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| xcabbi |
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Just pulling some numbers out of the air and would this be a good cam for a GRA LPG 250 turbo running a 3000rpm stall and transbrake?
inlet timing open - 35 deg close - 71 deg exhaust timing open - 82 deg close - 38 deg advertised duration inlet - 286 deg exhaust - 300 deg duration @.050 inlet - 214 deg exhaust 224 deg Valve lift inlet - .497" exhaust - .519" lobe center 110 approx rev range 2000-5500rpm Its the off the shelf GRA stage 4 cam for the 250 X flow. Is it too big or not big enough? |
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| EDXR8 |
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I always was told you want an inlet biased cam for turbos. The cam seems a bit big for a turbo setup IMO but it all depends on what you want from the engine, but by the sounds of it you are going for a drag type setup.
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| CHEF |
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I'd be leaving the stock cam in until you have the set up fully tuned and sorted, then see what the power curve looks like. You cant just wack a cam in a highly modified turbo motor based on theory, need to find out what you need the cam to do first.
Need to take into account some factors that will only arise once the motor is up and running... rise of boost, max boost pressure, timing through the rev range ect |
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| LTD351 |
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Ring wade cams they are very experienced with GRA stuff they helped develope those cams for GRA, they are cheap as well. They did the cam for Jason Ghillers 10.2 XD.
I would say 230/230@50, 114lsa. |
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| xcabbi |
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I've just got a head full of crazy ideas at the moment. I just want to see what can be achieved if I was to use off the shelf parts.
I was thinking of getting the following but its going to cost me a bit of a packet. X flow head opened right up and fitted with 2V valves. H beam rods Forged pistons possibly roler rockers (want to pull between 6000-6500rpm max) the above mentioned cam Snort pereformance exhaust manifold (I don't have the time to fab one up so an off the shelf one will do) GT 40 turbo 440 or 510 cfm GRA carb and twin B2 converters 3000rpm stall converter fully manualised C4 with transbrake mini spooled 3.45:1 barg warner diff boxed control arms If I was to build myself this I'd expect as close to a 9 as I can possibly get on 26x10x15 slick tyre. That's a big ask coming from the pushrod engine in a 1400kg car. Estimated budget being between 12 and 18k. Project to begin early next year. So what do you think? |
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You'd more than likely need a much bigger turbo for 9s... correct me if Im wrong but for a 9 you will need 450plus wkws... GT42 built to cope with over 2bar would be a start
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| xcabbi |
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But if you look at what the XR6T boys are pumping out at the wheels with their 35/40's then it should be a snack for the GT40.
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| EFFalcon |
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correct, there is now a BA into the 9's on a stock turbo.
if a lighter car can't do it on a bigger turbo, then theres something wrong 
_________________ FALCN6 - EF GLi Turbo, 20" Rims, Air Bag Suspension, Straight LPG, 225rwkw |
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The BA motors massive air flow is a different story to the sohc though
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| ltd35169 |
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Drop back to a 3.25
Get a cam from wade Use a 510 mixer If the primary goal is good times then use a GT4276R, and run a 1.00 large frame or a 1.15 small frame housing. You're going to be pushing upwards of 25psi into that, using the 42 over the 40 would obviously give more lag but it will make more power with less boost. I have been speaking with a dude that put that same turbo on a 265hemi and cranked 380rwkw's, it was into full boost by 3500rpm, he used a 1.15large frame the same housing I just got for my 351, with the 1.00 instead you would see boost a bit lower too. |
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| EFFalcon |
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CHEF wrote: The BA motors massive air flow is a different story to the sohc though
we're not talking SOHC here.
_________________ FALCN6 - EF GLi Turbo, 20" Rims, Air Bag Suspension, Straight LPG, 225rwkw |
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LOL, sorry... pushrod
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| EBXR8380 |
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The Gt3540 has .7 fronts and can come with 1.05 rears or bigger...
The Ford XR6 turbo has much smaller compressor housing and exducer... With along stroke like 250 I'd be looking at 216 inlet @50 208 @50 115 lob centre with 110 centreline.... 480 valve lift.... Or there abouts....
_________________ As in ZOOM 126 edition |
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Yeah 0.5 comp on the Ford GT40
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| Bert |
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If you want a decent cam then get one from Surecam. He made the cam for TTV8, RGV, and the Judge Giogotollo. He understands turbos with regard to cams.
That cam is an old school dinosaur grind, large advertised duration with relatively small .050" duration. There are grinds with 217@.050" that have 265 advertised duration and .300" lift. This profile should have the same rev range but idle smoother with better low end torque. |
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