04-17-2009, 02:53 PM | #15 |
Drives: Dodge Ram Megacab & Cobalt SS Join Date: Sep 2008
Location: Boise
Posts: 1,536
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I thought the STS type turbos had some real benefits in aftermarket systems. The main one is that the exhaust gas is several hundred degrees cooler so the turbos don't have to be oil jacketed for fluid bearings. Therefore it's more straight forward as a bolt on, even though you might not be able to get quite as much power.
But in a fully plumbed system hot air in the exhaust in front of the turbo expands which creates more pressure on the turbine side so it spools faster. I actually understood that was more the reason for the lag, not the length of pipe. As far as PSI, who knows- it's more airflow CFM then PSI. 5 PSI on a big housing can flow alot of CFM. And STS's run pretty large turbos. I see the appeal if you are trying to keep your engine as stock as possible. Most of my turbo knowledge is from my truck though. I haven't messed with my car's turbo so I'm not sure if it 100% applies. |
04-17-2009, 04:09 PM | #16 | |
Drives: 2009 Cobalt SS Turbo 97 tahoe Join Date: Apr 2009
Location: Colorado
Posts: 25
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Big turbo systems hook the turbo right onto the Exhaust Manifolds. The bigger the displacement the less of an issue it is but here is a pic of a twin turbo v6 .. Done right . Thats what I am saying ^ TT v6 ( porsche/VW )
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04-17-2009, 04:12 PM | #17 | |
Drives: 2009 Cobalt SS Turbo 97 tahoe Join Date: Apr 2009
Location: Colorado
Posts: 25
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04-17-2009, 04:14 PM | #18 |
SST...
Drives: SST Camaro 2010 Join Date: Oct 2008
Location: East Coast of Florida
Posts: 5,927
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Pick up a copy of the latest issue of Hot Rod. The place that made the engine on the cover (Nelson Racing Engines) is making complete twin turbo setups for the SS Camaros.
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04-17-2009, 04:20 PM | #19 |
Drives: 2009 Cobalt SS Turbo 97 tahoe Join Date: Apr 2009
Location: Colorado
Posts: 25
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I'm trying to tell them the days of just slapping on a power adder on are here. A lot of companies are even starting to offer the option of a turbo charger on 75% of the entire line up of vehicles.... The future is here.
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04-18-2009, 01:03 AM | #20 | |
Drives: 96 Bronco w/ a 5 speed Join Date: Mar 2007
Location: PNW
Posts: 296
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But you might be able to kill two birds and swap in shorter, forged rods and/or pistons that would allow high boost by being stronger and by lowering compression. But I don;t think there will be a problem with moderate levels of boost since as Dragoneye mentioned it runs fine on 87 octane. And more convincingly, there are already Cadillacs running around with blowers on the same V6. |
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04-18-2009, 01:17 AM | #21 | |
Drives: 96 Bronco w/ a 5 speed Join Date: Mar 2007
Location: PNW
Posts: 296
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04-18-2009, 03:04 AM | #22 |
Drives: 02 WS6 TA, 88 Fiero Formula Join Date: Aug 2008
Location: Utard
Posts: 296
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The issue of compression is not traditional and should not be viewed as such. No fuel/air is compressed in a DI engine. This is the reason they went with the high C/R. Because they could get away with it, because it makes a higher specific output powerplant. Having the high C/R in a boosted setup really would only be a question of fuel pressure, since the new TDC cyl pressure would now be 5-25 PSI + 1 bar X 11.1 instead of < or = 1 bar X 11.1, and you'd have to be sure that the 1200 psi (I think) max fuel pressure would be enough to atomize into such a high-pressure volume of air. It's been said a thousand times before. They didn't "tune" the engine for 87 octane. You can run any octane you like in it. They use 87 because it's a great selling point for customers and it illustrates the brilliance of the idea. You can't detonate dry air. Again, the biggest hurdles to FI on the LLT will be sufficient fuel pressure and perhaps head gasket integrity, not C/R.
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04-18-2009, 10:38 AM | #23 |
Drives: 2007 Mazdaspeed 3 Join Date: Apr 2009
Location: Jacksonville FL
Posts: 35
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Your biggest issue is going to be fuel management and ecu tuning,depending on how hard the ecu is to crack. DI is also a relatively new technology, what we do know is you can run higher C/R due to much more accurrate and cleaner fuel burn directly into the combustion chambers. Hard part is you better hope that the stock Injectors can handle an increased fuel demand.
On my Mazdaspeed3 with a 2.3L DISI it has a 9.5:1 C/R that puts out 256/280 hp/torque. Not bad for a 4banger. It took about a year to get anytype of tuning out as well as fuel upgrades. However, one of the first modifications to help with the fuel problems and detonation was methanol injection. You will aslo probably want to change your plugs out for 1 or 2degree colder plugs and run on 93 octane. You will get huge power from going turbo. I'd put pricing for a kit at around 4500 minimum for a single turbo setup. More than likely going to come with a enginemanagement of some sort,turbo, turbo manifold, downpipe, intercooler, piping, possibly fuel upgrades, and various hoses,fittings,and clamps. |
04-18-2009, 04:28 PM | #24 | |
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Drives: 2003 Cobra Convertible Join Date: Feb 2009
Location: CA
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04-18-2009, 10:25 PM | #25 |
Drives: 2009 Cobalt SS Turbo 97 tahoe Join Date: Apr 2009
Location: Colorado
Posts: 25
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If we are lucky
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04-18-2009, 10:38 PM | #26 | |
Drives: 96 Bronco w/ a 5 speed Join Date: Mar 2007
Location: PNW
Posts: 296
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They say that the fuel is injected during the intake stroke, while the intake valve is open. This still allows all of the fuel vaporization's cooling to go into the air instead of the intake valve which doesn't need it. The rest of the gains appear to have been made the hard way: better cooling of the chamber (like the oil jets squirting the bottoms of the pistons). |
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04-19-2009, 03:39 AM | #27 |
Drives: 02 WS6 TA, 88 Fiero Formula Join Date: Aug 2008
Location: Utard
Posts: 296
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I didn't go through it, but if that is true, why do they use such a high pressure fuel pump and injectors? Technically in a NA engine that air charge would be in vacuum.
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04-19-2009, 11:30 AM | #28 |
Drives: 2009 Cobalt SS Turbo 97 tahoe Join Date: Apr 2009
Location: Colorado
Posts: 25
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Because it is like a Diesel .. Normal injectors squirt the fuel in the opposite stroke towards the bottom. DI has a VERY VERY small window of time to get the fuel into the cylinder. we are talking quarters of a milisecond to get the exzact amount of fuel for every stroke .. VERY complex
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