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  1. #1
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    Need help with a turbo BBC combo (from old site)

    twotirefire
    Registered User
    Posts: 1
    (4/5/03 6:04 pm)
    Reply Monty - need help with a turbo BBC combo
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    Monty,

    I'm new here, but you seem to be the resident turbo expert so I would appreciate your advice....

    I currently have a 66 chevelle with a 11:1 632 big duke engine, single fogger setup. It is street/strip, and I'm considering a move from nitrous to turbo.

    First of all - is it a no-no to put a turbo on such a big inch engine? I notice that most people destroke their turbo motors for more RPM - If I ran my 4.600" bore and went with a 4" stroke, I would be 532. Heads flow 500cfm intake, about 350cfm exhaust.

    I would like to have a streetable setup that can be cranked up for maximum effort on the dragstrip - 1600-1800hp.

    So, what do you recommend for CR? (can I run 10:1 with less boost - these chambers are small so 8:1 would require a -40cc dish!!), single big mutha 106mm or two 88's like Doug Holmes? How many psi can I run intercooled on 92 octane? C16? How much more can I run with liquid/air intercooler?

    The bottom end can take it - bow tie block, lunati crank, oliver pro max billet rods, JE pistons (will buy new to drop CR).

    Any advice would be appreciated. I haven't spent a cent on this change yet to want to do the right thing.

    BlownSS502
    Registered User
    Posts: 57
    (4/5/03 7:23 pm)
    Reply Re: Monty - need help with a turbo BBC combo
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    Holy Hell! What kind of heads are you running? 500cfm intake/350 exhaust - that's wicked!
    -Brian

    twotirefire
    Registered User
    Posts: 2
    (4/5/03 10:43 pm)
    Reply Brodix big dukes
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    They are brodix big dukes, ported. They are 18 deg, similar to Dart big chiefs.

    Out of the box, I think they are 484cfm intake or so...

    Monty
    Registered User
    Posts: 15
    (4/6/03 7:36 am)
    Reply Re: Monty - need help with a turbo BBC combo
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    I'm new here as well, and hardly a turbo expert. I've just been working with them for a couple of years now, and still have much to learn.

    It's not a non-no to turbocharge a big ci engine, you shouls see some of the massive engines used in marine and industrial applications that are turbocharged. Most people tend to destroke or run smaller displacement engines with turbos becuase the turbos help create so much torque and power that the big displacement isn't either needed, or it's limited by racing rules, i.e. NMCA/NSCA/NMRA, etc. If you look at their rules, the turbo cars have the greatest displacement limits and minimum weights compared to the Nitrous and centrifugal cars.

    High rpm is not really needed to go fast on the street with turbos, but the turbo racers still spin their engines past 8000 so they build their engines and size the turbos for that and gear the car accordingly.

    I don't know alot about BBC heads, but those sound like pretty efficient heads, which is a benefit. The more efficient the engine, the less boost required to make a specific amount of power. Boost is a measure of stacked up air in the intake manifold, not necessarily in the combustion chamber. Obviously the goal is to cram as much fuel/air in the combustion chamber, and efficient heads allow this to be done easier.

    One of the real benefis of turbocharging is that the engine itself is relatively mild. You can run around 8.5 static compression with a conservative cam and it will idle like a Honda, but when you get the turbos spooled up the same engine becomes a monster. 1600-1800hp is alot for a street engine, but so is 1200 I guess . Nothing like driving around town with an extra thousand horsepower on tap.

    If this is a pump gas engine, I would try to get it down to at least 9.0 static compression or so. I run around 8.5 myself. You don't want to go much below 8.0 or so becuase the engine will become inefficient and lazy when not under boost. The key to making big power reliably is to maximize efficiency whenever possible.

    Whether or not you go with a huge thumper single turbo, or a pair of smaller one's (but still pretty good in size) will depend on what the rules, if any, will allow in the racing series you intend to participate in. Most only allow one power adder, so that means a big single. This is not necessarily bad, as the bigger a turbo get, the more efficient it is. This is a popular internet misconception that a pair of smaller turbos are more efficient than a bigger one, or that they spool up quicker than a bigger one.

    Actually, the opposite is true. Take a look at the compressor maps and you'll notive that a T100, which will flow up to around 180 lbs/min and capable of supporting aorund 1800hp, starts to makes boost a about 27,000 shaft rpm. Compare that to a 60-1 which requires a shaft speed of over 46,000 shaft rpm. The bigger turbos don't have to be be spun as fast on the high side either, which means they generally don't heat the air up as high when compressing it.

    If it were me, and you truly are gonna drive it on the street with that much power, I'd probably go with a T100 or so. You could run a pair of T72's or T76's and have enough turbo for 1600-1800hp, but it might get to be a real challange to package that into a full frame, full bodied car.

    Generally, you can typically run 20-25 psi on 92 octane with an appropriately sized air/air intercooler, a few lbs more with a liquid/air, and 30-35+ with 114+ octane. I'm assuming this monster is fuel injected, i.e. FAST, etc. That thing is gonna be sick if you build it!




    1982 Corvette
    1200hp/1000tq (pumpgas) Twin Turbo SBC 427
    4L80E



    XcYZ
    Registered User
    Posts: 287
    (4/6/03 7:54 am)
    Reply
    Re: Monty - need help with a turbo BBC combo
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    TwoFire... I think the 632 will be awesome. I know of a 705 being built with a turbo. But still, a 632 with a turbo/turbos will be nuts!! Sweetness!!
    Scott
    My 69


    Edited by: XcYZ at: 4/6/03 8:09:40 am

    twotirefire
    Registered User
    Posts: 3
    (4/6/03 11:33 am)
    Reply Thanks monty
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    I'm not worried about class limits - we have a small tire unlimited class here, no other rules.

    I am currently making about 950hp on motor on pump gas, and have sprayed as much as 400hp. For this season, I will run it carburated/nitrous, but I'm planning for the following winter.

    So it is possible to leave some compression in it (9:1 let's say) and run a single big turbo non-intercooled. Was reading in another post that big inch engines don't heat the air as much - If I can get away w/o a intercooler at first and just limit the boost - run C16 when I want to step it up, that would be better. I want a simple setup, so one turbo would be the way to go for me. Could add intercooler later.

    Is there a problem with running too big a turbo for my current goals? Do you have the curves for a T100 and a 106mm so I can compare where I would be on the map? I'm not really concerned about turbo lag, because a 632 engine with 9:1 will still make probably 650-700 ftlbs at low RPM...

    I went to Atlanta to watch the NMCA race a couple of weeks ago, and looked at Nick Scavo's camaro - single turbo, not sure the size. I see you get your stuff done at fasttimes, so you probably know him. I was hanging with Bob Curran in the pits (been getting traction advice from him via email) but Nick looked busy so I didn't bother him... I think his is 380 cubes, and it went 190mph so I'm guessing he's making 1800?

    I don't exactly pull a holiday trailer with this car, so I can put up with streetability issues. Currently 11:1 with a 286/296 @ .050" .830" lift roller.

    It's not exactly a pro-touring car, but someone told me to come here for turbo advice, so far so good!

    Hey, I want to get into details and specifics, so can you show me where to find the curves on 100's and 101's and 106's? How big do they go??

    66283.150m.com/66283.jpg
    66283.150m.com/66283bumpercam.jpg (right click, save as)


    twotirefire
    Registered User
    Posts: 4
    (4/6/03 11:36 am)
    Reply one more question
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    F.A.S.T. computers - I know I need sequential, wide band 02, but there are a gazillion part numbers listed on their site - do you know which box I would need? I make a baby step and go with the injection only and make my nitrous a dry system for 2004, but I will eventually have a turbo... thanks,

    Ryan

    Monty
    Registered User
    Posts: 16
    (4/7/03 8:42 am)
    Reply It depends on what options you want...
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    You need to decide if you also want Idividual Cylinder Control, fuel pump/electric fan control, IAC motor control, or Nitrous Control. Unfortunately, the current SEFI ECU's don't have enough I/O to handle all of the options, so there's a tradeoff.

    I run 30-213311 which is a SEFI, WBO2, ICC, IAC box. I don't run Nitrous, and I use Aeromotive pump controllers to control my fuel pumps. My electric fans are controlled either manually or by a seperate thermostatically controlled circuit.

    Here are the SEFI, WBO2 systems and PN's:

    SFI with Inductive Pickup - Wide Band Oxygen Sensing Option and Fan/Fuel Pump Control included
    30-213010

    SFI with Inductive Pickup - Wide Band Oxygen Sensing Option and Individual Cylinder Fuel and Spark Control Options and Fan/Fuel Pump Control included
    30-213011


    SFI with Inductive Pickup and 2-Stage Nitrous System Capability - Wide Band Oxygen Sensing Option included 30-213210

    SFI with Inductive Pickup and 2-Stage Nitrous System Capability - Wide Band Oxygen Sensing Option and Individual Cylinder Fuel and Spark Control Options Options included
    30-213211

    SFI with Inductive Pickup and Idle Air Control - Wide Band Oxygen Sensing Option included
    30-213310

    SFI with Inductive Pickup and Idle Air Control - Wide Band Oxygen Sensing Option and Individual Cylinder Fuel and Spark Control Options included
    30-213311


    twotirefire
    Registered User
    Posts: 5
    (4/7/03 5:29 pm)
    Reply One more question
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    Dumb question for an EFI virgin - do I need a new ignition box, or does the FAST box do it all? I currently run a digital 7 programmable.

    Monty
    Registered User
    Posts: 17
    (4/9/03 8:26 am)
    Reply You need still need your MSD box...
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    Not a dumb question, but you still will need your MSD box.

    The Digital 7 Programmable is overkill but will work very well. Since the FAST will control your ignition timing and advance curve via the Spark Maps, you won't need the programability funtionality of the Programmable Digital 7. Depending on which FAST box you get, it can also allow for individual cylinder control for both fuel and spark.

    There is a white "points" wire coming out of the FAST main harness near the ECM plug, you will connect that to the white "points" wire on the MSD box. The FAST will then control all timing functions and simply trigger the MSD box to fire the coil.

    Since you are going to use a sequential FAST, you will also need a cam position sensor. Most people, including myself, simply use a modified MSD, or equivalent distributor. All you have to do is remove all of the reluctors except for one, and that will provide a cam position signal to the FAST.

    twotirefire
    Registered User
    Posts: 6
    (4/9/03 11:47 am)
    Reply Thanks monty
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    I'm a long ways away from doing the EFI (this winter I hope) but I need to ask all the questions now.

    I have an msd billet distributor - I use a crank trigger and a jesel belt drive - isn't that enough? I locked out my distributor and just phase it via a hole in the cap - and control the timing with the D7.

    Monty
    Registered User
    Posts: 18
    (4/9/03 6:35 pm)
    Reply Re: Thanks monty
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    Yes, It sounds like you have everything you need- obviously the belt drive is a "nice to have" - I use one too. You'll probably still need to modify the reluctors, I can't imagine you'd have done that without a sequential EFI system, but that's an easy and a free mod.

    Good luck!
    1982 Corvette
    1200hp/1000tq (pumpgas) Twin Turbo SBC 427
    4L80E



    twotirefire
    Registered User
    Posts: 7
    (4/10/03 12:04 pm)
    Reply While I've gotcha here...
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    Do you mind helping with some rough numbers - let's say that I have the following:

    -632 9:1 CR (hard to go even that low with these heads)
    -F.A.S.T. sequential system obviously
    -101 or 106mm turbo (can't find the curves/maps on the internet )
    -liquid/air intercooler

    Where would that put me, approximately, for power at different boost levels?
    What is the best means to control boost?
    Would I be able to knock the boost down, WAY down and run it on the street?

    twotirefire "turbo-virgin"


    Monty
    Registered User
    Posts: 19
    (4/11/03 9:34 am)
    Reply Best guess...
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    It would be hard to say without actually dyno testing what the engine could make at different boost levels. I'm sure the turbo companies have software or formulas that could help but it would just be a wild guess on my part. I wouldn't really worry too much about boost though, it's just a measure of stacked up air in the intake manifold, and not accurately reflective of hogh much air you're actually cramming into the cylinders.

    Either of those turbos, 101 or 106, is enough turbo for 1800+ hp, and fully capable of producing 40psi+ of boost and still keeping efficiency over 70%. Obviously, these are badass turbos intended for serious racing in NMCA/NSCA/NMRA, etc. Turbonetics refers to them a their "Thumper Series Competition Turbos".

    The best means of controlling boost is via an electronic boost controller with uses solenoids to control pressure to the wastegate ports. The better one's are very accurate and consistent, some of them even incorporate their own MAP sensor to compensate for atmospheric conditions. Other funtions include programmable boost stages, boost rise rates, etc, even allwoing you to program a boost curve depending on what gear the tranny is, or based on elapsed time - for use in drag racing. These controllers are typically priced at $500+.

    You can also use a simple "air compressor" valve plumbed inline to the lines feeding the top of the wastegates. It's not as consistent on a day to day basis like the more advanced electronic controllers are, since it is more susceptible to atmospheric conditions, but it's cheap and effective.



    Sure you can keep boost way down on the street, simply stay out of the throttle and the turbos won't make boost. In normal daily driving, you won't see boost unless you want to - by getting aggressive with the throttle. That's the beauty of turbos, the power is always available, but only on demand.

    Additionally, all you really need to do is run light springs in the wastegates to limit the boost, and then when you want more boost, simply open up the boost controller. I run 7# wastegate springs, so with the boost conmtroller fully closed, it will only make 7# of boost. But if I need more power, simply open up or activate the boost controller and it will apply boost pressure to the top of the wategate, preventing it form opening, allowing the turbos to build and sustain more boost. You can practically do anything you wnat with the right setup.

    You need to be careful though, if you look at a compressor map, you'll notice that to the left side of the efficiency island is the "surge line". This is an area characterized by flow instability usually ca



    Monty
    Registered User
    Posts: 20
    (4/11/03 9:40 am)
    Reply Sorry, accidentally hit enter...
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    You need to be careful though, if you look at a compressor map, you'll notice that to the left side of the efficiency island is the "surge line". This is an area characterized by flow instability usually caused by compressor inducer stall. You need to size the turbo so that the engine doesn't operate in this range, operating there will cause turbo bearing failure. What this means is that too large of a turbo for the intended use and operating conditions is a bad thing.

    Too small of a turbo will cause you to operate to the right side of the compressor island, past the choke line. This is represented by the right most line where the compressor speed numbers are usually shown. This is the flow limit of the turbo, and operating here causes the turbo speeds to significantly increase, potentially beyond the limits of the assembly. Compressor efficiency will plungs, resulting in very high compressor outlet temps, which leads to detonation, and potential destruction of the turbo from overspeeding.


    twotirefire
    Registered User
    Posts: 8
    (4/11/03 5:56 pm)
    Reply Great advice!
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    I went and bought Maximum Boost by Corky Bell and have half finished reading it - enlightening. And other recommended reading?

    Also, I called Innovative Turbo yesterday and got some specifics on big inch turbo setups. They said everything you said, so I'm getting a consistent story here!

    They make a 115mm LOL - and they even didn't know what anyone would do with that much power...

    They told me from experience that with my induction system (500+ cfm heads), and ~ 8.5 to 9:1, I could make approx 1800hp air/air intercooled with 15psi, 101mm turbo. They would get into specifics when I am closer to buying the parts. First order of business is to sell my pro systems car, fogger system and nitrous stuff (product engineering regulators, triple bypass, 460gph pump etc.) and start buying parts for the fuel injection conversion.

    I have to obtain some maps for 101's, 106's, etc then we can start talking specifics. I'm an engineer who has actually taken several thermodynamics (compressors) and heat transfer (intercoolers) courses, so maybe I finally found a use for it! I'll pull out my old textbooks and go to town...

    THANKS FOR THE HELP!

    Ryan

    walapus
    Registered User
    Posts: 34
    (4/11/03 5:56 pm)
    Reply EFI myth!
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    You do NOT need Sequential if you don't have the ability to tune it to your specific engine. Batch fire will get you 99% of what you need, and takes a tenth of the time to tune. In order to really adjust seq, you need thermocouples and/or WB lambda meters on every cylinder, and a fist full of cash to hand over to your local dyno operator. It's just not worth it!

    twotirefire
    Registered User
    Posts: 9
    (4/12/03 10:05 pm)
    Reply But does it cost much more for sequential?
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    'Cause it might be useful for the first season, before I have the turbo - I will run N/A and nitrous - I was told that sequential was useful for nitrous. Any advice? If I did buy bank to bank, I could always upgrade the chip later, correct?

    camcojb
    Registered User
    Posts: 271
    (4/13/03 9:06 am)
    Reply Re: But does it cost much more for sequential?
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    I would seriously consider an Accel Gen VII over the FAST; and I've run FAST on every EFI deal I've built until now. First the Gen VII with wideband and sequential is much cheaper than the FAST with wideband and sequential. All of the Gen VII's can swap between batch and sequential in the menu, using the same box. The FAST units are completely different. The Gen VII can use many different ignitions with a change in the menu; again, the FAST would have to be sent back as they don't have that feature.

    The biggest advantage of the Gen VII is that it has a true barometric board, as close to OEM as is available in the aftermarket; complete altitude compensation and barometric comp. Once the mapping is done the O2 can be turned off in the ECU or removed as it literally doesn't need it. Plus it has MANY more features than the FAST and the ability to drive MANY more things like fans, two stage rev limiters, etc. The FAST can do these also but when you go to the sequential and other things you start losing other features.

    There is nothing wrong with the FAST. I've made great power with it and it is relatively simple to learn and tune. But it is years behind the new Accel Gen VII.

    My opinion of course!

    Jody
    MY CARS

    twotirefire
    Registered User
    Posts: 10
    (4/13/03 5:31 pm)
    Reply camcojb
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    I will check out the Accel systems. Do you sell them, if so, shoot me an email at [email protected] and we can talk about it.

    I recognise your username - do you post on chevelles.com? My username there is 66 283.

    Thanks for the advise! I'm full of questions, but I want to get it right. I should list my carb and fuel pump and nitrous system for sale - if I get any bites, I can start on the EFI.

    Ryan

    camcojb
    Registered User
    Posts: 272
    (4/13/03 9:21 pm)
    Reply Re: camcojb
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    Ryan,

    Yes I recognize your username from Chevelles.com; talk about a mis-leading name!!!!!!!!! I do not sell them but have a friend who is a dealer for both FAST and Accel. I paid $1422. for the Accl with harness and senders. It can be batch fire or sequential. It's another $900 for the wide band plug-in, but the FAST with wideband and sequential is about $3K.

    If it's tuned with a wide band you won't need it after tuning. I've always had the wide band with FAST and he talked me out of buying it for the Accel. We'll tune with it for sure, but not needed after tuning.

    You can contact Dan Fodge at Fodge Engineering for more info; (916) 714-3111

    Take care.

    Jody
    MY CARS

    twotirefire
    Registered User
    Posts: 11
    (4/13/03 10:32 pm)
    Reply where is he located?
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    Where is he located? I'll give him a call. I doubt anyone around here has a wide band setup I could borrow for tuning, so I'd have to buy it. I am excited about having DFI it for the data acquisition alone!

    Ryan

    camcojb
    Registered User
    Posts: 273
    (4/14/03 7:52 am)
    Reply Re: where is he located?
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    He's near Sacramento, California. He actually tunes over the internet also.
    MY CARS

    twotirefire
    Registered User
    Posts: 12
    (4/15/03 10:03 am)
    Reply thanks
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    Thanks - when the time comes, I'll give him a call.

    Ryan


  2. #2
    Join Date
    Apr 2009
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    4
    couple of thoughts; if E85 is available in your are it might allow you to run a higher compression ratio with out detonation problems at higher boost levels due to the alcohol content. The number of and size of injectors you will need to run this fuel may give you some challenges but if your like me thats half the fun.
    also nitrous works quite well as a cooling agent for the intake mixture on blown/turbo motors runinning on gas, you said you had no rule restrictions so you could use multiple power adders.

    I am in texas if you would like to talk.
    [email protected]

  3. #3
    Join Date
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    Location
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    Robert, this is a six year old thread and it does not appear that the initial poster "twotirefire" rejoined when we moved over to the new board.

    I'm just involved in that I copied a bunch of useful threads over (which, in retrospect, I wish I'd done more of - the old posts on the old site aren't available anymore)

  4. #4
    Join Date
    Apr 2009
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    4
    thanks derekf, I will pay more attention to the dates......