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Author
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Topic: Turbocharging
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Kyle
Gearhead Posts: 210
From: Sumner, WA
Registered: Dec 2001
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posted 05-02-2002 06:21 PM
   
I have been doing some serious thinking about building a twin turbo carb'd mustang. I have a '73 fastback that I want to do something with, and this would be different and kinda cool. After reading througha few websites, and getting a book on turbos, I want to hear from you who have expierence.I searched through the archives, and a similar question was asked Feb. '01. Alex was going to post what I assume to be a lengthy response, but it never made it to that thread. I'm interested to hear what you have to say, Alex. My idea: -'90 5.0 long block w/ 1.7 roller rockers
-Two Garrett T03 turbos
-Hyd. roller lifters, not sure what specs
-HV mech. fuel pump, boost referenced
-Fogger nozzle in the intake pipe for enrichment when boost exceeds 7psi
-Edelbrock performer intake
-Holley 650DP or an Autolite 4100
-C4 with a 2000 stall converter,
-Stock 8" gears or a set of 3.80's Can I do it like this? Who has done it? Help, please!
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jkilroy
Gearhead Posts: 1636
From: Vicksburg, MS
Registered: Dec 99
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posted 05-02-2002 08:13 PM
I have done a bunch of turbo motors, granted most of them were Buick V-6's, but they were turbo motors. Turbo's kick a$$ plain and simple. Superchargers aren't worth a damn compared to a good turbo setup. Anyway, I would suggest you use a bonnet like the old mustang supercharger setups, that way you don't have to seal the carb and pressurize the bowls. With a bonnet the carb acts just like a regular carb. -The two T03's will work fine.
-Toss the mech. pump and get an electric and setup a return line, you still have to refrence boost.
-Forget that fogger nozzle stuff, you don't need it. As long as the air is going through the carb, it will pull out the fuel.
-The stock 8" is NOT going to last long behind the torque of a turbo setup
-The stock C4 probably won't do real well either.
-Get a single plane intake, with the turbos you will have more than enough torque and the dual plane will just limit your power and screw up fuel distribution
-Stock cam will make more than enough power, with 10lbs boost, to bust your rear end, tranny and u-joints ------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big" [This message has been edited by jkilroy (edited 05-02-2002).]
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dzznuts
Journeyman Posts: 32
From: oakville, ont, canada
Registered: Apr 2002
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posted 05-03-2002 12:09 AM
i have been wanting to do this too.
what about compression? right now my motor is 10.5:1, will i have to drop the compression to 8:1? will it still run on street gas? right now if i want to drop my compression i would need to build another set of heads, so how much air will they need to flow?
if you dont use an infector/ or a fogger on the intake pipe, dont you run the risk of the motor running lean and detonating?i dont know what the bonnet looks like from the old mustang supercharger setups, do you have any pics? as mine budget is more restricted i was thinking of using the turbos off of a turbo coupe. i start working on my car this monday...man i really have to figure out exactly what im going to do to it this year, and quick.
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blown 351
Journeyman Posts: 49
From: Seattle, Wa. 98258
Registered: Dec 2001
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posted 05-03-2002 09:46 AM
With the bonnet, the float bowls in the carb are pressurized, through the vents.
Mechanical fuel pump will work with a boost reference to the diaphram, or a boost referenced regulator.
You don't need the fogger nozzle. If you start to run too high inlet temps, or begin to get greedy with boost, an intercooler is an efficient way to cool down the charge
the doublepumper works a little better with the blow through set ups.
But then my procharger w/8lbs blown through a 750db and an airgap dual plain with vic jr heads into a 351W is a supercharger application and doesn't work worth a *&%@ compared to a turbo.
At least my oil temp stays low when I'm not waiting for lag to catch up.
(just being funny)
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jkilroy
Gearhead Posts: 1636
From: Vicksburg, MS
Registered: Dec 99
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posted 05-03-2002 12:57 PM
10.5 is not exactly optimum. I would shoot for 8 or 8.5 like you mention. One trick way to mount the turbos is to mount shorty headers upside down, pointing forward, if you can work out the packaging. blown 351 brings up oiling, which is very important with turbo motors. As long as you feed your trubos a steady supply of clean cool oil, they will last forever. An important item is that the oil return from the turbo housing is NOT under pressure, it is gravity only. The oil should return to the pan as far above oil level as possible, with as straight and large a hose as you can fit. I am talking -12 size stuff if possible. An oil cooler should be mandatory for any performance engine, and doubly so for a turbo setup. The factory coolers off of third gen RX7's can be picked up cheap and they are better than 99% of the aftermarket units. I have even seen small power steering type coolers used inline with the feed to each turbo. JetHot coating the turbine side of your units will reduce under-hood temps a bunch, and it looks a lot better than rusting cast iron to boot. The compressor sides are generally aluminum and don't benefit from such treatment. Obviously the temps inside you exhaust system will increase a lot upstream of the turbo. Cast iron will last forever, quality stainless, like 316 or 17-7 will last great also. Regular ole steel will break down very fast without some sort of quality coating like JetHot. One way to cut down on lag is to put some one-way poppet valves in the bonnet. These allow air flow in but not out. They make them for aircraft so that the fuel or oil doesn't flow backwards when the craft experiences G forces. Two or three on the back of the bonnet will allow lots of air in while not under boost, and snap shut the instant there is any pressure. You can also put them in the tube from the turbo to the bonnet, on on the outflow side intercoller tank. ------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"
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Kyle
Gearhead Posts: 210
From: Sumner, WA
Registered: Dec 2001
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posted 05-03-2002 02:21 PM
Is the powerband of a turbocharged engine different from a n/a engine? I ask this question because I have read one opinion that says to use low rear gears (2.73) and one that said high (3.73+). Say I was going to build this car with a 15" rim and 26" tall slicks in mind. Which one is correct? Do you still want to use a high stall converter?When I go junkyard hunting for the turbos, what else besides the turbo T-birds/Stangs can I find a T3 turbo in? What are some problem areas I should look out for? Thanks for all the great info. I was looking at using K&N carb bonnet (pt#85-1060), which run around $160. I want to build this as cheaply as possible, but not so I have to worry about it blowing up or something.
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jkilroy
Gearhead Posts: 1636
From: Vicksburg, MS
Registered: Dec 99
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posted 05-03-2002 04:22 PM
A turbocharged engine acts like a much larger engine. For instance, you take a 302 and put 15lbs of boost on it and it is burning the same amount of fuel and air as a 604 cube big block. That is a really simple explanation but it is close. A turbo motor has a high and broad torque curve so you don't need nearly as much gear. Less gear also helps load the engine sooner, getting into boost faster.The bonnet has to COMPLETELY surround the carb top and bottom. The alternative is to get a carb setup to run blow-through, there are a lot of things to change. Either way you need to run solid floats, the pressure will crush and pop hollow ones. Obviously a vacuum secondary carb will be of little use so it needs to be a pumper. Look for turbo t-birds, SVO mustangs, and Merkur whatevers they were. You can also call your local John Deer dealer, and if he is nice he will cross refrence parts for you. Most all heavy equipment diesels have turbos. ------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"
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SteveLaRiviere
Administrator Posts: 31026
From: Saco, Maine
Registered: May 99
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posted 05-03-2002 06:58 PM
quote:
Originally posted by dzznuts:
i dont know what the bonnet looks like from the old mustang supercharger setups, do you have any pics?
Here's a pic of Blown289's setup:
------------------
'70 Mustang Mach 1 M code 351C 4V/FMX/3.25 open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Lok
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
MCA Member # 47773 The secret of success is sincerity. Once you can fake that, you got it made.
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chips67
Gearhead Posts: 651
From: louisville, ky, usa
Registered: Jul 2001
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posted 05-04-2002 12:48 AM
ok, check this idea out. forget the carb...go with the "spyder" intake and an aftermarket fuel injection...its all in a kit. no brainer, you get everything...the actual intake is an edelbrock victor jr. intake with bungs welded into each runner for the injectors and an adaptor elbow on top to go to your turbo/blower. it looks bad and it works great. if i hit the lottery thats what i want with twin turbos and aftercooler. that setup on a vintage car would kill. go run 10's all day, drive it around town at night. i love turbos on smallblocks.....takes bill gates money though.------------------
67 coupe, 650dp and rpm intake on 5.0 with afr 165 heads, 4 speed, 4.11's.....best so far is [email protected] in 1/8 mile with 1.79 60ft. time.
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Kyle
Gearhead Posts: 210
From: Sumner, WA
Registered: Dec 2001
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posted 05-04-2002 11:23 AM
So since a turbocharged enging needs more fuel flow, would it be a good idea to use, say, a 750dp or even an 850dp instead of a 650dp? The airflow would be up and you could get more fuel into the engine.I emailed Todd Aaron, who built a twin turbo fox body mustang. You can see his car at: http://turbostang.tripod.com/ When he was daily driving it, it got 21mpg (w/ a C4). He usually had the boost at 16psi. He dynoed the car, and at 14psi, he was getting 468hp, and the hp# would increase by 20hp for every one psi of boost he went up. Thats sweet for junkyard parts! Thats why I want to build a twin turbo. I figure get some exhause pipes form junkyards or exhaust shops to use in routing the piping. What is the optimal size of pipes for a T3 turbo?
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n2oMike
Gearhead Posts: 1367
From: Spencer, WV
Registered: Jan 2001
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posted 05-04-2002 12:24 PM
Here's a site you can't miss...http://www.toohighpsi.com/ There's also a 'blowthru' list on yahoo that deals with installing turbos and centrifugal blowers on carbureted engines. Go here to check it out.
http://groups.yahoo.com/group/BLOWTHRU/ Good Luck! ------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220
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thumpin cat
Gearhead Posts: 129
From:
Registered: Mar 2002
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posted 05-05-2002 03:42 AM
i know you dont want to hear about ricers, but the supra is the only ricer i respect and thats only because if you set up the supra inline 6 right and swap out the stock twin turbos for some bigger ones, your looking at about 1000 horsepower out of a
6 cylinder, thats what a turbo will do for you.
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jkilroy
Gearhead Posts: 1636
From: Vicksburg, MS
Registered: Dec 99
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posted 05-05-2002 06:49 PM
You will not need a larger carb. Carbs are CFM rated on a vacuum type flow bench, your turbo increases the observed atmospheric pressure and air flow goes up in turn.------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"
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