Hey gang,
I don't have an RX7, but my buddy does and I'm helping him do some work this weekend, so I have a quick question.

He has a 93 Twin Turbo that is basically stock. He bought a Manual Boost Controller for it today, it will be here on Friday and we're going to install it. I have quite a bit of experience with turbo cars, but never anything twin turbo. What is the difference in installing this MBC? I haven't gotten a chance to look at the car yet, but I'm assuming it has two vacuum lines, one to each wastegate actuator. Is that right? So how does that work with a MBC? Do I do 1 line from the intake to the MBC, then have the second line out of the MBC split into 2, one for each turbo?

Any help would be appreciated!

Thank you so much.

 

http://www.robrobinette.com/boost_controller.htm

 

Thanks!

Thats what I was looking for!

 

I can just install the MBC where it said for the primary turbo, without messing with the Secondary turbo Pre-spool controller, right? Because that sounds a lot more complicated than I anticipated. If it were my car, I would mess with it, but my buddy just got his car, knows nothing about it, and is taking my word that I won't blow it up.

He has aftermarket intakes, FMIC, downpipe, and just wants to add a couple lbs of boost, that is our goal with this MBC.

 

Unless your buddy has $5k to drop on a new engine, you do not just want to 'add a couple lbs of boost' to this car. With the stock ECU you should not go over 10 psi. If anything you should be reducing the boost to compensate for the IC, intake and downpipe. You need to read the FAQ.

 

Don't mess with it. It sounds like the car is much more complicated then what you're used to (not trying to put down your turbo knowledge) But like the previous post said, just adding more boost is going to cause lots of expensive problems.

Just my 2C.

 

Alright then, lets go another way with this. I'm sure he'll want to keep it safe and reliable, and maybe drop it a couple psi, because he said he runs between 11-13 lbs now. So, to drop a couple psi with a MBC, can I just install it in the vacuum line to the primary turbo, and leave the secondary turbo alone?

I just got confused with the How-to talking about the Secondary turbo pre-spool controller, etc.

Thanks for the tips

 

There's only one waste gate. You want to install the boost controller in the vac line for the waste gate, unless you're having transition problems. Don't change anything with the precontrol, or you'll cause a whole new set of issues...

And like they said above, with a stock ECU, keep it at 10PSI.

 

You don't need to mess with the secondary line. However, you should ensure that you reduce the boost to 10 psi. One cold evening is all it takes.

 

Outstanding!

I didn't know there was only one wastegate. That was where I was getting confused. I will talk to him tomorrow and find out exactly what mods are done. He bought it the way it is, but is still in contact with the previous owner. He might have more stuff done to it besides what I listed. I'll make sure we leave it at 10 if he is still running the stock ECU and stuff.

Thanks for the help, I think we'll be good now. However, I am definetely going to keep reading up on these cars, just by the off chance I work on one again.

A TOTALLY DIFFERENT ANIMAL!

I do have plans for a 13B powered Datsun 510 someday, so I guess I need to enhance my rotary knowledge.

Thanks again!

 

if its stock twins with sequential turbo, its got 2 wastegates. If you only have 1x MBC, here's a diagram from hks' evc 6. its the same as rob's site xcept you T up both primary and secondary. This way bypasses the stock solenoids.



hope that helps

 

Are you sure? I'm pretty sure there's 1 waste gate... or at least 1 waste gate actuator.

 

One wastegate. The other is the precontrol. Don't mess with it unless you are trying to tune the transition.

 

I was under the impression that the actuator right next to the wastegate actuator (and looks freakin' identical) is the pre-control actuator, not another wastegate actuator - so one wastegate. . .

 

Here's a good overview of the system:

http://www.autosportracetech.com/RX-...erOverview.htm

 

Ah, just beat me to it!

 

Damn.. i'm sorry. i meant 2 actuators. since our turbos' got internal wastegate, still use 2 actuator to control boost. one for primary turbo and another for both. But i put up the diagram because he's only got one MBC, so you gotta T them up. I just thought Rob's site might be a bit more confusing for him because Rob's running 2 separate MBC's. check out Dale's website with the same hookup for the AVCR solenoids as the HKS diagram.

http://www.clubrx.org/default.asp?id...ntent=68&mnu=5

 

Teeing them up is not necessary. Attaching a boost controller to the wastegate line only is sufficient. I know that some people do this but since the wastegate and prespool actuators have different activation points stock (because there are different pill sizes in each line) I'm not sure why.

 

Thanks for the help guys, I sure appreciate it. I did some other reading about it last night and I think I have a pretty good grasp of the system. Thanks again,

 

If your buddy wants to up the boost a little bit, and do it reliably and without spending tons of cash on a new tune and fuel system, tell him to get a reprogrammed ecu. Pettit racing sells one as do other manufacturers such as RE Amemiya and Knightsport. Normally you can find them on the board or on ebay for pretty cheap.