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I'm trying to educate myself on installing a turbo with my 250 in my '68 Camaro. It'll be a street setup, bored 0.030", mild cam, improved exhaust and intake, TKO-500 or T-5 trans, 3.08 gears. Probably will be staying between 1500-3500 RPM. Looking for decent MPG (20+) with as much HP and Torque and fun as I can economically get. I have a few questions.
1. Will a turbo increase or decrease MPG? 2. What kind of cost am I looking at? 3. What improvements in HP and Torque should be anticipated? 4. GUT CHECK,,,,,is this a good idea considering the parameters of my plan discribed above?
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your plan is good but alittle off target.
improved intake/exhaust is good and the mild cam also for a turbo setup.
the stick trans, 1500-3500 range and decent mileage are not good. now to answer some of your questions: 1. a turbo will most likely decrease mileage. 2. cost of around 2000.00 all done with a carb. realistic 3.30-50% increase mainly in torq because of your low rpm level. a 250 will run much better in the 3000-6000 range for power. in this range the hp will come up sharply. and still provide good economy in the 1500-2500 range. tom
Inliner Member 1716 65 Chevelle Wagon and 41 Hudson Pickup Information and parts www.12bolt.com
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These are the same questions I'm curious about except I've got a 4100lb truck in the equation. How will this affect me, especially #4?
1968 Camaro - 250 (No, I'm not gonna drop a 350 in it!....Jeez!) 1968 C-10 with 2 extra cylinders
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witherer 2000 - 4800 RPM range is doable. Pick a cam with about 204 degrees duration @ .050 Wide lobe center,115 . I agree w/Tom auto trans is much better especially w/a turbo. 4 speed auto w/a lock up torque converter. Use a smaller exhaust housing for the turbo. I can see making 300 HP easy /w/a ton of torque of around 380-450 ft lbs. While running on pump gas & 15 lbs of boost. I always recommend alky injection. And some sort of knock retard system Like a J&S Safegaurd system. http://www.jandssafeguard.com/ If you are light on the gas ,,,you could get above 20 MPG,,,, but w/a turbo,,,it will be very hard not to step on it, :-) Brad, it is a great idea,but it is not cheap. You really need to go with fuel injection. MBHD
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witherer, I would put more cam and more gear personally. 220 at 50 w/ 115 lsa as mentioned, 3.55's with the big overdrive of the t-5. I think you'll like the car better.
And I second the motion for alky injection. If you are going to forgo the intercooler, I would say it's mandatory. My brother has a snow performance one at it works good.
I looked at the knock retard. It looks pretty cool.
"The first rule of overkill: You can never have too much overkill." "Overkill is underrated."
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I think witherer is looking for low RPM engine range ,,,wants a lot of torque.Plus gas mileage of 20 MPG or better..
220 Degrees duration @ .050 on a 250 CI engine.,would not be a good cam for low RPM range & 20 MPG.
Two cents thrown.
MBHD
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Hi everyone- new member and new to L-6's- I have questions along the same line. My idea is for an odd vehicle- 90 c1500 5spd. 3.73 gears (currently running a holley tbi'd 355 w/ (2) 60 #/hr's.) I have a ton of questions for anyone w/ info- first, can I adapt my tbi, cpu, harness, etc, or at least use bits and pieces on a 292? Just looking to build something different, looking for 300-350hp and similar torque (all my borg warner tranny will handle) for light towing and street use. Mileage is not a concern, but cost is. And I know the stick is a poor choice for the turbo, but I have to row my own!
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If you have the underhood room, a drawthrough setup from the old 301" transams would be a snap, mounted sideways. Those turbos are good for 300 or maybe 330 horse worth of air. The turbine housing is a .82 A/R T3, and should be good to 4500, maybe 5000 on a 250".
Check out pics of turbo'd slants at slantsix.org. There are pics of that setup on a slant.
Dave
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HI Dave, I'm over here trying to figure out a turbo size for a 292 chevy 6. I found one in a late sixties 3/4 ton chevy truck with a t-400 behind it. I'm trying to buy it now. If I don't get that one I'm going to build a 250. I think I saw that a 301 turbo setup in Leo Santucci's book. I want to do some headwork/valves, a cam, fuel inject it and build the exhaust header for a turbo.
I'm still in the chassis design stage, and the 500 cad is still in the wings.......john
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Boogiemanz1- For a street 292, a 60-1 with a .69 to .95 turbine housing (or similarly-sized T04B variant) will run real well, with a wide LSA cam (114+), mild lift, headwork, and a GOOD ignition. That combo will make lots of useable torque all day long.
As a side note- Spa turbo makes a cast turbo manifold for the chevy that is affordable.
JEFF 68 Firebird 4.2 Trailblazer engine
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Thanks for the info Jeff. Is your 4.2 turbo'd? I bought a GM familiarization book and vhs tape on the 4200 engine.....I'm getting real interested in that myself........john
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It's 'in process'... I'm in the process of fabbing mny parts.
JEFF 68 Firebird 4.2 Trailblazer engine
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Tlowe on this board also has the turbo manifolds. Better price, too.
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I think the 4.2 may prove to be a more cost effective engine to build I saw a wrecked trailblazer on a repo site that went for 1200.00 and ran like new. Nodular crank powdered metal rods, DOHC with variable valve timing.....oughta run with a turbo on it........john
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the word had it that Glen Self had the 4.2 @ 1400 turboed. He also had it in a Nova wagon. I had a video link but no idea what i did with it.
Larry/Twisted6 [oooooo] Adding CFM adds boost God doesn't like ugly.
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http://www.1320video.com/dragweek.php It is on 3/4 the way through the video. Click on Day 2 link w/pic of Red Nova MBHD
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