Thread: W11 Avenir engine T25 Ball Bearing Turbo in a 1995 G20 Questions

Unfortunately no I don't have those pictures before it was installed, but I will mention all of this beforehand, my mechanic is reviewing everything but I just wanted to have some background knowledge to understand what could be causing the high psi issue. I will keep you guys posted. thanks again this has all been a great help so far!!

Hi again can I ask you guys what is recommended for a nice clutch kit for my setup? I currently have the ACT NX9-HDSS clutch kit, unfortunately it's slipping and not able to hold the power, I've heard of 6 pad sprung but from what I understand more gear rattle more aggressive engagement and wears out quicker if I'm driving this everyday. This will be a car I am driving everyday until November Any help would be appreciated

Well TinoG20, I have a W11 sr20det running in my vehicle an it came initially running 0.95 bar boost with an upgraded IMPUL ecu. What I have noticed is that the wastegate lines is T from the boost reference on the discharge piping to the wastegate and then to suction this allow the boost pressure to rise to .95bar, when you connect the wastegate solenoid to the mix it dropped the boost back to 9 psi. so check you boost reference setup.

Hey Speedracer thanks for the reference this sounds like my issue, I don't have an IMPUL ECU but mine is a JWT ECU stock setup initially from a U13 in which they mentioned will work for the W10 and W11 engines. I will ask him to check the boost reference setup but is it essentially all I need is a wastegate solenoid? Where can I find one through Greg at G Spec in California? He is a reliable source and I have bought all of my SR20DET parts from him. Sorry for the questions trying to figure out the technical info you just gave me My buddy mention that T is the shape of the lines I assume?

Just some advice, 14-15psi on a t25 plus the stock top mount intercooler = higher intake air temps. The ball bearing turbo will last longer at higher boost compared to the sleeve bearing version but 14-15psi is still to high, 12psi is the sweet spot for the t25. Check your wastegate, I got a Jdm det and it had an HKS wastegate actuator on it from the importer. Believe it or not HKS made a 15psi actuator for the s13/14 sr20det cars and they can be used on the fwd motor also. Plus the 370cc injectors are way past max flow at 15psi, it's only a matter of time before you have some sort of failure.
Good luck and happy boosting.

Think about it this way. A t3 turbo at 15psi should make 300hp on the sr20 while a t25 at 15psi will make about 260hp. That's shows you how much of an air flow(cfm) difference the larger turbo is putting out.

Hey se200, thanks for the reply man very helpful in knowing the range for the T25 BB turbo, I'm going to the mechanic after work and will ask him to investigate the high 14psi, I did call a distributor for Garrett turbos and they also mentioned 14 is too high and that around 10-12 is maybe a good range. I do have 370cc injectors on my W11 engine, and so far I hope that by finding out the culprit of the high psi this can allow me to keep the ACT NX9-HDSS clutch kit that I have on my car as it's a nice setup. That kit is rated at 240 ft/lbs capacity so even if I can bring it down to stock 9 psi I will be happy. This is my daily driver I never track this car so the 6 sprung pucks will too much for daily city and highway driving. Thanks for the help all of you have given me so far, it's very much appreciated

Hi se200 wanted to ask let's say the wastegate actuator, boost lines are all in working order, can I buy an add on that can lower the boost ? Thank you

Unfortunately you can only raise boost from the preset wastegate actuator. It sees to be your wastegate actuator is failing or is not the correct OE art. Make sure the actuator holds pressure with no leaks and that it has a direct boost/vacuum source. If possible don't use a shared port or line for the wastegate.

Hey everyone wanted to give you an update, so I believe and hope this is the issue. I had a W10 engine with Journal Bearing T25 and upgraded to a W11 engine with T25 BB, since the top mount setup was already configured in the first swap in 2009 what my mechanic did was keep the W10 actuator in the W11 setup. So with that being said I can only assume the W10 and W11 actuators perhaps are a slightly different length causing the high 14psi? I know se200 mentioned an HKS wastegate actuator from the S14 RWD style and that it has been used in FWD applications is this true? Tomorrow I'm going to bring my W11 actuator to the shop to compare lengths. If they are the same length and size then I hope that an HKS actuator will work for my W11 FWD stock application. Any input would be great I'm going to call Garrett Turbo and ask them if the W10, W11 and S14 have the same length rods in the wastegate actuator. I love learning new things everyday

Keep us updated.....