slow spool, bad wastegate actuator??

[ekizenbe]

i finally got to drive an almost bone stock 90 talon with a 14b and a 3 inch exhaust and i could not believe just how much faster it spooled then my 93 with a flywheel, cams, 14b set at 16lbs, 550rc's, and a full 3 inch exhaust and an safc. his 14b spools instantaneously. my car spools much slower. i did a boost leak test, i had a small set of leaks which i fixed. this did not fix the problem. i bypassed my boost controller by running a line from the j pipe to the wastegate actuator and i made 7-8 pounds and even then it definetly boosted slow. what else could cause this???

 

[Black91TSiAWD]

cams will effect spool, dunno if it would be as much as youre describing but its a possibility if you dont have any boost leaks.

Or your timing is off?

 

[ekizenbe]

if my timing is off it would be off by one tooth at best. so even then i dont see how that could affect it.

 

[Black91TSiAWD]

7-8 psi IS lower than stock, my old 1g was boosting like that when I got it, but it didnt spool slow though. It did end up being a bad actuator. I replaced it and the boost raised to 10-11ish. But spool was never an issue.

Its worth a shot to replace it, but the slow spool still might be caused from something else.

 

[ekizenbe]

yea i dont remember the exact numbers but it did spool slow ill give it that. i know this sounds noob but my turbo is ready and willing to spin up when i lightly touch the gas, i can hear it in my exhaust it sound so free and willing, for some reason it makes me feel that the turbo itself is not bad. another thing is that i get different levels of boost on certain day. my boost is set for 18 pounds full throttle in 3rd gear which it usually holds but on other times ill only get 14 or 16 it varies for no good reason, and i know its not boost creep because of my exhaust as this all happened with the stock setup just the same

 

[oldman]

1. Use proper grammar, punctuation and capitalization when posting in the tech sections of the forum.

2. How did you leak test? What were the results of the leak test? Details please.

3. What rpm are you hitting full boost in 3rd gear?

 

[ekizenbe]

My boost leak results were that I had a small leak in the throttle body, which i rebuilt and one at the j pipe also fixed. i would have to say im not getting full boost till the upper 3k range .

 

[oldman]

My boost leak results were that I had a small leak in the throttle body, which i rebuilt and one at the j pipe also fixed. i would have to say im not getting full boost till the upper 3k range .

What are you using to pressurize the system? How much pressure did the boost gauge show during the test? How long did it take to bleed down to 0 after pressure source is removed?

 

[ekizenbe]

We used a big compressor with a homemade boost tool. my friend ran that test up to and including 20 pounds. He said is was perfect. I do trust his opinion as well

 

[oldman]

We used a big compressor with a homemade boost tool. my friend ran that test up to and including 20 pounds. He said is was perfect. I do trust his opinion as well

So you didn't see it yourself? Do it again and make sure the 20psi he mentioned is the boost gauge, not the regulator gauge on the compressor, also make sure the compressor isn't set higher than 20psi. No guessing when it comes to a boost leak test, I always question the authenticity of the results when someone say 20psi because that is the most common number being thrown around when a leak test is discussed even though a real test rarely results in exactly 20psi.

 

[ekizenbe]

I know for a fact that job was done correctly, the reason I didnt get to see it was that I was manning the compressor(long story) but he and my other friend both reasonable long time dsm'rs performed the test. So lets assume that I am correct in stating I have no boost leaks

 

[Killa_dsm]

Your wastegate actuator might need a little preload on it. Just place a couple washers between the turbo and the actuator where the 2 bolds hold the actuator to the compressor housing. This helps to make sure the flapper door is completely closed.

 

[assault187]

Have you checked Ignition timing recently?

 

[99gst_racer]

First make sure your actuator arm is still connected to the flapper's arm.
Then verify that the flapper completely covers the wastegate passage. Too many times I've seen port jobs that were larger than the flapper itself.

Also, back when I ran a B16G a couple years ago, mine also had the actuator shimmed like what Killa_dsm was referring to. It seemed to do the trick. I had quick spool, and boost held strong at 23-24 psi.

 

[lapeer20m]

did you ever figure it out? My turbo also spools very slow......hits about 7psi around 6K rpm. I did a leak test and have just a small leak inside the intake/throttle body. When i pressurize the system during the leak test it takes about 30 seconds or so to go from 20 to 0 psi.

 

[ekizenbe]

it was the wastegate actuator i shimmed it and its better although i still feel something is up

 

[numlock666]

are you running an MBC? I just had the same problem you decribed, just one day boost went down from the usual 15psi by 3200rpms to 7psi by 4000 creeping to 10lbs by redline. Turned out to be my wastegate actuator wasnt closing all the way due to pressure being stuck in between the wga and mbc so I made a bleeder fitting with a small 1/32" hole in it (small male to male plastic barb with hole about the size of a paperclip in it) and stuck it between the MBC and WGA. Problem solved, weirdest thing was that it ran fine for years like that and one day poof! 7lbs.

 

[oldman]

Please tell me your Dejon didn't come without the bleeder hole, all ball and spring MBC's need the bleeder hole.

 

[lapeer20m]

I fixed the slow spool problem on my tsi today. Swapped out the turbo with one from the junk yard and found the hole inside the wastegate that the little wastegate door is supposed to cover when closed had been significantly enlarged. The hole was much bigger than the wastegate door which rendered the wastegate inoperable.