mattsstang87

I know that this question has been beat to death, but I am still trying to decide if the j-spec/mazdaspeed exhust cam is needed (at least for me).

I have felt a very good improvement (anything you can feel seat of the pants in the FS is a very good improvement LOL) with the recent install of the j-spec intake cam and the VTCS-less & ported intake, but I wonder if I'll see much more with the exhuast cam too. I would like opinions on the matter as I could find better places to spend the money SR wants for one cam if the gains will be minimal if any.

So, has anyone tried just the intake cam and then both? Or how about the cams vs the VTCS-less and ported intake?

Thanks for your patience and help...

Roddimus Prime

i dont know why anyone would go through the trouble of tearing apart that motor and installing only one cam and then re-doing it for the other! I'm just WAY too lazy to do that work twice.

The way I understood it was the intake cam makes about 10whp and the exhaust cams makes 8whp...hence the 18whp claim for both cams.

Phantom Cruiser

...but I seriously doubt that is the case! (because then my intake/header/exhaust would only be giving 1hp )

Roddimus Prime

i dunno. my second NA dyno was with the obx header and I made 104whp. Now, several months later I dyno again with obx header and j-spec cams AND a CEL and get 118whp 123tq


not quite the 18whp but I did have a CEL to throw it off so I just go along with the numbers.

Phantom Cruiser

0.333whp each for the intake, header, and exhaust woot

2.0GT

i was looking at the same cams a while ago, and was told that the maxdaspeed exhaust cams being sold now are no different than whats in our engines now. There USED to be j-spec exhaust cams, but are long sold out for a long time now. The exhaust cams being sold now are intake cams out of protege/5 FS engines that are re-pinned.

Roddimus Prime

yup. but thats not a problem since the mazdaspeed exhaust cam had the exhaust same specs as a standard intake cam. It's actually quite smart.

mattsstang87

I thought that the "true" Mazdaspeed (173hp) FS-ZE cam was the same specs as the j-spec intake:


From the Protege FAQ page:

2.0 liter engine:
Type
FS-DE
Displacement
1991cc
Cylinders
4
Valvetrain
DOHC 16 valve, direct shim over tappet actuation, timing belt
Horsepower
130hp @ 6000r/min (SAE net)
[MP3: 140hp @ 6000r/min (SAE net)]
Torque
135lbs/ft @ 4000r/min (SAE net)
[MP3: 142lbs/ft @ 4500r/min (SAE net)]
Bore & Stroke
83mm x 92mm
Compression Ratio
9.1:1
Induction Type
Natural
Redline
6500r/min
Alternator output
12V 80A
Ignition type
distributor-less coil pack
Fuel system
Multipoint EFI
Fuel injector rate
285ml/min
Manual Transmission type
G15M-R
Valve Timing
Intake cam duration
230° @ 0.003"
Intake cam opening
2° BTDC
Intake cam closing
48° ABDC
Intake cam lobe height
43.700mm (1.7205")
Intake cam base circle
35.052mm (1.380")
Intake valve lift
8.6487mm (0.3405")
Exhaust cam duration
230° @ 0.003"
Exhaust cam opening
48° BBDC
Exhaust cam close
2° ATDC
Exhaust cam lobe height
43.225mm (1.7018")
Exhaust cam base circle
35.052mm (1.380")
Exhaust valve lift
8.1737mm (0.3218")
Valve overlap
4°

2.0 liter engine:
Type
FS-ZE
FS-ZE (MazdaSpeed)
Displacement
1991cc
Cylinders
4
Valvetrain
DOHC 16 valve, direct shim over tappet actuation, timing belt
Horsepower
168hp @ 6800r/min (JIS net)
[MY2002.5-2003: 163hp @ 6800r/min (JIS net)]
173hp @ 6800r/min (JIS net)
Torque
131lbs/ft @ 5000r/min (JIS net)
[MY2002.5-2003: 128lbs/ft @ 5000rpm (JIS net)]
134lbs/ft @ 5000r/min (JIS net)
Bore & Stroke
83mm x 92mm
Compression Ratio
10.4:1
10.7:1
Induction Type
Natural
Redline
7000r/min
Alternator output
12V 80A
Ignition type
distributor-less coil pack
Fuel system
Multipoint EFI
Fuel injector rate
285ml/min
Manual Transmission type
G15MX-R
G15M-R
Valve Timing Standard
MazdaSpeed
MazdaSpeed
(revised/TSB fix)
Intake cam duration
241° @ 0.003"
241° @ 0.003" 241° @ 0.003"
Intake cam opening
5° BTDC
5° BTDC 5° BTDC
Intake cam closing
56° ABDC
56° ABDC 56° ABDC
Intake cam lobe height
43.700mm (1.7205")
43.700mm (1.7205") 43.700mm (1.7205")
Intake cam base circle
35.052mm (1.380")
35.052mm (1.380") 35.052mm (1.380")
Intake valve lift
8.6487mm (0.3405")
8.6487mm (0.3405") 8.6487mm (0.3405")
Exhaust cam duration
230° @ 0.003"
240.8° @ 0.003"
241° @ 0.003"
Exhaust cam opening
48° BBDC
48.3° BBDC
55.5° BBDC
Exhaust cam close
2° ATDC
12.5° ATDC
5.5° ATDC
Exhaust cam lobe height
43.225mm (1.7018")
43.700mm (1.7205") 43.700mm (1.7205")
Exhaust cam base circle
35.052mm (1.380")
35.052mm (1.380") 35.052mm (1.380")
Exhaust valve lift
8.1737mm (0.3218")
8.6487mm (0.3405") 8.6487mm (0.3405")
Valve overlap
7°
17.5°
10.5°

mattsstang87

Our intake and exhaust camshaft lift and duration are the same as the STANDARD FS-ZE exhaust cam (actually, our exhaust cam is exactly the same as the STANDARD FS-ZE). In order to have the same combo as the Mazdaspeed FS-ZE would require re-pining of what we call the J-Spec intake camshaft.

While on this subject, has anyone had one of these cams repinned?