Evo 9 RS Stock turbo, stock cams, E-85 at RRE
Jan 7, 2019, 08:37 PM
#16
Evolving Member
Nice, thanks for sharing the boost plots!
Forgive me for asking, but why does boost fall off so hard at 6krpm?
Is there a way to force the boost curve to stay flat or creep a little?
Forgive me for asking, but why does boost fall off so hard at 6krpm?
Is there a way to force the boost curve to stay flat or creep a little?
Jan 8, 2019, 08:55 AM
#22
Evolving Member
@2006EvoIXer Stronger wastegate? Is there a stronger wastegate for a stock IX turbo? Is the wastegate being blown open just before 5.5krpm and coincidentally boost, hp and torque all fall off too?
Is it possible to mod the existing components to help the stock IX turbo hold 27psi out to or past 6.5krpm?
Would a ported turbine housing with ported wastegate passages help and then an upgraded wastegate?
Are there upgraded turbine wheels and higher flowing O2 housings that help reduce back pressure? I’m asking for a friend that needs to keep his ride incognito for smog ***** in good ole commifornia...
Thanks in advance!
Jan 8, 2019, 09:35 AM
#23
I recall the stock WGA is 13 psi. General rule of thumb is it can hold up to double the boost (26 psi). So it is possible that your WG starts to leak. You can put on an 18 psi WGA to hold it shut better but you need to consider what that is really doing. Realize that your stock turbo is not designed to boost over 24 psi. So what happens when it is forced to? It will boost with more heat. As it starts boosting with more heat, the amount of oxygen will eventually be less with more boost, so you will start losing power with more boost.
If you want to squeeze out another 10whp, you can install 18 psi WGA and pay for a retune. Personally, I'd swap to bigger turbo and get a retune and get closer to 50whp. Your stock turbo is already overworked as-is. Make sure to check your turbo for shaft play every time you change your oil. If you run E85 often, make sure to use good oil with high Zinc and stick to 3,000 mile intervals.
If you want to squeeze out another 10whp, you can install 18 psi WGA and pay for a retune. Personally, I'd swap to bigger turbo and get a retune and get closer to 50whp. Your stock turbo is already overworked as-is. Make sure to check your turbo for shaft play every time you change your oil. If you run E85 often, make sure to use good oil with high Zinc and stick to 3,000 mile intervals.
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2006EvoIXer (Jan 8, 2019)
Jan 8, 2019, 04:18 PM
#25
@2006EvoIXer Been using Amsoil Z-ROD 10W30 for quite a few years now and I always change at 3k 
Jan 8, 2019, 04:27 PM
#26
@2006EvoIXer Yea I over maintain my car but I've never had an issue in 127k miles
Last edited by jr-mack; Jan 8, 2019 at 07:11 PM.
Jan 9, 2019, 08:51 PM
#28
@Wicked_X
Piston #2 grenaded on my way to work one morning. No CEL, not running hot, not running weird or anything. Literally NEVER had an issue with the car before that. Nobody can give a definitive answer as to what happened, but the most plausible explanation so far is that the piston pin got cracked somehow and eventually let go. Maybe a hard downshift at the track caused it to crack?
Piston #2 grenaded on my way to work one morning. No CEL, not running hot, not running weird or anything. Literally NEVER had an issue with the car before that. Nobody can give a definitive answer as to what happened, but the most plausible explanation so far is that the piston pin got cracked somehow and eventually let go. Maybe a hard downshift at the track caused it to crack?
Jan 9, 2019, 10:25 PM
#30
@Wicked_X Yep! I chalk it up to random failure. Got 123k out of the stocker with zero issues (bought the car in 2010 with 6700 miles). Did countless canyon runs and 4 track days at Buttonwillow and drove home each time (the track is 5 hours from where I live in San Diego). Can't beat that for reliability. A well maintained car will treat you right