Look, there is a huge issue with the non-linerarity of throttle to actual torque delivered to the wheels. While non-linearity is inherent to any forced induction system, we would rather have predictable non-linearity. Parallel operation without a transition offers this 100% of the time. Single turbo offers this 100% of the time. Serial turbos do not - atleast in Mazdas implementation.

You apply throttle in a non-seq or single turbo car, the torque is predictable even when generating positive pressure. With a stock FD3S sequential setup you're essentially gauging based on load (essentially guessing) when the second turbo will spool up and provide additional CFM to the system.

This is kooky and not preferred for any serious performance driving - especially anything involving lateral traction forces.

If you're more interested in ricky-racing around town and/or chopping up lanes on the freeway to impress the Impreza next to you, then have fun with sequential.

 

XST,

I really recommend, if you're seriously interested in non-seq, to perform the full modifications to the manifold, wastegate, and flapper doors.

It's also necessary to remove the CCV - another flow restriction when open.

 

Three random dyno graphs? Thanks for proving how long you've been around the FD community.

Brooks Weisblat's car was very well known, featured in magazines, and put down 364 RWHP. Brad Barber's car was also well known, also featured in magazines, and put down 367 RWHP, IIRC. My friend Brian's R2 was converted to non-sequential properly, and is a perfect example of the boost response of a non-seq. car done "right". These are not "random" dyno graphs.

BTW, you have heard of SAE correction, haven't you?

Fair enough, but I seriously doubt your car is set up or working right.

 

If there's any loss, it's because something is wrong with your car. You are aware that a sequential car is basically the same as non-sequential after the transition, right?

 

what is ccv?

 

I am very aware of sae correction as ive personally set up and run a dyno over 100 times. I said three random dyno graphs because you CANT compair them to eachother, its not a fair compairison. Ive seen dynos read as much as 20 horsepower different on the same day with the same car. but thanks for pouncing on me?

And I didnt lose power, I gained it with the midpipe. The graph is showing a gain in spool, but thanks for jumping on me for that one too.

The reason I even posted on this one was because it was starting to look like an "everyone should go non-sequential thread" and some newer people were chiming in and sounding like they wanted to do it cause it was the right thing. I was adding the other half of the argument. Either way ill be living the single turbo life soon so there is no argument.

The only thing I dont understand about this thread is the personal attacks.

 

And yes im fully aware they are the same after the transition, if fuel timing and boost are the same (on the same engine) your going to make the same amount of power.

 

i understand that you have to port the waste gates to 1.42" (correct me if im wrong) but how do you port the manifold and what do you port it to, and also what modifaction do you do to your flapper doors? im just trying to learn cause i really wanna go NS. thanks a ton

 

Sure it is. We're not talking about comparing average results, we're talking about comparing the best results for those cars on a given day, and with that assumption it is absolutely valid to compare them. They're not going to suddenly jump by another 20 horsepower, especially in the lower rpm range, which is what was being compared.

You're welcome, but you didn't come across as someone who knew much about what they were talking about.

I wasn't referring to your chart, I was referring to your use of the word "loss" and assuming you were comparing sequential to non-sequential, which is a totally logical assumption given the topic. Again, you're welcome.

Maybe you don't have the history to know that there have been multiple "disatisfied" non-sequential owners badmouthing the conversion who, when questioned, turned out to have done only the "poor man's" conversion and still have at least part of their emissions equipment on the car. One or two might even have had automatic transmissions. Your comments, especially about testing back-to-back on the same day, sounded very similar.

It would be extremely difficult to convert a car to non-sequential properly and test back-to-back in one day unless you had an extra exhaust manifold, set of turbos, block off plates, and an upper inake manifold just standing by, already converted.

 

There are other threads where this non vs seq debate can be discussed. Can we get back to talking about the diagram? This was a good informative read until midway the second page where the old debate started again.

 

can anyone tell me what is CCV?

 

can someone please tell me what you do to the flapper gates? I hear people say that you are suppose to weld it or somthing? please, i wanna do this project but thats the only thing i dont understand. thanks

 

Do you need some kind of engine managment to run non safely?

 

well there are basically three flappers...the one on the manifold (between the engine and the turbos) needs to be removed or welded full open.....recommend removing for safety reasons (you're stupid not to, its restriction). The second is the precontrol flapper, needs to be welded or braced open at about 90% to cause smooth flow to the secondary turbo. Third flapper is the Wastegate, Primary turbo has to be removed from the housing and then you'll see the wastegate door, which needs to be machined to 1.24 or 1.25 for boost safety.

And thats the flappers....figure the rest out by searching...like I did

 

No. All the boost controller does is restrict air to the wastegate. So it needs to be inline between the intake manifold (where it gets boost) and the wastegate. This method allows you to fine tune your boost setting and reduce boost spike (assuming you have a ported wastegate) by simply opening and closing the valve for adjustment.

 

1. Yes, take that damn rats nest out. I just used tin snips to cut it out so I didn't have to remove my ignition and stuff.
Just run silicone lines directly between the points in the diagram. Also to make it easy, get a pack of multiple colored zip ties, so you can color code your hoses with them at each connection. This makes trouble shooting without a diagram much much easier.
2. I got mine at rx7store.net and they fit perfectly. I used high temp silicone gasket maker for the seal.
3. Try to find some heavy duty rubber caps. I found mine at autozone. Get an assortment of sizes between 1/8th to 1/2.
4.No, the primary wastegate must be able to sense manifold pressure to open. Run a line from the wastegate to the intake manifold (be sure not to use the 4 nipples on the UIM that just pass through as mentioned before in this thread)
If you do not have a boost controller (which you should) than just place the stock restrictor pill in the line, close to the wastegate.

 

This is piece is pretty important because I am sure you have seen oily residue in your intake manifold. After time this will build up at the pressure sensor and could possibly cause problems. I would suggest cleaning the pressure sensor out regularly with some sort of spray that is safe for these types of components.

 

I think its 1.24" not 1.42"
Basically for the manifold you must grind out a tube in the flow path. and port the channel between the two exhaust paths.
Also port match the manifold with the turbo housings. Also the primary must be ported to a similar size as the secondary (or vice versa, I cant quite remember)
I will check into it more for you.

 

sweet thanks man. that would be great. cause i wanna get this project done soon. thanks

 

Do not do this.

Run a line from one the nipples on the compressor housing to an inline solenoid, bleeder valve, to the wastegate. These control lines are on the compressor housing just for this reason. Running to the UIM will decrease wastegate response and accuracy (stock IC/piping has a drop of around 3-4 psi based on what I've seen).

 

can I buy one of these at a local auto store? or do i have to go thro mazda?

 

fc1jz do you have pics of when you did this project?

 

Actually domestic speed shops sell similar type of filters. You don't need the Mazda OEM one, although it's typically smaller.

 

Alternatively, you can run a vacuum line with no restriction from the primary compressor housing to one of the nipples of the wastegate actuator, and then run a second line from the second nipple on the actuator to a bleed valve.

With the valve inline (as you described), the valve acts by restricting the pressure going to the actuator. After the actuator (as I described), it acts by bleeding off pressure requiring more to overcome the actuator's internal spring. The results are basically the same, but if the inline valve is closed for whatever reason, the wastegate will never open. With the valve after the wastegate actuator, it means you'll just max out at 7 psi, and even full open, you probably will not exceed 15 psi. It's safer to put the valve after the actuator, especially if someone else works on your car periodically and might accidentally close it.

I ran a line from the nipple on the primary turbo elbow to my wastegate actuator and a second line from the actuator to a brass barbed fitting. I did have a Sharpe valve (round dial-type, typically used to control air pressure for automotive paint guns) on the end of the line attached to the fitting, but couldn't reach the boost level I wanted, even with it fully open. Eliminating the valve and just using the brass fitting (which provided enough restriction in the line) not only limited my boost to 14.5 psi, but made a piercing shriek at full "steam" which was kind of fun.

 

You're absolutely correct Jim.

I didn't address the end-of-loop scenario because I wanted the focus more so to be on "use the compressor vent NOT the intake manifold for WG control!".

The trick in having a "safe" situation with the restriction device pre-actuator is to use a solenoid valve with default state NO (normally open) with a vent port that is switched on and off based on duty cycle.

(that is if you're using the electronic route)