Twins questions.

crewgirl

crewgirl

Inmate #28
Joined
Feb 16, 2007
Messages
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I'm gonna put twins on el trucko, and I frankly don't know diddly about twins. So, I've started researching, I've done site searches, but my questions aren't getting answered.
I'm sure the more I learn the more questions I'll have.
Since some of the questions and answers are going to be application specific, here's the setup. It's going to be a gt4294 as primary and my hx35 as secondary. The truck has head studs, but it's still the stock head gasket. I'm planning on going to a 150 horse injector when I put the twins on. The only other mod that has anything to do with performance is a Dr. Performance stage 5 box.
Here's the first few.

Clamps vs. Boots - Is there any reason to use boots? I would like to, for appearances, use v bands on all the connections.

WTH does Drive Pressure have to do with anything? Do I need to worry about it? It's a small twins set up.......

Both turbos are wastegated, should I run wastegates on both? Or just one? If the answer is just one, which one?

I see some twins set ups with the hot pipe wrapped or a heat shield, it's ugly, do I NEED to do this?

I'm planning on using AS pipe for all my piping? Anything I should know, like the gauge of the pipe etc?

I was told that the setup would be similar to if I got a BD twins kit (as far as piping it) what kinda radius do I need for the 180* turn in the cold pipe? I'm going to get a 180* mandrel bend (once again, this is about look more than anything else) and I don't want to order the wrong thing.


Thanks in advance to anyone who tries to help!
 
crewgirl said:
I'm gonna put twins on el trucko, and I frankly don't know diddly about twins. So, I've started researching, I've done site searches, but my questions aren't getting answered.
I'm sure the more I learn the more questions I'll have.
Since some of the questions and answers are going to be application specific, here's the setup. It's going to be a gt4294 as primary and my hx35 as secondary. The truck has head studs, but it's still the stock head gasket. I'm planning on going to a 150 horse injector when I put the twins on. The only other mod that has anything to do with performance is a Dr. Performance stage 5 box.
Here's the first few.

Clamps vs. Boots - Is there any reason to use boots? I would like to, for appearances, use v bands on all the connections. Less fab work when boots are used

WTH does Drive Pressure have to do with anything? Do I need to worry about it? It's a small twins set up....... Drive pressure is just about as important as boost. you want a good 1/1 ratio with the boost.
Both turbos are wastegated, should I run wastegates on both? Or just one? If the answer is just one, which one? unless you want to run alot of nitrous use the one on the secondary.

I see some twins set ups with the hot pipe wrapped or a heat shield, it's ugly, do I NEED to do this? No

I'm planning on using AS pipe for all my piping? Anything I should know, like the gauge of the pipe etc?

I was told that the setup would be similar to if I got a BD twins kit (as far as piping it) what kinda radius do I need for the 180* turn in the cold pipe? I'm going to get a 180* mandrel bend (once again, this is about look more than anything else) and I don't want to order the wrong thing.


Thanks in advance to anyone who tries to help!
Click to expand...

Thats about all i got.
 
crewgirl said:
I'm gonna put twins on el trucko, and I frankly don't know diddly about twins. So, I've started researching, I've done site searches, but my questions aren't getting answered.
I'm sure the more I learn the more questions I'll have.
Since some of the questions and answers are going to be application specific, here's the setup. It's going to be a gt4294 as primary and my hx35 as secondary. The truck has head studs, but it's still the stock head gasket. I'm planning on going to a 150 horse injector when I put the twins on. The only other mod that has anything to do with performance is a Dr. Performance stage 5 box.
Here's the first few.

Clamps vs. Boots - Is there any reason to use boots? I would like to, for appearances, use v bands on all the connections. Boots allow for flexibility (expansion, misalignment, etc)

WTH does Drive Pressure have to do with anything? Do I need to worry about it? It's a small twins set up....... Its something to look at but its not as terribly important as everyone makes it out to be. Its a result not something you directly can deal with.

Both turbos are wastegated, should I run wastegates on both? Or just one? If the answer is just one, which one? Typically the top is gated and the primary is not.

I see some twins set ups with the hot pipe wrapped or a heat shield, it's ugly, do I NEED to do this? It helps keep from melting anything on the firewall. It also help a little with keeping the heat in the system and available for the primary. You could try a heat shield or ceramic coating.

I'm planning on using AS pipe for all my piping? Anything I should know, like the gauge of the pipe etc? Most people use 3-3.5" schedule 40 pipe which has a wall thickness of 0.216"

I was told that the setup would be similar to if I got a BD twins kit (as far as piping it) what kinda radius do I need for the 180* turn in the cold pipe? I'm going to get a 180* mandrel bend (once again, this is about look more than anything else) and I don't want to order the wrong thing. Basically whatever will fit.


Thanks in advance to anyone who tries to help!
Click to expand...


For the wastegating you have some options.
Secondary: If you size the secondary turbine wheel and housing large you don't need a wastegate. If you want to spray you probably want at least one wastegate. Gating the secondary allows you to run a small turbine for good spool and to easily control boost pressure.
Primary: Usually people don't gate the primary for two reasons: 1) they are cheap 2) by not gating it they allow the turbo to be pushed harder. Like how more boost on a single makes more power even when out of its map. If you sized the primary right it doesn't need to be gated.

:Cheer:
 
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White Knight said:
For the wastegating you have some options. If you size the secondary turbine wheel and housing large you don't need a wastegate. If you want to spray you probably want at least one wastegate. Usually people don't gate the primary for two reasons: 1) they are cheap 2) by not gating it they allow the turbo to be pushed harder. Like how more boost on a signle makes more power even when out of its map. If you sized the primary right it doesn't need to be gated.

:Cheer:
Click to expand...


Anna if you are going to use a GT42 then you can use the piping kits for the S400's to do so. They mount up the same, only difference is the exhaust outlet is like 1-2" more rearward, Ron A has posted this before since he has had both sets.

Vbands are expensive so I would only use the one where you have to at the outlet of the GT42.

When you first get them installed use the wastegate on the top turbo to adjust your spool and once you get it all figured out then use the wastegate on the primary to keep your boost no higher than you want it.
 
White Knight said:
For the wastegating you have some options.
Secondary: If you size the secondary turbine wheel and housing large you don't need a wastegate. If you want to spray you probably want at least one wastegate. Gating the secondary allows you to run a small turbine for good spool and to easily control boost pressure.
Primary: Usually people don't gate the primary for two reasons: 1) they are cheap 2) by not gating it they allow the turbo to be pushed harder. Like how more boost on a single makes more power even when out of its map. If you sized the primary right it doesn't need to be gated.

:Cheer:
Click to expand...

Muddin_dude06 said:
Anna if you are going to use a GT42 then you can use the piping kits for the S400's to do so. They mount up the same, only difference is the exhaust outlet is like 1-2" more rearward, Ron A has posted this before since he has had both sets.

Vbands are expensive so I would only use the one where you have to at the outlet of the GT42.

When you first get them installed use the wastegate on the top turbo to adjust your spool and once you get it all figured out then use the wastegate on the primary to keep your boost no higher than you want it.
Click to expand...

I didn't really "size" anything, I saw a good deal on a turbo and snatched it up. Consulted a couple of people and got the same responses from both, almost verbatim. "It's small for a primary, but it will spool almost instantly, you'll like it".

I would like to use v-bands, for looks. I haven't priced boots. But the clamps for the v-bands are $20. The flanges are $15. I imagine that the price difference between that and boots and clamps for those would be negligible. Am I going to see enough boost or whatever with this small of a set of twins to make it where flex or whatever is necessary?
 
IMHO flexing is always necessary...things get hot and move around. When they can't move...they crack.
This motor cost more by itself than 95% of the trucks on this board....1 v-band...1 boot to allow for movement on each charger.
Those are precision 108's in case anyone is wondering.
todd.jpg
 
Didnt know precision had Twin 108's on a car esp a small cubic inch like that one. Got 2 new P98's for sale, Pro Mod only allows twin 91's now.
 
That's a billet 618" big block. ADRL XTF car. The 108's replaced a pair of 97's
 
I see now, just looked small my bad, 16 injectors running meth Im guessing ?
 
I'm planning on using AS pipe for all my piping? Anything I should know, like the gauge of the pipe etc? Most people use 3-3.5" schedule 40 pipe which has a wall thickness of 0.216"

???? For all the piping?? i see sch40 for the hot pipe!
 
I don't know if you're agreeing with the previous comment, or what. I plan to powdercoat all the pipe, so it doesn't need to be "pretty". Mild steel, with the right thickness, will stop a bullet fired from 50 meters, at 2000+ fps..... so I figure mild steel is good for my set up as well. But if I need to get better (read stronger, more resistant) stuff for the hot pipe, I'll do it. Maybe I can find some header wrap in pink...........

Edit: haven't found pink header wrap, but I did find pink engine enamel!!!!!
VHT SP756 - VHT Engine Enamels - Overview - SummitRacing.com
 
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TheBigNasty said:
On the hot pipe.
Click to expand...

You mean the cold pipe?

BigDctd said:
I'm planning on using AS pipe for all my piping? Anything I should know, like the gauge of the pipe etc? Most people use 3-3.5" schedule 40 pipe which has a wall thickness of 0.216"

???? For all the piping?? i see sch40 for the hot pipe!
Click to expand...

Good catch. :doh: Yes sch 40 for the hot pipe. The intake piping can be done out of regular exhaust tubing.



Anna,
I've seen a few twins without boots, it just puts a little extra stress on everything as things heat and cool. Since you wanted the piping to be clean You could try to hide it in the fender. Or if you can find pink 4" boot maybe that would make a nice accent
 
Brandon was trying for sarcasm.....

I'm planning on powdercoating all the piping to match my valve cover and intake horn. So, when you open the hood of my truck, there's gonna be alot of pink. I'll use a black boot for a nice contrast. If I do the piping the way I want to, I can put one boot on the cold pipe, roughly in the middle. Obviously the hot pipe shouldn't have a boot, because melted rubber stinks.
The pipe to the intercooler, I was planning on leaving the boot where it goes into the intercooler. The only other pipe will be from the air filter to the primary, boot needed there?
Since I found the pink hi-temp paint, I will probably get some header wrap and just wrap and paint the hot pipe.

I've thought of another question. For the oil lines to and from the turbos, do I need to use pipe, or can I use that heavy braided wire stuff?
Like this : Russell 632070 Russell Pro Flex Steel Braided Hose
I think I saw on a twins thread that someone used that stuff.
 
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