Doug71zt Posted June 22, 2003 Share Posted June 22, 2003 I just ran at test-n-tune last night and it was the first time that I had really floored the car with the new turbo (T3 stage3 .63/T04E60 running turbonetics internal WG) With the manual boost controller set at 7PSI - it briefly pauses there while on its way off the end of the gauge (20 psi). Yikes! No knocking or anything but still stock pistons. I had the internal gate bored oversize when the turbo was built. I think its .875". Am I going to have to go external on this turbo or what? The speed it shoots to 20 psi at 4500-5000 rpm makes me think that it needs a whole lot more bypass. I have a new GNX dual port actuator on this thing and everything is working right. 7 PSI and the arm goes full travel. I guess that 3" downpipe and straighthru exhaust means no real backpressure to work against. I ran 12 passes with the wastegate wide open and modulating the throttle. Not too much area under the boost curve like that - but still ran a somewhat consistant 12.7 at 107. My 60ft is around 1.8x with drag radials. Apart from the boost creep - everything worked great. How big can I go with this WG hole? Anyone with personal experience with a similar WG setup? Thanks - Doug Quote Link to comment Share on other sites More sharing options...
yo2001 Posted June 22, 2003 Share Posted June 22, 2003 Mine is .9xx". Seems to stick 10psi with my 60-1 and stage III Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted June 23, 2003 Share Posted June 23, 2003 That is a pretty big turbo to keep at 7 psi. I had that problem with mine, except I have the Stage V turbine. What I found out was I needed more tension on the actuator rod. If you are using a dual port WG actuator, you can use a dial a boost to introduce boost to the lower port, and that will help control it. I believe the boost control works opposite of the scale at that set-up. I pulled my actuator off and threaded the rod further in the hopes I could get better control that way, but haven't driven the car to see. I guess I would need Jeff to say if he did anything to the WG hole, I have no idea. I have gotten as high as 24 psi with mine fooling around, so be careful. It has been kind of inconsistent, so I am working on that to see what I can do. Try raising your boost to about 13 or 14 psi and see if you have less creep. You are bleeding a lot of exhaust gas to keep the turbo at 7 psi. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted June 27, 2003 Author Share Posted June 27, 2003 Adjusted the MBC to 15 psi and got a real surprise. It bounces from 15 to 20 about 4500 rpm and starts compressor stalling and chuffing as the computer cuts fuel at 22 psi. I could control it with the throttle when it was wastegated to 7 psi as there was enough time to modulate the throttle but not when it gets wound up to 15. A 1.5 inch flapper valve is on the way. The hole will be bored up to 1.25". That should cure the creep problem as the hole is double the area of the current one. Quote Link to comment Share on other sites More sharing options...
TimZ Posted June 27, 2003 Share Posted June 27, 2003 That is a pretty big turbo to keep at 7 psi. I had that problem with mine' date=' except I have the Stage V turbine. What I found out was I needed more tension on the actuator rod. <snip> Try raising your boost to about 13 or 14 psi and see if you have less creep. You are bleeding a lot of exhaust gas to keep the turbo at 7 psi.[/quote'] Sorry but this is not accurate. The amount of exhaust flow that needs to be bypassed increases with boost, simply because the ratio of the total exhaust flow to the amount of exhaust flow required to make a given boost increases non-linearly with boost pressure. It's generally much easier to hold boost at 7 psi than it is at 15psi, because there is less total flow at 7psi. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted June 28, 2003 Author Share Posted June 28, 2003 Very interesting point to ponder - thanks Tim. We'll see how the 1.25" hole works out. May have to go to a stage V wheel on this one. Cheers - Doug Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted June 28, 2003 Share Posted June 28, 2003 Doug, I believe the hole in my .63 GN housing is about 1 3/8" and I am running 24-25psi. 1.25" should help your flow quite a bit. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted June 29, 2003 Author Share Posted June 29, 2003 Scottie - Thanks for the reassurance - what size is the flapper on your WG? Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted June 29, 2003 Share Posted June 29, 2003 From the signature I would say I have a 1/8" border making it 1 5/8". It is a custom GN style DP. As you probably already know, try to see if all is aligned properly before you bolt it up. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.