HKS 2.1 stroker kit & camshafts
 

I would like your opinion on the improvements of the HKS 2.1 stroker kit and the relevant camshaft:

https://www.hks-power.co.jp/product_...t006_graph.gif

Notice the 20hp improvement in the middle and high rev ranges. In this graph there aren't any exhaust changes.

How it would compare with a stock engine and a good catless header with a tune? No E85 fuel comparisons please.

I dont think the cam used on this dyno is the one that is compatible with stock pistons. I believe the one that is, had very minimal gains mostly in the top end because lift cant be increased with out recessed piston heads for valve clearance, only a little duration and it wasn't worth it. If going all out NA looking for some high peak power and money isn't an issue i am sure it would add a little. I could see it stacking well on top of E85 or at least WMI for that top end. maybe some 210whp NAs could be possible on generous dynos.

Yes I agree. I believe most of the gains are from the stroker kit and the camshaft was used to enhance a bit the top end marked with black circle. The engine displacement increase from the stroker is minimal, but the torque increase looks to be substantial.

I checked also some results from a couple good catless headers. The difference is not that large, so I guess the effort and the cost to install the stroker kit is a serious disadvantage. I would say it makes more sense only if someone combines it with FI. There are other stroker kits too, but these are even more complex with a mandatory cylinder bore honing process.

Look at the chart again. That's not horsepower.

I converted kw to hp ;)

I will add here that one of the few cars here in the UK that had a blown engine was running a HKS stroker kit that let go shortly after install. HKS admitted manufacturing defect.

Very reassuring! Pheww!

Any update on this? Did anyone install the HKS 2.1 stroker & camshaft kit lately?