Anyone bigger than 3 inch
#193877
November 13, 2003 06:03 pm UTC
November 13, 2003 06:03 pm UTC
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Joined: Dec 2002
Posts: 290 Mississauga
Trevor R Cook
OP
Serious Member
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OP
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Posts: 290
Mississauga
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I have a 3inch exhaust on my gst, and was thinking of going 3 1/2 or 4 on my tsi awd. anyone have bigger than 3inch
04 STi 13.3 @ 102 with a downpipe 08 WRX, 99 Eclipse, 95 TSi 91 Jeep YJ
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Re: Anyone bigger than 3 inch
#193879
November 13, 2003 07:17 pm UTC
November 13, 2003 07:17 pm UTC
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Joined: Mar 2003
Posts: 542 Toronto, ON
Michael Druciarek
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Serious Member
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Posts: 542
Toronto, ON
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Originally posted by Trevor R Cook: I have a 3inch exhaust on my gst, and was thinking of going 3 1/2 or 4 on my tsi awd. anyone have bigger than 3inch Do you have a good excuse to go above 3" or do you "just want it"? If you can prove to yourself that anything bigger than 3" is giving you an advantage than go for it.
DNP T3/T4, GT30R, 272/272 HKS, Wiseco 9:1, Eagle Rods, Metal HG, ARP Studs, Fidanza Flywheel, Tial 44mm, FIC 850cc, 3" Turbo-Back, ACT 2600, Aeromotive FPR, AEM Wideband, Walbro 255, Huge FMIC, Greddy Type-S, Tein Adjustable Coilovers
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Re: Anyone bigger than 3 inch
#193882
November 13, 2003 08:26 pm UTC
November 13, 2003 08:26 pm UTC
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Joined: Mar 2001
Posts: 2,787 Malaysia
Jeremy Chin
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Malaysia
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problem is...tough luck finding larger than a 3" muffler.
piping is no problem, but you will run into trouble with shops unable to mendrel bend something larger than 3". Maybe truck shops would become your new best friend.
you might also run into trouble with ground clearance if your car is lowered.
still wanna go bigger than 3"? sure...if you must..but I don't see any performance improvements since your biggest restriction is the turbo's turbine housing....
300hp Talon to a 50hp Citroen. Lovely ain't it? Back to another Mits. A Mirage Cyborg as a future 4G63T candidate.
"I've had more Mitsu's than you can imagine"
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Re: Anyone bigger than 3 inch
#193884
November 13, 2003 09:15 pm UTC
November 13, 2003 09:15 pm UTC
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Joined: Mar 1999
Posts: 1,704 Calgary, AB, Canada
Sean Costall
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Posts: 1,704
Calgary, AB, Canada
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Most people find larger than 3" pipes won't clear the axle/suspension.
I thought Buschur's 3.5" was for an EVO.
I was under the impression that 3" exhausts are usually good for at least 11s, if not better. Beats me why you'd want to bother with anything bigger. Even some 500+ HP cars have 3" exhausts, I think.
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Re: Anyone bigger than 3 inch
#193885
November 13, 2003 09:52 pm UTC
November 13, 2003 09:52 pm UTC
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Joined: Mar 2001
Posts: 2,787 Malaysia
Jeremy Chin
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Malaysia
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Originally posted by Rob Strelecki: Adding to the clearance issue.. What about clearing the rear axle? You can go above or below - would it even fit above? And if you went below, would it clear the ground? better idea for you FWD guys....cherry bombs and side pipes...heheheh.....hows that for flow? ..for FWD, you more or less have to go over the axle which even 3" is pushing it (you only got about 6" of ground clearance under the rear torsion beam..)
300hp Talon to a 50hp Citroen. Lovely ain't it? Back to another Mits. A Mirage Cyborg as a future 4G63T candidate.
"I've had more Mitsu's than you can imagine"
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Re: Anyone bigger than 3 inch
#193889
November 15, 2003 03:41 am UTC
November 15, 2003 03:41 am UTC
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Joined: Jan 1970
Posts: 4,971 Beamsville, Ont, Canada
Steve Kinnaird
Senior Member, with Far TOO Much Time on Their Hands
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Senior Member, with Far TOO Much Time on Their Hands
Joined: Jan 1970
Posts: 4,971
Beamsville, Ont, Canada
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Perhaps a 2.0 litre N/A engine.
The best turbo exhaust is no exhaust.
Now, I'll have all kinds of time to talk about DSMs, because I won't be busy fixing mine!
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Re: Anyone bigger than 3 inch
#193890
November 15, 2003 06:39 am UTC
November 15, 2003 06:39 am UTC
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Joined: Jul 2002
Posts: 571 Hamilton, Ontario
Jonny Marszalek
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Posts: 571
Hamilton, Ontario
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Originally posted by Steve Kinnaird: Perhaps a 2.0 litre N/A engine.
The best turbo exhaust is no exhaust. 3" dp + electric cutoff for life! followed by the stock crap, etc...
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Re: Anyone bigger than 3 inch
#193892
November 15, 2003 10:39 am UTC
November 15, 2003 10:39 am UTC
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Joined: Apr 2002
Posts: 1,449 Toronto/LA
Steve Marton
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Toronto/LA
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I agree with Jonny and that's the setup I'm going with. Only drawback is it's less fun on the street, especially when the 5-0 catches you with it open While racing Jonny, are you actually running a cutout? How's the valve holdin up? I got the gtec, I hope it holds up. Do you get boost creep? I dunno if Amin's theory applies in practice, I guess testing's the only way to find out. Trevor, have you ever run with the exhaust open after the dp? Or even from the turbo if you so desire but that's optimistic. That should give you a decent indication of what you'll gain from the 4". Then you decide if it's worth it for you. I'm guessing it will be next to no difference assuming you have a straight-thru muffler. Go test it. I know on my fwd with stock exhaust I gained about 3 thents and 2mph by dumping out the dp versus full exhaust. Still a lot to be gained from the dp which I'll be doing... sometime... I wouldn't be so optimistic for you going from your 3" setup to 4" though.
Black 91 TSI FWD
"DSM: Making mechanics out of normal people since 1989"
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Re: Anyone bigger than 3 inch
#193893
November 15, 2003 12:15 pm UTC
November 15, 2003 12:15 pm UTC
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Joined: Jan 1970
Posts: 4,971 Beamsville, Ont, Canada
Steve Kinnaird
Senior Member, with Far TOO Much Time on Their Hands
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Senior Member, with Far TOO Much Time on Their Hands
Joined: Jan 1970
Posts: 4,971
Beamsville, Ont, Canada
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no exhaust has NOTHING to do with a big exhaust. It is about fluid dynamics. you create extra back pressure with bigger exhaust. huh? Extra "back pressure" with a bigger exhaust? Can you explain how that works? What you are after with a turbo car is the biggest pressure diferential across the turbine wheel. The best way to get that is to have no exhaust after the turbine wheel. (Or the closest thing to it).
Now, I'll have all kinds of time to talk about DSMs, because I won't be busy fixing mine!
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Re: Anyone bigger than 3 inch
#193895
November 15, 2003 09:31 pm UTC
November 15, 2003 09:31 pm UTC
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Joined: Mar 2001
Posts: 1,041 Toronto
Bart Cieslikiewicz
A$$ man
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A$$ man
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Posts: 1,041
Toronto
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Guys have gone 12's and 11's on 2.5" systems, no need for bigger unless you want more sound...
It's not a Talon, it's a Talonol... And now it's in the garage with a connecting rod sticking out...
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Re: Anyone bigger than 3 inch
#193896
November 16, 2003 04:03 am UTC
November 16, 2003 04:03 am UTC
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Joined: Jan 1970
Posts: 4,971 Beamsville, Ont, Canada
Steve Kinnaird
Senior Member, with Far TOO Much Time on Their Hands
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Senior Member, with Far TOO Much Time on Their Hands
Joined: Jan 1970
Posts: 4,971
Beamsville, Ont, Canada
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But when you make the exhaust bigger the infact disrupt the flow of air. you need lower bck pressure in ANY engine, that is obvious. Ok, but keep in mind how much a rotating turbine blade disrupts airfow. Anything PAST that point is non consequential IMHO. FWIW: any "fluid dynamics" guy I've talked to HATES the term "back pressure". There's no such thing. It's a restriction.
Now, I'll have all kinds of time to talk about DSMs, because I won't be busy fixing mine!
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Re: Anyone bigger than 3 inch
#193897
November 16, 2003 08:08 am UTC
November 16, 2003 08:08 am UTC
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Joined: Apr 2002
Posts: 1,449 Toronto/LA
Steve Marton
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Toronto/LA
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But a flow restriction does cause a rise in pressure behind it, so it makes sense Maybe it's not a fluid dynamics term but it works I don't know if you can even classify turbulence as a restriction. I tend to think of restrictions being physical. But enough about terminology. I say we let Trevor do his 4" exhaust and he'll do the fluid dynamics experimentation for us But to be fair I can guarantee that the money can be put to better use elsewhere.
Black 91 TSI FWD
"DSM: Making mechanics out of normal people since 1989"
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Re: Anyone bigger than 3 inch
#193898
November 17, 2003 03:00 am UTC
November 17, 2003 03:00 am UTC
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Joined: Jan 1970
Posts: 4,971 Beamsville, Ont, Canada
Steve Kinnaird
Senior Member, with Far TOO Much Time on Their Hands
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Senior Member, with Far TOO Much Time on Their Hands
Joined: Jan 1970
Posts: 4,971
Beamsville, Ont, Canada
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Yes, it does make sense.... and you're right, it's a term that's used often enough.
I can't see a 3" exhaust being a restriction at all for most people, so going to a 4" shouldn't make any improvement.
But, hey... if you wanna build one, why not?
Now, I'll have all kinds of time to talk about DSMs, because I won't be busy fixing mine!
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Re: Anyone bigger than 3 inch
#193899
November 17, 2003 04:49 am UTC
November 17, 2003 04:49 am UTC
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Joined: Jun 2001
Posts: 131 Vancouver
Fraser Cassells
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Posts: 131
Vancouver
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No sh!t, you want 3.5"? 4 "? kickass, do it! I hate hearing techno-babble dribble out of peoples mouths like they know wtf they are saying, said with such conviction you would have to be an idiot not to believe them.
A local tuner just brought in a shipment of 22gauge 3.5", lightweight for sure, and with mandrel bends it will flow all you can throw.
Will I buy it? maybe not, but its cool people DO that sh!t rather than sit on their hands NOT doing fark all and guessing the outcome.
1990 Talon AWD 12.0@115.9
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Re: Anyone bigger than 3 inch
#193901
November 17, 2003 03:04 pm UTC
November 17, 2003 03:04 pm UTC
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Joined: Jun 2001
Posts: 131 Vancouver
Fraser Cassells
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Posts: 131
Vancouver
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The Foo, L&R racing. he has 3.5" SS and 4" SS in the 22 gauge. I guess this is for guys who want to out-supra the Toyota guys.
1990 Talon AWD 12.0@115.9
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Re: Anyone bigger than 3 inch
#193904
November 27, 2003 02:46 am UTC
November 27, 2003 02:46 am UTC
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Joined: Mar 2001
Posts: 1,004 Portland, OR
toddmeunier
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Posts: 1,004
Portland, OR
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From www.magnaflow.com: For turbocharged engines, 2.5-inch is the minimum size pipe that you would want to run, even for the smaller engines. For 2,000cc and bigger engines, 3-inch works well, and for bigger engines the biggest (usually 3.5-inch) you can find is appropriate. It is almost impossible to have too big of an exhaust on a turbo car. I would go with a 3" Trevor.
90 Talon 10.089 @ 139.34 Mastah-tuned TPG + Meth
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Re: Anyone bigger than 3 inch
#193906
November 27, 2003 09:32 pm UTC
November 27, 2003 09:32 pm UTC
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Joined: Mar 1999
Posts: 1,704 Calgary, AB, Canada
Sean Costall
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Calgary, AB, Canada
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Flow calculations and fluid dynamics go in the trashbin once the turbo gets going. Steve is right, it's all about the energy used to spin the turbo. For turbocharged cars, no exhaust is the best exhaust.
For non-turbo cars, there is an "optimal" point where the exhaust pulses move along the pipe most efficiently. If you go bigger than this you end up trading low-end torque for high-end horsepower - a tradeoff some, but not all, people are willing to make.
"Backpressure" is a bullshit automotive term made up by people who didn't know any better at the time. Still, if we must use it, bigger exhausts do not create more "backpressure", they create less.
And I still think he's going to have problems getting a 3.5"+ system to clear everything. There are seriously fast cars running 3" exhausts, so I still don't see the point.
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Re: Anyone bigger than 3 inch
#193908
November 28, 2003 02:50 am UTC
November 28, 2003 02:50 am UTC
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Joined: Jan 1970
Posts: 4,971 Beamsville, Ont, Canada
Steve Kinnaird
Senior Member, with Far TOO Much Time on Their Hands
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Senior Member, with Far TOO Much Time on Their Hands
Joined: Jan 1970
Posts: 4,971
Beamsville, Ont, Canada
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Even if the turbo where stopped, you've still got essentially a fan blade in the path of exhaust.
You want some restriction (or backpressure, or whatever you want to call it)? You got it!
Now, I'll have all kinds of time to talk about DSMs, because I won't be busy fixing mine!
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Re: Anyone bigger than 3 inch
#193909
November 28, 2003 10:49 am UTC
November 28, 2003 10:49 am UTC
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Joined: Jul 2001
Posts: 205 Edmonton, Alberta, Canada
Blaine Bilocerkowec
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Member
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Posts: 205
Edmonton, Alberta, Canada
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Originally posted by Steve Kinnaird: Even if the turbo where stopped, you've still got essentially a fan blade in the path of exhaust.
You want some restriction (or backpressure, or whatever you want to call it)? You got it! I agree with Steve.
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Re: Anyone bigger than 3 inch
#193910
November 28, 2003 09:26 pm UTC
November 28, 2003 09:26 pm UTC
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Joined: Mar 1999
Posts: 1,704 Calgary, AB, Canada
Sean Costall
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Calgary, AB, Canada
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Originally posted by Rob Strelecki: What is a turbo car when the turbo isn't spooling any boost? By god, it's just like an NT! Nobody cares. Why would they? Turbo cars are designed to perform under boost. Nobody cares what happens when they're not boosting. Show me one guy who runs around off the boost all the time, much less anyone who does the 1/4 mile without any boost. :rolleyes: If you wanted a turbo car to make power when not under boost, you would change the pistons to a higher compression to make more low-end torque. Nobody would care about spoolup time on the turbo because we'd all be modifying for unboosted performance. Essentially, everyone would be converting from turbo to non-turbo - a generally pointless exercise if ever I heard of one.
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Re: Anyone bigger than 3 inch
#193912
November 28, 2003 10:12 pm UTC
November 28, 2003 10:12 pm UTC
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Joined: Apr 2002
Posts: 1,449 Toronto/LA
Steve Marton
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Toronto/LA
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No, because of what Steve said. "Even if the turbo where stopped, you've still got essentially a fan blade in the path of exhaust."
More than enough "backpressure". I think "backpressure" is necessary because of cam timing/overlap issues. In this case, you got it.
To answer your question, the more open the exhaust the better, at low rpms as well as high, because it means the pressure after the turbo is smaller, so it spools faster. Turbos are driven by the pressure differential between the exhaust gases before- and after the turbine, right?
Black 91 TSI FWD
"DSM: Making mechanics out of normal people since 1989"
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Re: Anyone bigger than 3 inch
#193914
December 01, 2003 06:38 am UTC
December 01, 2003 06:38 am UTC
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Joined: Jun 2001
Posts: 131 Vancouver
Fraser Cassells
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Member
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Posts: 131
Vancouver
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[/qb][/QUOTE]you don't worry yourself too much. [/QB][/QUOTE] I am not fluent in broken English, what is the intent in this statement. And please feel free to add more of your delusional self-taught techno babble, its funny as hell
1990 Talon AWD 12.0@115.9
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Re: Anyone bigger than 3 inch
#193915
December 01, 2003 09:42 pm UTC
December 01, 2003 09:42 pm UTC
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Joined: Mar 1999
Posts: 1,704 Calgary, AB, Canada
Sean Costall
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Posts: 1,704
Calgary, AB, Canada
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If you can explain where any of this discussion is going wrong, Fraser, you go right ahead. Originally posted by Rob Strelecki: Sean I think you may have missed my point.. It only applies to people with upgraded turbos.
I don't think so. Anyone who thinks our engines, stock, have any kind of low-end grunt to them is sorely mistaken. They don't have any kind of low-end torque, at least not when compared to a nice non-turbo V8 engine. Even the stock setup is intended to perform only when boosting. One might argue that 2G cars are a little different, and they are. The smaller turbo and higher compression design of that engine was specifically intended to restore some low-end torque and make the car more "driveable". And it did, at the expense of high-end power. But even 2Gs don't have nearly as much oomph down low as most performance NTs, as far as I know. Also as far as I know, people who put in higher-compression pistons do not do so to regain low-end torque. They do it to get more overall power out of the engine, true - but because they want more top-end power, not more low-end power. Low-end power is just a side effect - kind of a perk, if you will. Now, I suppose I could be wrong. But I have never seen anyone really serious about making big power suggest that you should install higher-compression pistons to combat turbo lag. The preferred solutions to lag is to get a less laggy turbo setup. Neither have I ever seen anyone making big power complain that the car has no low-end torque. Nobody cares. Drag racers certainly don't give a crap, and autocrossers or road racers just go with smaller, less laggy turbochargers that they can take full advantage of. Having said all that I suppose you could install higher compression pistons if you wanted more low end. I've never considered it before, but it would work, provided you didn't mind running less boost on an otherwise identical setup. I just can't figure out why anyone who wants low end power would want a DSM in the first place. It's a terrible platform for that kind of thing, especially when compared to the V6 and V8 cars. Plus, with the turbo setups you can get these days, there isn't much excuse for the turbo not spooling almost identical to stock. Full boost by 3500 RPM is quite commonplace these days. But YES, I believe a big exhaust will always affect your low-end power, turbo or non-turbo. I think Steve and Steve disagree with me here. But I'm not aware of any reason why an NT would require an exhaust restriction because of camshaft/valve overlap issues. As far as I know it's all about the cylinder scavenging that arises from the speed of the exhaust flow through the exhaust piping. Can anyone elaborate on this?
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Re: Anyone bigger than 3 inch
#193916
December 02, 2003 04:01 am UTC
December 02, 2003 04:01 am UTC
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Joined: Jan 1970
Posts: 4,971 Beamsville, Ont, Canada
Steve Kinnaird
Senior Member, with Far TOO Much Time on Their Hands
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Senior Member, with Far TOO Much Time on Their Hands
Joined: Jan 1970
Posts: 4,971
Beamsville, Ont, Canada
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I do disagree, sort of... I agree that any exhaust after the turbo will add to restriction. (an exhaust after the turbo, HAS to be more restrictive than no exhaust after the turbo...) Whatever you've got after the turbine wheel is part of a system. Everything in that system affects how the car behaves. There ARE going to be differences between a 3" exhaust, and a 4" exhaust for example. However, having said that I still believe that pressure differential across the turbine wheel is the major factor here. I don't think anything else in the "system" is going to come close to affecting the car's behaviour more than that. So, yes, I agree that the exhaust WILL affect the low end of a turbo car. I just don't think it will affect it enough to be noteworthy. As a side note: the above is all based on the little squirrel cage spinning in my head. It's based on nothing but the (mostly) common sense I would like to think I have..
Now, I'll have all kinds of time to talk about DSMs, because I won't be busy fixing mine!
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