Now it has been said that with the greddy turbo for the Si if you use a 3” downpipe that boost spike will occur. But what if you use the 3”dp with a 2.5” catback exhaust. I want to put the 3”dp on my car before I go to get it tuned. I’m going to be using the hondata to tune the car when I get back from Miami next month. I’m just looking to tune 15psi max for now. Does anyone know if doing a 3”dp with 2.5 catback will be a problem or will I be okay. Does anyone with a greddy turbo have a 3”dp? PM me.

Thanks.

 

3" rules damian, come ot me and ill make you a dp.... mayeb it spikes cause you have an internal wastegate

 

Well I heard you get spiking when you run full 3" turbo back but I don't know I might have you make a 2.5"dp

 

The internal wastegate in these Mitsu turbo's doesn't like to hold boost very well, especially with larger exahusts. I know I had a hell of a time spiking all over the place with a 2.5" DP and 3" catback on my GReddy kit.

 

on other mitsu turbos on dsms (i.e. 16g's, big 16's, ect.) they have the same problems...if you plan on keeping the turbo you could prolly send it out somewhere and have them port the wastegate opening out and install a larger flapper. that usually takes care of the problem

 

Well I'm planning on saving that for when I send it out to Forced Performance they said they can upgrade me to a FP green turbo with a larger internal wastegate. But I will just run a 2.5DP with my N1 Cat back 15 psi should be okay.

 

Where do you guys get your information from? You can upgrade to a 3" and you won't have boost spike. Call GReddy and they will tell you themselves