Is my boost to high on a stock TTA ?

[transampacecar]

Hi
I purchased a stock TTA with 33,000 miles on it. Car has no mods.
When I am at WOT, at around 4800 rpms, it starts to miss or buck. Up to that RPM it is fine.
Here is my concern. When it reaches the 4800 rpm, the factory dash boost gauge goes to 19 and sometimes 20. I see that the redline on the boost gauge is between 17 and 20
It has the factory chip as well
Is this boost to much? Any ideas why it would seem to miss when it hits 4800 rpm and the boost being 19 or 20 at 4800 rpm ?
Also,what is the factory maximum boost suppose to be when it was built ?

 

[Lee_Burough]

A scan tool might tell you why its acting up....It can also keep you from blowing your engine into pieces.

If you have knock retard, (something a scan tool will tell you), you may be on the verge of breaking your crank

Get a scan tool and report back with some data, and some of the master TTA owners will help you troubleshoot your drivability issue

 

[transampacecar]

Thanks
two other questions.

1. Is there a way to turn the boost down on a stock TTA ?

2. What should the max boost be since it is stock ?

 

[Lee_Burough]

Stock boost for a TTA was around 16-16.5 PSI.

I've heard it reported that a few TTA's had adjustable wastegate actuators from PAS....If your car is one of them, you can adjust the boost downward. Stock wastegate length is 5.25 inches....I think.

If not, you can look Here to see a description of a home made adjustable wastegate actuator. The longer the actuator, the less boost....

 

[Gokou]

You say 33,000 miles and all stock, and it starts to "miss" at 4800 rpms... my hunch is the valvesprings are weak and they're starting to float.

If you suspect high boost, try an aftermarket gauge, if only temporaily; the factory gauges can be quite a bit off.

Troy

 

[TTAfreak]

my 10k mile TTA did the exact same thing when I got it.

there is a small vacum line that connects to the turbo. if this comes off, you will experience high boost and you could do some damage.

check this line. its a small line that goes into a Y connector comming off the side of the turbo.

 

[src76ta]

That line came off on my car also. The rubber over time becomes weak. Cut about a half inch off the end and if it still seems loose, a small black tie wrap will hold it on.

 

[1BADDAM]

Bad coil will cause it to miss/buck/surge at higher rpm's if the above mentioned doesn't cure. Ohm meter can tell you if one is bad.

 

[mark b]

Those "Y" lines take a beating from the underhood heat generated by turbo cars. If they are the stock units, they may be leaking even if not visibly cracked and would be worth replacing.

Also check to make sure the actuator thing is not binding or sticking.

Cheaper fixes than a headgasket (or worse) from too much boost....