Rb20det Forward Facing Plenum

[Proximity Motorsport]

Hey,

I want to put a FMIC on my car... 1989 R32 4 door with RB20det. Mods are 3" turboback exhuast with 2.5" split dump, turbo smart bleed valve, and a rebuilt highflow rb20det turbo.. think its rated 450hp. ATM i am running below stock boost as i dont have a boost gauge... Need to see how my mates justjap gauges look cause i cant justify $1000 on gauges for defi.

Anyways what i want to know is with the forward facing plenum i know the throttle cable will have to be shortened / lenghened. I was also thinking about getting a new throttle body.... would i need managemnt for this or it should be ok without it. Im guessing it is s my brothers s14 has a bored throttle with no management.

Anyways i have a hybrid core at home i got for free... vgc. I was thinking custom piping so i wanted the forward facing plenum to help reduce the pipe lengh to reduce lag with that turbo. It doesnt start really getting into it till around 4500rpm.

So question is what else will i have to do to all the hoses and stuff that go into my stock plenum. Can someone please post pics of their forward facing plenums, or brands of recommended plenums.

thanks

[fEkuaR]

Reduced piping will make minimal difference in lag. What will make the biggest difference is engine management. At the moment the car is not even starting to utilize the current set up without it.

[Proximity Motorsport]

also forgot to mention it has a walbro pump and fuel pressure regulator. All of which were on the car when i got it.

Yeah that might be true but it will help a bit and when i put everything on... i want it done properly the first time round. Dont wanna slap on a cheap kit then want something better later down track.. if you know wat i mean.

[Min_R32]

Im not to sure but i havnt seen any known brands (greddy etc.) who make forward facing plenums for rb20's but correct me anyone if im wrong. It would probably cost an arm and a leg anyways.

Another option would to have the original plenum modified. As in cut off where the inlet pipe would normally go and weld it shut. I had one on my car (still have it sitting in the shed) but had to go back to the stock one since i was defected. (supposedly it changes the numbers whilst testing for emissions).

As for the intercooler piping i personally dont think it makes a difference except maybe the looks with the extra piping needed.

[Proximity Motorsport]

obviously shorter piping is going to meen less lag. Hence why wrx has a top mount... or mad drifters have v mount... less piping meens more response... anyways.........

I dont know if the greddy plenum is forward facing or not. I have found a few but there is a pic... it looks forward facing but it sais we have these to suit... rb25, rb20, sr20, etc... so i dont know if it might be a sr20 one or what in the picture.

[ahh 33 s2]

strich9 just did a wicked right up on a greddy style ebay plenum for a rb25. would presume fairly similar to rb20. link below

http://www.skylinesaustralia.com/forums/in...howtopic=181826

[TTT]

I would have thought a rechip would be higher on the list of next mods than a plenum.

especially since you have a hi-flow turbo and fuel mods and nothing controlling how it all gets mixed.

the stock plenum has been used by people making 300rwkw on the RB20

Search the NSW forum for user "Legend01" I think it is..

Also speak to user CEFFIE about re-chips.

he has/had a similar turbo to you on his RB20 and programmed his own ecu.

making 240rwkw and boost coming on ALOT earlier than what you are describing..

Your choice..

just think money would be better spent on tuning rather then "fully sick forward facing plenum bro"

when the stocker is a good unit.

[GunmetaL]

upgrading to a forward facing plenum is an excellent idea IMO i'm currently doing it in my s13 Rb20 conversion.

It Shortens the IC piping required and you can shorten it even further by mounting the intercooler upside down with the outlets at the top of the core.

Have heard that it offers midrange and top end power gains (i cant confirm this as yet).

And even if you dont need the plenum (to make the power your aiming for) yet it will always be there in the future if and when you need it. And you will not need to modify your intercooler piping setup twice.

Having said this there is no point to the plenum at all if you do not use aftermarket management to take advantage of the gains the plenum can offer wether it be a rom, emanage, ems or powerfc etc ideally you will need one of these and a full retune.

The retune will be required due to the turbo upgrade regardless of the plenum to prevent it from leaning out.