Best A/R for a PT6262 T4

[prj]

Ramp rate seems slow.
If the map is for smaller turbo then I know why as well.
It should be better after I map it...

[Thuppu]

The map is made for a T03/04 5855 AR.63. Forgot to mention the head is now lightly ported, seats and valves re-shaped.

[V6quattro]

note that the AR is relative. 0.82 AR for a small frame turbo is not the same as the 0.82 AR for a large frame.

You meaning T3 and T4 right?

After some time their spray pattern goes to cr*p. They still work at higher IPW's, but car starts misfiring at idle, if trying to idle at lambda 1.
Setting idle to lambda 0.9 mostly cures this problem, but then you're running rich at idle all the time.
The injectors are not even specced by the manufacturer to run below 1.5ms, but you need about 0.8-0.9ms to idle at 800 rpm with lambda 1.

Fit EV14, and the misfiring goes away, and car idles perfectly smooth at lambda 1.

Experienced this on multiple cars now.

I will take a look at the EV14. Sounds good. Tanx.

[Billman]

When talking about spool here, how does this sound..? CT3B 5658 AR.84, boost starts to raise from 3000rpm, 1bar@4000, full boost 1,7bar@4800-4900. 7A ex cam and cut AAN ex cam as intake cam. Not mapped yet.

I don't know the exact specs and what gear but it sounds very laggy.

[Thuppu]

I don't know the exact specs and what gear but it sounds very laggy.

Jeah, propably need to re-clock the cams..?

[prj]

You probably have map for smaller turbo so N75 duty is like 50% or something by 3500 already, that's why it spools like ****.

[Thuppu]

You probably have map for smaller turbo so N75 duty is like 50% or something by 3500 already, that's why it spools like ****.

Ok, hope thats it. Not my favorit job timing cams... and the cam-setup I use have been used before with good results.

So I can test the spool unplugging the wastegate hose?

[Thuppu]

When talking about spool here, how does this sound..? CT3B 5658 AR.84, boost starts to raise from 3000rpm, 1bar@4000, full boost 1,7bar@4800-4900. 7A ex cam and cut AAN ex cam as intake cam. Not mapped yet.

Tested the spool more today. On 4:th gear it's like this:

0,1 - 2000
0,2 - 2500
0,3 - 3000
1,0 - 3900
1,7 - 4200

How does it look?

[Billman]

seems better! Still a bit laggy but better.....maybe it is like this because of the cam profile. You should check what Prj said.

[Thuppu]

Got confirmed of my mapper, porkkis, that the map isn't like that for a small turbo. One reason can be my diy exhaust manifold, the pulsses don't suit the divided turbo hot side..?

[Nik0las]

http://turbodirect.co.za/site/index.php?option=com_content&view=article&id=709&Itemid=21

[A80Avant]

Tested the spool more today. On 4:th gear it's like this:

0,1 - 2000
0,2 - 2500
0,3 - 3000
1,0 - 3900
1,7 - 4200

How does it look?

those look to me worse than a GT3076R with 0.82AR which i had with adu cams by about 400rpm. That CT5658 is supposed to be the equivalent to the 3076, and the 3BB version is made that way to overspool the garrett. That difference could by partially down to cams though, but im not sure 400rpm would completely be eliminated. My car had stock head and at the best of it's time(enginewise) had 2bar at 3900rpm on 4th gear. and at the time when the compression was low, it had it at about 4000-4100rpm.

[Nik0las]

I would not recommend Precision to any one! They sesms to be a bargain but on what price is the question:

"This specific Precision shaftwheel’s blades measure 1.4mm thick and this component is made in China by a company called Worldturbocharger, this company is well known for manufacturing “copy” products of OEM original Garrett, KKK, IHI, Holset etc – this company uses a material called K18 for the turbine head, which is a steel derivative with a high thermal ceiling, but by no means anywhere near the same quality as the Inconel 713LC material used by Garrett, KKK or Holset, hence the thicker blades on the Precision turbine, thicker blades simply mean more weight, and for any component which relies on its ability to accelerate, weight is not great. The shaft also appears to have been friction welded onto the turbine head.

What is also interesting is that Precision and TurboneticsINC both use this component in their turbochargers, in fact the shaft in this Precision turbo still has the Turbonetics logo cast into the back of the shaftwheel which an be seen in the pictures below."

http://turbodirect.co.za/site/index....=709&Itemid=21

[Billman]

That's why for a budget -high tech- turbo people should consider less fancy bullet proof turbos with 360 thrust bearings.