Extenal Wastegates Options

[elvasoshexai]

ok.. so the wastegate actuator on my ct20b is fubared.. i get boost creep like crazi...

i was going to get an external wastegate to replace it and weld the internal one shut.

i just hv a question about size.

i was planning on getting a tial 38mm w/ either .5(7.252psi) or .6(8.702psi) bar... i hv an mbc and plan to run probably 10psi neway tho...

however, the shop my car is at, a customer has a 48mm wastegate but wants a 38mm and he said that customer is asking if i want the 48mm turbosmart wastegate in exchange for a tial 38mm...

i'm assuming 38mm is a good size for a 5sfte...

would i b better off w/ the tial 38mm or the turbosmart 48mm?
the 48mm seems kinda big... i'd possibly get a lot of lag?
not sure what other pros/cons there would be between the 2?

any help? thnx

This post has been edited by elvasoshexai: Nov 28, 2007 - 12:59 PM

[OOBE]

Why 38mm? A 35mm is cheaper and capable of supporting more than enough power. My Supra had a Tial 40mm and I got 530WHP out of it. You get it too big, or too small and you get creep, spikes or both. I have a 1st gen Tial 35mm in my Celica and it works like a charm.

ESIT: Silly new Logitech wireless keyboard.

This post has been edited by OOBE: Nov 28, 2007 - 2:03 PM

[elvasoshexai]

tial don't make 35mm no more

[OOBE]

Get a 38mm then.

[elvasoshexai]

but if i get the 48mm there won't be any cons right?

[rjbibeau]

just a dent in your wallet

[OOBE]

Dude, a 48mm wastegate hole is huge. You'll probably get boost problems. You don't need it. It's overkill. There are Mirage 4G93 engines in the island pumping over 400 WHP on 35mm wastegates like mine. Why spend more money and risk getting in trouble, when you can go for the tried and tested route? Get a 38mm and be done.

[Tony_the_Tiger]

Dude, a 48mm wastegate hole is huge. You'll probably get boost problems. You don't need it. It's overkill. There are Mirage 4G93 engines in the island pumping over 400 WHP on 35mm wastegates like mine. Why spend more money and risk getting in trouble, when you can go for the tried and tested route? Get a 38mm and be done.

Stop spreading misinformation. You can't get "boost problems" with a larger wastegate. You can never "overwastegate" a turbo setup. The larger the wastegate valve, the lesser it has to move to evacuate exhaust flow. This also means faster control of boost since the valve only has to crack ever so slightly to maintain boost.

The only downside is cost and finding room to install a larger wastegate. Other than that, there are no downside in the performance aspect.

Also, no one rates wastegate with "WHP". It goes with manifold design and exhaust pressures. The lower the exhaust pressures, the more wastegate it needs. Every engine is different in terms of exhaust pressures. Anyhow. larger turbos always use large turbines which greatly reduce exhaust pressures, thus, we commonly read about the need for larger wastegates for larger turbos. Lastly, manifold design, such as the wastegate placement has the largest impact on wastegate sizing. A wastegate placement that is opposing the direction of exhaust flow will have a hard time redirecting exhaust out of the wastegate. A manifold such as that, would need more wastegate.

Example of a poor wastegate design that requires a larger wastegate... Notice how exhaust needs to turn the opposite direction to exit the wastegate:



Example of a good wastegate placement that requires a smaller wastegate:


This post has been edited by Tony_the_Tiger: Dec 2, 2007 - 9:25 AM

[Kadett]

Why dont you just replace the broken actuator with a Forge Upgrated Actuator. Problem solved for 100 bucks.
This one

http://www.forgemotorsport.com/content.asp...product=FMACGT4

[presure2]

Why dont you just replace the broken actuator with a Forge Upgrated Actuator. Problem solved for 100 bucks.
This one

http://www.forgemotorsport.com/content.asp...product=FMACGT4

X2
less hassle.

[Tony_the_Tiger]

Why dont you just replace the broken actuator with a Forge Upgrated Actuator. Problem solved for 100 bucks.
This one

http://www.forgemotorsport.com/content.asp...product=FMACGT4

I checked Forge's website and that would be $100 euros not including $55 shipping they quoted.
The total cost appear to $200 USD plus applicable taxes (14% in Canada). Definitely not a $100 solution.

I have the Forge internal actuator for my GT2871R in my turbo Integra, and their units work great but they don't last. Their diaphragms always end up ripping in matter of months, and I believe I am already on my 4th replacement diaphragm in the past 2 years.

This post has been edited by Tony_the_Tiger: Dec 5, 2007 - 10:54 AM

[LewFX]

check ebay for new and used forged products

[OOBE]

Bla bla bla...

Follow your own advice, and don't spread misinformation.

[x_itchy_b_x]

38mm works excellent for me.

[OOBE]

38mm works excellent for me.

How's your setup going?

[Tony_the_Tiger]

Bla bla bla...

Follow your own advice, and don't spread misinformation.

Just take it like a man and hit a few books, build a few cars before deciding to share a "tech post" of your own

I would love to see you quote where I misinformed anyone.

[easternpiro1]

i was just asking myself what different size wastegates were for and after this discussion, its clear.
LIKE diluted mud . Can someone re-word? i follow, but want to be sure

[Tony_the_Tiger]

i was just asking myself what different size wastegates were for and after this discussion, its clear.
LIKE diluted mud . Can someone re-word? i follow, but want to be sure

Here's how wastegate really works... All it does is vent and redirect exhaust away from the turbo and bypasses it to maintain boost. The few main factors to consider are manifold/wastegate design, exhaust back pressure and the amount of boost you plan to run. Don't even look at WHP at all because I had cars in here at 300 WHP needing a 50mm wastegate.

If your manifold has a wastegate location that is in clear path of all manifold runners, then you can mostly get away with a smaller wastegate. If you have a manifold that has a wastegate location that only vents out one or two runners only and has a nasty bend, etc, then you may want a larger one.

If you are running a turbo biased with a much larger turbine housing and wheel, such as most Garrett GT series turbos (smallest compressor trim within its family), then it has more "turbine" then "compressor". Turbos will larger turbines will dramatically lower exhaust back pressures, and therefore, it requires more wastegate. The natural least restriction path for exhaust to flow out is through the turbo instead (because of big turbine and lower back pressures between turbo and exhaust ports), and it would mostly likely keep going through the turbo instead of going out of the wastegate if the wastegate is too small. AKA boost creep

Another thing to look at is the amount of boost you plan to run. If you have a really large turbo say a GT35R, and you somehow want to run only 6 PSI, this would require a much larger wastegate too. Assume that 100% of flow going through the turbo equals max boost of 20 PSI for example.. Now you want to run 6 psi kinda puts it at 30% through the turbo and 70% out of the wastegate. The lower the boost, the bigger the wastegate.

So all this boils down to really... Run the largest wastegate vs price that you can afford and physically fit in your engine bay. That is why the Tial 44mm became so popular because it was compact and it is the largest wastegate in its size without breaking the bank =)

[Jeunesse]

Bla bla bla...

Follow your own advice, and don't spread misinformation.

Just take it like a man and hit a few books, build a few cars before deciding to share a "tech post" of your own

I would love to see you quote where I misinformed anyone.

hmmm... i wanna see where this is going...

[easternpiro1]

Now, now, Jeunesse dont go starting fights lol..... Thanks Tony that clears it up alot for me, how can you tell if your wastegate is going bad? car wont build boost right? I think i was having this problem with my 3s, i just started noticing it before i got into my accident.

[elvasoshexai]

Now, now, Jeunesse dont go starting fights lol..... Thanks Tony that clears it up alot for me, how can you tell if your wastegate is going bad? car wont build boost right? I think i was having this problem with my 3s, i just started noticing it before i got into my accident.

my wastegate was bad because it was creeping like crazy

[Tony_the_Tiger]

Now, now, Jeunesse dont go starting fights lol..... Thanks Tony that clears it up alot for me, how can you tell if your wastegate is going bad? car wont build boost right? I think i was having this problem with my 3s, i just started noticing it before i got into my accident.

Internal wastegates show a few symptoms of going bad... It works with a diaphragm that pushes a spring which in turn moves the wastegate flapper.

If the diaphragm is ripped or leaking, then it will fail to properly push the spring to open the wastegate flapper. This would cause abnormal boost spikes and also boost creep. As RPM increases, the boost reference signal (vac line to wastegate) is leaked out and the diaphragm no longer does its job controlling the movement of the flapper properly.

If the wastegate spring has fatigued from aging or thousands of heatcycles, then it you would get wastegate creep. This is when the wastegate flapper prematurely opens as exhaust pressure overcomes the fatigued spring in the wastegate, forcing it to open before it builds full boost. You will get a really laggy turbo and boost takes forever to build.

[easternpiro1]

i think that was what was happening to me, as i accelerate it would be real sluggish but my boost guage would be reading 15 psi (what i had it set to by the MBC) I thought it was real strange

[lagos]

99.999% of the time, the problem is something other then your wastegate. aftermarket downpipes or incorrectly set boost controllers are the cause of most of these problems. what gear did you set your boost in, and how much does it creep by?

i think that was what was happening to me, as i accelerate it would be real sluggish but my boost guage would be reading 15 psi (what i had it set to by the MBC) I thought it was real strange

you probably had a boost leak and didn't realize it or that flimsy relocation bracket that tweak made to clock your turbo wasn't sturdy enough. internal wastegates almost never fail.

This post has been edited by lagos: Dec 13, 2007 - 4:23 PM

[easternpiro1]

99.999% of the time, the problem is something other then your wastegate. aftermarket downpipes or incorrectly set boost controllers are the cause of most of these problems. what gear did you set your boost in, and how much does it creep by?

i think that was what was happening to me, as i accelerate it would be real sluggish but my boost guage would be reading 15 psi (what i had it set to by the MBC) I thought it was real strange

you probably had a boost leak and didn't realize it or that flimsy relocation bracket that tweak made to clock your turbo wasn't sturdy enough. internal wastegates almost never fail.

i had the stock 2inch dp BUT i did have a XS power MBC (heard they were crappy). I dont understand about setting the boost though, what do you mean what gear did i set it in?
I think at the time, i had it all the way open, but the car was still sluggish. sheesh, i still have alot to learn.

[lagos]

when you set your boost you have to set it in 4th gear. some people will try to set 15psi in 2nd or 3rd and then wonder why they hit 18psi on the highway.

[easternpiro1]

it did go over 15 a few times but usually when it was pretty cold when setting the mbc i didnt know i had to choose a gear

[Punisher]

electronic boost controller FTW!!!11!1

[easternpiro1]

i dont know about EBC's too tempting i like manual's (abeit inconvenient)

[Punisher]

Yea.. I mean whats the point of an EBC really.. It keeps you from overboosting in different temperature conditions and it gives you the ease of setting and forgetting.. not to mention all the extra readings that some of them display and being able to have a low boost and high boost setting or even using an extremely low boost wastegate spring so you can pretty much disable boost when you want to with out having to get out of the car and take a guess when you turn the knob on that stone age device they call a manual boost controller.

Silly product if you ask me.

[easternpiro1]

Yea.. I mean whats the point of an EBC really.. It keeps you from overboosting in different temperature conditions and it gives you the ease of setting and forgetting.. not to mention all the extra readings that some of them display and being able to have a low boost and high boost setting or even using an extremely low boost wastegate spring so you can pretty much disable boost when you want to with out having to get out of the car and take a guess when you turn the knob on that stone age device they call a manual boost controller.

Silly product if you ask me.

YEAH! EXACTLY WHAT I WAS SAYING!

sarcasim! just what i wanted for christmas!!!

This post has been edited by easternpiro1: Dec 21, 2007 - 1:38 PM