20g really late spool up?

[giovanniv]

Alright well I need help with my 20g. I just got it installed and I have to say the turbo pulls hard as hell at my stock external wastegate pressure (14.5psi) but this turbo is a ton laggier than I thought it was going to be. I am hitting my 14.5psi at like 3900-4200rpms. Is this "normal" for this turbo? Also for some reason when I tried turning up the boost with my mbc it doesn't up the boost when I tighten the screw in on my MBC. I know my MBC works fine and I know I have all the hoses ran correctly. (Bottom wastegate port to side of MBC, bottom of MBC to turbo housing. My first thought was that I have a boost leak and I have fixed 99% of my boost leaks except one little one at my throttle body elbow. Can anyone help me out? Thanks. Oh and my wastegate has a brand new diapragm that I installed so I know it's working correctly.

 

[boosted240]

i had a 20g on my stock longblock 1g and i was in full boost right around 4200 4300. So that sound right.

 

[giovanniv]

Oh really? I thought I had read about people starting to get boost around 3200-3500rpms?

 

[DSM-sagacious]

You should check to see if your turbo is bolted up correctly. You may have an exhaust leak between your turbo and manifold or manifold and head.

 

[boosted240]

Yea i started getting boost then but thats not full boost.

 

[giovanniv]

Ya I'll check for an exhaust leak today but the only thing that I have noticed is that at idle I sit at like 7-8vaccuum but I think that is because of my 274 cams? Isn't it? And like when I rev it the vaccuum drops down to 12-20. Is that normal?

 

[95gst_sweetie]

I think thats normal as far as boost, im running a fp18g and dont hit full boost until 3800-4100 rpms.... As far as the vacuum I sit on about 14-16 with fp2 cams........

 

[96_charcoal_tsi]

What 20g are you running? I have a 20g with a tdo5 hotside 7cm and I receive full boost 22psi by right around 3500-3800. I am running dsm link external gate this also completely untuned. I see nothing leaner then 10.0 to 1 on the wideband under wot. I am in the process of dialing in airflow because of gm maf. I will get back to you on the exact spoolup once I get it dialed in acording to map sensor.

 

[giovanniv]

Ya I am running the tdo5 hotside 7cm. It is really weird, like the car just feels super laggy

 

[juanpac0]

My TD06 20g is at wastegate pressure (18psi for me) @ around 3800RPM, and starts spooling (actually building positive pressure) at around 2500 rpm, sounds like you have a boost leak or something. My vacuum without cams is around 19-20. Even with cams I don't think you should be at 7-8 vac at idle unless you're at a really high altitude.

 

[96_charcoal_tsi]

I also come from a .82 t3 6176 so to me this is super fast spool. I would looke for either exhaust or a boost leak. Mine also has a exhaust leak where the manifold was tapped for a egt but I don't have on and can't get to hardly seal up so this is also with an exhaust leak.

 

[giovanniv]

Well I fixed all of my boost leaks except my throttle body elbow and my idle biss screw and those gaskets/o rings are coming in tomorrow. Other than those 2 I have NO other boost leaks. I did my BLT with 30psi and I had no leaks except the 2 mentioned above. I have heard that people with cams sit at right around 10lbs of vaccum instead of 20?

 

[juanpac0]

Depends on the cams (lift/duration), how you adjust them, and your altitude.

 

[beihl304]

i dont seem to be hitting full boost on my tdo6 20g until about 5500 in first gear but 3500 in 5th? i dont have any boost leaks besides 2 cylinders with slightly low compression. ialso dont see or hear an exhaust leak.can them 2 cylinders that still have 125 psi compression be the cause of such a slow spool? thanks

 

[Jiggalude]

You're very close to the service limit of those two cylinders, which is 121 psi. Also, even with cams 10 lb/hg seems low and I'm confused as to how the car stays running. Also, they may only be two leaks, but they are probably pretty significant in leaking air as well. Also, first gear is a pretty short gear, with not as much load as 3rd, so I wouldn't expect as much boost in first as compared to third.

 

[black_gst]

i have a td06 T3 flanged 20g and boost starts building at about 3k and slowly builds 10psi then jumps to about 20psi at 4k in 3rd... im only boosting 20psi right now or it would be 25psi

 

[donniekak]

i dont seem to be hitting full boost on my tdo6 20g until about 5500 in first gear but 3500 in 5th? i dont have any boost leaks besides 2 cylinders with slightly low compression. ialso dont see or hear an exhaust leak.can them 2 cylinders that still have 125 psi compression be the cause of such a slow spool? thanks

Full boost at 3500 rpms is fine. Whats the problem? Your not going to get full load in 1st and 2nd gear. The best way to get boost in 1st, is to launch the car.

 

[beihl304]

i guess i really never thought about it that way... its just soo much laggier and slower due to the compression im hoping.

 

[4G63conquest]

I have HKS 272 cams on a engine that held 18in/hg at idle. This is on a 8.5:1 compression buschur engine. Now with cams and no boost leaks it is prob a tad under 10@700rpm. I couldnt adjust idle with the cams so I pulled the trigger on a Jackal setup. Monies well spent my friend.

 

[19904G63turbo]

If i am correct, even though you turn up the boost with your MBC it won't build any more boost then what your wastegate is set to. The spring opens up at 14.5 lbs of boost and won't build any more.

 

[JusMX141]

You're not correct....and thanks for reviving a 2-1/2 year old thread.