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| Shortshift |
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Nice! And you haven't pushed the motor into the danger zone with the revs.
Watching a lot of the engine builders on youtube revving the motors to 7000+ rpm to get big hp doesn't really translate to a street motor 
_________________ AU2 XR8 with Raptor VL, ported Yella Terra GT40P heads, Scorpion 1.6 RRs, XE264HR-14 Comp Cam, ceramic coated Hurricane Headers, 60lb injectors, Walbro 255, 200cfi cats, 3" exhaust & Snow Performance water methanol injection |
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| Littlefoot |
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BOTTLEDUP wrote: Use a Comp XE276HR-12 with 1.6 rockers will give 0.512" lift. Change your springs any time you run a performance camshaft the factory springs will not support the faster ramp rates of a decent performance camshaft. That cam, ported Explorer intake, unported GT40P heads made 291rwhp in a manual AU XR8 ute. You'll need the ecu retuned and a minimum of a 2800 stall. Mate, this is the perfect answer! Why the heck did none of shops just give me simple instructions like that. I've had to ring soooo many damn people  I mean heck, the dyno guy didn't even show up!
_________________ It's always funny until someone gets hurt. Then it's just hilarious. |
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| Littlefoot |
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I decided not to port the heads a couple of months ago so they are on the motor. I wonder how much those gt40ps actually gain from porting?
Many googles told me. .. not much
_________________ It's always funny until someone gets hurt. Then it's just hilarious. |
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| BOTTLEDUP |
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It comes down to $$$ vs return... And with GT40Ps unless you have the expertise & equipment to port them yourself it very quickly becomes unjustifiably expensive.
_________________ TE50 T1 P01 |
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| Littlefoot |
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Completely agree.
I had another thread on here about porting them but as I'm short on time and had no definitive guides, I decided it's best to leave it. When I got a quote for someone else to do them, it was ridiculously over priced and he couldn't tell me the gains, probably because they would've been very, very minimal. When, I mentioned about copying the 220's and port matching them, he said that it does f-all performance-wise, but looked really good on a buyers brochure haha. I think it was mentioned earlier and in other forums that a lot of people actually lose flow with DIY porting on these heads
_________________ It's always funny until someone gets hurt. Then it's just hilarious. |
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| BOTTLEDUP |
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Yes unless you know what you're doing it is very easy to waste a lot of time porting for no gains, or even go backwards as you mention.
_________________ TE50 T1 P01 |
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| xafalcon |
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Stock untouched GT40P have a flow potential of about 390 FWHP. The post by Bottledup shows a combo that made the equivalent of 340-360 FWHP with untouched GT40P's. Look at the flow data of GT40P heads, they peak around 500-525 thou lift. So look for a cam with 525 intake lift. Spring change is a must. Look at the Crane Cams 44308 kit. These work well with cam lift at/below 540 thou, and the yella terra roller rockers work with no interference. They fit the stock head and can be fitted without removing the heads if you are careful. If you have an ecu and you don't want to tune it, keep lobe separation wide, around 114-115°. You will loose some peak power, but get a wider torque delivery. Add duration to reach the power/rev range that you want, probably around 226° @ 050. Add 4-6 degrees extra exhaust duration at 050. A cam with these specs can be ground out of your stock cam, costs me around $150. You will need slightly longer pushrods as the base circle will need to be reduced to get the extra lift
Of course you need to have supporting equipment that is also capable of the same HP or slightly more - intake, MAF, exhaust, injectors, fuel pump etc
_________________ XA Faimont 351C, AU2 XR8 Manual 5.0, DA LTD 5.0, Mk1 Capri 5.0, 1995 Mustang 5.0, EF2 XR8 Manual, EF2 Fairmont Ghia 5.0, AU3 XR8 Auto, AU2 XR8 Auto, AU2 XR8 Manual Ute, TE Cortina 5.0 Manual, DU LTD 5.0 soon to be manual |
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| Littlefoot |
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Hey XA
I will be running a J3 and get it tuned What lobe separation do you recommend if I do?
_________________ It's always funny until someone gets hurt. Then it's just hilarious. |
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| BOTTLEDUP |
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Being an auto I'd not go any tighter than 111° personally. That XE276 (35-328-8) would fall right into the range xafalcon mentions:
224°/230° @0.050" 0.512"/0.512" with a 1.6 rocker 108° ICL 112° LSA http://www.compcams.com/Company/CC/cam- ... =1061&sb=2 Milling the heads to gain some compression would also be of help, but you'll need to be very careful about piston to valve clearance.
_________________ TE50 T1 P01 |
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| Littlefoot |
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Yeah heads have been milled,
I'll compare price of ordering direct vs getting mine grinded in Adelaide. A couple of shops had a $400 "transfer" fee it seems... they wanted $700...
_________________ It's always funny until someone gets hurt. Then it's just hilarious. |
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| BOTTLEDUP |
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Try Camtec Cams in Sydney.
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| Littlefoot |
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Cool, I'll give then a call Tues.
Thanks mate.
_________________ It's always funny until someone gets hurt. Then it's just hilarious. |
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| xafalcon |
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I prefer 114° lobe separation for EFI, seems to make idle surge less likely / easier to tune out.
If you buy a new cam, make sure they use the right core. Comp have (or had) two different cores that required different distributor/CPS gear material. From memory one core was OK with factory dizzy gear, the other core needed a gear change - don't use bronze. IIFC -8 needed the gear change, -9 didn't. But check this because I only use factory cams and have them re-ground to my specs.
_________________ XA Faimont 351C, AU2 XR8 Manual 5.0, DA LTD 5.0, Mk1 Capri 5.0, 1995 Mustang 5.0, EF2 XR8 Manual, EF2 Fairmont Ghia 5.0, AU3 XR8 Auto, AU2 XR8 Auto, AU2 XR8 Manual Ute, TE Cortina 5.0 Manual, DU LTD 5.0 soon to be manual |
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| Littlefoot |
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By the looks XA, you've owned a few 5.0's lol
_________________ It's always funny until someone gets hurt. Then it's just hilarious. |
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| Littlefoot |
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Also,
xafalcon and BOTTLEDUP There's still a couple of concepts I don't grasp. I understand what lift and duration is etc however I don't understand the formulas for X degrees = Y result You mentioned about power @ revs. Does this comp cam/custom grind increase the top revs? I always understood the 302's to run out of puff at 4750, like the ohc I6's
_________________ It's always funny until someone gets hurt. Then it's just hilarious. |
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