Thanks Kev and everyone. Your slant looks awesome
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| Supercharged Cam Help https://www.slantsix.org/forum/viewtopic.php?t=45148 |
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| Author: | John1972 [ Sun May 29, 2011 7:01 pm ] |
| Post subject: | Supercharged Cam Help |
Hi Guys, Sorry if this has already been posted, but need help to locate the correct cam. I'm building a supercharged motor and aiming for 400HP. Specs are: Block with all oil mods, long rod conversion, 9:00.1 comp, stage 3 race head from Pentastar Parts + 1.6 ratio rockers, Aussiespeed blower manifold, Weiand 144 or 142 blower running 15 pound boost, 750 Demon DP & Aussiespeed 1 & 5/8 headers. I want a cam that sounds super tough and chunky but still works with the blower so I thought one with a longer duration would be the go. Aussie Camtech Cams have the 2 following cams which I was tossing up between but when I contact them they recomended one with a much smaller lift that I don't think will provide the sound/style I am after. The 2 they offer are: advertised duration @ .050 valve lift 275˚ 285˚ 238˚ 248˚ .480" .500" 108˚ 284˚ 289˚ 248˚ 252˚ .526" .534" 109˚ They recomended: Advertised Dur Duration @ .050" Lobe Sep Cam Lift 270/277 238/244 113 .330"/.342" And they said: I have asked around and i have no way of getting Roller billets for this application, i can only offer you a solid flat tappet for this application if you are so i will quote you accordingly. Considering the cubes of your motor and the low boost levels you are building the engine to i don’t think you should be going to big on the cam also would stick with 1.5 rocker ratio less stress on valve train components plus the lift on this cam will be plenty I have also kept the lobe separation a bit tighter than i normally do to help give you a bit more cammy note, this cam should have an rpm range 3000-6500+ with 15 psi of boost. If anyone could provide some advice it would be greatly appreciated. Would either of the 2 larger lift cams work with the Blower? Any other recomendations would be gratly appreciated. John |
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| Author: | Joshie225 [ Sun May 29, 2011 7:23 pm ] |
| Post subject: | |
The bigger cams will work with the blower, but the low speed performance will suffer and fuel economy will be in the toilet. Even well worked slant six heads tend to run out of flow around .500" valve lift and lifting the valve more just adds stress and wears out parts. If this were mine I would go for 230° duration at .050" tappet rise on 108° lobe centers. It will sound tough and perform well without sending huge amounts of unburned fuel out the tail pipe below 3000 RPM. I can get this cam with .490" gross lift ground here on a used core for $70 US. Don't try to buy off the shelf. Buy what's right for the application. |
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| Author: | John1972 [ Mon May 30, 2011 1:50 am ] |
| Post subject: | |
Thanks for the response Joshua. I had it the wrong way around, I thought had to run more duration. If I wasnt worried about fuel economy and was chasing outright power and that real lumpy race car cam sound, would you change the specs or leave as you suggested. Also am I unlreastic re chasing 400HP? Lastly roller cams, who's reputable over there who could do me a billet roller cam with these specs? I'm not to fussed over price if I can get what I want. Thanks |
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| Author: | DusterIdiot [ Mon May 30, 2011 8:02 am ] |
| Post subject: | No one... |
Quote: Lastly roller cams, who's reputable over there who could do me a billet roller cam with these specs?
There are no roller blanks available at this time. A limited run had been made by Cox brothers a decade back, but they closed and all the blanks are in use or are sitting on somebody's shelf as a collector's item.These did not have a gear hobbed on them for distributor or oil pump, FYI. -D.Idiot |
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| Author: | Joshie225 [ Mon May 30, 2011 10:52 am ] |
| Post subject: | |
You have to work with the engine you have. It's under square and doesn't like to turn all that fast. Long duration cams for high RPM naturally aspirated engines are not going to work well. You'll blow air and fuel right into the exhaust. What you should do is pick the overlap you want to run, then the lobe centerline and the duration is derived from there. You don't need a roller cam to get 400hp. |
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| Author: | 1974duster kev [ Tue May 31, 2011 12:56 pm ] |
| Post subject: | |
400hp should be cake with a poweradder. My turbo motor cam is 220@.50 464lift 114lsa ended up fairly rumpy with my exhaust setup. Kev |
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| Author: | John1972 [ Wed Jun 01, 2011 2:28 am ] |
| Post subject: | |
Thanks Kev and everyone. Your slant looks awesome
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