WASTEGATE TIAL 38 MM

[evoinputra]

i mean the w/g drop off... :(

 

[piscargot]

How the heck did your wastegate drop off? Man, sounds scary, coz I did mine in JFA as well. Same thing, very shoddy workmanship, but compliments to them coz they did it very quickly for me, as promised.

I bought my Tial 38mm from KSP for that same price... got a 0.3bar spring thrown in with no charge as well. Not a bad deal.

I'm not too sure whether this would help anyone, but if you have a 1.8 car and need your boost to be lowered to below 0.5bar, you would need a bigger wastegate than 38mm. Specific to TD04L and similar spec turbos. With 38mm, it will rise to 0.6bar at high revs, near 5-6k rpm, which is quite dangerous to have boost spikes that close to redline.

 

[AlucarD]

Urm... bro, why would you need a ext wg for a TD04?? Unless its making insane boost why lower it to 0.5bar ... sorry just darn courious? Unless you're someone that I know that is driving a FORD!! with a lovely GFB Bov!! :huh:

 

[Joeker]

I don understand how a bigger diameter wastegate is suited for low boost.

A force applied on a wider surface exacts less pressure than on narrow surface (given both are applied with same force)

 

[SDF]

it shud be the other way round...

smaller turbo to use smaller diameter...furthermore stock td04 wastegate opening isn't even more than 35mm.. :o how wud it be possible for a td04 to fill up the space inside a larger than 38mm w/g.. ;) unless of course u running 2bar or more... :D

 

[dolly]

external wastegate is one of the only way to combat boost creep, which most ppl get after doing upgrades to intake/exhaust.

boost controller will not help with boost creep, only way to combat this is to lower the duty cycle so that the boost will creep to the level you want at the rpm you want. but this means lowering boost
other way is to port the internal wastegate

maybe thats why you need a wastegate for a td04?

 

[piscargot]

Originally posted by AlucarD@Feb 18 2005, 22:58
Urm... bro, why would you need a ext wg for a TD04?? Unless its making insane boost why lower it to 0.5bar ... sorry just darn courious? Unless you're someone that I know that is driving a FORD!! with a lovely GFB Bov!! :huh:

Hahaha AlurcarD... that's me all right. Who are you la? Lepakker at Peter's place or at Ken's place? :D

My car's an NA to begin with, so I was targetting for a low boost - high compression setup (something like the kits for Hondas). After much researching, i found out the TDO4L is quite suitable for my car (1.8) so I took the turbo from the GSR.

Problem is, the TD04 spools up quite fast and reaches a boost of 0.8bar stock. Even with manupilating of the actuator leg (which is a cekai way of adjusting boost hehe) I only managed to slow down the buildup of boost. It will always fly towards 0.8 on higher revs, regardless.

Then on further research and some personal R&D, I found out that even with the internal wastegate fully open all the time, the boost will eventually go up to 0.8bar, given enough revs on a 1.8l engine. Surprising huh? Well this is because the TD04's internal wastegate's hole is not big enough and angle of flow is not optimised to bypass enough exhaust gas. Hence I opted for a external 38mm wastegate. So far its been doing the job of keeping 0.5bar boost very well, except on pedal-to-metal over 5k rpm, it does creep to 0.6bar.

BTW Joeker, the size of a wastegate denotes the diameter of the flow channel (ie means its 38mm across). BUT the gate is not activated by the exhaust gas' pressure, it is activated by the BOOST input (via silicon hose from chargepipe). When and how much it opens depends on the SPRING inside the wastegate. So if I'm using a 0.3bar spring inside the 38mm wastegate, meaning once the boost exceeds 0.3bar, it will already start overcoming the spring and in result open up the gate to divert exhaust away from turbo. It works the same way even if its a 42 or 50mm wastegate.

If I misunderstood what you meant, then hehe just take it as if I'm jabbering la. Sorry mate! :)

 

[AlucarD]

Pis .. I'm that gila fella that is suppose to get you that 0.5bar actuator!

Wah, gone down the external wg route... :o like that gotta do the banana again at Jiang Hang? Just slap on a HKS GT snail .. later! Hahahh

 

[piscargot]

AlurcarD... ooo its you! Heheh how has it been bro? I did my repiping at JFA, couldn't afford to wait coz Ah Wah was damn busy.. waited for over a month still he got backlog. Workmanship sucks, but they got it done in a day, so no complaints.
Anyway I think we have hijacked this thread enough... we better take this elsewhere before kena flame for offtopic! Hehe.. :unsure:

ps - Tial wastegate rocks!! Looks good, and does the work!

 

[Joeker]

External wastegates are actuated also by the exhaust pressure.

If the wastegate is rated at 0.3 bar, the spring tension is actually about 0.5~6 bar.

Flow of exhaust gas create pressure, using a wider surface valve will require higher pressure to actuate the valve.

Therefore when using a 50mm 0.5 bar wastegate, the exhaust gas generated by the engine at 0.5 bar load might not be able to acutate the valve despite the diaphragm chamber being at 0.5 bar as there is insufficeint exhaust gas pressure.

 

[Joeker]

Originally posted by piscargot@Feb 20 2005, 23:52
Hence I opted for a external 38mm wastegate. So far its been doing the job of keeping 0.5bar boost very well, except on pedal-to-metal over 5k rpm, it does creep to 0.6bar.

Your motor is having overboosting creep problem.

I doubt the Tial 38mm is insufficent to flow the exhaust gas @ 0.5 bar.

Overboosting may also be caused Air/Fuel ratio. U might wanna have a look there.

 

[piscargot]

Wow, good info sifu Joeker. I really didn't know that. Hahaha.. sorry back to school for me. :)

How does the air/fuel ratio affect the boost creep? This is quite interesting... so I'm assuming that a lean mixture would give boost creep due to the hotter EGT? Or is it because of another reasoning?

 

[Joeker]

I'm not sifu, just Sifat (cantonese for backside) :P (Borrow from SDF ngek-ngek)

Lean does not necesarasily mean higher exhaust temp nor does running Rich vice versa.

Ignition timing also may affect the temperature (since u mentioned that you're a turbocharged N/A, your mechanic might have retarded timing far too much, just a wild guess)

Anyways, since most dyno centers in Klang valley are offering air fuel ratio readout cum dyno run at RM100~RM200 a go, why not get one done rather than spending hundreds maybe thousands later fixing broken parts.

Better be safe than be sorry.

 

[Joeker]

Originally posted by piscargot@Feb 21 2005, 15:14
How does the air/fuel ratio affect the boost creep?

As exhaust temp. increases, exhaust gas expands and spools the turbine faster.

Even though your wastegate is open, the expansion of the hot gases pushes the impaller to spool faster and faster and faster, boost overshoots and climbs higher and higher.

 

[AlucarD]

Ahhh ... sifat joeker has spoken!!