Help me plumb my external wastegate

[2.216VTurbo]

On the GLHS I have a tubular header system with an external wastegate that has two ports and a threaded set screw in top of the spring assembly. It came with a few different rate springs but dissasembleing the 'hat' to change springs is a PIA. To this point I have just put in the spring that allows 10 PSI with the set screw all the way 'open' and about 14 with it all the way turned in.

When I run manifold pressure to the top port, the gate doesn't open at all, when I run manifold pressure to the bottom port, it opens at the level the the spring is set to.

So obviously the boost controller gets plumbed in between the two ports. I have a couple manual boost controllers I can use. One is an older HKS MBC (manual boost controller). also I have some Grainger valves.

So any ideas on the sequence of how they get hooked up? Do I just run maniflod pressure into the controller, then to a "T" with one leg of each T going to top and bottom ports? I have dug through my stack of Turbo/Sport Copmpact Car magazines and though plenty of those cars run external gates, it looks like both ports are hooked up, just can't tell in which order:o

Mopars at the Strip is just 8 days away...

[altered7151]

Alan, I just picked up a tial unit and here is the diagram it came with: http://tialsport.com/documents/w3_tial_wginstall.pdf

It seems the way they tell you to hook it up is to run a t'd line with one hose to the bottom port, and one to the top, with the top having a bleed in it. The point being the bleed controls the pressure difference between the diaphram. So the less air you bleed the more pressure it takes to open the valve, so higher boost.

BUT... I talked to a few guys down in Sac. that I know running hondas with excellent results, and they run a ball-spring type mbc like we are, and they just run a single hose going to the bottom port, with the mbc inline with that hose. So basically the bottom port wont see boost until the mbc opens, just like how its set up on an internal wastegate setup. Thats the way I plan on setting my tial up. I did some searching on honda-tech. com and a couple other sites and they seem to be doing the same thing.

[8valves]

I have been running a TiAL 38mm gate on my car for all of last year with the above setup described. I don't even have a fittign on the top port, just a normal MBC going to the lower port of the WG. Works flawlessly.

Aaron Miller

[altered7151]

I have been running a TiAL 38mm gate on my car for all of last year with the above setup described. I don't even have a fittign on the top port, just a normal MBC going to the lower port of the WG. Works flawlessly.

Aaron Miller

How do you like that WG Aaron? I just bought one, and if it works as good as it looks I'll be more then pleased. It was so pretty when I got it, I wanted to set it on the mantle to display, the wife wasn't too keen on the idea though:) To bad it has to get tucked away behind the motor where no one will see it.

[8valves]

It has been 100% flawless. TiAL makes escellent products, we use two of their 44mm WG's on our Talon. Those are actually anodized a purple color that looks very bad----, and used to match the compressor back cover, but not anymore.

The only problem I had were that the bolts liked to back out of the TU header, but that problem has been solved now. Also, hint hint, DONT route the wasetegate exhaust back into your downpipe. Unless it is done very nicely with lots of attention being paid to routing it back in the exhaust stream very smoothly, it can cost you power. Lots of DSM and 350Z guys have seen anywhere from 20-40 WHP (Yeah!!) from dumping their wastegates to the atmosphere with a seperate 1.5" or 2" dump tube. You will now see 2 donwpipe's behind my motor this year! :D

Aaron Miller

[altered7151]

Yep I'm going completely divorced on the external wastegate, it'll be running a seperate 1.5" pipe dumped under the car. The 3" will get routed to the rear through a magnaflow muffler, so it should sound pretty cool when the wastegate opens at full boost.

[8valves]

Yep I'm going completely divorced on the external wastegate, it'll be running a seperate 1.5" pipe dumped under the car. The 3" will get routed to the rear through a magnaflow muffler, so it should sound pretty cool when the wastegate opens at full boost.

It depends on who you talk to. I've personally never been too big on the sound of an open wastegate... just sounds like a pissed off chainsaw if you ask me, but it grows on you after a while. I'll tell you what, it's a hell of a lot more intimidating! If you're the type who likes to instigate on the streets, you can cause some confused looks by being on the gas and letting it hit full boost for just a second letting the dump tube open in their window and then release and let the bov scream right after it... lots of audible intimidation there.

I guess it's about as close as we can get to the "insta-torque" chassis twist intimidation move by F body/Stang boys. That one always gives me goose bumps... those that have seen it know exactly what I'm talking about. When a real serious Fbod/Fox boy gooses it and it looks like the whole car wants to roll over, that'll always get my blood going.

Anyways, back on topic. Yeah, bottom port only with a boost controller works fine. Try to pick a base pressure spring that is compliable with your max intended boost. a 1 bar spring or the common .8 bar( 7-8psi on TiAL's I think) will work fine up until around 30 some psi, above there they start to be a little harder to control. If you plan to run more than that, a higher base spring tension is recommended.

Aaron Miller

[2.216VTurbo]

Sweet:thumb: It never seems to work out that the easiest solution is the best one, but a Grainger on the bottom port is easy, clean , and cost effective. Sounds like a sure thing.

Thanks for the responses guys.

BTW my gate is a divorced dump tube as well, since my turbo is over the trans, strait down from there is right in front of the drivers tire. It does sound like an angry chainsaw:eyebrows:

[8valves]

Do you have any pictures of this setup? I have drawings of an equal length header that mounts the turbo in that region at an angle, pointing the downpipe back towards the center of the car allowing a 90* on the compressor outlet and a nice path for inlet air, etc. Wastegate would be right where you're talking about to be dumped down behind the drivers tire.

I'd be interested to see how yours works, thanks.

Aaron Miller

[2.216VTurbo]

I have lots and lots of pics of the whole build, sadly 80% of them are locked in my 'old' computer with a corrupt hard drive:( All I really want out of that thing is my pics... Checked with a couple of data recovery geeks-sheesh-holy high dollar! The other 20% are on my SD chips for the digital but I have no way to send any. Yet pretty lame I know. Know anyone who is going to Mopars at the Strip next weekend? They can take all the underhood pics they want and share them :thumb:

[8valves]

No I don't sorry. I guess I'll just have to keep refining my drawings and build it next winter. Time shall tell.

Aaron Miller