Rb20 With Rb26 Inlet Manifold Power Loss?

[migs]

hey guys in in the process of installing an rb26 inlet manifold on my rb20det

we will me needing the space to install our top mount turbo manifold and new turbo

Ive heard that you lose hp is this true? if so what kind of power loss do you get?

Right now we are building the car as an every day car that we can take to the drag strip on weekends

Our project is a Mitsubishi sigma we used this as it has a very light weight body (its about 996kg) way lighter than i GTS skyline or a cefiro

the motor bolted up very nice in its engine bay, we also swapped the stock 3.5:1 rear end for a 4.3:1 rear the 3.5 was a bit sluggy

the motor setup we are running rite now is

*stock rb20 motor

*300zx 45v3 t3 turbo

*turboXS boost controller

*13 psi boost

*blitz bov

*blitz LM 3" intercooler

*2.5 intercooler piping

*3" free flow stainless exaust

*apexi n1 tail pipe

*rebuilt gear box

*upgraded ecu flashed\remaped by raymond of ems tuning( also no speed/boost or fuel cuts )

*fidanza 4.3 Performance 6puc ceramic Clutch

*NGK iridium spark plugs

*3 core

*All oil seals and belts changed

*walbro external fuel pump

other upgrades coming soon

*adjustable cam gears

*Cometic head gasket

*ARP bolts

*high flow turbo manifold

*Garret gt30r or Turbonetics GTK ball bearing

*Tiial wastgate

*Greddy or Haltech engine management system tuned to about 20psi

*550cc nismo injectors

*sard fuel press reg

*water/meth injection kit

then we may prob change the cams

Edited July 14, 2010 by migs

[migs]

[TiTAN]

Dont need to bother with the ARP bolts if they are for the head, also dont need to worry about the head gasket unless something is wrong with the current one.

[wlspn]

Will you be running the RB26 ITB's or grafting a bigger single on the front of the plenum?

If a street car I personally would be going RB26 setup but curious what your plans are...

[migs]

im going with a single TB setup

a 26 will be good but we dont get them in the part yards here in the island of Tobago

this sigma is just one of our project cars this one we are keeping it Rb20for now,

we have other projects

like a bmw 361i with a 1jz-gte twin turbo transplant,

ford cortina with an with a 280zx l28 transplant soon to be RB25 powered

[STATUS]

Just do it

One of the best rb20 setups we had through ran a KU engineering plenum and it made a respectable 280 odd rwkw on std engine. So with your planned upgrades for the turbo it should work out OK, it will be a little soft with the 300zx setup.

The ultimate issue with rb20 is the head port size not the plenum.

[Adriano]

To be honest you will lose power everywhere except at about 7000+ rpm. The standard manifold is good for over 300rwkw, and your currnt turbo is only goood for about 220. Unfortunately rb20's need all the power they can get down low, and these manifolds have poor cylinder filling down low. But it looks like you are almost done, so i would keep going and do back to back power runs and see for your self

[sav man]

i've got rb26 ITB and plenum on my 20, and the port sizes are pretty diferent between the two. But my car is still in build, so i havn't got to test the engine yet.

[waxracing]

I wouldnt think you will lose power at all, your engine will not be as smooth if the manifolds are shorter, the long runners aid in nice smooth power.

I havent run an rb20 on the dyno with a 26 manifold so I cant say for sure.

[STATUS]

I wouldnt think you will lose power at all, your engine will not be as smooth if the manifolds are shorter, the long runners aid in nice smooth power.

I havent run an rb20 on the dyno with a 26 manifold so I cant say for sure.

its the low speed filling thats the issue. ie slow 60ft times.

[rob82]

With a KKR440 you will loose about 15 - 20rwkw thoughout the entire rev range until aboyt 7000rpm where it will make the same power as the std manifold maybe a smidge more. You will also loose about 500rpm spool rate. I'll see if I can find the dyno graph.

Runner length is heavily dependant upon rpm not mass air flow. Hence even if you have a turbo that can make huge airflow down low its unlikely that a short runner will make more hp than a long runner, until the topend anyway.

[migs]

yes please find the dyno graph

[esky_mad]

whilst i didnt have a 26 plenum i did have a custom plenum and found the response was perfect, didnt peak at massive revs, came on nice and smooth. it would seem people go on what they might here from some random source than a genuine experience.

[migs]

what other mods did you have on the engine

?

[T04GTR]

just dont put a massive tb on it. 75mm max. waste of time going any bigger than the piping. all that will happen is loss of torque at light throttle and down low.

[migs]

upgrade completed

and i am very happy

http://www.skylinesaustralia.com/forums/Rb...b2-t342017.html