keep in mind... unported gt40p heads besides intake runner mouths only barely gasket matched to the lower intake... Gasket matching every single port face to the next in its BOLTED position has some good gains thanks to pretty bad alignment originally. The intake guys obviously didn't have a good relationship with the head guys at ford.
The way I picture it sounds dumb when i'm porting but filter to intake valve is 1 big waterslide, picture yourself flying through it start to finish at high speed and make it smooth enough that you'd ride that bad boy at that wicked high speed and you'll make the horses.
Results and interesting findings are...
All together the heat insulating has helped intake temps stay cooler to the cyl, the evening out port flows in the lower have cylinders getting phenomenally even flows now... no more rich 1/5 and lean 7/8... #5 actually gets a hair more air than the rest now despite it's length and curves, with 8 getting the least (all within 4% total spread measured by egt temps/cyl fuel trim/track times over 20 runs with cyl-cyl adjustments to confirm egt measurements) apparently with restrictive bends removed, things are liking the longer runner length indicating the P heads/lowish rpm cams like longer runners yet than the explorer upper +1" spacer have throughout the rpm range tested up to 6100...
The runner mouths in the upper intake see 1kpa above atmosphere...
Dropped a full second 1/4 et... same weight/trans/gears/tires over stock explorer stuff with Alternative auto Lidio chip and tune that made 240rwhp.
The 75mm tb at 85% throttle position is letting 99% atmosphere pressure into the upper plenum (101% atmosphere at full open) for those wondering how big is big enough, 65mm is not missing out on much at all.
Moving the iat sensor to the upper main tunnel helped heat soak allot (have a 2nd sensor the the air filter to a wot switched relay so at full throttle the computer sees actual air inlet temps with no heat soak cooling time which causes leaning out early in a run)
30lb injectors see bang on 75% duty cycle at their peak NA (very close +/- to 300rwhp).
Car makes best power at 13.3 afr (13.1 at sub 4500 60' zone) indicating very even/ efficient flows and combustion chambers, EGT temps stay at a very safe 1300* all cylinders being +/- 20* with no fuel trim per cyl
Car makes best power at a very surprisingly low 26* total timing even on 93oct also indicating very efficient combustion and cyl to cyl uniformity. The gt40p heads are looking to be worth the hype. That works out to 6-10* base timing set with the distributer and timing light depending on the ford ECU used and it's wot curves.
3.73 gears, heavier than stock, 28x10 fronts/12x30 rears on heavy steel rims, 3600rpm converter WITHOUT LOCKUP in 3rd/4th and it gets 25mpg at 40mph and 21mpg at 65mph calculated via actual fuel cc/min injected compared to speed calculation. Best cruise efficiency is at 17-17.5 afr with lots of timing 40-45*. City is really bad but haven't calculated it.
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