recently just swapped setups on my rx-7. this is temporary till i get my t04z but its good for everyone who wants to know the advantage to a dumped wg. well here are 2 dynos, both at 14.5 psi you can see where the re-routed wg starts to restrict the flow but has slightly more tq at 4.5k rpms. here is the sheet.

 

Nice. Finally some proof for all the people that say there are no gains to be had with the wastegate vented to atmosphere. I'm glad that mine is. Thanks man.

Dee E.

 

finally somebody showed so proof.

 

Looks like 17rwhp. Not to be a jerk....but I wonder what it would look like with 20+psi? I would guess, alot more than 17rwhp. CJ

 

sorry abt thread hijack, but did u swap a sr20 into the skyline ???
going backwards ?

 

at 20+ psi it must be a good drop. considering i was having trouble getting the boost to hold above 15psi.

sub9lulu, it is a s14 240sx with a skyline front end and an sr20 motor.

 

I would have to say that I agree.

 

Got a pic of how this is hooked into the exhast? In my mind that should make quite a bit of difference.

 

its the a-spec t3 gt35r kit its plummed well..

 

I think I will keep it dumped to atmosphere. Thanks for the hard facts.

R.K.

 

I've always had it in my mind, if I wanted to make power....you can't stay quiet.

 

Sounds like some of the gain with your open dump may be due to exhaust restriction. I had problems holding boost above 15 psi as well, until I changed my catback. Large street port, t3 1.06 a/r 35r.

 

The huge A/F ratio change is showing that. The power/afr difference is consistent when running an open downpipe with no exhaust system.

 

Sorry, this isnt proof of anything untill you show us how its plummed. From the looks of the dyno I'd say its not plumed well at all

 

um ok well here is the same exact kit pictured. it only makes sense that a atmo dump wg makes more no matter how its plummed. its like a 3 lane highway with a merging 2 lane highway entering... anyway here is the link.

http://www.negative-camber.org/crispyrx7/gt35rpage1.htm

 

Its plumbed in at a 90* angle, I wouldn't say that's optimal.

I like the idea of using an idependant muffler for the wastegate, I think I'm going to go this route when re-making my exhaust over the winter

 

There is someone who will always argue with the facts

 

Facts of what? He showed us pics and its pulmbed in at 90 degrees to the downpipe.

Maybe I missed something

 

It may be a fact, but only for his complete system( turbine wheel/housing/exhaust system etc).

I don't think you would see those results on a system with less backpressure...

 

Be interesting to see the result comparison on a 4" exhaust set-up. G

 

Im not tryin to be a dick or argue someting. Im going off what I have seen.

When you blow air into a 90deg dump it blows air out of the inlet of the downpipe.

When you blow air into a straight on dump in the last curve of the downpipe it sucks air into the inlet of the downpipe.

That is a fact as I have done it with an air compressor and a malbro.

See attached.

That being said I think you would see much different results with some better plumbing.

Obviously a seperate dump is the best power wise. However, for those wanting a bit quieter setup the sacrifice your seeing is not par for the course.

It can be improved on, and it can be done with minimal hp loss. Or at least an ammount that makes up for it by not making your brain itch every time you mash the pedal

 

By the way, thanks for taking the time posting the dyno stuff and the pics, Its always nice to see how this stuff turns out in the real world

 

You would be hard pressed to feel a 17 hp difference at that power level. I'm seeing more and more instances where people get pulled over and get tickets written for obnoxiously loud exhausts. I feel the better option is to plumb it back in with a smooth transition and run a large diameter but adequately muffled exhaust. I also noticed the slightly leaner a/f on the higher power run, which could contribute to the power increase as well.

 

I was going to post how the "final proof" was performed decades ago, but after reading through the posts I see that some people still don't get it. Amazing.

For those who do not need to pass emissions testing and want separate plumbing for the wastegate but need to keep noise levels down, just install a small muffler at the end of the wastgate tail pipe. Once again, this has been known for decades.

I find it ironic that so many people who like boost tend to live in a vacuum, lol.