My friend Evan and I have spent a while building my 91 Si Turbo daily driver. Other than AC, my biggest requirement for this build has been OEM or better reliability. After destroying several EF Si transmissions and a pedal box (due to the heavy clutch) I decided to switch to hydro. The Full Race cable to hydro doesn't hold up to a heavy clutch so I made a pedal box. Here are some pictures of it.

Here is the original EF pedal assembly and a 1989 Prelude pedal assembly. The Prelude unit has a bar that runs from the clutch arm, through all the pedals to the passenger side to operate the clutch master cylinder. This allows you to put the clutch master cylinder on the passenger side of the brake booster. The only problem everything else.

 

The first thing to do is drill out the welds holding the gas pedal assembly and remove it, then weld it to the Prelude box

 

Drill a hole and attach the gas pedal return spring

 

Where the Prelude box attaches to the underside of the dash is at a different angle then the CEF one, so you need to cut the top off and weld it in at the correct angle.

 

With the pedal box installed, you can mark on the firewall where the master cylinder hole needs to be and drill that. Also, you can measure for the brace from the end of the tube to the firewall. I tied that brace directly into the mounting bolts for the MC but didnt really take a good picture of it.

 

The next issue is the brake pedal. It will hit the steering column when depressed so you have to cut the civic and prelude pedals at the same spot and weld the civic one to the lude top half. you can see in the second picture the bend in the civic pedal.

 

Next you have to add the part that holds the column. I forgot to mention, you need to cut that off of the dash and weld it to the tube that the clutch shaft goes through. Take care on this step to get it the original height. I didn't on my first try and ended up with a column that didn't tilt anymore and was permanently at the low setting.

 

Then paint and install

 

As for the MC mounting on the firewall, the spot where your hole will end up is not flat. I used a piece of piping to take up the space (as opposed to a stack of washers) and then bent a piece of sheet metal around it all and attached it to the firewall. Some seam sealer holds it in place and some paint covers it all up. I flared a line to go to the OEM hose, then all OEM bits from there on.

 

I also forgot to mention this lets you keep your stock vents. I have seen some people mount the MC under the dash backwards so they don't have to change the pedal box and while this "works" you need to ditch the driver side vent tube and the leverage is wrong (since the length of the pedal is made for the cable clutch) which gives bad pedal feel.

 

Nice work.

 

Just so I understand correctly, this custom job allowed you to run fully hydro?

Reason I'm asking is i'm currently piecing together parts for my gsr/sir tranny (hydro) swap.

Do you know of any other models the pedal assembly would work for such an endeavor?

 

Seems like a lot of work. Props to you for doing a nice job.

 

This is great stuff, thank you!

 

from what i hear the conversion for this is not bolt on the way they sell it. so this is refreshing, seems like if you can weld then you are in! good job!

 

thats intense but looks great. good job

 

Nice solution!

 

AWESOME! I was waiting for someone to do an OEM-style hydraulic conversion on a CRX.

Now make more and sell them for $$$!

 

So I am finally doing this install. I bought the Prelude pedal cluster last year but have been too busy to get to it. My question is do I need to take the dashboard out of the car?? I really don't want to as I have a pretty complex alarm system wired all over the place (installed in 1991!!).

Thanks in advance for all your information and photos!! This is really a top notch effort and as stated I have not seen anyone else do this so "OEM"!!

 

its a great idea. hydro ftw !!!
Thanks for sharing

 

Looks good, just ALOT of custom work that most average people would be unable to do. Just a question: Why would you not have went with the Hush22 cable->hydro setup which is "bolt in" only requiring the welding of a washer onto the unit (if memory serves correctly)? Sincerely, just a question. I like what you have done just seems involved for your "average Joe". I know I have no access to welding here at my house so thats why I am asking.

Hush22 Performance V2.9 EF Cable-Hydro Conversion Kit

 

 

This is absolutely amazing. I wish I had access to the tools for this. Hush Performance doesn't have anymore DA kits and doesn't know when they'll get/make more

Think I'm just gonna use the hasport cable fork for now in the hydro trans.

But I still wanna go full hydro.. I am definitely going to consider trying this for my DB2GSR. Thank you so much for posting this, I know this is an old thread, but so happy to see the pics here still.

If you're still around, some comments on how it works would be great. I guess it would probably feel pretty stock eh?

 

Apparently I might. I am gonna go this route. Hopefully it'll work as well in a DA (well, DB2 GSR)

I think I might order the innovative clutch cable adapter so I have a backup plan, so I can easily drive my car out after swapping transmissions but.. still gonna try and do this.. just gotta find the lude assembly and an extra teg assembly..

thanks again for posting.. I know old thread..but the pics still work and it's a wonderful idea. I wish I'd thought of it. I was thinking prelude due to them having remote reservoirs but..!