Why do I need 2 blow offs and 2 wastegates?
 

I am trying to find the reason as to why I need 2 wastegates and blow offs? I am setting up a pp motor with a t6 81 front and 1.23 rear on alcohol. Any info for this is appreciated as well as options, thanks

i think the general answer is this...if you have to ask about wastegates and bov's at this point in time...you most likely shouldnt go with a PP motor....

but anyways...2 wastegates to better control boost creep..

2 wastegates control boost better. A PP motor moves A LOT of air. 2 BOV's is the same concept, you need to release a lot more air when you let off or your turbo will start spinning backwards to compensate (compressor surge) which is bad bad bad for the turbo.

thewird

you dont actually NEED 2. but is is much better to do so. I am running dual wastegates myself on a manifold i just finished making. well, kinda. i still have to pick up the other deltagate...

but dual blow off valves is kinda over doing it. I seen plenty of motors running 30psi on one BOV.

what size gates and BOV are you using?

Hell, ive ran 35psi in the past for over 10k miles without a BOV and no damage, but it really can depend on the situation, ive seen some thin shaft turbos snap real easy.
No harm, in running two, but prob not need unless they two poor flowing ones, OR you using them to regulate boost when using a 2step or transbrake, which is sometimes done, but involves more electronic trickery to open them when they shouldnt.

But 2x wastegates isnt a bad idea, too big is rarely an issue, too small will mean a LOT more messing about and work to correct.

^35psi and no damage means you have a surge protector on your turbo. like diesel turbos.

No, no ported shroud inlet on the turbo, just a turbo that can take it.

Stav , you dont run 35psi on your rotary, I am assuming its 35psi on one of your other cars. What turbo did you run on 35psi on what car? yes a lot of big shaft turbo you can run without a BOV, but would recommend a ported shroud to go with it

Who the hell said I ever ran 35psi on a rotary?! We are talking turbos/wastegates/bovs here, no mention of engines are they are totally irrelivant to this.

Ran 35psi (and anti-lag, anything up to 29psi with a fully closed throttle) on my Cosworth, over 30psi for similar miles on one of my GTTs.

Hope this helps you BlitzBoy.

Stav x x

Ps- What cars have you run mega boost on?

I was just clarifying given this is a rx7 forum what car it was you run 35psi on.

Still asking what turbo it was you ran 35psi on your Cosworth, quite interested?

I have run high boost (or mega boost as you call it lol) on my previous cars, eg 200sx, Pulsar GTR, 300ZX , all had uprated turbos, but these all had big external single wastegates (except the 300ZX) with them.

But on a Rotary to run these big boost pressures (30 psi plus) very large turbos are used, hence why sometimes dual wastegates are used.

If you buy a large quality wastegate, like the HKS 60mm or Tial version normally one is enough.

But I think BUSTN car is going to be a Drag car, seen many PR cars running dual wastegates to control the boost correctly at these high boost pressures, BUSTN turbo will be flowing a lot more air then your Cosworth turbo Stav at the same boost pressures.

Clarifying the irrelivant, good work :)

Im not sure if you are just trying to dig at me or you cant read, but whats dual wastegates got to do with anything I said?

I reccomended dual wastegates in my post, its common sense, too much is better than not enough in this case.

We was talking about blow off valves when you decided to chime in, ie on the inlet side, to reduce the chance of damaging from rapid slowdown of the compressor when you shut the throttle, but you seem to have tried to deflect the point.

And whats running big boost or big turbos got to do with two wastegates? If anything the bigger the boost the less wastegate you need, lol. :scratch:
If you running "enough" boost on the right turbo you dont even need any wastegate...
Might want to stick trying to stalk me about stuff you understand about mate, or call your tuner to ask for info on what wastegates are for first ;) :lol:

And the Cosworth turbo was a GrpA (or early WRC one, whatever) with a Mar-M 247 shaft/turbine, etc etc. Hope that helps.

Hold on this post is about Dual wastegates and BOVs.
I was giving my info on the wastegate side.

I suggest you do more research on this forum on the big power setups and why they run larger or dual wastegates. you want good steady boost control at high boost, as running 35psi you want it steady boost curve not have it boost creep or spike to 40 odd psi and have it blow the engine.

But as you such a "know it all", and your attitude when you write on various forums gets peoples backs up no wonder you are hated on most of the forums you post on in the UK(Driftworks). Various people talk of your reputation at the various japshows I have been to, and all agree you are indeed have your head up your own arse.

Because the way you word your threads and talk down at people as if you are such a fduking tuning god just because you write in a car magazine.

Are you a tuner = No
Have you produced any noteworthy results = No
Have you trashed a lot of good cars = yes
Are you a knob = yes



Ps, Yes I have tuner to do my latest setup on the rolling road, but also I have road mapped and tuned other peoples Rx7s and 200sx's, so dont need to ring my tuner about anything else thank you very much and good night, I wont be posting on any of your threads because you are a waste of breath.

I feel sorry for that gorgeous FC you bought from Japan because you will ruin that like every other car you have owned.

So please guys ignore Stavs advice on Rotarys as he has none

What an idiot statement!!!!!
Which Performance turbo car does not run a wastegate????!!!!! :lol:
fduk it im not posting on this tread again lol

When turbo's started being used, a wastegate was not used. The turbo was sized so it would only generate a certain amount of boost. It was designed for the application.

thewird

Yes agreed about the old turbo days , but we are talking about today in the modern world, where boost control is essential in a rotary

I have to back up Blitz post here

Stav knows nothing about rotarys and is hated on most UK forums as his know it all attitude stinks.

BUSTN, you should talk to people who have real experience with PP turbos, like Enzo250...

Andy Barnes in the FUUJIN R33 GTR, which im sure you know, has many a time, as has many drag cars.
And a lot more drag cars run with nothing more than a popoff on the inlet side if you want to be pedantic about it.
Hell, even ive done it on an old Volvo just for fun, was my daily for a fair while like that.
Hope that helps :)

And I suggest you go down spec-savers and sort your vision out, as I said from the start to run TWO wastegates.

This thread was fine and everyone was on the same wavelength until you chimed in taking it off topic trying to slag me off.
Why dont you come and say stuff to me at a show etc if you want to call me names, or at least PM me, rather than being an internet hero and slagging off someone you know nothing about (most of your comments are totally wrong, shall I make up some stuff about you?), stop spoiling what was a helpful thread to the OP.

This isnt about rotarys, this is about turbos, and everything I suggested has been by everyone else, as its correct, not like youd understand.
My attitude 'stinks' to you lot as I dont just suck up to people who clearly are wrong, and dare to speak out, unlike you sheep who are too pre-occupied brown nosing your peers :icon_tup:

I recognise your name, didn't you post pictures of your penis on Driftworks :scratch: That's what I'd call spoiling a thread.

Its a rotary forum therefore im guessing everyone apart from you are talking about applying this to a rotary car.

I think you are on the wrong foum ?

Yes its the same guy :lol:

Anyway apologies for off topic im dun :D

The OP is asking for advise and help with relation to a PP rotary engine StavFC, thats why most people have been offering rotary advice not just turbo advice. I probably dont know as much about wastegates etc as most people here and because of that I dont tend to offer advice, maybe something you should consider doing too.:dunno:

I have replied to your PM Stav , you seem to think I dont have the minerals lol

Just because Mr Barnes runs without a WG on the Skyline does not mean its the ideal way, you are overspeeding the turbo therefore the turbo will be more prone to failure.

Sorry must not retort to Stavs superior knowledge, I must stay silent and be a sheep. lol

I am looking at 2- 50mm bov's and 2- 44mm wg's, alky set up, the turbo front is
.81 and rear is 1.23 t6 114mm front wheel and 104mm rear. Twin 60mm TB's with 4- 2800 Motec Injectors on a Fastec mech pump, hope this helps. The motor is getting put back together by the end of next week, rotor issues have slowed things down.Thanks guys.

We have a guy running a 13b pp motor in the UK running a HKS 60mm wastegate, he is getting good boost control with it.

Make sure you buy a quality WG eg HKS,Turbosmart or Tial