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  #61  
Old 07-30-2001, 01:59 PM
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If you have a 2-barrel engine then your CR would be OK (but not the best) for low levels of boost. A 4-barrel engine is supposed to have 10:1 CR which is way too much for any real boost unless you are planning on running some good intercoolers. Your ignition timing will effect this of course. I would reccommend intercooling in any case since even the 2-barrel engine is supposed to be 9.2:1.
A pair of junkyard T3's would work fine at lower RPM's but would start to become fairly inefficient when trying to flow enough air for your 383 at higher revs. There would be almost no lag whatsoever though. The main problem with inefficiency is that it heats up the air more. I personally would reccommend a pair of modified T3's. You could go to the T3/T4 hybrid but that would be overkill for an otherwise stock 383.
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  #62  
Old 08-03-2001, 11:59 PM
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I also have a 69 RR with a 383 and auto tranny. I'm going to have to rebuild it so what would you recomend. I want to do the twin turbo setup. But I don't really know enough and don't have enough to have someone do it. What all would I have to fabricate to do the turbo thing? Thanks
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  #63  
Old 08-04-2001, 10:07 AM
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If you're wanting 500 hp or more, you need to upgrade the heads. Working on the exhaust port will make big gains according to the pros. You also need an intercooler. These were my two big mistakes.

As far as fabrication goes, you'll need to whip up some headers adn new exhaust from the turbos down. Once you get past the turbos, size does matter. Bigger is better.

Other than that, there's not much fabrication, You will need to get the oil to the turbos and back into the pan. Then there's also intake piping to work with, but that's fairly easy.

Grab the book we referred to and get input from a pro on the turbo sizes. Once you have it all laid out, then begin your spending spree. If you do it this way, you'll save mucho buckage and be happier with the results.
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  #64  
Old 08-06-2001, 11:29 PM
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How did you get the headers to face forward? Did you hack them off at the flange then weld tem back on or what? Thanks for the info
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  #65  
Old 08-08-2001, 01:27 PM
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i got thinking (uh oh thats never a good thing) can a dual quad setup be adapted to twin turbos just by making a different air-hat. i want the cool looks of a dual quad setup and the power of twin turbos. i was thinking twin e-brock 500's on either a 383 or a 383 stroked to 426. with turbos they dont need that much carberation i realize. but i wanna know if i can get daul quad twin turbo setup to work well.
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  #66  
Old 08-08-2001, 02:01 PM
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The turbos won't care what they are blowing into, as long as they are appropriately modified for boost. You will notice that very small throttle movements will make for a lot of power increase (touchy throttle) once you have enough rpm for the turbos to spool and give you pressure in the hat. This will make it a bit more difficult to get your accellerator pump shot right.

I had a 1000 CFM throttle body on the TT340 and replaced it with a 625 so it would be easier to drive, as EFI and a big throttle body shows the same problem.
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  #67  
Old 08-08-2001, 02:12 PM
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but is dual 500s too much?
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  #68  
Old 08-08-2001, 02:29 PM
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I would just go ahead and use whatever CFM carb(s) that you would use if the engine were naturally aspirated as a starting point. Dual 500's on a 383 would probably be too much but would most likely work OK on a 426. My 383 uses a 750 and I sure wouldn't want to go any bigger without a larger cam and some head work.
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  #69  
Old 08-08-2001, 09:56 PM
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you can actually go a little smaller on turbo carbs. by the time you are using the limits of the carb.. you are into boost already, and that is forcing the air thru them. which would again allow the use of something smaller. Id keep the total cfm to less than 850. that low end throttle response is also going to help with getting rid of turbo lag.
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  #70  
Old 08-09-2001, 01:21 AM
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is there away of me limiting a dual quad setup to 850 cfm? i have access to cnc machines so i could make some kinda restrictor plate. other wise ill have to forget about cosmetics and go with a afb/e brock 750. oh well its like that saying
Quote:
"going fast is looking good"
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  #71  
Old 08-09-2001, 08:31 PM
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there are some 370's or something like that. as far as dual 4 barrels go, i woudnt know about that. although going with two 2 barrels would be easy to get the right carbs for. I dont think a restrictor plate will give the benefits of throttle response and driveability. maybe if you redo all the squiters, air bleeds and such.

go with a 6 pac setup. looks, not the real carbs. those are way to expensive.! think about weber side drafts? now that would be unique!!! and look cool. you wouldnt really have a carb hat. just the ducting running straight in instead of up, over, and down.!!
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  #72  
Old 08-09-2001, 08:58 PM
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well i had thought about tri power setup using weber down drafts. much like 6 pak except you can adjust air flow from 200-400 cfm per carb. i think it was $800. ive heard quite a bit about predator variable venturi carbs but i think boost would interfere with the variable venturi (i think). oh well a carter afb/e brock 750 may just have to be the way to go. there is some one on this board that made a double oumper afb. is double pumper a good idea for turbos?
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  #73  
Old 08-09-2001, 10:56 PM
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yeah. shouldnt be that much of a prob. the vac goes off of the pressure differance. so that still works. but, it can be modified so that the secondaries only come on under boost. adding to the tunability. some...
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  #74  
Old 08-10-2001, 01:49 PM
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I have always wanted to do a multicarb setup with the old Holley/Weber progressive two barrel that was used on lots of old 4 bangers. The version used on 70 vintage Pintos was pretty much non-emissions and they work very well with turbos (I ran a turbo Pinto 2.0 for a while). The carb did much better with boost than the double pumper Holley I ran on the TT340. The carbs are rated at about 350 cfm, but they are a two barrel, so that is at 3" of vacuum, so they are really much smaller than that. They are also progressive, so you would run on 3 barrels until you stepped on it to bring in the other 3 barrels. This would give you very good throttle response. These carbs are very tunable and all of the jets and bleeds are accessable and replaceable.
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  #75  
Old 08-10-2001, 02:05 PM
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keep in mind that the 3" vs. 1.5" of vaccum is negated once you touch boost! instead of 3" of vaccum, you have 10 pounds of boost pushing it thru. and the carb size only needs to add up to a total of what the engine is going to need before boost comes in. (well not entirely) but subing a 500 instead of a 750 will work better than you would think. I have a 900 cfm throttle body, only because i had it before the turbos. and, and its the only one that will support the horse power levels. otherwise i would have had to go with a different pump, larger injctors and a few things.
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  #76  
Old 08-10-2001, 09:51 PM
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Dewme: The 1.5 vs 3.0 still holds under boost because you are talking about the amount of pressure drop through the carb, not the total pressure the system is running. When a NA engine is running wide open it is seeing 1 atmosphere of pressure or 14.7 psi. At 10 pounds of boost it is seeing 24.7 pounds. In both cases you have the pressure of the system on both sides of the carb, with the only difference being the pressure drop through the carb. If you take a 500 cfm 2 barrel (rated at 3.0 inches) and compare it to a 500 cfm 4 barrel (rated at 1.5 inches) you will see the same flow difference under boost as you do NA. This is with a blow through system. Remember that the engine is using the same volume of air under boost as it is NA, it is just compressed so it has more oxygen molecules for combustion. The carb works strickly on volume, so it really doesn't know, or care, if it is under boost or not.

It is true that you can run a slightly smaller carb on a blow through turbo, because you have so much pressure available you can spare more in pressure drop across the carb, and thus flow more air.
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  #77  
Old 02-09-2003, 01:06 PM
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I'm just curious if you could use a pair of turbo from the first generation Cummins.. they are 3 inch in and out have internal wastegates. According to the the specs on my cummins the tubos will make 22 lbs of boost...

Would they work?
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  #78  
Old 02-09-2003, 07:03 PM
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bbaspense, it is possible to take turbos from anything and put them onto anything else. It all depends on your application. Basically the most important thing is to use the compressor flow map to match a turbo to an application. That is the main step in determining whether a turbo will "work"... There are several ways to do this; if you already have a turbo, you can check out its flow map and see what engine it would be happy with. Or, if you already have an engine, you can check out a bunch of flow maps to see what turbos would supply the required airflow and pressure.

To all, I have begun my own Mopar V8-turbo project; you can see it at http://www.wsu.edu/~426hemi/ttmonaco.html
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  #79  
Old 02-09-2003, 07:25 PM
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I was wondering what about using to garret t2 turbo's from the old turbododges there capeable of making 22 lbs of boost on a 4 cylnder what about 2 of them for a v8? (or 4 )
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  #80  
Old 02-09-2003, 08:53 PM
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Hey Goose, once you finish the turbos on that beast, you could use it for running moonshine thru the back woods- after all, the suspension mods are already done ! Have fun.....djs
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  #81  
Old 02-09-2003, 10:02 PM
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68plyval, the Garrett off a 2.2 is a popular turbo to use in twin-turbo V8 setups. Lots of guys with 5.0's use that exact setup. Some of them also use the slightly larger-trimmed Garrett off the 2.3 ford SVO cars. A pair of Garretts off the Mopar 2.2 are capable of delivering over 400 hp stock, and in the neighborhood of 500 with larger A/R pieces. Using 4 of them would put you in the 800-1000 HP range... that's my next project actually after I get done with my current twin-turbo setup. I could either go with 4 turbos in parallel to make the 800 horses at ~22 PSI or I could make a series setup with a max boost of ~44 PSI. Depends on which engine I feel like using.

djs, didja notice that the car was also already painted flat black? Not just the body, but also all the chrome and everything. The car is completely non-reflective... makes one wonder
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  #82  
Old 02-10-2003, 12:04 AM
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My 400 is a stock piston, ported head (open chamber), 484 cam motor with an M-1 dual plane intake and 750 holley. it has run a best of 12.80 @ 106 at 3750..

I figure I make about 330hp to the back wheels... would a dual 2.5/2.2 turbo feed this engine or choke it...
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  #83  
Old 02-10-2003, 01:28 AM
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bbaspense, a pair of 2.2 T3's would not give you any noticeable power gain; the compressors are way too small, especially since it appears that you are already making over 400 horses at the crank. You would probably just lose power due to exhaust restriction. A good setup for you would be the hybrid T3/T4 which is a Garrett T3 with a larger T4 compressor mounted to it. It is a popular upgrade because it uses the T3 body/turbine which gives good throttle response without choking the exhaust terribly, while the T4 compressor flows considerably more air than the T3. Feets's TT440 uses the T3/T4 hybrid turbos actually.
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  #84  
Old 02-12-2003, 10:26 PM
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Goose, -this must be the same car Steve Earl sings about in the song "Copper Head Road". ha ha ha
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  #85  
Old 02-02-2004, 03:57 PM
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Just FYI-

Some of you guys where wondering why stock turbo cars route the bov (blow off valve) back into the intake before the turbo. This is done for one main reason. On most EFI systems air is monitored via a mass airflow sensor. If the bov vents to the atmosphere, it is letting air out of teh system that has been accounted for by the maf. Since the air has been metered the ECU is going to send the proper amount fuel for that amount of air but if that air is let out through the bov, the ECU will not know that and cause the car to run overly rich. This can cause stalling problems and backfiring. Also, most stock bovs leak under vacuum so it will be sucking in filtered meter air as opposed to whatever is floating around the engine bay. The rich condition is pbviously not a problem for those of you running carbs but be aware that the bovs can let it unfiltered air under vacuum.

Im not very good at putting thoughts into words but I hope that makes sense. I have a modified 88 supra turbo that I have been working on and that is how I know this stuff.
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  #86  
Old 02-03-2004, 06:50 AM
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if you visit the forum at turbomustangs .com , there is lots of info for turboing real motors (ie not wee lil 302s and the like) for 800 bucks you can get this semi turbo with a 4 inch inlet and a .95 a/r..? i don't know the turbo scene that well so don't quote me on that as i kinda skimmed through it. the guy had one on his 408 cleveland and didn't build full boost till 5000 rpm but i bet it would be damn cool on a 440, only needing one.

diesel blow off valves release into the atmosphere, obviously there is no mass air sensor but would a diesel bov be prone to leakage under vacuum as well? i knew that stock bov's were just cheaper, designed for lower boost, and all but the saab bov's will leak if over 8 psi or so. but a diesel can see 20 psi easy.
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  #87  
Old 02-03-2004, 02:33 PM
kcmcuda69 kcmcuda69 is offline
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Quote:
Originally posted by fastmopars .inc
i knew that stock bov's were just cheaper, designed for lower boost, and all but the saab bov's will leak if over 8 psi or so. but a diesel can see 20 psi easy.
Bosche makes the saab bov as well as the porsche spec bov. I have the porche spec and it holds 20psi....

Also that turbo you described sounds pretty worthless IMO. Full boost at 5000rpm on a 408? You want full boost before peak torque. Sure it flows hella air but probably isnt beneficial over a smaller quicker spooing turbo unless it is in a high revving race application.
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