Open downpipe yes or no?

Supra_Villan

Supra_Villan

needs his car done
Nov 10, 2007
662
0
0
Wellsville MO
I have ran open downpipe on my supra during the entire period i have owned it, aside from the two days i needed to pass inspection:evil2: , and i have not seen and or felt any performance difference...(a little shaftplay...but it is a 19 year old car and the turbo has not once been removed until this rebuild) but anyways, i have heard it can fatally damage the turbo, but i've also heard it can hurt the pistons? (I could care less about the old ones i'm getting ready to run a full built motor)so i need to know for the future.. is this true?, and if so to what extent
 
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87mgte

87 Turbo Targa
Sep 9, 2007
536
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Sequim
cliff notes:
-does running open downpipe positively affect performance?
-can it damage the turbo?
-can it damage the pistons?

sorry, just didn't want anyone else to have to read that whole paragraph to get those few questions out of it. as for an answer to your questions, i don't understand how open DP would affect your pistons at all. i've never seen a thread about it damaging the turbo. damaging people's ears and setting off car alarms, though... yeah, definitely.:biglaugh:
 
Poodles

Poodles

I play with fire
Jul 22, 2006
16,757
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Fort Worth, TX
You said you can't feel any performance diference?

Stock DP has a cat in it that likes to clog, get rid of that and it gets mean (and louder). Get rid of the crappy elbow and it opens up more...
 
D

Dan_Gyoba

Turbo Swapper
Aug 9, 2007
1,836
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Alberta
www.gyoba.com
Performance: Well, with a turbocharger, the less restriction that there is after the turbine, the easier it is to make the turbine do work. This does mean increased performance, but it's a law of diminishing returns, too. A 3" exhaust isn't a whole lot of restriction. I'll be (hopefully) installing an 80mm / 3" system from the turbo back this weekend. I expect that this would be a performance increase from the stock turbo elbow and stock downpipe that I'll be getting rid of, even without the crappy exhaust behind it.

HURT the turbo? Um... How? Once the exhaust is past the turbine, the turbocharger is DONE with it.

What can hurt the turbo is leaving the compressor outlet open which will cause it to overspin. That's the "cold" side of the turbo, not the hot side.

Pistons? Um... Well, if you had a severe boost leak and grenaded the compressor wheel, then sucked chunks of it into the engine, that would hurt the pistons pretty bad.
 
Adjuster

Adjuster

Supramania Contributor
Apr 8, 2005
1,166
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Meridian, Idaho, United States
www.adjusteridaho.com
LOL, those chunks would need to make it through a few feet of IC pipe, and the FMIC... and then the throttle body, and then the valves...

And keep in mind, most stock intercoolers are coated pretty well inside with oil.. so think large K&N filter to trap your debris in there..

Just a theory as I've never blown up a compressor turbine, but have blown some broken plug ceramic out past the exhaust wheel, no damage that I could see upon close inspection of the wheel..

Then again, the Inconel that wheel/shaft was made of is pretty tough stuff. (And the compressor wheel is made of much softer stuff, and not flowing out, but drawing in, so the debris will do different things for sure.)

Noise is nasty.
Power is fun.

Finding the right balance between the two is the key to a great car/bike/anything if you think about it. (Think of the loud women you know, and then find the right balance... LOL) ;)
 
starscream5000

starscream5000

Senior VIP Member
Aug 23, 2006
6,359
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Hot and Humid, KY
Kinda sort true... Not really ;)

The turbine itself provides all the backpressure the motor needs to be driveable, everything after the turbo, well, the sky's the limit ;)
 
TurboFreak

TurboFreak

NOBAMA
Jan 22, 2006
1,374
1
0
East Coast
YES. I loved the sound of my old car with an open DP. Kinda too loud for a DD though...

Its a close second to having a NON-rerouted DDP with 3.5" exhaust, IMO that is the best.
 
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Supra_Villan

Supra_Villan

needs his car done
Nov 10, 2007
662
0
0
Wellsville MO
the performance difference was phenomenal(typo?, lol) it was such a faster spool and it gave the car ALOT more balls...alot more. When i had the stock cat-back on after the downpipe(it is an aftermarket tms 3inch by the way) for the time i had to pass inspecion it just didn't have what it used to..and for those of you who hate on the sound....screw all of you it may sound like a tractor at idle but anything over 3k rpms was viscious and you can here the turbo spool like a t88hd although its only a ct26:evil2: :evil2:
 
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OneJoeZee

OneJoeZee

Retired Post Whore
Mar 30, 2005
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aboard the Argama
Supra_Villan said:
the performance difference was phenomenal(typo?, lol) it was such a faster spool and it gave the car ALOT more balls...alot more. When i had the stock cat-back on after the downpipe(it is an aftermarket tms 3inch by the way) for the time i had to pass inspecion it just didn't have what it used to..and for those of you who hate on the sound....screw all of you it may sound like a tractor but anything over 3k rpms was viscious:evil2: :evil2:
Click to expand...

Your car had a stock catback on it. Of course the open DP made huge difference. The stock catback is like breathing through a vein.

Before you say "screw you" to those who don't appreciate the obnoxiously loud annoyingness of an open downpipe, put a proper 3in catback on your car and see how it is.
 
Supra_Villan

Supra_Villan

needs his car done
Nov 10, 2007
662
0
0
Wellsville MO
OneJoeZee said:
Your car had a stock catback on it. Of course the open DP made huge difference. The stock catback is like breathing through a vein.

Before you say "screw you" to those who don't appreciate the obnoxiously loud annoyingness of an open downpipe, put a proper 3in catback on your car and see how it is.
Click to expand...
....well it had a hollowed cat and a megan tip!!!lol borrowed it from a fellow supra buddy, if feel bad for even using it lol, but yeah i like both about the same, but when you are not trying to talk open dp is friggin great
 
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