well to start off i dont drive an evo, i actually drive an rsx-s with a bolt on greddy kit but i have some questions about the turbo.

there isnt a lot of info available on the turbo because most people go with a t3 flange setup and i dont have $1,000+ for a t3 garrett/precision/bullseye, etc turbo, plus the cost of all the other supporting parts so thas why this question comes up.

so on the rsx greddy kit the manifold is a piece of **** and cracks so naturally it happened to me.

the turbo i have is a mistubishi turbo on a td06 housing, the turbo name is T517Z and from what ive read it is the equivalent to an 18g. i know the rebuild kit is"Mitsubishi TD05/TD05H/TD06 Complete Superback and EVO Rebuild Kit" and the description to the rebuild kit says"This is a complete rebuild kit for Mitsubishi TD05/TD05H/TD06 turbochargers. This kit will ONLY work for superback compressor wheel models such as big and small 16G, 18G, 20G, and EVO turbos. If you are converting an older style flatback compressor wheel turbo to the newer style superback (ex: 14B to 16G), you will need this kit to complete the conversion (as well as the 16G compressor wheel)."

the turbo comes with a 7psi internal wastegate, however i want to convert it to an external wastegate. my reasoning for this is 90% curiosity and yes, i have the knowledge to modifying the turbo and setup, i just want to experience it with this specific turbo. with my boost control solenoid i can raise it to a maximum of 15psi and ive "heard" stories where people raise 16/18G's beyond 20psi on dsm's/evo's, whether this is true or not, i dont know because ive never worked on a mitsu.

obviously 15+psi is out of its efficiency range but i was wondering if anyone was still making power on this turbo, or the equivalent, passed 15psi and if the power sustained to redline? or if anyone knows the recommended safe boost levels, as well as max boost levels.

yes, it sounds like stupid questions and the reasoning is even worse but im curious and no one on ClubRSX will know the answer to these questions.

tia

 

On DSMs, 16g's and 18g's don't even start making real power till about 20psi. Remember, just cause its out of its peak efficiency range doesn't mean it wont still flow more air. Thermodynamics gives us equations for an ideal gas that for our case says temperature will increase proportionately with pressure, but because turbos are adding entropy to the system the air heats up more than the ideal gas law states.

This difference is how the efficiency % is calculated. So increasing boost past the peak efficiency island will still give more air volume, just not a 1peak efficiency) ratio.

Of course you have to think about cooling also, more boost = more heat even if 100% efficiency was possible. Your car will have its own threshold of how much heat it can handle before detonation. Evo's have a very good head design which was improved from the 1g and 2g designs to now make the same power with less timing and less propensity to knock.

Short answer, 15psi is barely scratching the surface. English Racing lets their EvoIII 16gs spike to 40psi when going for max power.

E98 FTW

 

Strictly Modified is in Schaumburg, they can help explain some of this to you I would bet.

External gate is completely unneeded. You are better off saving the money to put toward future mods like a T3 conversion. Even if you TIG and get the parts cheap you are halfway there by the time you get it all done.

The boost to power threshhold is a funny operation. On a larger turbo like the one on my car, it makes 495whp at 19psi, but 588 at 23. Just that little step added almost 100whp. Add 3 psi more and its only at 623. 15 on a 16G is pretty low, but since the K series head flows well it might be using more airflow (cfm) at a given boost level. Have you dyno'd the car? That will speak volumes on what you need to do with the boost.

aaron

 

Pun intended?

 

no i havent dynoed the car. i want to get a dyno tune once and be done with it. im running hondata kpro (popular k series tuning solution) with a greddy baseline tune. i added 15% fuel across the board and my AF is perfect at cruise, idle and wot but more importantly, i get no knock so ive been driving around like that for now on 93 octane.

i understand that the k series 3 lobe vtec heads have great airflow and the turbo wont sustain high boost all the way up to 8,600rpm due to the cfm but its just an idea i have in mind.

i essentially have a t25 manifold and tial wastegate at my disposal that i want to try this out on. basically all i will be spending money on are a downpipe (i want to get a 3" one anyway) and welding the wastegate swing valve shut so the cost really wont be so high.

would it really be a waste of my time and something i should just give up on? i know its a pretty noob question and it wont really compare since the rsx and evo motors are so different, im just trying to get a second opinion to make sure im not doing something pointless lol.

ill go to that shop if i feel as though im stuck. just want to poke around first lol