T28 Spool Time

[fuzzydoodle]

I tried searching but only found pages upon pages of t28 vs. 16g question. I recently turnd down my boost via adj. WG on a agp bt28, cause I could not tune out knock. So I turned it to 14 from 17 which is what I got it set at, now I can boost 14 with timing at 14-15 most of the time, sometimes dropping to 12. But I start to boost at 2800-3000 and hit 14psi at around 5000... I dont think it should take that long at all. I have a dejon big sidemount installed, and a small crack in my exh. manifold, that would not have that much affect....? Help. Let me know what else you need to know. Thanks.

 

[rich3389]

The crack in hte exhaust manifold would cause slow spool up.

 

[boostnbuds]

the crack will mess with things, but my guess is you have bigger turbo issues, you should be spooling much earlier then that, and without knock, what are your iat temps under boost?

 

[GVR4592]

Do a boost leak test.

 

[fuzzydoodle]

I had done a boost leak test but the car sat for a little while then I started driving again, I will do another tomorrow after work and let you know. As well as watch the iat temps on my way to work.

 

[GVR4592]

I don't see what monitoring IAT's is going to do, air temp is measured before the turbo, so it's not going to give you any useful information. Unless I'm missing something.

 

[fuzzydoodle]

Yeah the iat temps stayed between 61-68 this morning on my way to work and it didnt matter if I was boosting or not. I forgot my boost leak tester at home so I will have to do that tomorrow but I will let you know how that turns out. I just done see why it would take so long to spool when everyone says it hits full at 2800.

 

[fwdeclipse]

You have a huge leak somewhere or your turbo is on its way out. My t4 60 trim hits 24psi at 5100. So that should give you a clue.

 

[daren_p]

Yeah the iat temps stayed between 61-68 this morning on my way to work and it didnt matter if I was boosting or not. I forgot my boost leak tester at home so I will have to do that tomorrow but I will let you know how that turns out. I just done see why it would take so long to spool when everyone says it hits full at 2800.

Not sure the point of watching your IAT's as this is the inlet temp before the turbo, measured at the MAF sensor. Something is defently up, you should be seeing 14 psi WAY before 5000 rpms (like around the 3000 rpm range). First things to check would be for a huge boost leak or exhaust leak. Then check the turbo for shaft play. Did the turbo spool the same way you you were running 17 psi? If it was okay at 17 psi you may have the actuator backed off to much so the flapper isn't ever completely closed. Check the actuator/flapper & make sure there is some preload on the flapper.

 

[dsm_racing]

Also, are you sure you don't have an exhaust leak besides the cracked manifold. I had a warped exhaust manifold flange cause me all kinds of wierd problems a while back. How bad is the crack in the manifold? Can you post a picture?

 

[fuzzydoodle]

I did'nt think tha iat would do anything, but I was just replying to a post that was made, no biggie i'm over that. The turbo has no shaft play, it was used from someone on this forum. I'll do the boost leak test tomorrow (I forgot my tester, an i'm about an hour from work, in a shop i.e. air, any real tools) The crack in the manifold is really not that bad...Small hairline didnt notice till I had it off an in the solovent tank, but it does show through to the inside...which would give me a good idea its leaking. At 17 it was kinda the same but for sure I don't know cause I was pulling timing to around 5* so I never really got on it, cause no matter how much fuel I added it never went away (I'm trying to tune with a afc, bad choice, so I think i'm on to bigger an better things after this blows over, like dsmlink) Lemme know if ya want me to pull the manifold and post a picture.

 

[kenamond]

I did'nt think tha iat would do anything, but I was just replying to a post that was made, no biggie i'm over that. The turbo has no shaft play, it was used from someone on this forum. I'll do the boost leak test tomorrow (I forgot my tester, an i'm about an hour from work, in a shop i.e. air, any real tools) The crack in the manifold is really not that bad...Small hairline didnt notice till I had it off an in the solovent tank, but it does show through to the inside...which would give me a good idea its leaking. At 17 it was kinda the same but for sure I don't know cause I was pulling timing to around 5* so I never really got on it, cause no matter how much fuel I added it never went away (I'm trying to tune with a afc, bad choice, so I think i'm on to bigger an better things after this blows over, like dsmlink) Lemme know if ya want me to pull the manifold and post a picture.

And I agree that you should check your WGA. If WG is not held closed, backpressure in the upwind end of the turbine housing may push it open. Or it may be open just sitting there.

 

[daren_p]

Do what I mentioned above but also when you say your timing drops to 5 deg, when does it do this? If this is happening during spool up, this is normal. Timing is supposed to drop when the turbo is spooling, will dip to a low & then should start to increase all the way to the redline. If the timing is pulled in this area then you have an issue but if its an initial drop on the onset of boost, thats normal & what is supposed to happen.

 

[ILLiCliPSE]

+1 for a pic of the crack in the manifold.

 

[fuzzydoodle]

No from what i could watch on the logger and drive at the same time it seemed to drop to 5* and stay there pretty much till I let of throttle. I was going to do a boost leak test tonight but when I was turning the crank someone stuck a pen magnet down in there to "find tdc" and when the piston came up it bent the clip, which eventually I had to break of then spend an hour fishing it back out. But oh well from what I did hear was only through the valve cover which I didnt get a chance to take my pvc (crap ass shucks one) out to cancel that noise, so either that or the throttle body is leaking. I'm racing tomorrow so I wont have time but probably sunday I will try again, as well as snap some pics of the exhaust man. I will turn the boost up a little from 13 to see if that helps I pretty much backed that WG adj. off all it could go, so it probobly is not really tight. Other than that how would you check that?
Thanks.

 

[player69x]

My t28 spools at at 2500-3000 at 15 psi and i have a crack in my mainfold as well so i dont think the manifold is the problem.

 

[fuzzydoodle]

Finally got around to taking me manifold off, i'm pretty sure she is no good as I could see drop light through the crack. It's hard to see on the one in the runner but it's there right next to the light glare. But I also have these cracks from porting in the housing...other than these two, I don't know besides a boost leak which I will probably do tomorrow after work...hopefully. Last time all I heard was from the valve cover which probably is the pvc. Unless the valves are open. If the boost leak comes out ok, what else would this be? Cause its really bugging me I could not pull too far away from an srt4 (which was drivin by an extremely beautiful girl)

 

[fuzzydoodle]

Ok I swapped the exhaust manifold with one off a car that I bought from my buddy (92 awd tsi, no main bearing caps but 16g rc injectors 2g exh. man. new head, afc, hoping for fuel pump have not pulled yet) But that didnt make too much difference. Just got done boost testing and the biss screw leaks and the throttle body seals, at least I think sounds like coming from behind (right where the throttle cable is) So that being said, just ebay or napa for the seals? Or isnt the 1g bigger? If swapping the 1g, do you eliminate the relays and switches, like fp relay?