30Tooth

iTrader: (1)

You know it, we're after tractable power. Whatever that is, seems to be some sort of low end power that extends smoothly towards the top as the engine pulls.

NitroVein

Pretty much, all out power is usually not the ticket in offroad, just look at how much people choke their engine with a small carb insert.

30Tooth

iTrader: (1)

Both RB S5 I had felt like light switches on the 2087 despite the a main description being a smooth power delivery I can't agree with it. Now on the other non homologated pipe it's too peaky and hard to drive tomorrow will try the 2058 see how it goes. Want to see if RB engines are aggressive or are the pipes I've tested that make the engines that way.

NitroVein

I have no knowledge/data on either the engine or pipe, but if you got other pipes to try with just go for it.

30Tooth

iTrader: (1)

Going by "seat of pants" dyno.

NitroVein

Yes, when it's going faster you know you're doing something right!

30Tooth

iTrader: (1)

Yes going to keep the comparisons simple and fair, lap times and runtime are the only factors that matter and will keep clutch and car the same.

30Tooth

iTrader: (1)

And testing has been completed on 2058 and 2087 with shorter manifold.

Further playing with the needles I've found a base where the engine works good for me. Haven't measured idle gap but it's around 0.75mm.

That said, I've done back to back runs and I can say that the 2087 with the shorter manifold from the 2062 (I'd say same length as the 2058 manifold, can't use the 2058 manifold because the mounting is incompatible) is less peaky than the 2058 and is biased towards bottom power than top. That's the difference for me, the 2058 sings from mid to top. The 2087 needed a slightly leaner LSN than the 2058 yet engine temperature was around 94ºC even with the low heatsink (24ºC, 11Km/h wind 29% humidity unverified on the spot). The leaner LSN wouldn't be possible on the 2058, both pipes are really different in this regard.

Thinking this setup with the shorter manifold made the power delivery smoother than the first runs, this is the way I'm going to run this engine. To me the 2058 is a top end power pipe, with an aggressive hit, at least as much as the 2087 with the RB 192mm boomerang manifold. Works well with normal short gearing (46/13 for my mp9) in offroad but never with a increased (14/46 or 14/47 for the mp9) gearing. It might even work well with the 192mm manifold and increased gearing depending on average RPM on track.

In conclusion, with no way to tune out the peaky nature of the 2058 I am using the 2087 and shorter manifold while trying to use less fuel and RPM. Engine feels great with both pipes!