How-To Guides
Knightsports EBS III boost controller install
I've always thought these were pretty cool, and happened to stumble onto one on Ebay. Here's a how-to on installing, using, and generally "the deal" with this neat boost controller from Knightsports.
Tools required: 10mm socket, screwdriver
Difficulty (1-10): 4
Time required: About 1-2 hours
There's a world of boost controllers out there, but wouldn't it be cool if you could simply control the stock boost control system? That's what Knightsports Japan thought as well! The FD actually has a pretty decent boost control system, but unfortunately you have no control over it with the stock ECU - until now.
The EBS 3 has been out for a LONG time in Japan, and truthfully I don't even know if it's still made any more. Browsing through Ebay the other day, I found one for sale from a seller in Japan. Ended up buying it for $130 - a STEAL!
Came with all the parts and everything, so I know I was good to go.
So, what exactly do you get with the EBS 3?
The primary components are the display/control unit, which comes in a nice fiberglass replacement for the top of the steering wheel column surround, the main brain box that everything hooks up to, the "sequential control adapter" that plugs in between the stock engine harness and the ECU, and a thin vacuum line. The parts I got also came with the bottom half of the steering column surround - don't know if that's how Knightsports sold it, or the guy pulling it off the car threw that in the box as well.
So, how does it work? The sub-harness taps into constant power, switched power, and ground from the ECU to power the unit. It also taps into 3 control solenoids - wastegate control, turbo precontrol, and charge control. The EBS 3 totally controls these solenoids, giving you boost control. Neat, eh?
There's also a small vacuum line that you plumb into the manifold. It comes with a nice aluminum "T" adapter to convert from the small plastic line to the regular size 3.5mm vacuum line.
So, time to hook it up. Remove the passenger side scuff panel with the RX-7 logo, then remove the passenger side kick panel to get access to the ECU. Undo the 3 bolts holding the ECU in place, pull it out, and disconnect the wiring harness from the ECU. You should end up with a big ole rats nest -
With that done, it's simply a case of plugging the Knightsports harness in between the stock harness and the ECU.
Carefully arrange the wires and the ECU and get the ECU bolted back into place. Took a little trial and error, but I finally got it together nice and clean.
Next, time to put the control unit in. Undo the 3 screws that hold the steering column surround together, and remove the metal trim ring around the ignition switch. Carefully pry the 2 halves apart, then undo the ignition switch light from the bottom half by twisting the bulb a half turn.
My EBS 3 came with a whole bottom half for the steering column surround, so I used that - read more on that later. The tabs that fit up into the top half of the surround have small holes drilled, and the fiberglass top half has corresponding holes. I went to the hardware store and got 4 self-tapping black anodized screws to hold the halves together. I assume the kit originally came with the screws, but you miss out on stuff like that buying things used.
Anyhow, run the cable to the display unit through the space between the cluster and the column, and set the control unit in its new home. It's cool, ain't it?
Screw that sucker together. I was able to get to all 4 screws just by turning the steering wheel slightly - no need to remove the steering wheel.
Last part is running the vacuum line to the engine bay. Run it through the firewall with whatever your preferred method is and hook it up. I still don't have a boost gauge in the car (I know, it's in the "to be installed" box) so I removed the rubber cap from the boost gauge nipple, put the cap on the T that came with the kit, and ran a short piece of vacuum line to the nipple. I tucked the T and the vacuum line behind the ABS shield, as I'm not sure how the plastic line will tolerate heat.
OK, now it's time to hook everything up to the main brain box. I decided to stow the brain box in the center console, back behind the stock ashtray, as there's quite a bit of room in there. The cable lengths actually fit about perfect for that location, leading me to believe they designed it like that.
There's 3 connections for the brain box - the cable from the wiring harness to the ECU, the cable from the display/control unit, and the vacuum line.
I parked it in the center while I was testing to make sure it all worked. The vacuum line is kind of neat to hook up - pop the plastic line over the nipple on the unit, then screw the nut down. Makes for a VERY clean and tight connection.
The harness coming from the ECU has a green wire coming off of it as well. This is an illumination wire - hook it up to a wire that gets 12v when the headlights are on to dim the display when you switch the headlights on. I tapped it into the ashtray light - worked great.
Here's a pic of the car running, and the display doin' its thing. Note the amber illumination for it - matches the stock gauges quite nicely!
So, how to operate it? Well, I got the manual with the unit, but it was all in Japanese. A post to the Far East forum on the RX-7 forum got me together with Inukai, who was happy to help translate the manual. He actually works for RE-Amemiya in Japan! Neat!
Anyhow, it's pretty simple to operate, and there are 3 modes. When you start the car, it's at mode 1 - Display. This shows boost or vacuum in real time, in kg/cm2. In the pic above, it's reading vacuum with the minus in front of the number. Boost shows as 3 digits - x.xx, where 1 kg/cm2 of boost would be 1.00, stock boost is 0.70, etc.
In Display mode, you can press the Up button to get a peak reading of the highest boost achieved. When looking at the peak mode, press Up again to go back to display, or hold the Down button to clear the peak memory.
In Display mode, you can use the Power button to toggle the boost control on and off. An LED just to the left of the Up/Down buttons will light if it's on. With the controller off, you'll run the minimum boost the turbos can produce - about .5 kg/cm2, or 7 psi. Yes, the car is slow with it off!
Mode 2 is boost setting. This goes from .60 to 1.70 kg/cm2, which is 8psi to about 23psi. This isn't the exact amount of boost you'll run, but close. You have to watch the display and/or your boost gauge to see what you're really getting.
Mode 3 is unknown at this time. I need to re-scan the manual for Inukai and have him take a look at that part. All I know is it says ".00" and you can increase the value in .02 increments.
So, does it work? Sure does. No check engine lights or anything funky. There's more I'd like to learn about it - there are some switches and a knob on the brain box, which I believe the knob is to increase sharpness/gain for the controller. Not sure on the switches. The display is nice, but is definitely no substitute for a boost gauge - a digital display just reacts too slowly.
Remember how I said I had a problem with the steering column? Turns out the right-hand drive column surrounds are different - the wiper stalk is on the *left* side, and the turn signal stalk is on the *right* side. The holes in the surround for the stalks to move through their travel are different, so with the RHD surround on I couldn't do a right turn signal or use my wipers. Oops! Some dremel work on the top fiberglass half and re-fitting the LHD bottom half did the trick. The holes are a little bigger than they need to be in spots, but it's not too bad.
Here's a copy/paste of a post from Roy on the RX-7 forum with some more info about the switches on the brain box -
As you look at it from above switches they are as follows/right switch is wastegate switch,left switch is overboost alarm switch and the volume type dial to bring boost in at various speed.Set the right switch(waste gate)to the right -set the left switch(alarm switch)to the left so alarm sounds if you go above your set boost and set the vol dial at 12 oclock and adjust from there.If you turn it left boost responce is faster and if you turn it right boost will pick up steadier and you will have more control over it
Interesting! I'll have to play with those and give you guys an update.
I will also have a PDF version of the Japanese manual for you to download when I get a clean copy of it scanned in. Not a lot of use, but it's good to have.
- Dale
