Am I being dumb, or.....(good turbo question inside!)

I never "trued" my flanges after welding, and no leaks yet...even with a gasket I had to modify to fit my oddball manifold some one (who will remain nameless BRANDON) sold me!! :D:D Good thing it was cheap!

Chris
 
I can get them cut too. It's $10-20 depending on the flange and how many I make.

brandon.
 
Thanks for the replies on the flange question. Looks like I'll be making mine after seeing the Source Automotive prices:Throwup: .
 
Dont know if this is rigth or not (its late). My brothers turbo rx7 that he runs, we custom fabbed all his intercooler piping and downpipe out of S.S., I could swear he has the wastegate dumping right under the engine, not tied back into the exhaust. That makes fabing easy.
Then again fabbing pipe is easy for me.
Thats what I do for a living.
UNION PipeFitter
 
I cant believe what they get for those plates. A B2 plate cost me 10 bucks, and a 35 or 40 hot plate cost me 25. I can get B2 compressor outlet flanges made for 10 bucks.
 
prolly sanded down with a belt sander after welding, am i right? at least that's what I would do
Click to expand...

A mill would be better.

Jim
 
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Can someone explain the recommended hookup for the controlling air line(s) on a TiAL external gate (38mm) when used to dump the exhaust on the small turbo in a twins set up?

The instructions indicate to just dump the top one to the atmosphere. But when pushing 50 or 60 lbs of boost, which the actuating line on the side will see, I've heard that can rip the diaphram. My thought was to plumb the top one to the cold pipe between the big turbo and the litte one, then maybe install a needle valve to control it. That would add pressure to the top line, and therefore the top of the diaphram, thus letting the TiAL work with the true net boost the little turbo is producing (input pressure vs. output pressure).

Does this make sense or am I way off base?

By the way, to prevent warping of the flanges, I welded around the inside of the flange where the end of the pipe meets the machined "shoulder" in the flange. It's tight, and wasn't easy, but it can be done.

Thanks,
-Jay
 
You need to run a boost line, through a regulator, to the top port. You need to set the regulator pressure so that the:

Spring pressure in the wastegate + the "regulated pressure" = Total Boost

Doing it this way, I really don't even need a "Boost controller"
Chris
 
I cheat on my wastegate setup. I have a line running from the outlet of the small compressor to a 12v air solenoid then it runs to the top of the wastegate. the solenoid is controlled by the 2nd stage on my NX controller. You could also run it off of a hobbs switch.
 
Signature600 said:
You need to run a boost line, through a regulator, to the top port. You need to set the regulator pressure so that the:

Spring pressure in the wastegate + the "regulated pressure" = Total Boost

Doing it this way, I really don't even need a "Boost controller"
Chris
Click to expand...

Chris,

So, by way of example, lets see if I understand what you're saying. The wastegate currently has springs for 20.2 lbs. Let's say total boost under load is 60 lbs. Then the regulator would be set for about 40 lbs, and its supply will be the total boost from a tap at say, the intake manifold.

Do you have a suggestion for a best-bang-for-the-buck regulator (model and a source for it)?

Jff24Gordn: thanks for the input, but I am unfamiliar with your controller and, assuming it's a bit more complex, would prefer to stay simple and inexpensive (that is, mechanical, like my motor and pump!).

Thanks,
-Jay
 
JGK said:
Chris,

So, by way of example, lets see if I understand what you're saying. The wastegate currently has springs for 20.2 lbs. Let's say total boost under load is 60 lbs. Then the regulator would be set for about 40 lbs, and its supply will be the total boost from a tap at say, the intake manifold.

Do you have a suggestion for a best-bang-for-the-buck regulator (model and a source for it)?

Jff24Gordn: thanks for the input, but I am unfamiliar with your controller and, assuming it's a bit more complex, would prefer to stay simple and inexpensive (that is, mechanical, like my motor and pump!).

Thanks,
-Jay
Click to expand...

You got it...I couldn't find any "good, cheap, regulators," so I went fancy, and bought one that is adjustable from 5-60psi, and has a large dial on the top. You simply set it where you want it, and tighten it down...no guessing, then test driving;)

Hopefully, someone else can tell you where they got their's...mine came from McMaster-Carr

HTH,
Chris
 
Chris,

After thinking about this over night, let me take my example just a bit further to make sure I'm on track.

In my example, the regulator would be set at 40 lbs. So both sides of the wastegate diaphram will see the same total boost pressure up until boost hits the 40 lb mark. Then the regulator will stop any more pressure from building on the top of the diaphram (which is, in effect, aiding the springs in holding the gate closed). As the boost builds beyond 40 lbs, the under side of the diaphram in the gate will see the additional boost, which is only being held closed by the springs now. Once 60 lbs is reached, the gate begins to open since its hit the limits of the 20 lbs springs. Am I OK so far?

If so, my concern now is that this will allow the little turbo to continue to see exhaust (drive) flow until overall boost reaches 60 lbs. Wouldn't this be a situation where it is being driven way past its map range? I realize the big turbo is running now, but only on whatever exhaust gases are getting through the top turbo. The little one is still boosting until total boost reaches 60 lbs.

Thank you for your input,
-Jay
 
JGK said:
Chris,

After thinking about this over night, let me take my example just a bit further to make sure I'm on track.

In my example, the regulator would be set at 40 lbs. So both sides of the wastegate diaphram will see the same total boost pressure up until boost hits the 40 lb mark. Then the regulator will stop any more pressure from building on the top of the diaphram (which is, in effect, aiding the springs in holding the gate closed). As the boost builds beyond 40 lbs, the under side of the diaphram in the gate will see the additional boost, which is only being held closed by the springs now. Once 60 lbs is reached, the gate begins to open since its hit the limits of the 20 lbs springs. Am I OK so far?

If so, my concern now is that this will allow the little turbo to continue to see exhaust (drive) flow until overall boost reaches 60 lbs. Wouldn't this be a situation where it is being driven way past its map range? I realize the big turbo is running now, but only on whatever exhaust gases are getting through the top turbo. The little one is still boosting until total boost reaches 60 lbs.

Thank you for your input,
-Jay
Click to expand...

You have it correct, in both ways!

I didn't notice you had twins before...that will take a lot more "tinkering" on your part. You want to open the wastegate early, to help spool the big charger AND keep drive pressure in check once you get on the top end. Somewhere between 20-30psi is where most guys end up opening the wastegate.

You end up with a compromise only having one wastegate in the system...sacrifice spooling on the big charger in order to keep drive pressure down once you get it lit.

Any of this making sense?
Chris
 
Chris,

My apologies for not making it clear that this was twins setup. Yes, its true that only the little turbo is being wastgated (with the TiAL) at this time. So does that alter your approach or recommendations?

I'm still a little fuzzy on how this will work. I'm going to have to sketch it out. For the moment, I'm still not clear how regulated pressure to the top of the diaphram from the total boost supply will prevent the top turbo from overspooling, but it may be just a matter of working it through. It just seems this will keep the wastegate closed until much higher boost is reached (the point that the regulator is set, say 40 lbs in my example). But I know I have to consider the boost being supplied to the little compressor by the primary turbo.

Going on vacation Friday for a week. Maybe I'll have time to think it through.

-Jay
 
JGK said:
Chris,

My apologies for not making it clear that this was twins setup. Yes, its true that only the little turbo is being wastgated (with the TiAL) at this time. So does that alter your approach or recommendations?

I'm still a little fuzzy on how this will work. I'm going to have to sketch it out. For the moment, I'm still not clear how regulated pressure to the top of the diaphram from the total boost supply will prevent the top turbo from overspooling, but it may be just a matter of working it through. It just seems this will keep the wastegate closed until much higher boost is reached (the point that the regulator is set, say 40 lbs in my example). But I know I have to consider the boost being supplied to the little compressor by the primary turbo.

Going on vacation Friday for a week. Maybe I'll have time to think it through.

-Jay
Click to expand...

The wastegate pressure can't be set at total boost...you have 2 turbo's and one wastegate, so you have to basically "split" the wastegate (NOT EXACTLY SPLIT, but that helps get the point across). You'll want it to open up very early, say 25psi TOTAL, to keep boost down in the higher ranges! You are relying on the large housing of the big charger to keep boost down, and keep drive pressure down.

Chris
 
Th tial 38mm that I had with my KSB-1 was welded directly on to the exhaust manifold and it vented into the down pipe. No spacer needed between the turbo and manifold. Only problem I've had with it is the tube that stuck down in the manifold got brittle after 60k+ miles and broke off and lodged itself in the turbo. Got lucky and never made it to the wheel though.
 
BgBlDodge,

That's exactly how my set up is. A 38mm pipe welded to the manifold right in the middle with some of the center rib removed to vent both halves of the manifold through the wastegate. The output is piped back into the hot pipe to the big turbo.

Chris,
I acknowledge the wastegate is set to open early - I have the 20 lb set of springs - but boost supplied to the top of the wastegate (the top of the diaphram) will effectively raise the point at which the gate will open by helping the springs keep it closed. If I set the regulator to 40 lbs, then up to 40 lbs of additional pressure is being added to the top of the diaphram to support the 20 lb springs to keep it closed. So it would seem to me that the gate won't open in this case until the total boost pressure supplied to the gate (the underside of the diaphram) exceeds the sum of the 2. That's where my conflict is in understanding this. That setup doesn't seem right.

-Jay
 
JGK said:
Chris,
I acknowledge the wastegate is set to open early - I have the 20 lb set of springs - but boost supplied to the top of the wastegate (the top of the diaphram) will effectively raise the point at which the gate will open by helping the springs keep it closed. If I set the regulator to 40 lbs, then up to 40 lbs of additional pressure is being added to the top of the diaphram to support the 20 lb springs to keep it closed. So it would seem to me that the gate won't open in this case until the total boost pressure supplied to the gate (the underside of the diaphram) exceeds the sum of the 2. That's where my conflict is in understanding this. That setup doesn't seem right.

-Jay
Click to expand...

You are correct on all points...if you set the regulator to 40psi, the wastegate won't open until either:

A. Drive pressure passes 60psi and blows the gate open
OR
B. Boost pressure passes 60psi and open the gate!

That would be the correct line of thinking for a single charger setup!



For twins, you can't use ONE wastegate to control TWO chargers directly. You have to open the gate early to control them...basically, if you keep the gate closed, and continue driving the smaller charger, drive pressure will go up, and efficiency out of the small charger will drop. This is bad.

I don't seem to be able to explain why you can't do it the way you want!
Sorry,
Chris
 
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