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THE LOBBY A gathering place. Introductions, sports, showin' off your ride, birthday-anniversary-milestone, achievements, family oriented humor. |
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#41
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Thank you for the leeson on how these newer engines use blowers.
From those diagrams it is obvious a top draw intake is pretty much a no-go. |
#42
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Just what I am looking for under the hood of my 71
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#43
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That is awesome. I have been halfway considering a centrifugal unit on my firebird. This would for sure be an option as well. Im just concerned that if I added 150 HP I would be past the limits of the stock 400 block.
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1967 Firebird 462 580hp/590ftlbs 1962 Pontiac Catalina Safari Swapped in Turd of an Olds 455 Owner/Creator Catfish Motorsports https://www.youtube.com/@CatfishMotorsports |
#44
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Quote:
For a pure drag car, I think a centrifugal would be a better choice. My goal with this project was to get a package that could be used on the street, fit under the hood, and make decent power even for a guy with unported cast iron smog heads and low compression. With this example, if you keep a sensible redline of 5500 RPM (or lower) you make all the power with cylinder pressure-not by revving it. This is a lot easier on a stock block, and you can get respectable HP numbers and still get by with less than a full aftermarket block. Not trying to say a forged bottom end and an aftermarket block aren’t an advantage- of course they are, but with modest boost, a sensible redline and the tight engine management that comes with sequential EFI, you can do a lot. Here is a graph from Richard Holdner who probably dyno tests more blower motors than almost anybody, comparing boost curves from a twin screw (in this case a Kenne Bell) with a Vortec centrifugal. Notice how flat the twin screw boost curve is across the range, and how little boost the centrifugal is making under 4000 RPM.
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1964 Catalina 2+2 4sp, 421 Tri-power 1965 GTO, Roadster Shop chassis, 461, Old Faithful cam, KRE heads 305 CFM, Holley EFI, DIS ignition. 1969 GTO 467, Edelbrock 325 CFM, Terminator EFI 1969 Firebird Convertible |
The Following 2 Users Say Thank You to darbikrash For This Useful Post: | ||
#45
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i want one
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#46
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Very good post on the comparison of the two boosting units.
TV
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#47
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If this can work with a stock-looking shaker hood, it's a game changer for me.
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#48
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Any chance you have the 3d scans of the engine alone to share?
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#49
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If there's an interest list being made, I know my dad and I would wanna be on it! He's got his '75 Grand Prix and I got my '68 Firebird.
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#50
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By the way everyone here loves pictures, feel free to start a thread and share some of your cars. Frank
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Poncho Huggen, Gear Snatchen, Posi Piro. |
The Following 2 Users Say Thank You to 4zpeed For This Useful Post: | ||
#51
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I am scheduled for two days of engine dyno testing at Westec sometime next month, so it will be interesting to see the HP numbers. I will be bringing several different pulley diameters, so we can see a good variety of boost numbers. One other aspect of this particular system that I'll mention is the idle bypass feature. Below you can see a butterfly plate that is below the intercooler, this is used to bypass any boost made by the screws at idle, or at low idle conditions (such as highway cruising). Neither the screws nor the intercooler brick is shown in this view. This bypass diverts all the boost at idle using the vacuum modulator you can see on the lower side of the blower. It is not electronic -it uses engine vacuum to actuate the butterfly and divert boost. I have this setup to start opening at ~8.5" of vacuum, and is fully open at 10" of vacuum. Any cam with more than 10" of vacuum at idle will work fine, which I think includes most "streetable" cams. This is important because this system makes boost right away, from idle speed and upwards, with no lag and importantly- no blower surge. Also, these screws take up to 60 hp to turn at full boost, when you are at highway cruise conditions with high engine vacuum, all the boost is bypassed and it takes less than 1/2 hp to turn the screws. I mounted the throttle body today, its a 102 mm.
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1964 Catalina 2+2 4sp, 421 Tri-power 1965 GTO, Roadster Shop chassis, 461, Old Faithful cam, KRE heads 305 CFM, Holley EFI, DIS ignition. 1969 GTO 467, Edelbrock 325 CFM, Terminator EFI 1969 Firebird Convertible |
The Following 5 Users Say Thank You to darbikrash For This Useful Post: | ||
#52
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This is awesome. With a Shaker scoop hat, this would be the dream setup for my 74 T/A.
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Panos Little Miss G Racing |
#53
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Very interested in this setup. Looking forward to hearing the performance numbers. IMHO, This is a much needed piece.. Best of luck with the engine testing. .
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Jim www.raceV8s.com 1972 Trans Am drag car, 3300lbs, 468 ci, Iron D ports, 428 block, 9799103 crank, 9.48 @ 143mph, 6.0 @ 114mph in the 1/8th. |
#54
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Very cool! I’d definitely be interested. It’s hard to beat OEM reliability. If I could make a real 950rwhp and remain streetable I’d strongly consider this set up over going turbo.
Is there enough room to run -8 or -10 cooling lines from the rear of the block to the water manifold? I assume PICO/EV6 style high impedance injectors fit no problem? I have Terminator X and don’t want to upgrade to HP or Dominator.
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James 1970 Trans Am Spotts Built 484" IA2, Highports, EFI Northwind Holley Terminator X sequential EFI fabrication and suspension by https://www.funkhouserracecars.com/ |
#55
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Is there room behind the tensioner assembly to retain my 12x crank trigger setup?
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James 1970 Trans Am Spotts Built 484" IA2, Highports, EFI Northwind Holley Terminator X sequential EFI fabrication and suspension by https://www.funkhouserracecars.com/ |
#56
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No problem on the high impedance injectors, the below the blower, in the valley setup that is pictured uses Holley 100 lb/hr flow balanced injectors with EV6 connectors, which are plug and play for the Terminator X. The Injector Dynamics 1050 also fits. No sure what you mean about the cooling lines, the air/water intercooler mounted in the blower does not share engine coolant, it has its own circuit.
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1964 Catalina 2+2 4sp, 421 Tri-power 1965 GTO, Roadster Shop chassis, 461, Old Faithful cam, KRE heads 305 CFM, Holley EFI, DIS ignition. 1969 GTO 467, Edelbrock 325 CFM, Terminator EFI 1969 Firebird Convertible |
#57
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How are you getting the cam signal? Sometimes a simpler approach is just to use the Holley dual sync distributor. This setup can also be configured for CNP/COP if you prefer individual coils. [/url]
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1964 Catalina 2+2 4sp, 421 Tri-power 1965 GTO, Roadster Shop chassis, 461, Old Faithful cam, KRE heads 305 CFM, Holley EFI, DIS ignition. 1969 GTO 467, Edelbrock 325 CFM, Terminator EFI 1969 Firebird Convertible |
#58
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Cool. Those are the same injectors (holley 100lb flow matched) I’m currently using N/A on E85.
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James 1970 Trans Am Spotts Built 484" IA2, Highports, EFI Northwind Holley Terminator X sequential EFI fabrication and suspension by https://www.funkhouserracecars.com/ |
#59
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I use a Holley dual-sync distributor for the cam signal. We initially got it running with only the dual-sync (cam and crank signals) but the timing was a bit finicky so we switched to the 12-1x with hall-effect sensor for more stability and resolution. I’m running Holley Smart Coils (CNP) with brackets to mount them on a Pontiac valve cover. If I wasn’t using smart coils, I’m confident the dual-sync would’ve worked just fine for all timing functions. The crank trigger is a Holley SBC 556-171 kit with a custom bracket to fit a Pontiac. On a side-note, I’m having some extra brackets made if anyone is interested in changing to a 12-1x setup. Just PM me directly so this thread isn’t muddied up. Your LSA blower project is really cool! I look forward to more updates
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James 1970 Trans Am Spotts Built 484" IA2, Highports, EFI Northwind Holley Terminator X sequential EFI fabrication and suspension by https://www.funkhouserracecars.com/ |
#60
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That mod is deeply flawed. Coolant that has bypassed the cylinder heads results in lower temperature readings at the water crossover. Moving the sensor to the cylinder head would tell a different tale. HTH.
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