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Guest Message by DevFuse
 

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My wangon project and a different turbo question


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12 replies to this topic

#1 IASUBE

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Posted 19 September 2007 - 10:23 AM

Some back ground first,the car is a EA81 wagon, weber, D/R 4 speed running 235-75-15's on 6 hole chevy wagon wheels. The wagon is a total rust bucket, so I'm in the process of putting a bunch of pipe in it to tie it all back together, a 3 in lift/front sub frame is welded in place and work has started on the re-structuring the rest of the chassie (BTW I blame Scott in B. for the inspiration on it)
This will be mostly be a toy and a Mud-dragger. OK I was thinking about putting a turbo from an EA82T on it probably a draw thru (got a couple of them) but with a bit of a twist... Turbo guys help me out here please. It needs some bottom end power as anyone who's got big tires and no T-case knows.
If I were to install a restrictor disc in the up pipe to the turbo, can I lower the rpm that the turbo will spool up and start boosting? I understand this will choke off the upper rpm at some point and that's ok. For right now.... I'd happily give away some top end power, for boost (TQ) at lower rpm, say 1500-2000 rpm, if need be a large external waste gate could be added to let it rpm if the internal one wont flow enough.
Sorry for the lengthy post, Fire away.
IASUBE (edit..... so I can't spell...what the hell is a Wangon?)

#2 VaporTrail

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Posted 19 September 2007 - 10:58 AM

Hey! Where are you located?

#3 IASUBE

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Posted 19 September 2007 - 11:17 AM

Hey! Where are you located?


Hea McBrat, about 130 miles west of you, Percival Iowa, south of Council Bluffs about 30 miles. IASUBE

#4 The Dude Abides

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Posted 19 September 2007 - 01:58 PM

sweet another iowa suby guy we keep on growin and growin and growin. should just turn this into a iowa subaru soundoff.

Ben

#5 The Dude Abides

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Posted 19 September 2007 - 02:02 PM

Some back ground first,the car is a EA81 wagon, weber, D/R 4 speed running 235-75-15's on 6 hole chevy wagon wheels. The wagon is a total rust bucket, so I'm in the process of putting a bunch of pipe in it to tie it all back together, a 3 in lift/front sub frame is welded in place and work has started on the re-structuring the rest of the chassie (BTW I blame Scott in B. for the inspiration on it)
This will be mostly be a toy and a Mud-dragger. OK I was thinking about putting a turbo from an EA82T on it probably a draw thru (got a couple of them) but with a bit of a twist... Turbo guys help me out here please. It needs some bottom end power as anyone who's got big tires and no T-case knows.
If I were to install a restrictor disc in the up pipe to the turbo, can I lower the rpm that the turbo will spool up and start boosting? I understand this will choke off the upper rpm at some point and that's ok. For right now.... I'd happily give away some top end power, for boost (TQ) at lower rpm, say 1500-2000 rpm, if need be a large external waste gate could be added to let it rpm if the internal one wont flow enough.
Sorry for the lengthy post, Fire away.
IASUBE (edit..... so I can't spell...what the hell is a Wangon?)



I think your going to find that most people are going to tell you to do an entire motor swap. Like (and correct me if im wrong) ej22 out of a legacy. They have more power although the benefits of fuelinjection are great for going up inclines probally stink for mudbogging. But other people will chime in. Welcome. Check out some of the other areas there having a meet and greet i believe this weekend in your neck of the woods. Under trails

Ben

#6 Reveeen

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Posted 19 September 2007 - 02:10 PM

If I were to install a restrictor disc in the up pipe to the turbo, can I lower the rpm that the turbo will spool up and start boosting?

No, you want a smaller turbo, a restrictor will slow your turbo down, causing less boost at low rpms. Saab LPTs do just that, install a restrictor, causing lower turbo pressures (LPT= low pressure turbo).

All kinda moot anyway, your naturally aspirated engine won't last long at pressures greater than 6-8psi.

+1 on EJ22(T) swap.

#7 VaporTrail

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Posted 19 September 2007 - 02:27 PM

this place is perfect for soobs.....

http://www.ultimates...ead.php?t=78471

#8 IASUBE

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Posted 19 September 2007 - 02:41 PM

If I were to install a restrictor disc in the up pipe to the turbo, can I lower the rpm that the turbo will spool up and start boosting?

No, you want a smaller turbo, a restrictor will slow your turbo down, causing less boost at low rpms. Saab LPTs do just that, install a restrictor, causing lower turbo pressures (LPT= low pressure turbo).

All kinda moot anyway, your naturally aspirated engine won't last long at pressures greater than 6-8psi.

+1 on EJ22(T) swap.

Sorry a motor swap ain't happening, I just love the pushrods! :grin:

Reveeen, thanks for the heads up on Saab's light pressure turbo, they are doing exactly what I want to do, which is putting more area under the TQ curve... by restricting the inlet to the turbo the gas velocity is increased, decreasing lag and boost threshold, granted the total Power out put of their motors is barely above a N/A motor, the driveability is greatly enhanced to to the good bottom/mid-range TQ increase.
And boost will never go above 6-8 psi... Just need some grunt to pull the tires in the mud... Below is a short article on the Saab LPT

Thanks, IASUBE



Posted ImageLight pressure turbocharging is one of the most popular power boosting technology in recent years. Saab, the pioneer of turbo in saloons, is the first car maker put it into mass production. In 1992, it surprised many by introducing the Saab 9000 2.3 turbo Ecopower. The engine had only 170 hp, that is, just 20 hp more than the normally aspirated version and 30 hp below the standard 2.3 turbo. Basically, it was just the standard engine with a smaller turbo and lighter boost pressure.
While other car makers were still pursuing "on paper" peak power, Saab's clever engineers realised that less equals to more. Despite of lower peak power, light turbo engine remains to be strong in torque, thus aids acceleration. Most important, it has very much better drivability due to the inexistence of turbo lag. Throttle response is nearly instant. Besides, Saab proved that the better torque curve enables taller gearing, thus actually delivering better fuel economy that a normally aspirated engine of the same size !

#9 Reveeen

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Posted 19 September 2007 - 03:40 PM

granted the total Power out put of their motors is barely above a N/A motor, the driveability is greatly enhanced to to the good bottom/mid-range TQ increase.

Saab is an odd car manufacturer, gone all to crap now, that they are owned by GM. Sadly I *think* you can keep your LPT systems, unless the boost gauge is broken on my 9000, I see 5-7psi at idle, close to 21psi at red line, roughly 300hp, no LPT systems here, or wanted.
No sense having a turbo without the "lunge".

#10 IASUBE

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Posted 19 September 2007 - 03:53 PM

Hummmm..... Interesting, I've Never heard any turbo/blower car having boost at idle? Well not without power braking it....
But I think your missing my point, with my old EA82T the boost wouldn't come on till 2500-3000 rpm... In this application that won't do me much good when the big tires and mud pull the motor down, I think that's where a flat TQ curve could have some benifit. Anyone else?..... Reveeen your idea for a smaller turbo is noted, I'll look into that.
Thanks IASUBE

#11 j2coe

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Posted 19 September 2007 - 04:12 PM

do those low pressure turbos have boost at idle? I think he just means it reads on the gague since the turbo is always spinning due to the exhaust gas running through it, low at idle and high at red line. the boost is usually activated by the gate opening. or am I way off?

#12 Reveeen

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Posted 19 September 2007 - 04:59 PM

I've Never heard any turbo/blower car having boost at idle?

If the system is "making boost" where would it go?

the boost is usually activated by the gate opening

"The gate", or what is called "the waste gate", allows exhaust gas pressure to by-pass the turbo when a pre-set limit is reached. The waste gate is controlled by either a pre-set, or adjustable, diaphragm hooked to the intake manifold for signal working against a spring. They are normally closed until intake manifold pressure overcomes spring pressure (in the diaphragm) forcing it open.

I am far from a turbo expert, but to see boost at low RPMs you might want a turbo from a small displacement engine (eg Suzuki), you have to be careful it doesn't "overspeed" (and blow up). The pipe sizes, and length, between the exhaust port, and turbo are critical to both maintain flow, and velocity.

#13 ausubaru92

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Posted 21 September 2007 - 07:24 AM

By placing a restrictor in the uppipe, sure gas velocity is gonna be fast moving through the restrictor, but the turbo relies on the bulk mass of air moving past its blades to make them spin.

Smaller turbo or an EJ would be the way to go




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