HKSA (ebay exhaust N1 style) vs. Rx7.com brand exhaust
Senior Member
Joined: Apr 2001
Posts: 352
Likes: 0
From: Winchester, VA
Correct me if I'm wrong, because I don't claim to be a turbo expert, but the internal wastegate under my impression on the stock twin setup doesn't divert exhaust through either turbo. Instead it's a bypass for excess pressure to be diverted to the exhaust so you can limit the desired pressure that the turbos are building. Or it's a bypass of exhaust gases so the turbo's only spool up to a certain speed/ pressure. I believe that the actuator is responsible for adjusting the flap to divert exhaust gases to the secondary turbo. If you port your wastegate than you have a larger bypass of your turbo's therefore you can control boost alot easier. The main problem with the stock wastegate is that it doesn't flow enough. kind of like a sink drain. It works fine when you aren't flowing that much water, but backs up when you have more water flow. The boost creep is just backup from my impression. I can't remember whether the Wastegate is pre turbo or post turbo venting though.
Originally posted by crazyrx7
It diverts the exhaust gases to the secondary turbo. The faster it opens the bigger the boost spike is. When you port the waste gate you make the hole bigger therefore lessening the boost spike/boost creep.
It diverts the exhaust gases to the secondary turbo. The faster it opens the bigger the boost spike is. When you port the waste gate you make the hole bigger therefore lessening the boost spike/boost creep.
root
Joined: Mar 2001
Posts: 1,200
Likes: 0
From: Phoenix, AZ
Yeah, crazyrx7 doesn't know what he is talking about...
The wastegate bypasses the exhaust so it does NOT go through the turbo.. It is used to regulate boost..
There is a flapper door similar to a wastegate on the FD though.. but there is also a wastegate
-Zach
The wastegate bypasses the exhaust so it does NOT go through the turbo.. It is used to regulate boost..
There is a flapper door similar to a wastegate on the FD though.. but there is also a wastegate
-Zach
Ex fd *****
Joined: May 2001
Posts: 1,782
Likes: 1
From: Ventura CA USA
The are 3 flapper valves in the exhaust/Turbo system on the FD:
1-The Turbo Control Valve - closed below 4500 rpm , blocks exh flow to second turbo, Biggest flapper visible through the engine side of the turbo manifold.
2-The Turbo Precontrol Valve - smaller flapper, bleeds exh to second turbo for prespool, also partly controls primary boost (acts like wastgate for first turbo) the smaller flapper visible through the engine side of the turbo manifold.
3-The Wastegate, another flapper, Diverts exh around BOTH turbos to control Both Pri & Sec boost, The wastegate is under a cover on the exh side of the turbo manifold.
1-The Turbo Control Valve - closed below 4500 rpm , blocks exh flow to second turbo, Biggest flapper visible through the engine side of the turbo manifold.
2-The Turbo Precontrol Valve - smaller flapper, bleeds exh to second turbo for prespool, also partly controls primary boost (acts like wastgate for first turbo) the smaller flapper visible through the engine side of the turbo manifold.
3-The Wastegate, another flapper, Diverts exh around BOTH turbos to control Both Pri & Sec boost, The wastegate is under a cover on the exh side of the turbo manifold.
Last edited by maxpesce; Nov 14, 2002 at 10:50 AM.
