200rwkw N/a Rb, Whats Required?

[zebra]

If there was 2.75" i'd definately get that.

2.5" has very linear power from low to high. Gives more precise throttle adjustment/levels too. Revs faster or more responsive. Lacks the kick in power and i'm guessing max power compared to 3" by feel.

3" is pretty empty down low but is a blast at high rpm (5k and over) like VTEC just kicked in yo. Lack of back pressure makes the throttle feel weak at low RPM and not very precise. Feels like it has more top end power than 2.5".

This is from a guy who just got his cat back changed today.

This is a race car though, and the way to do a race car exhaust is just dump the exhaust primary's into the biggest bastard exhaust system you can fit under the car, who cares if the car feels a bit weak driving around the pit garages, the actual exhaust pipe has very little to do with how the car makes power, thats all in the primaries ala extractors.

[SKiT_R31]

I think you should go RB30 with a stroker crank. Spool have a 3.4L option (or you could go custom) along with max oversize pistons. It will limit your revs to about 8000rpm but is a better option, and would sound tough. If people can and have hit 170's and 180's with relatively mild builds (mild in comparison to what is possible and how spastic you can go with cams, revs and even compression) 200kw with a 3.4 (or possibly 3.5 combined with max oversize??) should be similarly achievable providing you can get it to flow the air.

Edited August 27, 2010 by SKiT_R31

[TurboDoseBro]

This is a race car though, and the way to do a race car exhaust is just dump the exhaust primary's into the biggest bastard exhaust system you can fit under the car, who cares if the car feels a bit weak driving around the pit garages, the actual exhaust pipe has very little to do with how the car makes power, thats all in the primaries ala extractors.

Yes, but as the exhaust diameter told me, depending on how much power you make or mods, a bigger exhaust diameter will push the powerband higher but thinner so a compromise is a must. Also with the lack of back pressure, the throttle feel was on or off which I don't think is good for racing.

EDIT: There was a VERY noticeable difference in power with 75% throttle and 100%.

Edited August 27, 2010 by TyresBro

[rb26zed]

I think you should go RB30 with a stroker crank. Spool have a 3.4L option (or you could go custom) along with max oversize pistons. It will limit your revs to about 8000rpm but is a better option, and would sound tough. If people can and have hit 170's and 180's with relatively mild builds (mild in comparison to what is possible and how spastic you can go with cams, revs and even compression) 200kw with a 3.4 (or possibly 3.5 combined with max oversize??) should be similarly achievable providing you can get it to flow the air.

This does sound good but I want to keep in the under 3L class.

Does anyone have any idea on the price of getting a serious NA head built, excluding head as I already have that.

[zebra]

$3k+ if you find someone who knows what they are doing

[rb26zed]

That raises a good question, Is there anyone you recommend?

[zebra]

For NA RB stuff im not sure tbh, might need to grab a stuffed head cheap and get a head workshop to have a play with the ports.

[GTS4WD]

I hevent read th thread.

But in my opinion, the benefits you will gain from using a 26 head a not worth spending the extra money as opposed to a 25 head.

26 head = ~ 2K

25 head = ~$500

Take the difference in $1500 and spend it on the engine.

As far as I am concerned. Power figures when it comes to NA engines are dependent on 2 things:

1) intake runner length

2) compression ratio

my advise. If you want good power figure (throwing out drivablility):

Reduce weight: lighten the bottom end, balance it, lighten the box (including clutch and flywheel) driveshafts/s and diff (spool diff would be nice) this will let the engine rev harder and faster.

Tune runner length: the shorter the the intake runner length (yes, ITB's ARE worth it!!!!) the narrower the power band will be, the higher in the rev range it will be, but the more power it will produce. this is ESSENTIAL to get right with the next step

Cam profile: You want a nice healthy valve overlap to get as much fresh air into the engine as possble. Cam lift and duration will be dependent on alot of factors including the runner length, volume of the engine and ecu tune.

Exhause manifold: No. Coby extractors will not do the job properly. Get it built from scratch, get it tuned right (spend the 1.5K difference here and the ecu, and ITB's, the benifits will far outweigh a 26 head!!!!)

the right Juice: tune with and run E85 (you will have to use e85 friendly fuel system - or drain it after every drive) 109 octane etc. for best results

200NA kw is easily acheivable.