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questions/ideas for building a turbo slant
https://slantsix.org/forum/viewtopic.php?t=39165		 Page 2 of 2
Author:  Shaker223 [ Tue Mar 02, 2010 10:09 am ]
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Quote:
All of the successful 225 builds I've seen with turbos (HP = 400 to 630) make good power at low RPM (peak around 5000). RPM kills motors much more than boost.

Lou
Lou is right. Turbo66valiant runs 10's shifting at 5200rpm!! No need for more than 6000-6500 max.
Author:  nwstal [ Tue Mar 02, 2010 3:41 pm ]
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The 225 is designed for low RPM TQ. but what if it was better? Turbos don't boost at low rpm or high rpm based on which one you chose. I've had a few N/A SL6's one with all the clifford stuff that ran real well considering it was in a 4x4 with 33's. It won't explode under boost and you can't run it at 7200 like a race motor so you run taller gears (or OD) to make up the speed, and provide boost across the entire RPM band sounds like a good prospect to me. It already has tons of low end power but what if it had more?
Author:  turbo66valiant [ Tue Mar 02, 2010 5:24 pm ]
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Didn't the twin turbo Supra (?) have a system like your trying to achieve? Two different sized turbos. One for low and other for higher rpm.
Later
Ryan
Author:  nwstal [ Tue Mar 02, 2010 6:58 pm ]
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Yes but even a small turbo takes time to spool and the boost doesn't compound the same. There is pressure loss because a turbo is an open compressor. Using a roots type blower there is always boost it takes about 35hp to run the Eaton M90 at 14000. 2:1 pulley on a SL6 would get around 8psi boost which if your shifting at 5200 would be a blower speed of 10400 being around 30hp loss but the boost would be at an idle and as the turbo spools it is compounded by the Blower multiply the Pressure Ratios Blower being 1.54 add 1.95 (14psi) from a turbo to get a 3.0 pressure ratio 30psi, and you have a "twin charged" Engine. I'm learning more on this setup but to me it seems like it would work well on the sl6. I would think the turbo would sppol quicker being as there is already more air going through the engine to start with. your car is in the tens? What rpm do you hit max boost? What boost level?
Author:  Shaker223 [ Tue Mar 02, 2010 7:14 pm ]
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On the chassis dyno (5/2009), starting at 2,800rpm in third gear (boost was 4.3psi) I reached 20psi @ 3650 and full boost of 22psi @ 3900rpm.

When foot braking at the track I hold it around 3-4psi for launch. This is somewhere 22-2300rpm. At 2500rpm & footbraking it woill go over 10psi.
Author:  turbo66valiant [ Tue Mar 02, 2010 10:08 pm ]
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Quote:
I would think the turbo would sppol quicker being as there is already more air going through the engine to start with. your car is in the tens? What rpm do you hit max boost? What boost level?
I'd say around 2500 it has about 5 psi. At this level I can hold it. I leave the line most times at 3800- 4200 at 23 or so psi. I'm at full boost (27 psi) just off the line. I've often wondered why people would run a blower and turbo. Are you sure your going to have 8 psi at idle? It also takes rpm to make boost from a belt driven blower.
Ryan
Author:  nwstal [ Wed Mar 03, 2010 1:22 pm ]
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It takes rpm to make boost from a belt driven supercharger... Roots type blowers are basically an air pump The M90 displaces 90 cubic inches per revolution using the formula (Pratio x 14.7 x volume) / (displacement/2) -14.7 = a 2 to 1 Drive ratio makes around 8.87lbs boost figuring in valve overlap (5% per 10 degrees) and intercooler loss it might be 7.5. Im guessing your around 450HP based on your pressure ratio and a 160hp starting point. (14.7 + Boost) / 14.7 = Pressure ratio x Base HP = estimated power. I know mathematics aren't real world and the Gen 1 m90 isn't very efficient at that level I would run with a 1.8 Pulley Ratio for about 5psi (6.46 - losses) to slow the blower down at high RPM. It looses efficiency fast when you get above about 10k. I have a Gen 1 but im selling it and am going to spend the money to do it right with a Gen 3. Soon as I finish with my pinto ill be finding a suitable platform to build on. Trucks are heavy but it would allow me to mount the turbo (s) in the bed and run Lil Red Type stacks. Maybe a later 4 door valiant Street sleeper. Se what I come up with maybe I can find that 67-69 Barracuda I've been looking for
Author:  turbo66valiant [ Wed Mar 03, 2010 3:48 pm ]
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Very interesting! I wish you luck and keep us posted.
Author:  nwstal [ Wed Mar 03, 2010 7:44 pm ]
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Will do I've always wanted to build a Slant... Someone once told me it was a waste of money. Seeing the few cars here yours in the 10's especially tells me different. There is this certain camaro in the 10's on juice that I'd get a kick out of stomping all over the street. Ever since i started researching this twin charger setup It sounded better and better all the time. Then I started doing the calculations and it would deffinately be a killer combo done right. Rather than slap it together and see what happens I think ill take the time and do it right. Will keep it documented with pictures. Using the Information here to help.
Author:  66aCUDA [ Thu Mar 04, 2010 5:25 am ]
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I just bought a gen 3 and am looking at a gen 5. Eaton says we can spin a 5 at 18K which will be 3 to 1 running a 6K slant.
Ideas on the boost psi?
Thanks,
Frank
Author:  nwstal [ Thu Mar 04, 2010 11:56 am ]
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spinnig an m90 at 3:1 is 20.58 lbs boost without intercooler / cam loss (5% for every 10 degrees valve overlap). Gotta run a big intercooler thoough outlet temp would be in the 400 degree range and i would guess around a 50hp loss Pressure ratio would be 2.36 based on 150hp starting point youd be around 300hp... I dont like the blower for high boost applications because of the hp draw at higher speeds although it would be mean as hell off idle and the power curves would be flat. it'd be like having 300hp all the time
Author:  turboram [ Thu Mar 04, 2010 3:32 pm ]
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Quote:
I had to open my yapper so here are the Photos.
Image
As you can see I used what I had. Toilet flanges and all. Built a box around a 500 cfm AFB. 1" thick 18 ply box w/ 1/2" lexan lid. Headers were homemade duals into 3" pipes. All used tubing. Got info from 21st Century Turbo if you all remember them. I still get heck from my friends for putting 2 toilet flanges on my car. They called it the flying toilet. Long story short, 71 Duster needed an engine soon after and Valiant sat till Thread started here a year or so back. Car was put together (turbos) back in 94 or so.
Image
Would like to see someone put twins on a Slant. Not for sure what the advantage would be but would look pretty cool. Good luck to any who try!!
Later
Ryan


My first turbo on my suzuki samurai had drain pipe for tubing. good to see I'm not the only defferent one :lol: I would pop the hood and everyone would laugh until they rode in it .
Author:  Dart270 [ Thu Mar 04, 2010 8:45 pm ]
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Turboram,

Any chance we can entice you to the Hagerstown, MD race on May 22-23 this year? Or, another Slant race? Clay City, KY on Oct 9-10?

Would be cool to meet and see yer truck run.

Lou
Author:  turboram [ Fri Mar 05, 2010 4:13 am ]
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I would like to make Hagerstown if money permits. still behind on funds for my truck. I was broke down before both those races last year :(
Author:  Dart270 [ Fri Mar 05, 2010 4:53 am ]
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OK, no worries, but would be nice to see you if it works out.

Good luck with the truck.

Best,

Lou
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