PRODUCT: Jun Type III Camshafts for Honda B16A/B18C engines
DATE: 25/11/1999


If you are going for the ultimate set of aftermarket cams for your Honda, this is it! The Jun Type III cams are designed for streets/race setups. Unlike other aftermarket cams, Jun Type III cams use a different profile for both the low-cam profile and the high-cam profile, as compared to the stock Honda cams.. 

Jun Type III cams Profile #1 Profile #2 Profile #3
Intake camshaft 63(252)-9.0 76(304)-12.0 60(240)-6.5
Exhaust camshaft 60(240)-6.2 76(304)-11.5 63(252)-7.8

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As you can see, the Jun Type III cams are designed with a wilder profile compared to the stock Honda cams. The advantage of that is an improved mid-range performance  (while the low-cam profile is engaged). This is an area which is lacking with the use of the stock cams. You will notice that the dip in the mid-range performance is  significantly reduced. The downside to the wilder profile is a slight tradeoff in idle quality. If the cams are properly tuned, a decent engine idle can still be achieved. 


Once the engine revs past 6,000 rpm (optimum cut-in point for the high cam profile), the engine pulls much harder. The change in the engine note (as well as the exhaust note) is unmistakable. Unless you have raised your rev limiter, you will soon be hitting the rev-limit in an instant. With the profile chosen for the high-cam, the engine is breathing well way past the stock redline. Herein lies the 'downsides'. To take advantage of the power which extends past the stock redline, you will need to raise the stock rev limit. To do that, you will need to either remap the ECU or install a device which can remove/raise the rev limit.  As the high-cam profile has a max valve lift of 12.0mm and a duration of 304 degrees, there will be added stress to the valvetrain components. To ensure reliable operation and to avoid costly engine rebuilts, you will need to upgrade to Jun's valvesprings and titanium retainers.


Having ensured the reliability of your valvetrain components, your next concern will be fuelling. Forget about fuel controllers such as the SFC-VTEC or the Apexi S-AFC for the moment. As a standalone device, they do not provide sufficiently fuelling with this set of cams, especially so if you have other intake and exhaust upgrades performed. These devices are not able to alter the injector pulse duration directly. You will need to invest in Jun's ECU (programmed for operation with Jun cams). You will be taking a risk if you think that other aftermarket ECUs can do the job. Alternatively, you can invest in the Apexi Power FC or other programmable engine management systems.


If you have been reading up to this point, you will notice that there are a number of 'hidden' costs associated with the proper use of this set of cams. Purchasing the set of cams is just the first step. Apart from the above mentioned component upgrades, you will probably need to spend some time on the dyno to optimise the cams settings. Having said that (hope I have not frightened off potential buyers for this set of cams), there are some 'poor man's' methods to save you from emptying your wallet. If you are willing to sacrifice the additional performance beyond the stock redline, you can still retain your stock ECU (saving you $$$). To handle the additional fuelling required, get the following:

        1) SFC-VTEC/Apexi S-AFC/Any other similar fuel controllers

        2) Adjustable fuel pressure regulator

        3) Honda Prelude 2.2 VTEC injectors


What about the valvetrain components? If your engine is relatively new (low mileage) and you make sure that you keep to  the stock rev limit, upgrade to Type R's dual exhaust valvesprings and lighter Type R valves. These stock factory components should not cost you an arm and a leg for them!


I hope potential buyers will have a clearer picture of what is involved with this set of cams. Despite of the added costs required, the Jun Type III cams deserve an A rating as I am impressed by the performance improvement.