Thread: Hori Turbo Throw Together

$210 seems a bit extreme - postage I guess? You should be fine to use any wastegate actuator if you can find a cheaper one locally. Even second hand. Not much can go wrong with it IMO. You might need to weld up an appropriate bracket for a different one, that's all.

Yeah USD$40 to ship.

You make a good point, this one for a SR20 should fit. I just try and avoid buying from Scarles though.

http://www.trademe.co.nz/990788964

Sent from my Nexus 4 using AULRO mobile app

Originally Posted by BadCo.

I'm thinking maybe a Turbosmart Boost Tee might help me overcome the wastegate spring issue and its cheaper then an adjustable wastegate. Thoughts?

I've used a cheap manual boost controller in my 300zx for a number of years before I went to an Turbosmart eBoost2.
The MBC limits what pressure the wastegate spring diaphragm 'sees', so can help delay boost creep.
The wastegate actuator is not all or nothing- a 20 psi spring will start to open well before 20psi, so limiting the pressure as best as possible with a MBC is a good idea.

Originally Posted by Toxic_Avenger

I've used a cheap manual boost controller in my 300zx for a number of years before I went to an Turbosmart eBoost2.
The MBC limits what pressure the wastegate spring diaphragm 'sees', so can help delay boost creep.
The wastegate actuator is not all or nothing- a 20 psi spring will start to open well before 20psi, so limiting the pressure as best as possible with a MBC is a good idea.

Right so a MBC is only going to limit boost creep with the wastegate actuator and not actually increase the boost? Or does it limit creep and hence increase boost if you can adjust it enough?

I'm at 8 pounds with the factory actuator and spring and I only want to experiment with 10, 12 and maybe 15 pounds to see when the turbo stops being good haha. As 18PSI is clearly not in its happy place.

Originally Posted by BadCo.

Right so a MBC is only going to limit boost creep with the wastegate actuator and not actually increase the boost? Or does it limit creep and hence increase boost if you can adjust it enough?

I'm at 8 pounds with the factory actuator and spring and I only want to experiment with 10, 12 and maybe 15 pounds to see when the turbo stops being good haha. As 18PSI is clearly not in its happy place.

So I might have given a bum steer.
Am I right in uderstanding you want to run maybe 15psi, but have a spring that is rated to 8psi? If so, you need a boost controller to keep the wastegate closed for longer.
The wastegate spring suffers from wastegate creep- ie where the spring is overcome by boost pressure before the 'rated' psi, and bleeds off boost-building exhaust gases before your desired boost pressure- this reduces performance.
The above, is also different to boost creep, which is when boost spikes above that of the desired boost level. This is bad as it cahn lead to an overboost situation, and cause engine damage.

Your second statement is sort of correct. A MBC will help to increase your boost, which somewhat assists with preventing wastegate creep - mainly through giving the engine more boost to use, while limiting the effect siad boost has on the wastegate. It will still be affected by wastegate creep, but to a lesser degree. The ducks nuts however, is variable (rising rate) electronic boost controllers which can alter how hard the boost comes on through a pulse width modulated boost solenoid- this would be a great option, but pricey. It basically uses an air solenoid to pulse boost to the wastegate actuator to confuse it into making more boost. It wil bleed off boost thru the boost pressure line to the actuator to build engine boost, and hold onto it to make the wastegate open.

On the other hand, boost creep- where you overboost, is mainly a function of the exhaust / turbo's ability to flow and bleed off boost via the wastegate. This could be due to too small a wastegate for the engine capacity (flow) or a restrictive exhaust which limits the ability of the wastegate to do its job.

Caveat 1- I'm not a professional, but my experience and understanding (could be wrong!) is that:


Your wastegate controls / throttles the engine boost by bypassing hot gases around the turbine wheel (and thus preventing further boost to be made on the cold side).
The wastegate actuator controls the actuation of the wastegate, using a pressure sensing diaphragm and a spring. The spring will be overcome at a boost where the pressure going into the actuator overcomes the spring pressure, and hence opens the wastegate. The spring is not all or nothing- there is wastegate creep that robs the engine of boost by bypassing gases before your desired boost pressure. This is a limitation of the spring.
The MBC / EBC controls the actuator via resisting boost pressure that the wastegate actuator diaphragm can see. This tricks the wastegate actuator spring to hold closed longer than the actual boost pressure would dictate. If you were to remove the boost lines going into the wastegate actuator, you'd see as much boost as the turbo could make, or the engine could handle before something gives up the ghost. Ideally you'd have some boost control in place before that stage!

The spring you use should match that boost fairly closely, or else the majority of the heavy lifting will be done by the EBC / MBC and this will run out of capacity if the variance is too big- which could lead to boost creep / overboost.
You can also bench test the wastegate actuators by using compressed air and an air pressure regulator to see at what pressure the wastegate starts to open.

Originally Posted by Toxic_Avenger

So I might have given a bum steer.
Am I right in uderstanding you want to run maybe 15psi, but have a spring that is rated to 8psi? If so, you need a boost controller to keep the wastegate closed for longer.
The wastegate spring suffers from wastegate creep- ie where the spring is overcome by boost pressure before the 'rated' psi, and bleeds off boost-building exhaust gases before your desired boost pressure- this reduces performance.
The above, is also different to boost creep, which is when boost spikes above that of the desired boost level. This is bad as it cahn lead to an overboost situation, and cause engine damage.

Your second statement is sort of correct. A MBC will help to increase your boost, which somewhat assists with preventing wastegate creep - mainly through giving the engine more boost to use, while limiting the effect siad boost has on the wastegate. It will still be affected by wastegate creep, but to a lesser degree. The ducks nuts however, is variable (rising rate) electronic boost controllers which can alter how hard the boost comes on through a pulse width modulated boost solenoid- this would be a great option, but pricey. It basically uses an air solenoid to pulse boost to the wastegate actuator to confuse it into making more boost. It wil bleed off boost thru the boost pressure line to the actuator to build engine boost, and hold onto it to make the wastegate open.

On the other hand, boost creep- where you overboost, is mainly a function of the exhaust / turbo's ability to flow and bleed off boost via the wastegate. This could be due to too small a wastegate for the engine capacity (flow) or a restrictive exhaust which limits the ability of the wastegate to do its job.

Caveat 1- I'm not a professional, but my experience and understanding (could be wrong!) is that:


Your wastegate controls / throttles the engine boost by bypassing hot gases around the turbine wheel (and thus preventing further boost to be made on the cold side).
The wastegate actuator controls the actuation of the wastegate, using a pressure sensing diaphragm and a spring. The spring will be overcome at a boost where the pressure going into the actuator overcomes the spring pressure, and hence opens the wastegate. The spring is not all or nothing- there is wastegate creep that robs the engine of boost by bypassing gases before your desired boost pressure. This is a limitation of the spring.
The MBC / EBC controls the actuator via resisting boost pressure that the wastegate actuator diaphragm can see. This tricks the wastegate actuator spring to hold closed longer than the actual boost pressure would dictate. If you were to remove the boost lines going into the wastegate actuator, you'd see as much boost as the turbo could make, or the engine could handle before something gives up the ghost. Ideally you'd have some boost control in place before that stage!

The spring you use should match that boost fairly closely, or else the majority of the heavy lifting will be done by the EBC / MBC and this will run out of capacity if the variance is too big- which could lead to boost creep / overboost.
You can also bench test the wastegate actuators by using compressed air and an air pressure regulator to see at what pressure the wastegate starts to open.

Cheers for the read, it was good information!

Alright so I picked up an older Turbosmart MBC:



Installed it:



I got to 10 pounds, then the clutch started slipping. Yay.

Anyway, I need to do something about the clutch. I'm thinking the Extreme Clutch Kit (klr28003-1ax) or if that is expensive maybe just finding a turbo truck pressure plate for now.

Well this arrived today.



Anybody have any tips? I have never done a clutch before haha. I have access to a 2 post hoist and gearbox jack, so no problems there.

Is there anything else I should do whilst the gearbox is out? I read a bit about a rear main seal?


Thanks in advance,

BadCo.