My throttle body / ported intake manifold project (08/14/2013 Update)

[L_RAO]

Personally, I would just bump up the redline by no more than 250RPM, keep your existing valvetrain or replace the springs/retainers/keepers with new OEM stuff, and then adjust your cam timing for the remaining last bit of power. That should be a safe route.

I haven't looked at the specs for the Comptech cams, but I guess the OEM springs are compatible for lift? I looked once at the Comptech springs (the link I gave you earlier for the eibach specs IIRC), and the springs looked to be overly stiff. But I am certainly no expert in this stuff.

Based on his experience with other Hondas, and the critical numbers (rod:stroke ratio, piston speed), my engine guy felt the NSX bottom-end (crank, pistons, rods) itself would be fine up to 9200 RPM, provided everything (i.e., oil pump gear, valvetrain) was up to the task. I personally don't think we'll need 9200 RPM, at least not with a plenum manifold. ITBs would be a different story.

Adjusting cam timing for the purposes of extracting that last bit of power is a lost cause IMO on the NSX because it is absolutely cost-prohibitive. Essentially, the only way to do it "right" would be to do it on an engine dyno, since adjusting the cam gears on the NSX requires you to drop the motor every time you want to make an adjustment. Plus, you are left with the dilemma of whether you want to set your gears for maximal area under the curve or absolute peak power. This is where having VTC like on the K-series would be HUGE.

Before my engine guy died, I gave him (without naming names) the specs for the Eibach, Supertech, and Manley springs. He said the Eibachs were most ideal. Believe it or not, the Supertechs and Manleys were even stiffer than the Eibachs!

 

[Mac Attack]

Rob had rigged up special valve covers that allowed him to do just that - adjust the cam timing on the dyno. Apparently he witnessed first-hand the piston-valve clearance and ruined another engine that way. He saw HUGE gains in peak power right before interference.

You're right. I explored a VCT retrofit and then gave up on it. A tuner shop in FL had a setup on an S2000 engine running awhile ago. That was when I also wanted to get away from the inferior TB and thought it would be a good way to kill two birds with one stone. I already have the AEM to control it too. Maybe someday when I get bored.

Interesting on the bottom end. Hope he accounted for the titanium rods since those are somewhat of a gimmick. I am running static 0.050" quench with the titanium rods and pretty much all other factors OEM (crank, cams, valves, bearing tolerances, etc). I have a dynamic simulation program that I used to design and have made custom rod bearings (long story). When I modeled everything, the OEM rod profile with my lighter pistons at 8k RPM showed that one of the weakest areas was the rod small end (no surprise). That's why I didn't bush the rod small ends for my engine build to weaken that area further - I had the floating piston pins DLC-coated instead so I didn't have to worry about galling on the steel pins and titanium rods. Anyways - my point is that you may be the highest RPM with a stock bottom-end. I think when Danny did his 9k RPM engine, it was already built somewhat with steel rods and forged pistons. I could be wrong. Did you ever find out more info on his engine config when he was N/A?

 

[RYU]

I am still alive...I still have those heads with the cams...some day i will just sell them ,but have held on to them because I am hoarder....and I still enjoy the thought of building another strong NA motor.

Please sell to me.

 

[L_RAO]

Please sell to me.

No, sell to me. Your build is (near) finished!!!

 

[docjohn]

....torn between two HP lovers.....my cams feelin like a fool....reving for both of you is breakin all the rules....