Lotus Elan Central

by **Rice crispy** » Tue 16.11.2010, 20:23

Well finally fitted the link to the airbox and plumbed it in

all went easy and works fine :banana:

now doesn't do a granny and small children WOOSH just a very very quiet scares small animals woosh

by **kenich** » Tue 16.11.2010, 21:13

Should get some pics up of it all fitted if possible.

I will get some of mine done soon :oops:

by **Enright** » Tue 10.06.2014, 14:47

Holy thread resurrection Batman!

But it seems about the most appropriate home for it so...

I don't propose getting into a debate about the various pros and cons of dump valves - there's been plenty of discussion about them in the past (just put "+dump +valve" in the search box and you'll soon see).

This is simply my budget “stealth/OEM-ish” dump-valve solution for anyone that's interested. It only requires 1 small hole to be made in the intake boost hose rather than cutting out an entire section and relying on even more jubilee clips to let go. There are no stainless steel or anodised bits, so if you want bling it’s not for you. But if you want something that looks as though it could belong alongside its neighbouring components, then read on. Here goes:

The dump valve is the same physical size and performs the same function as a Bailey DV30, which means it can be used in an open or recirculating configuration, but will cost about 1/10 of the price to buy and install.
It comes from late model Saabs (9-3/9-5 turbos), and can be picked up from eBay for as little as £10 (and probably less than that from scrapyards).
If you obtain one from a scrapyard, be sure to get the short pipe and the spring clips that connect it. If you can also find a similar piece of pipe but with a 90 degree elbow in it, even better.
I bought a 21.5mm overflow/tank fitting from B&Q for the princely sum of £1.98. If you wish to use the dump valve in recirculating mode, you’ll need 2 of these (the other one is for the dustbin end, which is what the aforementioned elbow pipe connects to).

Now here comes is the scary bit: cut a hole in your intake pipe which goes into the throttle body, at about the point indicated in the 2nd pic. Remember to start small, because you can’t add material back in if you make the hole too big!

Cut as much of the hex end off of the tank fitting as possible or it will be blocking intake airflow, but just leave enough to provide a bit of structural strength. You might be able to see in the first and second pic that I’d already started to cut mine before taking the pics.

Put the tank fitting inside the intake hose and poke it out through the hole, then flatten the hose to get it to seat flat and put the big nut on the outside. I had a spare washer, so put 1 on the inside and 1 on the outside.

Cut down the short hose so that it slots fully onto the dump valve and the threaded part of the tank fitting. Don’t forget to put the spring clips on before final assembly. Use some silicone sealer on the threads where the hose covers them, and around the hole where the tank fitting comes through the boost hose. It’s only got to withstand up to 14 PSI, but it WILL go off with a pop if not secured properly, and then until fixed you’ll be getting no boost and pulling in un-filtered air.

At this stage the only thing that gives away that it’s not OEM is the fact that the big nut that you can see is white, so if you can find a place that sells black versions, please post below. Otherwise you’ll have to either paint or cover it.

Run a piece of fuel line from one of the blanked-off ports on the throttle body to the small port on the top/side of the dump valve (depending upon which orientation you chose), attach end of the boost hose as usual and go out for a play! :burnout: