Broken Cycling valve. Options?

[Glassmuseum]

In the midst of doing Venturi delete, vacuum line replacement and replacing my turbo, my cycling valve plastic lines snapped. Didn’t apply much pressure but all 3 were so brittle and they’re gone..

Trying to come up with a solution here and would appreciate if I could get some advice on options forward. I have a 86 turbo with a stock 26/6 turbo and wastegate. As I understand it, I guess I have 2 solid options and 1 probably not so ideal wildcard.

• bypass the cycling valve and run a manual boost controller. I’m fairly new to the 951 and trying to understand the MBC. Can I run a Lindsey MBC with a stock turbo and watergate setup? Can someone explain exactly how it works? Before this happened, I was also considering a Lindsey boost enhancer. Can these both be ran together?

• replace the cycling valve. Not great since the only place I see it in stock it’s $600

• Try to hack the cycling valve back together or rig it. I attached a picture of the damage. All 3 ports are broken . Could I try to glue some vacuum fittings or barb together to rig it up? Probably not a great option as I would assume there needs to be an air tight seal and the broken ends are pretty cooked so I don’t think I can glue those back on. [/ list]
  
  Again, any advice would be appreciated.

[MoeMonney]

My suggestion,

Manual boost controller and Vitesse chip. You will see a nice jump in power and not have to worry about the valve failing.

Boost controller is about 20 dollars on eBay or alibaba and chip is about 350 but there are cheaper options out there.

Boost controller you can hook up in about 20 minutes and chip in another 30 minutes.

[944m3]

Really good explanation of different boost controllers.

My advice, pay about half the cost of cycling valve and get an electronic boost controller. MBC is Victorian age tech compared to EBCs. Honestly don’t understand why more folks don’t use them.

For full effect, I would also recommend a dual port wastegate. The video explains how the bc works with a dual port. Worth the investment.

[chrischrischris]

That is an excellent video. I literally watched it about a dozen times, since I needed that many times to understand it completely - and it is entertaining too.

When someone says MBC, it could mean a whole bunch of different things, unfortunately.

I'm sure you can find a used cycling valve, but you will probably have to make some calls or direct inquiries. The one from a classic saab 900 turbo ( they call it APC valve for Automatic Performance Control) looks almost exactly the same (to me).

[944m3]

Haha same here. I had to watch it a few times and then sleep on it before the light bulb went on.

In a way the stock cycling valve is an EBC. So why not upgrade with a ton more features and control. It might seem intimidating but once you figure it out you won’t regret it.

I will add that I’m using my standalone’s EBC and it’s been a game changer. No matter how much I fiddled with the MBC it never came close to working as well as an EBC.

[Glassmuseum]

Thanks for all the suggestions! I watched the video and will need to watch it again as someone else said! I was eventually planning to mod the car, but not now. I wanted to get this project done and drive it for a bit to get a feel for what I want to do in the future. I think I’m going to stick with locating a decent used CV and go from there..

With that said, just for my knowledge, if I switched to either a manual boost controller or electronic boost controller, does an upgraded chip and/or dual port wastegate have to follow with those or can you safely run on a stock setup? If so, does anyone else run this setup. Thanks again for the info. I’ve had a few NA’s but the 951 is new to me so just trying to cover the basics here!

[944m3]

You do not need chips for either setup. Generally speaking you would only need chips if you’re upgrading your turbo (more air), larger injectors (more fuel), changing airflow (changing VE) are some of the main reasons for needing new chips.

You don’t need a dual port wastegate either.

If you are keeping it stock, check the condition of your wastegate. Also check for exhaust leaks on your headers and crossover pipes.

[chrischrischris]

To the OP, best bet is to keep it stock for now and make changes later once ready. Also, definitely agree that the stock valve is an electronic boost control valve, but it is kind of a "bad" one since it is programmed to open wastegate too early. This forces the purchase of the Lindsey "boost enhancer" (LBE) which is plumbed in front of the cycling valve. The LBE "tricks" the stock CV into seeing less boost so the wastegate stays closed longer allowing for a more robust spool-up.

[Tom]

You do not need chips for either setup. Generally speaking you would only need chips if you’re upgrading your turbo (more air), larger injectors (more fuel), changing airflow (changing VE) are some of the main reasons for needing new chips.

You don’t need a dual port wastegate either.

If you are keeping it stock, check the condition of your wastegate. Also check for exhaust leaks on your headers and crossover pipes.

I would add boost pressure to that list. With stock chips you will hit the so-called overboost protection if you increase the boost too far above stock. If you keep the boost to stock-ish levels with a boost controller and dual port wastegate, you can run stock chips -- but what's the fun in that

[Glassmuseum]

Appreciate the info. I was able to locate a good used cycling valve. For now, going to keep it stock and go from there. I am considering the Lindsey Boost enhancer though, but not yet! I’m going to focus on getting this project done - replacing the whole top end rubber and Venturi delete, aos seals etc and swapping the turbo with a newly rebuilt spare 26/6. The turbo that is in the car has compressor damage (I guess something got caught in there at some point ) so just swapping this one in to start fresh stock. I’m sure down the line the more I drive it, I’ll get the itch.