2G: Probly a dumb question but im going to ask

JuGs · 06-04-2012, 10:42 AM

Ok Im sure this is a dumb question and I already know the anwser but i would like more opinion. heres my setup so far

walbro 255
fic 650
vrsf fmic
greddy bov
6 bolt swap
dsm link v3 full
fp intake pipe
k&n filter
holset wh1c with bep housing
afpr
stage 3 f1 racing pressure plate
stock clutch disk
38mm wastegate off o2

Now for my question

I have the stock exhaust at the moment but I would like to get a tune so it runs better and has more power. With having the stock exhaust would that kill getting a tune for around 18 psi? Or can i get a decent tune that will still allow me to actuly accel full throttle with no knock or sluggish feeling?

Fejery4491 · 06-04-2012, 10:45 AM

Stock exhaust is going to seriously bottleneck that whole system. If possible, I wouldn't get something else.

H@xtGSX · 06-04-2012, 10:54 AM

You can still get quite a bit of boost thru the stock exhaust, but for what you are running it is going to produce some heavy back pressure. I wouldn't try to run anything smaller than a 2.5" exhaust pipe with that large of a turbo. It is worth the trouble changing out the stock system. I am running a 3" pipe with a 14b and it did make a world of difference in the overall response of the turbo. Basically, the less back pressure, the better. Turbos benefit greatly from a bigger pressure differential, and that's what the larger pipe provides. You'll be paying for a tune twice if you tune it on the stock exhaust, so unless you know for sure you won't be changing it out, I would just wait until I could afford a larger pipe... Heck, even a crush bent 2.5" exhaust from a local shop only runs a couple hundred, and that would still be a major improvement in your situation.

JuGs · 06-04-2012, 01:23 PM

Thats what I thought. Im actully working on picking up a full 3in exhaust with in a week or 2. but if i wasnt able to get it i wanted to know about the tuning so i can at least have the car running properly, well more properly than it is now. Thanks for the responses

Now my next qustion is. With the stock exhaust would that be whats causing my bad knock when i get on it? I can only drive smoothly if i keep it at 30% throttle or less. Rarly i can go over 30%. Before I was running a 16g and would have knock at low rpm so I adjusted the knock cel to 30% throttle and 3200 rpm, and the knock went away. I read on here to do that. I know I cant and and shouldnt adjust it any higher but Im guelling thats my knock issue for sure

Arnie · 06-04-2012, 01:50 PM

You can search the forums and you will find out why is making your car knock. Several people posted issues with knocks and got different answers from different areas of the car.

H@xtGSX · 06-04-2012, 01:53 PM

It shouldn't be knocking at all at such low levels... It isn't really even boosting hard at that throttle level. That tends to make me think you have a bad knock sensor OR someone is secretly maintaining a small campfire in your intake... I tend to think it's the former though.

Arnie · 06-04-2012, 02:13 PM

Get your engine checked before something happens bro, before worrying about other things.

JuGs · 06-04-2012, 03:04 PM

I know its not a bad knock sensor. I put a new one in when I did the 6 bolt swap. I only get know under hard accel tho. I can ease the throttle to more than 30% with no know but its real sluggish. Kinda like flooring it in 5th gear at 55 mph, it doesnt go very well lol. I know my compression is good last check before I did the swap it was at 165 all 4 cylinders. Im not getting any kinda smoke out exhaust, though i do have a exhaust leak at the flange of the WG where it dumps back into the o2 housing(ebay external wg not aligned very well could only use 1 gasket and 3 bolts to bolt it on). Front o2 is good rears getting replaced with the wideband sensor, but i have to gut the cat or get the bigger exhaust with cat delete.

Even at 30% throttle i hit 9 lbs of boost whitch is what I have it set on for now. It reatches boost levels at what i believe is normal for the turbo and ammount of throttle which is around 3500 rpm. Idle is smooth for having bad ics/iac which ever one wants to call it(just recently went bad like 2 or 3 days ago)

What should I look for I cant make a log since my battery is shot in my laptop and i dout a log at idle with reving wouldnt help at all. Im getting good mpg 22 to 25, whick i believe is goodfor what I have for a setup.

JuGs · 06-05-2012, 03:44 PM

Ok did another compression test....beween 150 and 155 all cylinderson a dry test. But as I was pulling the plugs every tip of the plug was real loose. Im sure thats causing some of my issue. Im going to post 2 logs here later tonight of no knock and one of knock so i can get more info from everyone.