Wastegate Explained.

[veilsideboyz]

need some advise..
better 0.5 or 0.7bar for SR20det FW (stock)

SR20DET stock turbo actuator is already 0.7bar... go for 0.7bar spring and get a boost controller...

 

[qarl_toran55]

looking for 0.7 rate spring..where to find ah..wastegate already got..but my spring is 1.1 rate..want to go for 0.7 bar rate..got people or shop selling ah?

 

[veilsideboyz]

Got.. but a bit expensive...
better change spring bro... if not the boost kill your engine :D

 

[speed2horizon]

looking for 0.7 rate spring..where to find ah..wastegate already got..but my spring is 1.1 rate..want to go for 0.7 bar rate..got people or shop selling ah?

Aiyo... susah susah for wad. If don;t wanna buy, see if there is any friend getting the same brand wastegate, call them to get with stock 7psi spring. Then mae swap lor....

Like mine, I got 14psi... but plan to boost only .7 bar. Change with jinkl that bought 7psi. then upboost with boost controller.

And 1.1 bar won;t kill ur engine. just increase ur fuel injectors n go for retune. should be fine.

If u really really want to use 10psi spring, then go Tong TUrbo, then made some of it. Should be selling <100

 

[kanan]

It functions like this... An external/internal wastegate also react the same way. However, the external wastegate are more robust/durable/stable because the valve opens directly without any actuation rod inthe middle that may bend/deform due to the pull and push of the spring and diaphram.

When exhaust begin to spool the turbine, and turbine spins the compresor via the shaft.Air within the intercooler piping begin to pressurized. At this moment, the exhaust trying to push the wastegate open. But the spring counter the exhaust force. when the compressed line boost up to a preset level(according to the spring) The air pressure is sufficient enough to counter the spring pushes the valve in the wastegate to open and release the excess exhaust to the environment, then the boost maintain cause it keep moving up and down to maintain the boost.

Say when U have a 0.5bar spring, and u are boosting at 0.5 bar. And u install a boost controller on the hose connected from the intercooler piping to wastegate. What a boost controller does is to bleed out some air from the hose to reduce the pressure at the other end.

In other words, u need to boost higher to counter the 0.5bar spring due to the leakage u've applied on the boost controller.

P0 = Spring rate
P1 = Intercooler piping pressure/hose before controller
P2 = Presure after controller
P3 = Bleed out pressure

Ideally, P0 = P1

Increase boost.
P1 = P2 + P3

P3 < P0

So, u need to increase the Boost pressure of P1 in order to achieve P3 = P0

Un..?

Okeh very detail explaination. Please correct me on this is how I understand from above. my basic knowledge please verify...

Wastegate it operates by bypasssing the exhaust gas that is going to enter the turbine housing,to slow down the turbine speed hence control the boost produced by the compressor turbine connected to the intercooler piping inlet. The wastegate start to bypass the exhaust when the pressure in the intercoller piping achieve the spring rated pressure (eg: 0.5 bar in this case). How it knows because there's a small (like brake hose connecting from inter. pipe to the inlet of wastegate actuator). So what pressure in the inter. also will applies to the actuator to open the gate.

What the boost controller do is it bleeds the hose(between inter. n wastegate) to achieve the pressure in the intercooler piping as was set by the user (through the lcd monitor). for example I set 0.4 bar, so theoritically boost controller bleeds whatever excess pressure in inter.(more than 0.4 bar in this case) whenever it senses. Say I'm still using the same spring rate as above, I want to achieve 0.8 bar. so i set 0.8 bar in the boost controller. But even at the maximum rev of the engine, I will still cannot get the 0.8 bar in the intercooler . Because In this case even though the boost controller doesn't bleed the pressure in the hose(because it hasn't achieve 0.8 bar) but the wastegate is bypassing the exhasut gas because the actuator in the wastegate already opened when the boost 0.5 bar achieved. so it keeps on opening bypassing the exhasut gas from entering the turbine. so even engine rev high(lots of echaust gas coming out but it doesn't hit the turbine blades) so the turbine speed will maintain as it is. Unless the outlet of wastegate is too small It cannot bleed faster making the targetted boost achievable but with pain to the engine.
Is sit correct sir?

 

[qarl_toran55]

Aiyo... susah susah for wad. If don;t wanna buy, see if there is any friend getting the same brand wastegate, call them to get with stock 7psi spring. Then mae swap lor....

Like mine, I got 14psi... but plan to boost only .7 bar. Change with jinkl that bought 7psi. then upboost with boost controller.

And 1.1 bar won;t kill ur engine. just increase ur fuel injectors n go for retune. should be fine.

If u really really want to use 10psi spring, then go Tong TUrbo, then made some of it. Should be selling <100

notice that, but my car still got boost cut..it cuts at .9 bar..that is why i cannot use this 1.1 rate..haha..looking for .7 rate then maybe later up boost to .8..

 

[speed2horizon]

Okeh very detail explaination. Please correct me on this is how I understand from above. my basic knowledge please verify...

Wastegate it operates by bypasssing the exhaust gas that is going to enter the turbine housing,to slow down the turbine speed hence control the boost produced by the compressor turbine connected to the intercooler piping inlet. The wastegate start to bypass the exhaust when the pressure in the intercoller piping achieve the spring rated pressure (eg: 0.5 bar in this case). How it knows because there's a small (like brake hose connecting from inter. pipe to the inlet of wastegate actuator). So what pressure in the inter. also will applies to the actuator to open the gate.

What the boost controller do is it bleeds the hose(between inter. n wastegate) to achieve the pressure in the intercooler piping as was set by the user (through the lcd monitor). for example I set 0.4 bar, so theoritically boost controller bleeds whatever excess pressure in inter.(more than 0.4 bar in this case) whenever it senses. Say I'm still using the same spring rate as above, I want to achieve 0.8 bar. so i set 0.8 bar in the boost controller. But even at the maximum rev of the engine, I will still cannot get the 0.8 bar in the intercooler . Because In this case even though the boost controller doesn't bleed the pressure in the hose(because it hasn't achieve 0.8 bar) but the wastegate is bypassing the exhasut gas because the actuator in the wastegate already opened when the boost 0.5 bar achieved. so it keeps on opening bypassing the exhasut gas from entering the turbine. so even engine rev high(lots of echaust gas coming out but it doesn't hit the turbine blades) so the turbine speed will maintain as it is. Unless the outlet of wastegate is too small It cannot bleed faster making the targetted boost achievable but with pain to the engine.
Is sit correct sir?

Something like that. more precise is... say, wastegate spring 0.5 bar... on a complete nice hose, the boost will push the wastegate to bypass the exhaust to the turbine. So, boost maintain at 0.5bar. Wen u add on a boost controller, u bleed out 0.2 bar to the environment... So, the pressure to the wastegate only remain 0.3bar.. so, cannot open the gate. And the turbine will continue turning the compressor.

So, boost will rise up to 0.7bar. So, the pressure reaches the wastegate remains 0.5bar. sufficient to open the gate.

notice that, but my car still got boost cut..it cuts at .9 bar..that is why i cannot use this 1.1 rate..haha..looking for .7 rate then maybe later up boost to .8..

Throw the boost cut lor... SR20?
go Ah Tong there ask that fella... HE sure have it.

 

[kanan]

Something like that. more precise is... say, wastegate spring 0.5 bar... on a complete nice hose, the boost will push the wastegate to bypass the exhaust to the turbine. So, boost maintain at 0.5bar. Wen u add on a boost controller, u bleed out 0.2 bar to the environment... So, the pressure to the wastegate only remain 0.3bar.. so, cannot open the gate. And the turbine will continue turning the compressor.

So, boost will rise up to 0.7bar. So, the pressure reaches the wastegate remains 0.5bar. sufficient to open the gate.



Throw the boost cut lor... SR20?
go Ah Tong there ask that fella... HE sure have it.

Now i really understand how the boost controller operates to achieve certain boost. So if using 0.5 bar spring rated, the max i can boost up to only 1.0 bar using a boost controller assuming the hose is in perfect condition. Where's the best place to tap & connect the pressure hose to the actuator wastegate? issit before inter cooler or just before the throttle body (after intercoller)?

to make sure the pressure is really what the boost controller senses, we need to install small pressure gauge meter tap a long the intercoller piping rite? I mean to double check the resulted regulated pressure after using boost controller.

 

[speed2horizon]

Now i really understand how the boost controller operates to achieve certain boost. So if using 0.5 bar spring rated, the max i can boost up to only 1.0 bar using a boost controller assuming the hose is in perfect condition. Where's the best place to tap & connect the pressure hose to the actuator wastegate? issit before inter cooler or just before the throttle body (after intercoller)?

to make sure the pressure is really what the boost controller senses, we need to install small pressure gauge meter tap a long the intercoller piping rite? I mean to double check the resulted regulated pressure after using boost controller.

It doesn;t really matter as... Cause pressure is pressure, they should same along the line. as long as it's located after the intercooler. Cause the air will have a lower density after intercooler.

Preferably use PU hose instead of silicon. Cause PU hose is more rigid. Same applies for ur BOV.

 

[eiril_77]

I used a twins turbo engine (mit) and it have a 2 internal wastegate... can I make it to used only 1 external wastegate?

 

[speed2horizon]

convert to single turbo lo... hehe

 

[SDF]

I used a twins turbo engine (mit) and it have a 2 internal wastegate... can I make it to used only 1 external wastegate?

no you can't.

single turbo with twin wastegate = OK
twin turbo with single wastegate = NO

 

[speed2horizon]

no you can't.

single turbo with twin wastegate = OK
twin turbo with single wastegate = NO

Sifu, wads the advantages of using twin wastegate??? Say, ppl boosting 1 bar... Is there any difference using 2 38mm n 1 50mm in terms of response n hp?

 

[SDF]

by far, most people use twin mainly for the following reasons :

1. Twin entry turbine housings, to divert the exhaust gasses out individually. This way there will be less choking.

2. High boost applications, to vent out the exhaust gasses quick enough and prevent choking.

So far it's been proven to help especially twin entry turbine housings, the power is more linear and less choking at point of entry into turbine housing, hence more efficiency.

hope this helps.

 

[kanan]

hi all, i'm new to car modification. I was looking for a shop that can offer a good workmanship on welding & mounting the 2 wastegates for my 6A12TT engine. Which shop would you recommend. I don't mind paying a bit higher as long as the work quality is good. Please help TQ