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#21
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according to an email i got from Dave as of earlier this year SD does not do the heart shape chamber mod to E-heads anymore. the link above is for the Eheads with the heart shaped chambers & then SD's porting work.
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#22
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SD Performance
I sent an email to Dave to inquire about opening up the 72cc chambers to around 100cc’s. That would drop my compression to 9:18. If I wanted to put in a 4.5 stroke crank (Scat forged)and get 495ci the compression would bump right back to 9:65 ish. Assuming I had 325 cfm E-heads and the 4.50 stroke I suspect with the same hydraulic cam (237/244 on a 112 lobe separation with .533/.549 lift at 1.65) it might boost horsepower from ~500 to ~580. I have no idea how much more power the e-heads will make over the 6x-4’s with that cam(or a very similar hydraulic roller). Any thoughts on power and reliability of a 4.25 versus 4.5 stroke? This will be road raced and street driven with a 6-speed.
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#23
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Quote:
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#24
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Compression
Yes, I would like to keep the compression low for a couple of reasons, it’s a Pro-Touring build that will be street driven and road raced. It’s hot in Texas and it will heat soak after running hard at a road course(even with as good a cooling system as possible). I’ll also open road race and averaging 130-135( depending on what class I enter) really taxes an engine going 53 miles(and 53 back) The second reason is the next step; a turbo system. With lower compression it will be less of a hurdle than exceeding 10:1. This ethanol blend 93-octane is not very good. On my 462 with 6X-8 heads I have to “spike” the fuel with Boostane to ensure it doesn’t ping in the summer.
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#25
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ok just curious. i was going to say, "unless you plan to turbo it" but didnt think that was in your plans.
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#26
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Heads/Stroke
Any thoughts on power and reliability of a 4.25 versus 4.5 stroke?
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#27
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A 4.5” crank in a factory block would scare me for endurance purposes depending on how many races take place before you get to tare it down to inspect it.
With a turbo the 4.250” crank will make more then enough torque and HP and lessen loading by a worthy amount!
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
The Following User Says Thank You to steve25 For This Useful Post: | ||
#28
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Are these typical 20 minute race sessions Randy?
Tom V.
__________________
"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. |
#29
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Tom, yes normal 20 minute sessions on 1.5-3.0 mile road courses but I’ll open road race at least once yearly. If I enter a 130-135 mph average class with a tech speed of 168 each leg of the course would also be around 20 minutes to go 55 miles.
I don’t have a turbo now but with the supercharger out of the picture I’m talking to the chassis shop about a single G42 and limiting boost to prevent the YY 455 block from splitting. I’ll probably go NA and just save to build the turbo on a aftermarket aluminum block. I have to get the cylinder heads figured out and a stock height manifold for multiport injection to go under the shaker. I’d love to go with a Motec ECU but will likely go Holley HP. The cage is done and the 3-link is waiting for the CNC drawings to come back as parts. It’s a full floater 9-inch with a MillerBuilt kit so I can run C7 hubs and C6 Z51 brakes.. The coil overs are JRI. Front suspension is SpeedTech with spindles using C6 hubs, JRI coil overs and a custom splined sway bar. Of course it’s a Magnum 6 speed. The shop is run by Mike DuSold; the same guy who’s ‘67 Camaro with a TT LS427 has two Optima Championships and 6-7 LS Fest wins. He was running compound turbos at Pikes Peak this year but also has a tradition TT setup. He fabbed both systems. Good thing that Garret is a sponsor. The compound setup put out over 1350 RWHP. It’s been a month now so it could be the same compound with a G42 and G45 or more likely twin G42’s as the back pressure from the smaller turbo(1st turbo) limited the G45’s potential. Maybe thats the next frontier for OEM’s, it’s the ECU’s capability not the Engineers limiting turbo output. |
#30
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PM to you Randy
Tom V.
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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. |
#31
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Replied Tom; thanks for the assistance.
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#32
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Hey Randy, I would dish the piston and get the compression where you want, and keep a good quench. Win win situation.
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68 Firebird, trying a q-jet now. 434/10.5:1/997's/240-242 HFT/4L80E/2800 Yank/3.42's/ Vintage Air/ 13.0 @105 mph 70 Lemans, 350/350, A/C, mostly stock 14 Ram CC, 5.7 Hemi, 8-speed, 3.92 lsd 97 Trans Am, HPP Aug 2012 http://www.highperformancepontiac.co...tiac_trans_am/ ***Sold*** |
The Following User Says Thank You to quicksilver97ta For This Useful Post: | ||
#33
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I've got a set of 87cc eddy's that I would trade for the 72cc ? GT |
#34
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BLUEGHOST, Are your heads new or used?
Tom V. I will have to visit Gilmore's at some point.
__________________
"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. |
#35
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There off a motor that spun a rod bearing. Don't want to sell out rite but would trade for smaller chamber. GT. |
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