Shimmed wastegate. What else?
09-04-2002, 03:01 AM
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Shimmed wastegate. What else?
The car is a -89 turbo. It has 270hp at 5400rpm, with max torgue of 393Nm at 4280rpm. And by the way I'm talking about the engine hp, not the wheels. This is only with the chips changed, everything else is stock. Maximum turbo pressure is 2.0bar, and it's dropping pretty fast after that 4300rpm.
Now I was thingking about shimming the wastegate, but what else has to be done? Are the stock injectors still OK? Turbo pressure is some what adjustable, so if I just take it down a bit after the wastegate is shimmed? Or maybe remove the adjuster completely that came with the chips? And finally, how much to shim? I do not want to pass that 2.0bar of turbo pressure, because after that the ignition cut off kicks in...
Now I was thingking about shimming the wastegate, but what else has to be done? Are the stock injectors still OK? Turbo pressure is some what adjustable, so if I just take it down a bit after the wastegate is shimmed? Or maybe remove the adjuster completely that came with the chips? And finally, how much to shim? I do not want to pass that 2.0bar of turbo pressure, because after that the ignition cut off kicks in...
09-04-2002, 05:23 AM
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Looks like you've got it covered. You really need to do both; shim the wastegate and install, at a minimum, a manual boost-controller (electronic would be better). That's because these mods addresses two different, but related boost-management issues.
First, shimming the wastegate will increase the spring-preload and prevent the exhaust-pressure from forcing open the wastegate valve at high-RPMs. I would shim it about 3.5-5.0mm:
Then with higher spring-preload using the same boost-control signal from our boost-controller will give too much boost. So you'll need to turn down the controller. However, you cannot simply get rid of it because the stock programming in the KLR computer rolls on the boost slowly and rolls it off at high-RPM. So keep the manual controller in there.
First, shimming the wastegate will increase the spring-preload and prevent the exhaust-pressure from forcing open the wastegate valve at high-RPMs. I would shim it about 3.5-5.0mm:
Then with higher spring-preload using the same boost-control signal from our boost-controller will give too much boost. So you'll need to turn down the controller. However, you cannot simply get rid of it because the stock programming in the KLR computer rolls on the boost slowly and rolls it off at high-RPM. So keep the manual controller in there.
09-04-2002, 07:24 PM
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Is there any advantage to me shimming my waste gate with the AVC-R installed? Maybe to make sure the exhaust isn't opening it at all? I run around 15.5psi of boost with my K26-8 and see full boost at 3650rpm in 3rd gear and was able to see it holding steady at a little over 5000rpm in 3rd gear but was not able to keep watching the gauge. Can you shim the waste gate without removing it?
09-04-2002, 09:55 PM
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[quote]Originally posted by tazman:
<strong> Can you shim the waste gate without removing it?</strong><hr></blockquote>
yes it is possible but not very easy
Konstantin
<strong> Can you shim the waste gate without removing it?</strong><hr></blockquote>
yes it is possible but not very easy
Konstantin
