rb20 questions

[stewie8apie]

i'm doing an rb20 swap in my s14 and will be shooting for ~400whp.

I will be rebuilding the motor with basic things such as (oil pump, water pump, timing belt, tensioner & idler pulley, headstuds, gaskets, bearings...) which i know SHOULD be done. however, i've been searching through this forum and can't seem to find somethings.

How much can the stock rb20 pistons hold? I realize that with the proper tune anything is possible, but what is reasonable on the rb20? also, if i need to upgrade, will aftermarket pistons work with the stock rb20 rods? also, the only pistons i've found are CP's which are what i use on my honda and i know they are great quality...but the only place that even carries rb20 pistons sells them for like $1300 which isn't cool.

Also, what turbo would you guys recommend? I want to keep it simple and don't want to have to upgrade the turbo manifold just yet, so i've been looking into internally gated t3/t4's and of course something like a gt30 if needed. only problem is that i'm having trouble finding an internally gated turbo that will support 400+whp.

I know that injectors and fuel pump is a MUST, and have had good luck with the walbro in the past, so as for fuel pumps go, i'll probably do that. however, i'm not sure what injectors to go with. rb20 stock is high impedance correct?? i can't seem to get a strait answer on this, but if it is correct, will the rc high impedance saturated work?

lastly, driveshaft...every thread i've seen about driveshafts says to take it to the local place and have them make you one, however, i don't trust any place around me to make me a driveshaft, so that is out of the question. mckinney makes one, but its horribly expensive. is there another alternative?? or do i need to bite the bullet on this one?

oh yeah, and i will be tunning it with a soon to be determined rom emulator. any suggestions there?

thanks for the help

[rbsileighty]

You're kind of going the right way... but with the wrong logic.

Cheap and 400whp RB20 don't go together. Total bits required to make the power could be more effectively purchased in conjunction with a RB25 with new pistons and rings... or RB26 with more boost and a few other things

So for starters... rethink what you're aiming for... if 400whp RELIABLE is a must and you want the most area under the curve... either up the budget or buy a RB25 and install pistons (with new rings of course), Greddy manifold, FMIC and cams (plus standard supporting items ie fuel pump etc)... and some turbo (budget desides what) and preferably some exh manifold

Problem with a RB20 is that it peaks out around 6100 (don't get me wrong... I have one)... so you'll need cams and an intake manifold to fix that because you will need a lot more RPM's to make that power useable. The head is a big restriction so it's a good idea to have it worked a bit... FMIC instead of the stock interheater... a log exh manifold (ie stock) will definitely not work to well on a path to 400whp... so ditch that and get a new one of those as well... as well as probably the only way you'll be able to fit the GT30+ sized turbo (depends on if you want to make this on pump gas or not) onto the motor as you will need a external WG... unless you pioneer the ATP bolton solution http://www.atpturbo.com (as they have a new bolton internal)... and then... you'll need to manage all of those far from stock changes with something reliable...

So you get the idea... don't want to burst your dreams... just want to make them realistic as I've been in the same boat... just ask Carl how much he's dumped into his if he'll tell you. I put the $ in the chassis first... and researched the motor in the meantime... I recommend the same (if you haven't already) as that's what's between the motor and the road, and it will save you from a lot of unnessary purchases as you learn more about how it all works. An engine is a pump that is only as big as it's displacement and only as efficient as it's internals make it.

Just my $1.50

[stewie8apie]

i'm definitely not going for cheap here. i daily drive a 12sec boosted integra. trust me i know how much it takes to make a car fast. the reason i'm going with an s14 and rb is because its different and i've always loved the rb motors. i first thought that the rb20 would be good for 400hp, but from what you say, it doesn't seem too practical. however, my budget is ~$5,000 for the engine and setup....i don't think that will get me an rb26 from what i've read, and i thought that with that budget i could take an rb20 there. so then maybe i should go with the rb25 with pistons/rods? even so, i'd still have the same general questions.

[Carl H]

well, i can say from first hand experience that building a high power rb20 isnt hard but you have to have a good strong tune to keep it alive.ive learned alot about how to tune a turbo car with my car, and i still wonder why the hell the guy who owned my motor before me added 30* of advance to the ignition map...heres a quick breakdown of parts i have on my car:rb20det 1200$hks cast manifold and wastegate 900$greddy 720cc injectors 200$garrett true gt30r 1200$rips front facing plenum 1200$fmic 300$tomei cams 550$greddy cam gears 300$apexi pfc 650$

as far as management goes, std ecu is fine but make sure that you know how to work it...it will need to be tweaked but it is a very good control unit.before i blew the motor it made 387whp @17psi on a motor with poor compression (145psi across)...currently power is estimated at 300whp @ 14psi.the above mentioned parts were installed (except powerfc) when i pulled that inital 387whp number...and on a poor stock block to boot.its kinda silly to drive a 400whp car daily so i almost never have the boost up past base.think what you will but dont bother building a rb20, long blocks are so effin cheap that if it blows just buy a new block

[rbsileighty]

Don't forget to add:Fuel pump - 100-240 for what you'll need (basically covers Walbro to MKIV)FPR - 100-300Exhaust - ... depends on what you want but you'll need itMisc - 200-500... remember these are used motors

We're here to help... which is also to help keep things realistic... hope this helps

[Yellow4g63]

Head work is going to be very important. Bigger valves and someone who can go a very good port jobs with tricks to get the head to flow. The stock RB20 rod isn't weak and the piston is a turbo piston. Here is a pic of a RB20 rod next to a 26 rod.

[Carl H]

the problem with fitting bigger valves to the 20 head is the fact that there is little space to work with, i inqueried my machinest about this and he said that unless i expanded the bore some it would be hard to fit larger valves and still clear stuff.cams fix most of the breathing problems, so headwork is overkill...i mean my car pulled hard to 8k...

[Yellow4g63]

I know someone who could do it. Fumio Fukaya could do it but it wouldn't be cheap.