Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Are you in the market for a new car and having a hard time finding affordable options? A reporter would like to speak with you; please reach out to [email protected] by 2/26 for more details.

Turbochargers & Superchargers: Theory and Application



  • I have seen huge numbers for chips on turbo diesels also. I think part of it is a substantial boost increase but suspect they are also capable of moving the torque peak to a higher rpm. Because the torque peak is at such low rpms on a diesel, a move of a few hundred rpm could make a substantial horsepower gain. That gain won't buy you much in terms of real world acceleration but it sure looks impressive on paper.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    Hmmm...I wonder about a chip's effect on torque unless the engine was of substantial displacement. Torque is related directly to individual cylinder displacement. I can't see much happening with a 2.0L diesel unless it's a one cylinder.
  • I was just talking about moving the torque peak higher in the rev band. That can be done by varying valve timing and/or duration. In the old days, we had to use a new camshaft to do that. But some cars have electronic control of those variables and could therefore be modified by a chip.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    Oh I see...well I"m told by the pros that many chips actually do only that...they don't increase HP or torque but move it around on the power band. Not QUITE what some buyers thought they were getting however, or what was advertised.

    I'd be very careful about over-boosting on stock engines, however, especially ones that have some miles on them.
  • You are so right about naturally aspirated engines . They usually are more fuel effiecient.Example: My 5.0 mustang gets 21 mpg in town and 24mpg hwy. and will hit 140MPH on the interstate. No turbo or SC.
  • hey guys I'm doing a project on the topic of here in this forum and i was wondering if you guys could give me some solid info comparing the two so that I could get started. Personally I am partial to the turbo because you can get more power by increasing the boost. Plus a s/c runs off the belt so if it breaks its causes more problems,while taking a way from the power that the belt uses to run other things. ... For the problem of drag just buy a smaller turbo. The spoil time is based on the size of the turbo. If you want off the line speed go small, you want high speed go big.
  • Wow!!! I am really impressed on a few of you all comments about Turbos vs Super chargers.. I am turbo guy all the way.. I do believe that a four banger can make 400+HP and be driven everyday and then go to the track a wip a few other car here and there.. The difference for me to understand is, If i drive from Raleigh NC to Orlando Fla with a super charger at 75mph i am going to be putting in around 8psi of boost while i am driving. With a turbo I will be in Vac most of the time and only have boost when i need it.. But great post from all of you..

    Later Derek
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    Exactly.....there is no "better" right out of the box. It depends on the engine for sure, your budget, what you are stuffing it in, and your particular tolerances for certain driving characteristics.

    I am a SC kind of guy because I like that boost way down low and I like to boost torque down there, too. Also it's kind of a natural for a V-8 car, sitting right there in between the cylinder banks. Turbos on V-8s can get into a LOT of plumbing.

    If I were going to turbo a large displacement engine, it would be twin-turbos for sure and that can get expensive and complicated.

    SCs tend to be more expensive though initially compared to a turbo installation.
  • Actually, you are not going to be pushing 8 psi of boost into your engine while cruising at a steady speed. Your engine will only take in as much air and fuel as it needs to maintain the speed. So, the pressure in the intake manifold will be nearly the same as it would be in a normally aspirated car. While cruising, your throttle plate is nearly closed, causing a large pressure drop across it and vacuum conditions in the intake manifold. Typical supercharger set-ups also have some type of an air bypass valve so that the supercharger is essemtially freewheeling during low load conditions, thereby minimizing parasitic losses. Some even have an electromagnetic clutch on the supercharger, so that you aren't even spining the SC.
    So the difference between an SC and a TC, from a fuel economy standpoint, isn't that great.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    There seems to be (not here but around) quite a bit of misconception about air/fuel mixture.

    Basicallly many people don't realize that if you increase fuel (larger carbs, bigger injectors, or a computer chip) you have to increase AIR if you want any kind of *substantial* gain. The "chips" they sell do take advantage of the factory's propensity to lean out mixtures for emissions and thus put in more fuel electronically, but without increasing air the HP gain from just a chip or a re-flash can't possibly be that great all by itself.

    So too, conversely, if you put in a LOT more air, like a turbo or SC or even an actually working "ram-air" system, you really need to address the fuel issue as well, for power,cooling, etc. Now the factory may do this with factory turbos but sellers of bolt-on stuff may or may not engineer this correctly or advise you properly. Very often you can just go lean and lose power. This happens A LOT with so called "cold air intakes". You SOUND faster but you ain't.
  • driftracerdriftracer Posts: 2,692
    been trying to push that point for years, especially to some of the yayhoos back home.

    I'm seriously looking at a twincharger system for my Ion Redline - a turbo, mounted just like a turbo would normally be, rams air into the intake, then it gets compressed again by the Eaton blower. They company I saw (can't recall the name) runs a piggyback ECU setup and elminates the boost control module on the supercharger. Two blowoff valves are used.

    I just saw this setup on a Mini Cooper S, and although dyno results weren't shown, the article writer freaked out pretty seriously over the incredible power.

    Mark from Psi-fi (turbo tuner folks from New Jersey) says:

    "The benefits are surely worth the cost. On our Mini twincharger kit we have bumped power on pump gas up 120+whp. The power increase can go much higher as we still have another 100whp left in the turbo if we crank the boost up. Performance wise the twincharger kit puts the Cooper S into another league entirely dropping 1/4 mile Ets about 1.5-2 second and bringing trap speeds up from low 90's to 105+ on pump gas and street tires.

    The Redline and Cobalt SS have a very efficient Laminova air to water intercooler, these intercoolers have been tested to about 86% efficiency. GM did the intercooling system right on these cars with a very large front mount heat exchanger as well. This type of intercooler can deal with the thermal load increases from increased boost as well as twincharging. We are currently developing parts(pulleys, Engine management, driveline products etc. as well as the aforementioned twincharger kit) for this platform. The beauty of twincharging over nitrous is the power is there all of the time and if tuned correctly the car runs around town feeling like stock till you hit the loud pedal :D then its all business!"
  • bigdaddy1bigdaddy1 Posts: 47
    We love our '05 Pac. It fills all our needs, except one! The 3.5 L. , 250 hp 6 just doesn't move this heavyweight the way we need. We have been considering a Paxton s.c. Is anyone familiar with this application? We have seen estimates of $5,000. completely installed. Is this reasonable? Is there a less expensive way to go? Will Chrysler offer any option in the future? Comments are welcome. Thanks.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    That's quite reasonable for a quality job. I only hope it is well-engineered, warrantied, etc. Of course, you will void your warranty I assume or at least that part of it connected to the engine.

    Don't they make a turbo version of the Pacifica? Maybe you should consider just taking a hit on trade-in and getting that model instead, already done for you from the factory.
  • bigdaddy1bigdaddy1 Posts: 47
    No, there isn't any turbo option avail. The 250 h.p. is the large version! I believe the base model is 205 or 210. We love the vehicle, it's just the lack of "ooomph" is starting to bother me. Any other thoughts are appreciated.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    Well if you lose your warranty (and I think you will) and if you can't test-drive a similar car with this kit already on it, I don't think I'd do it.

    I wonder why 250HP isn't enough? Seems like it should move right along. I wonder if it's running right? You should be around 0-60 in 9 seconds, similar to a Passat or a Volvo XC90.

    It's the weight that's killing your performance. The Pacifica is kind of a porker. If you're thinking a SC will cut your times dramatically, I really don't think it will. It'll be a lot better, but the SC might give you 75HP or so, maybe a little more. It's not going to make your nose bleed or anything.

    Also I'm wondering how much boost they are going to run in this kit. You have 10:1 compression in that engine--you may be burning very high octane fuel with a SC.
  • bigdaddy1bigdaddy1 Posts: 47
    One fella that did the installation is saying 350 h.p. with 6 lb. boost. I believe he runs higher octane fuel. The warranty question always comes up and I 'm not sure of the real answer. Also, some claim the s.c. while driven sensibly won't damage this engine. I was by the dealer this a.m. and was surprised to see how the prices have dropped on some of these vehicles since their introduction. The pac, 300c and crossover all look a lot less $ than last fall. Thanks for the help. I will continue to investigate.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    Yeah, I don't the SC would damage the engine, especially if it's new. But SC or TC will seek out any ailments in head gaskets or valve seating and amplify them. One must never install an SC or TC on an engine that doesn't show outstanding and even compression ratios.

    However, I'm almost certain DC would revoke your warranty on the engine, should you make a claim, and I think they'd win any dispute, too. I'd imagine the rest of the car would retain the warranty. In any case DC would have to show that the SC damaged whatever part of the car you are claiming warranty service on. So, they could make a good case for engine damage but not for brakes----now for transmission, with an extra 100HP running through it---well---they might win that dispute, too.

    100 HP is plausible though I bet the dyno wont' show that. Usually a good SC setup at 6 psi can give 30-40 boost in HP, so he claims are not outrageous. I'd like to see the dyno slips though.
  • steverstever Posts: 52,457
    Apologies if you saw this link elsewhere on Speed Shop today:

    steve_, "Awesome Cars -- Let's see 'em!" #11, 6 May 2005 8:02 pm

    Steve, Host
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    My post #70 should have read "30-40 PERCENT boost in HP"
  • realty_prorealty_pro Posts: 85
    There is nothing sweet er than a blown engine. I had a 5.0, 5 speed mustang with an 8LB Paxton Kit. In addition, 3.55 gears, 65 mm throttle body, 1 5/8 shorty headers, 2.5 mandrel bent exhaust pipes, high flow cats and Flowmaster 2 chamber mufflers. The car would smoke through 2nd gear and pull all the way through 4th gear. I don't know how much power the SC added, but it felt like I increased the displacement by 100 cubic inches. It reminded me of the power band on a motorcycle.
  • jpstax1jpstax1 Posts: 197
    I had a 3.5" SLP pulley installed on my '98 GS last Friday. The Buick dealer also installed a module between the IAT sensor and its wiring harness. It's supposed to maximize spark advance by 1-2 degrees, and increase HP. In another forum, two guys said to be careful using it, because it could cause engine knock, resulting in piston damage. Here's a link to SLP's site, showing the module:

    Does anyone else think the module could cause major engine damage? BTW, the new pulley increased S/C boost by 3 psi (from 7 to 10). I noticed a big difference in acceleration. SLP says gains up to 25 HP are possible with this pulley. The bottom line is should I also use the module?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    Well if it doesn't disable your knock sensor I don't see the problem. If it does disable it or change its tolerance (the map of what octane it will tolerate), then you either have to be sure not to lug this engine or use higher octane fuel.

    It's the combination of pinging plus lugging the engine that's a piston-eater.

    Actually as I think about it, a 1-2 degree bump in timing isn't a whole lot.

    10 psi should be okay because your engine was designed for a SC to begin with. However, higher boost will seek out and magnify any defects you might have in compression or head gasket sealing, so it's important that you only do this with a very tight engine.
  • First, most turbo cars run in vacuum most of the time, and idle just like a stock lexus. They get good gas mileage because in vacuum they don't make any power when in vacuum. My bud's Toyota Supra Turbo car gets about 20mpg city and 26 highway and makes over 1000HP with a large turbo idles quietly at 650 rpm... (here is a link )

    Secondly, exhaust restriction you speak of is vital to producing low range horsepower. You need a certain amount of back pressure to create horsepower in the low rpm ranges. It is not an issue of back pressure with forced induction at max power- otherwise my bud's car couldn't make 1000HP. (read this about turbos: )

    Remember this: You only burn more fuel when making power. So in english, if you keep your right foot out of it, a low compression turbo motor will get good gas mileage provided you can keep your right foot in check. (here read the tech in this link! )

    Turbo' car's drawback was emissions control. not gas mileage.

    Thirdly if you were to create a lagless turbo, it would have many good advantages, you can run a larger compressor than normal. That allows the compressed air to be cooler and denser at a lower boost level. Translated in english, You no longer will need intercoolers and you will make more power at lower boost levels than previously possible. I design turbos and my company is creating the first lagless prototype turbo. Should be finished this year.
  • jimvetajimveta Posts: 96
    Which company is this? Is this lagless turbo a VGT? If so, are you using an existing design or
    model like from Holset's? Or is this something like Garrett's hydraulically driver compressor? What sizes/specs will you offer? And while I agree with the higher peak effeciency of the larger turbo when spun up to its range, I don't think you can eliminate the need for an intercooler..

    .. while I know many will think them ideal for smaller engines, I think there may be an even bigger market for larger engines! Simply because I think most in that crowd already care or are more conscious about power delivery to justify the extra cost :D
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    Most larger engines respond better to twin turbos, both to reduce lag and also because it's an easier fit, one turbo for each bank of a V type engine.
  • eugenieugeni Posts: 1
    I have an imported 1984 300D with no turbo. The engine is the same 5 cyl., but the fuel injector pump is different than the regular turbo engines. I have a turbo off another car that I want to install in. Do I need to do any aditional adjustments to the injector pump, exhaust pipes, etc. Thanks
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    I inquired about this from the benz diesel experts around town and they all told me it can't be done, but didn't explain exactly why. They were all pretty discouraging, but I'm sorry I couldn't get many particulars.
  • I own a 2002 lancer oz-rally, its a 2.0l 4-cyl, engine with 120 hp. do you think i would benefit more from a T/C or a S/C?? Any help will be appreciated
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    All you need is money!

    Have a look here:
  • buiwichedbuiwiched Posts: 1
    I have a 1989 Buick Riviera and want more power and was thinking about a supercharger from a later Park Ave or Riv. Just wondering what all I will need to make it work and the small details like throttle cables and the correct mass airflow sensor. Any help appricieated! I might also consider a tuned port fi. I love this car and want to make driving it more enjoyable! Thanks!
  • danpaudanpau Posts: 1
    Hi, I'm the owner of a 1996 Buick riv 3.8l Supercharged. The rev and the top speed are limited by the computer. I tryed to find a chip that could bypass the computer. I've been told that there is no chip for this model as the computer is sealed. Is there a solution for my problem? Could the 1997 computer model fit my car?
  • alfa164alfa164 Posts: 1
    I have an Alfa Romeo 164L and I've found it very hard to find aftermarket performance parts/modifications (possibly because they don't sell them in the US anymore). Does anyone know if there is some sort of universal turbocharger that will fit just about anything, or are they all custom made for each make of car.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    That going to be a tough car to turbo I think. Of course with a lot of money you can do anything (see Monster Garage for instance). That engine begs for a twin-turbo set up.

    Turbo systems need to be very well engineered and field tested, so I would say your best bet is to find any Alfa Specialty catalogues you can (like Centerline, or Alfa International) and see if these companies have developed their own turbo or supercharger systems specifically made for these cars.

    Personally, having owned a 164L, I think you might want to try to replicater 164LS specs instead (different cylinder heads I believe).

    Last of all, be prepared for one fact---that whatever you find out there, if it is of good quality, it's going to cost you more than your car is that's also a sobering consideration. You might be better off just going out and buying an LS.
  • qbrozenqbrozen Posts: 28,807
    Hmmmm.. you think that engine would take turbocharging without mods to the internals and heads?

    Maybe I'm talking out of my rear, but I'm thinking the lack of tuning mods for most Alfas (and, even where tuning mods exist, they don't add very much power at all) is due to reliability issues. I mean, I know they are tough little powertrains ... when stock.

    '07 ML63, '08 Charger R/T Daytona; '67 Coronet R/T; '13 Fiat 500c, '14 Town&Country Limited; '18 BMW X2. 53-car history and counting!

  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    Well you really don't want to slap a turbo on ANY old engine, and since all Alfas in the USA are old, this could create a problem. But Calloway did a turbo kit for the Alfa GTV-6 and that worked out okay; of course Calloway knows what he is doing.
  • jorgecjorgec Posts: 6
    I have a 96 as well Supercharged and is awesome why would you want to mess with that. The car is a blast period :shades:
  • jimvetajimveta Posts: 96
    Holy thread ressurection.. lol

    I've driven the supercharged 3.8 gms and yeah, they are pretty fun.. but there's something wrong about squealing the front tires

    But as to chipping his car.. because anything can always be better that's why! :D
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,482
    You can get amazing power out of the turbo GN...that was a GNX wasn't it?

    The one bright light in the 1980s Dark Ages in America.
  • bfennbfenn Posts: 4
    My car has a garetts T25 Turbo and a heavy duty clutch on it. It is 3 years old. Whenever I floor it(or really get on) the gas, around 3.5 rpm where the turbo kicks in, my car briefly looses power in a big THUD that shakes the car. It does it in 2, 3, and 4th the most. Does anyone have an idea if its the clutch or turbo?
  • Does anyone know by chance if/when a manufacturer (TRD or otherwise) may be coming out with a turbocharger or supercharger for the 2007 Camry V-6? The stock engine is strong but I need more. Also any thoughts on corresponding necessary mods for the engine/trans/suspension to handle the turbo or supercharger? Thanks for your thoughts - Dave
  • benztunerbenztuner Posts: 76
    Has anyone actually driven a car or installed a turbo system that isnt placed in the engine compartment. I have heard of some turbo kits that are for newer cars, such as the C6 Corvette, that are not installed in the engine compartment due to the lack of available space. Instead the turbos are placed at the tail lights and the tubes bringing the exhaust to the turbos are ran from the engine along the rocker into the rear of the car and so on. There is a slight loss of boost but the air temp drops about 100 degrees F and in turn gives an extra 10 HP. I have not seen any of these kits done or driven any of the cars, so I was just wondering if anyone has seen them or driven a car with them? I am interested to see how well they work.
  • paisanpaisan Posts: 21,181
    Heard about one for the GTO as well.

  • qbrozenqbrozen Posts: 28,807
    sounds like a lot of money and effort for 10 hp.

    '07 ML63, '08 Charger R/T Daytona; '67 Coronet R/T; '13 Fiat 500c, '14 Town&Country Limited; '18 BMW X2. 53-car history and counting!

  • paisanpaisan Posts: 21,181
    I think he meant 10hp more than a turbo in the engine bay.

  • qbrozenqbrozen Posts: 28,807
    you may be correct.

    '07 ML63, '08 Charger R/T Daytona; '67 Coronet R/T; '13 Fiat 500c, '14 Town&Country Limited; '18 BMW X2. 53-car history and counting!

  • maudit87maudit87 Posts: 20
    link title

    That might help. They also have sections explaining Turbos and Supers in detail.

    Looks like a Turbo also increase gas mileage in cars that arn't floored all the time. :D

    Sorry if that was already posted but I wasn't getting a clear cut answer, and that did the trick.
  • 944s944s Posts: 42
    yeah, ive seen that same setup on a C6 vette and i think it was a Twin turbo setup, the turbos were located before the mufflers, with a front mount intercooler. havent driven it, but that s**t looks and sounds dope son!
  • A bit late to this thread, but a good read so far, and to my surprise, a couple of supercharged Riviera owners posting here! For the Riviera nuts out there, check

    I'm a fan of both turbo and blown applications, but feel that each has their place. For all-out racing, it's turbo hands-down. The most efficient power adder for getting huge output. It's raw, nasty, peaky horsepower for going fast, period.

    But then you have daily driven cars with turbos attempting to use lighter turbines, dual turbines, sequential turbines, tuning, etc. to make a "street-friendly" torque curve... basically to do what a blower does naturally. I can understand it, but I don't completely agree with it. If you want throttle response (low-end torque), get a large displacement N/A or add a blower. It's that simple.

    I own a 1998 Buick Riviera with the 240 hp supercharged 3.8L V6. It's my daily driver, bought 4 years ago with 24.5k miles. It used to go 0-60 mph in 8.5 secs, and run the quarter in 15.5. To the earlier posters claiming this engine is boring and can't be compared to Japanese turbo motors, you'd be surprised at what happens when you spend a few dollars to mod the 3.8L supercharged V6. You'd be astounded at what can happen with a bit more $.

    Soon I began modding the car, adding the following bolt ons: cold air intake, SC overdrive pulley, high-lift rocker arms/valve springs, exhaust headers, custom tuned PCM, and not much else. The car now does 0-60 mph in 5.7 secs, and ran a 13.9 in the 1/4 mile. This is a 4000+lb FWD Buick on street tires. I have amps and a sub box in back, even kept the jack and spare tire in!

    On the dyno, over 300 crank hp and 370 lb-ft. Still have stock exhaust system and original transmission. The best part is, the car just turned 146k miles and I still drive (abuse) it 60 miles to work each day. I have no back up vehicle, this is it! You want fuel economy? I averaged 31.5 mpg on my last 600 mile trek through the mountains.

    But my car is slow compared to the top FWD 3.8L V6s running 8 and 9 secs in the 1/4. Interested in learning more? Check these links:
  • paisanpaisan Posts: 21,181
    They each have their place. SC is good for low end and provides power across the entire RPM range, however, the newer turbos provide peak torque which is where the smaller displacement motors need the help. The advantage of the turbos is that since they don't kick in until higher RPMs, when you are out of the turbo, you gain milage.

    I like both and both can be used for different purposes, tuning on either one can be tricky and expensive.

  • I was thinking on doing the turbocharged /supercharged Buick 3.8 does anyone know of people doing this other than VW?
This discussion has been closed.