Hey everyone, I have been working on a weird Frankenstein swap. I got a S5 Turbo 2 motor going into a Triumph GT6. Due to very little room I am wondering if it is bad to put the Tial blow off valve upside down or can I leave it on its side like I have it now? Also with the stock turbo when I went to put on the down pipe I noticed that there isn't hardly any room for the factory waste gate to open as its covered with a plate. Is this normal? If the stock turbo doesn't work like its supposed to then I guess I am going to have to see about putting a aftermarket setup in the car. Not looking for crazy numbers, just wanna have fun with this little British sportscar.

 

the bov can be put on in any position. orientation doesnt matter.

the wastegate needs it full actuation range. if not then you will have some pretty nasty boost issues. if there is something impeding its motion then correct it. whats this plate youre referring to?

 

Orientation of the BOV on the pipe does not have any effect on its performance.
But location between the turbo outlet and throttle body does have a minor affect.
As the valve opens, all parts of the intake system after the compressor outlet will start dumping air towards the valve.
It is best that the majority of that air flow is towards the throttle body.

 

i didn't have one, so i've been running without for years, its loud...
https://www.rx7club.com/single-turbo...-valve-884695/

 

The stock turbo has a 1/2 inch metal cover that seems to cover the waste gate. The downpipe sold by racing beat then bolts to this cover. Seems like it is blocking the gate from opeing all the way but maybe it doesn't need much to vent.

 

Interesting, I read through that thread and it was interesting but I already have the Tial BOV so I'm gonna use it. LOL

 

if you have access to compressed air, put 10-15psi on the actuator vacuum line and watch it actuate. youll be able to see if its hitting or not

 

The stock wastegate does hit the turbo backing plate.

There may be some increase in wastegate flow from relieving the turbo back plate so the wastegate flapper can open further as well as the usual wastegate passage porting.

With stock compressor S5 turbo and 3" exhaust porting this work should be enough to limit boost creep.

If you do have undesired boost creep after that, I recommend a more restrictive muffler because I have gone down the rabbit hole of trying to eliminate boost creep on a very free flowing exhaust with hybrid S5 turbo and it was a lot of work with its own trade-offs.

 

The K24-7400 in my Volvo has a built in recirculation valve, and I was too cheap to buy a block off plate, so I stretched the spring on it to about double its free length and put it back together. The world has thus far failed to end

You can't have a recirc or bypass on a turbo five cylinder. It's against the rules, I looked it up.

 

Thanks guys, I was more worried about getting dirt in it if I mounted it upside down. I think I will just leave it mounted on the side instead of straight up and down.

 

i think you can summarize this thread with a "it doesn't matter where you put the thing"

 

it won’t matter wrt how it performs, but you might consider other factors like pre vs post intercooler etc.
.

 

Post intercooler makes the most sense because that way the airflow doesn't change direction.

Really what makes the most sense is intake ducting geometry such that air only wants to flow towards the throttle body.



Large tubes have slow airflow, low speed means high pressure. It's done this way for absolute best throttle response, but it does not work with a blowoff valve because all those do is throw away boost pressure that has to be rebuilt after a shift.

I'm doing a high effort per dollar EJ20 build right now and trying to incorporate as much of this theory as I can in the turbo plumbing.

 

well if you maybe consider thinking about it some more, you don’t need to dump it completely, just the excess so that it’s not stalling the compressor into surge. Which in theory nothing would flow backward and boost pressure could always be maintained between the turbo and TB. In that case pre-IC would make more sense to me.

or other alternative combining strategies when say maybe an electronic wastegate that can be infinitely controlled under any variety of conditions is employed.
.

 

That is the funny thing about non positive displacement impellers. Stopping the flow takes the load off of them, so they don't just stop.

Stick your hand on the end of a hair dryer or leaf blower to stop the flow and notice how the motor speeds up. It isn't moving air anymore so it is not under load.

Or stick a 73mm turbo on a Buick, brake torque it to 15psi, snap the throttle shut, and listen to it choo-choo-choo for what feels like a minute. It wouldn't be doing that if it stalled the turbo in the stopping rotation sense.

 

maybe it was just too far out of the box then.

 

Cant say how it worked over more conventional IC plumbing, but that is what I tried on my 2001 BLUE TII build. 2" turbo compressor outlet-> 2.25" IC pipe-> 2.5" IC inlet->2.75" IC outlet->2.75"-3" Modded Greddy TB elbow. All knife edged and internally polished with just 1 90 deg bend and 1 15 deg coupler.

I had hogged out and polished and modded TB, UIM and LIM which made revving in neutral a little lazy, but revved well with boost/load. Required a stupid amount of cold start and tps fuel enrichment.