP sensor on the 2000+ cars isnt anything but a safety switch and the ecu doesnt use it to make any adjustments to how it controls the turbo.


He could try a MBC but they tend to produce surging issues at part throttle when there is high load on the engine. So it causes the boost to go on/off way too much during part throttle.

 

I had a similar issue with my Starlet GT Turbo. I put a full stainless job on and opted for a larger bore piping to allow for bigger turbos to be fitted and the exhaust then holding it back. Well my bore was to big and the turbo then started to smoke. I cut the tail pipe off and put a small washer in between the can and the tip and it was big enough to increase the back pressure

 

basically, he would have to remove the ecu control of the wg. new turbo kit, external wg, ecu tune.

 

haha yeah thats a little bit out of my price range, i guess i ll just save up for a new ecu, my friend told me also that if i change the plugs (stock ones) that that should help, so i guess i will do that.

 

oh and my turbo spools around 2and a half k, to 3... :/