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Old Grey · 15-03-2015, 08:44 AM

Lets look at the B8(BP) 16V SOHC 1.8 and see what different specs do.

Baseline std
112.536 Cubic Inches @ 6000 RPM with 92.00 % Volumetric Efficiency PerCent
Peak HorsePower --- 111.4hp
Peak Torque Lbs-Ft - 108.1ft/lb

Header Design Specs --- for 112.536 CID from 4000 to 6500 RPM
1st Y-Segment Dia.= 1.413 Length= 14.8 to 16.1 inches long
2nd Y-Segment Dia.= 1.538 Length= 14.8 to 16.1 inches long
Header Collector Specs (Conventional Straight Tube)
Diameter= 2.170 to 2.420 Tuned Lengths= 18.2 best and 9.1 or 36.3
Total Exhaust System Tuned Lengths (Primary ends to TailPipe end)
Best HP/TQ Tuned Collector Lengths= 18.2 , 36.3 , 72.7 , 145.3 inches long

Now increase the VE so it makes more power
112.536 Cubic Inches @ 6000 RPM with 110.00 % Volumetric Efficiency PerCent
Peak HorsePower --- 148.7hp
Peak Torque Lbs-Ft - 144.3ft/lb

Header Design Specs --- for 112.536 CID from 4000 to 6500 RPM
1st Y-Segment Dia.= 1.339 Length= 13.1 to 14.4 inches long
2nd Y-Segment Dia.= 1.464 Length= 13.1 to 14.4 inches long
Header Collector Specs (Conventional Straight Tube)
Diameter= 2.044 to 2.294 Tuned Lengths= 16.8 best and 8.4 or 33.6
Total Exhaust System Tuned Lengths (Primary ends to TailPipe end)
Best HP/TQ Tuned Collector Lengths= 16.8 , 33.6 , 67.2 , 134.4 inches long

Notice the pipe sizes getting smaller

Looking a the Hurricane the pipes are 41mm(1.61"), 44(1.73")mm, 57mm(2.24").
The lengths aren't stated so I have to guess from the photo - 1st seg - 14", 2nd seg - 14"
http://www.hurricaneperformancevicto...au/ford-4-cyl/

Lets go back to the 1st std engine figures and see at what rpm the Hurricane tunes at.
I can't actually get the Hurricane figures to line up because it has miss-matched components, but using 7000rpm and a lowering VE to keep the HP realistic is the closest.

112.536 Cubic Inches @ 7000 RPM with 75.00 % Volumetric Efficiency PerCent
Peak HorsePower --- 92.9hp (actual engine would have less than 80hp@7000rpm)
Peak Torque Lbs-Ft - 77.3ft/lb

Header Design Specs --- for 112.536 CID from 5000 to 7500 RPM
1st Y-Segment Dia.= 1.623 Length= 14.3 to 15.6 inches long
2nd Y-Segment Dia.= 1.748 Length= 14.3 to 15.6 inches long
Header Collector Specs (Conventional Straight Tube)
Diameter= 2.529 to 2.779 Tuned Lengths= 17.0 best and 8.5 or 34.1

Just looking at the pipes it looks like the lengths are close, it's just the diameters are too big.

15-03-2015, 08:44 AM	#2
Old Grey Junior Member Join Date: Apr 2009 Location: Sydney Car: Astina BG 1991 - Rx7 S4 Posts: 105	Lets look at the B8(BP) 16V SOHC 1.8 and see what different specs do. Baseline std 112.536 Cubic Inches @ 6000 RPM with 92.00 % Volumetric Efficiency PerCent Peak HorsePower --- 111.4hp Peak Torque Lbs-Ft - 108.1ft/lb Header Design Specs --- for 112.536 CID from 4000 to 6500 RPM 1st Y-Segment Dia.= 1.413 Length= 14.8 to 16.1 inches long 2nd Y-Segment Dia.= 1.538 Length= 14.8 to 16.1 inches long Header Collector Specs (Conventional Straight Tube) Diameter= 2.170 to 2.420 Tuned Lengths= 18.2 best and 9.1 or 36.3 Total Exhaust System Tuned Lengths (Primary ends to TailPipe end) Best HP/TQ Tuned Collector Lengths= 18.2 , 36.3 , 72.7 , 145.3 inches long Now increase the VE so it makes more power 112.536 Cubic Inches @ 6000 RPM with 110.00 % Volumetric Efficiency PerCent Peak HorsePower --- 148.7hp Peak Torque Lbs-Ft - 144.3ft/lb Header Design Specs --- for 112.536 CID from 4000 to 6500 RPM 1st Y-Segment Dia.= 1.339 Length= 13.1 to 14.4 inches long 2nd Y-Segment Dia.= 1.464 Length= 13.1 to 14.4 inches long Header Collector Specs (Conventional Straight Tube) Diameter= 2.044 to 2.294 Tuned Lengths= 16.8 best and 8.4 or 33.6 Total Exhaust System Tuned Lengths (Primary ends to TailPipe end) Best HP/TQ Tuned Collector Lengths= 16.8 , 33.6 , 67.2 , 134.4 inches long Notice the pipe sizes getting smaller Looking a the Hurricane the pipes are 41mm(1.61"), 44(1.73")mm, 57mm(2.24"). The lengths aren't stated so I have to guess from the photo - 1st seg - 14", 2nd seg - 14" http://www.hurricaneperformancevicto...au/ford-4-cyl/ Lets go back to the 1st std engine figures and see at what rpm the Hurricane tunes at. I can't actually get the Hurricane figures to line up because it has miss-matched components, but using 7000rpm and a lowering VE to keep the HP realistic is the closest. 112.536 Cubic Inches @ 7000 RPM with 75.00 % Volumetric Efficiency PerCent Peak HorsePower --- 92.9hp (actual engine would have less than 80hp@7000rpm) Peak Torque Lbs-Ft - 77.3ft/lb Header Design Specs --- for 112.536 CID from 5000 to 7500 RPM 1st Y-Segment Dia.= 1.623 Length= 14.3 to 15.6 inches long 2nd Y-Segment Dia.= 1.748 Length= 14.3 to 15.6 inches long Header Collector Specs (Conventional Straight Tube) Diameter= 2.529 to 2.779 Tuned Lengths= 17.0 best and 8.5 or 34.1 Just looking at the pipes it looks like the lengths are close, it's just the diameters are too big. Last edited by Old Grey; 16-03-2015 at 03:52 PM.