2G - stock turbo, new front mount - boost issue?

[stratt134]

I have a completely stock 2G. I needed a new side mount factory intercooler and wanted to upgrade to the "hard pipes". The existing intercooler was cracked almost in half!! Hit something I guess . Anyways, after some research, I all I could find was the hard pipes for $250..... no including a new/used intercooler to fix my issue. Plus my stock plastic 2G BOV leaks....

So I found the VR-Speed.com FMIC.... installed it with the stock turbo, full hard pipes, and new 1G BOV.... took it for a drive.....

AAAAAND now the boost spikes at 17psi (!!!!) and falls off steadily to 10psi by 7K rpms from about 4500/5000rpms.... I assume that is normal for such a huge intercooler, a BOV that doesn't leak, and most importantly - the stock t28 that doesn't even want to pull past 5k rpms anyways....

on the bright side, throttle response is WAY better (no leaks now)(no hole in intercooler now) and the turbo spools WAY faster

What are your thoughts on the turbo spiking to 17psi and falling to 10psi now?? It used to spike 14psi and hold 13psi to red line.....

 

[Detective Coating]

Try getting rid of the MBC and run your line from WG to compressor housing, see if it still spikes at stock boost. Could be a bad MBC but I have heard of it happening a lot with stock turbos with a FMIC.

 

[stratt134]

I haven't hooked up/used the MBC i got yet..... it is still sitting in a box.

Since there is so much throttle response now, and it takes a much smaller load/throttle to boost the turbo even 1-2psi, i'm guessing the new hard pipes and lack of leaks is letting the turbo spool extremely easily - hence the 17psi spike. The factory intercooler was coated in oil as well, i'm sure that didn't help with airflow. And with the boost falling off to 10psi for the last 2k rpms, I assume that is because it just can't keep that huge intercooler full and pressurized when the motor is spinning that fast/sucking that amount of air.

Fine by me. Need to race a friend now and see the difference

 

[97boostedTSI]

its probably a boost leak or your MBC is taking a shit. I had this same problem after i installed my FMIC. Try the boost leak test and then if you can borrow someones MBC and see if you can solve the problem...

Good luck

 

[e39a]

samething happened to me with my friends gst it would spike to 25 and go down to 19 onhis 16g >>>then i replace the mbc and the problem was gone>>>also when you upgrade 3inch exhaust in will absolutly spike more

 

[stratt134]

again... no MBC installed or being used....

... also... if it had a boost leak still, how would it spike to 17psi?

 

[scoby41]

I'll sell ya a td05 20g, that should help the top end a little

 

[lq1driver]

when did the t28 come stock? and also t25 is known for spiking and not being able to supply enough air do a boost leak test and up grade to a bigger turbo the single best upgrade you can do for your 2g is to goto a bigger turbo 14b on up

 

[knochgoon24]

when did the t28 come stock?

Yeah, sorry but you're running a t-25.

 

[spydermanX98X]

17 shouldnt blow anything up and wont cause fuel cut so you should be fine. now it's time to up grade big time though.