rb20 intake manifold

[Carl H]

since it seems that no one has a nice intake manifold for the good old rb20 i'll post the one i had made up by RIPS in newzeland.manifold build is awesome and rob was great to work with.there are velocity funnels (not stacks) welded onto the plenum to aid with airflow, its well built and solid.

[Carl H]

another pic showing the acc arangement.

[Carl H]

manifold mock mounted

[Carl H]

another

[Carl H]

aac valve

[Yellow4g63]

Sweet can't wait to order mine.

[Eikon]

Looks real nice Carl. Well done.

Is that a stock Throttle Body? Just out of curiosity, why wouldn't you put on a Q45 TB if you were having the mani custom made?

I like the black and polish look. Very sharp.

How much do they charge?

[Carl H]

q45 is too damn big for an rb20 your throttle response would be terrible.the manifold is set up for a 5mm overbore tb so if i manage to outflow the stocker (which is around 450bhp) then all i have to do is bolt on an overbored one.the entire kit is very comprehensive it includes the following:intake manifold/plenumwater pipe kit (for the upper radiator hose)modified thermostat outlethoses and clampsgaskets for intake mani and TB5mm over tb (i opted out for this one)all in all it cost me about 1.2k shipped over here, but i also got some other gaskets and bearings along with so its a touch less than what i paid.if you are seriously interested in one of these manifolds i would contact rob directly, he's a great guy and very helpful.rob can be reached at [email protected], it takes about a day to hear back from him as he is on the other side of the world but he is prompt and courteous.

[AmoebAssassin]

That is a very beautiful plenum, look very well and knowledgeably made. Should make some good power for you, post some dyno numbers if you get the chance! I'll probably go this route if I end up with an rb20.

Carl H, would a larger TB really decrease throttel response in this case? With respect to fluid flow, if the pressure behind the TB plate remains relatively constant and the cross sectional area of the TB increases, the velocity of the air through the TB decreases, decreasing the probability of turbulence caused by the throttle plate and shaft. This would, then, aid in throttle response by creating a less turbulent volume of air in the plenum before the runners/injectors. Please correct my logic if i am wrong, i dont mean to d!ck you out or belittle you or anything.

[Carl H]

while i dont have engineering background to back me up on this, this is how i understood it to work.take for example the idea of itbs, they keep velocites high as to aid in airflow into the ports.so a tb is like that but for for all the cylinders, sooo while a larger tb may move more air into the plenum, the velocity that the smaller tb provided is lost which gives the idea of poor throttle response.again, i could be completely wrong on this, but having talked to ppl who have put significantly larger throttle bodies on simmilar engines (ie 2.0l) they made it out that even tho the tb did provide more aiflow that their initial throttle response was worse than what had been on it from the factory.even then i would think that you would want some turbulance in the plenum to aid in the air/fuel mixture.either way there will be a turbo pushing air thru the tb, so its not like an na car.

[AmoebAssassin]

Ah, i forgot about velocity in the runners. Yeah, a smaller TB actually makes a bit more sense now. Thanks for clearing that up.

About the turbulence, btw, ideally you want a nontubulent high-velocity volume of air in the plenum itself, and laminar flow through the headers. However, you want slight turbulence in the head post-injector for atomization and mixing of fuel. The reason for this is that nonturbulent air will flow faster, so you get a higher velocity through your runners and good mixing in the head.

[Eikon]

wow... you guys are wicked smart.

how big is the RB20 TB? Is it 60mm?So.. the question then is... Should I ditch the Q45 throttle body that I have already bought in preperation for a custom intake?

I have a Megan Racing intercooler with a 3" outlet. I figured that a 90mm MAF to a T3/T4 turbo to a 2.5" IC inlet, then to a 3" outlet to a 90mm TB would be a good piping situation...

Do you agree? I think I need the MAF cause I hear that the RB20 MAF won't support much more than 250hp tops.. I am figuring a T3/t4 turbo with an external wastegate will get me to 400 hp with little lag.

If the air coming out of the IC is in a 3" pipe, why would you want to shrink it to 2.5". Besides.. aren't you going to loose that velocity when it enters the large space of a manifold. I think pressure is much more important than velocity anyhow. When the air is forced down a 3" pipe, then into a large (say 10") cylander or compartment like a manifold, then has to make a hard right turn to flow into a velocity stack, you are not going to keep that velocity. I would think that the more important factor in getting the air into the velocity stacks and ultimately the cylanders would be pressure. I would think that you would have greater air pressure in the manifold from a 3" entrance and a 3" pipe than you would from say a 2.5" entrance. If you shrink the opening you will get more velocity, but less pressure into the manifold because you are building and storing that pressure before the entrance.

????

[Carl H]

well idealy 3" ic piping is going to lead to more throttle lag and again bad throttle response.again bigger pipes may mean more potential airflow but its also space that needs to be filled up with air before anything can happen.if you can keep the ammount of potential air the same in your setup as your stock setup then you will have throttle response simmilar to your stock setup.when i say this i mean total "fluid" capacity (ie 12 liters of air in the intake track), and again bigger pipes will move more air but you have to think how does the air get there.the larger the volume of the intake track the more work the turbo and the engine must do to transition from vac to boost.remember that until the turbo spools up the engine has to pull the air in first, therefore a larger capacity intake track is going to add to throttle lag.

[kickboxin]

How much did that intake manifold cost?

[blk90s13]

How much did that intake manifold cost?

yeah how much was it ?

[Eikon]

yeah how much was it ?

Alright you two... first one to read the posts above and find the answer wins. ready....... GO!

[blk90s13]

duh thats alot of money

[Bluefire]

Hmm... It would be cool if you move the air regulator underneath the manifold. Also do you have any pics of the inside of the manifold. As for the throttle body, you could maybe use an N15 throttlebody? I dunno what the stock size is, but the n15 is 70mm I believe

-Bluefire

[Carl H]

well the manifold is setup so i can bolt on an overbored tb, so when the time comes (ie 450bhp) to upgrade the tb i can.

[StricNyne]

that looks awesome, i bought one form rbpwr240, for me price was a serious issue and his deal he offered me was toooo good to pass by on, i heard so much about rips manifold must be awesome, i will post me results with my manifold, wish me luck heh, btw paint job on that motor OWNS

[Carl H]

hahaha, thx man.its not paint tho its actualy powdercoated, local shop to me did all the valve covers and the front timing covers for 30$.i did sand the center coil cover down and spray it with flat engine paint, its a nice contrast.

[turbo-sil40]

Does anyone want to sell the rb20 manifold from this page or how can i get one made i need one asap thanks

[Easy Pickle]

Does anyone want to sell the rb20 manifold from this page or how can i get one made i need one asap thanks

Have you tried reading the thread? And are you really willing to plop down atleast $1200 for it? Didn't think so.

[Sky80]

HOLY back from the dead thread!!

[RB20DETodd]

Beautiful manifold carl, i talked to rips , and 1500 shipped, ouch!

[Carl H]

Beautiful manifold carl, i talked to rips , and 1500 shipped, ouch!

outch indeed, i guess rob bumped prices due to paypal sucking fees and currency conversion rates.unless that number was in nz dollars in which case isnt nearly as bad.

[RB20DETodd]

outch indeed, i guess rob bumped prices due to paypal sucking fees and currency conversion rates.unless that number was in nz dollars in which case isnt nearly as bad.

USD, but comes with a bigger TB, the stryer isnt lookin too bad now