Thoughts on manifold mounted wastegates

[camman420]

I was just thinking about getting my evo III manifold flanged for a tial but im kinda hesitant on doing a manifold mounted setup instead of a 02 housing setup. The only reason im considering this is becuase I have a o2 elim DP and dont want to have to sell it just to get a custom 02 housing. What are your guy's thoughts on this type of setup?

 

[candela]

is it externally dumped? If so then just cut/weld the dump tube to an external mounted somewhere conveniently. If its internal then either try to sell it for a new housing or again..cut and weld a passage going to wastegate (make sure the passage is direct and quality).

However I dont think a manifold mounted gate is such a big deal. Everyone used to do it back in the day, now its obvious that its limited now and most everyone branches of evenly from the runners now.

What turbo we running?

 

[L2RTSiAWD]

If the external gate is off the collector it's fine, I'm not a fan of the ones flanged on the #1 runner.

 

[camman420]

If the external gate is off the collector it's fine, I'm not a fan of the ones flanged on the #1 runner.

Why are you against ones flanged on the #1 runner?

To answer your question candela im not sure what turbo im going to be getting since im still trying to figure out if im doing a external or internal wastegate setup, but I am leaning towards a PTE SCM50

 

[chrisdob30]

If the wastegate is mounted on the #1 runner when you hit full boost it can only regulate the exhaust pulses in that runner. The other 3 runners are not redirected from the turbo. However if the wastegate is mounted on the collector it can regulate all the runners and all the exhaust gases.

Chris

 

[DSMJim]

Originally posted by chrisdob30
If the wastegate is mounted on the #1 runner when you hit full boost it can only regulate the exhaust pulses in that runner. The other 3 runners are not redirected from the turbo. However if the wastegate is mounted on the collector it can regulate all the runners and all the exhaust gases.

Chris

This is not true. The manifold has pressure across the entire system. If you open a hole in the manifold anywhere, pressure across the entire system goes down. It's no different than the water in your house. If you turn on one tap anywhere and you flush a toilet in another part of the house does only the faucet near that toilet lose pressure or does everything in the house momentarily while it's flushing? Same principal.

If your still unsure try drilling a 38mm hole in one of the runners of your intake manifold away from the plenum and let me know if just one cylinder starts running bad . The whole thing is going to be screwed because pressure across your entire manifold will go down with a big gaping hole in one runner.

There have been cars well over 500whp with the wastegate from one runner so there are very few people here who will ever need to worry about getting one from the collector. It's simply not a concern for most of us as we will never exceed the efficiency of that setup. The only thing it will help you do is sleep better at night.

A good example is mclarin55. His car makes well over 500whp and had the gate from one runner using a turbonetics manifold.. Too bad he doesn’t have any pics of his engine setup on his gallery to show this.

Mclarin55 gallery - 524whp, 11.30 1/4, Turbonetics manifold with wastegate from one runner.

 

[ianv3]

524whp, 11.30 1/4

scratches head...

 

[chrisdob30]

I see your point dsmjim and that does make perfect sense. But having the other pulses travel back up the number 1 runner can't be to effiecent but as you said 500 is more than what more than most will make.

Chris

 

[ianv3]

pluses travel up all the runners. if youre that conserned with pulses, get an equal length manifold, thats seems to be their main benifit.

 

[miamieclipse]

sorry for this newbie question, but what does the O2 sensor connect to on each side. I kno it goes manifold>dp>testpipe>catback. Where does the O2 sensor go? Thanks

 

[candela]

manifold --> turbo --> o2 housing --> DP ---> cat/test pipe/full lenght DP may also bolt right to catback --> catback --> earth's beautiful fresh crisp air

 

[Lancer14]

I ran a manifold mounted Tial 40mm w/g for awhile. Never had any problems at all. It was off of the #1 runner.
I'm in the process of installing a new turbo with the w/g mounted on the exhaust housing, we'll see how much of a difference it makes (if noticable).

Chris

 

[ModInProgress]

In my opinion having the wg flanged on a runner lessens efficiency of the manifold/turbo, when at full boost the exhuast finds the easier exit to be the wg hole. Then exhaust from the other 3 runners must run down to the collector to go back up to the wg, causing unnecessary backpressure that you defenitely dont want at 4,000 plus rpms.

 

[hostile]

But really it is all nitpicking. I mounted my gate on the o2 housing because it was the best way.

But I doubt my car would be slower if I was using one on the manifold.

Look at the fast guys on the turbontics t3 manifolds. It definantly isn't holding them back.