Help me pick a turbo! (and supporting items)

[Joe]

Ok everyone, its finally time. after having my RB in for 3 years and it seeing track duty for 2, i came to the realization this weekend the horsepower is finally limiting me. so its time.

What i want: 330-360whp on low boost ~400whp on high boost with the QUICKEST RESPONSE HUMANLY POSSIBLE. that is absolutley ESSIENTAL!!!! i honestly believe i wont ever need any more than 400whp for HPDE/drifting. I want to do this reliably but i have a budget. our season just started here in AZ and im gonna be really broke for the next 8 months haha.

Manifold: would like to use stock mani or HKS cast one.

Fuel managment: probably gonna be an AEM EMS but im open to suggestions

Injecotrs: not 100% decided but 650's are likley candidates.

this car sees some hellish abuse so i want to overbuild a bit. and FYI for those wondering my Mines ECU w/ N60 MAF will be for sale

SO: help me pick a turbo!

[Kansei240sx]

Well, Extreme Response and Reliability for racing, and budget.... shoulnd't even be used in the same sentence. Nor Paragraph. Make sure its done right. With myself been in racing for several years growing up as a wee kid to now i've seen people half ***, or budget build, and that stuff either works magically forever or breaks within two races of the season.

Even though most people are against it, I'd go with a GT3071R Internally wastegated. You could get away with at most using a spacer and some longer studs on the stock manifold and save space. Plus you dont have to worry about fitting some rediculous External Wastegate contraption with the limited space we have being the steering column is in the way.

If you're crazy though, you could just put a holset turbo on and not lag horribly. My friends KA24DE with a holset turbo and a custom .68 a/r i think on his exhuast spools him at 3500 and on 12 psi is around 325-330 rwhp-ish

If you havent already PUT on a lightweight flywheel or lightened your drivetrain assembly in someway, that helps alot. EI, Aluminum Flywheel/Driveshaft/Halfshafts

RB25DET Camshafts are pretty effecient, but if need be, you could always go with tomei poncams for some gewd response.

Standalone wise, AEM i dont really trust, i've heard alot of people complain about it. The reason i dont trust AEM as much is becuase they do everything, you cant be good at everything as a company, i mean for gods sakes, from honda civic intakes to god knows what to RB EMS?

The Apexi Power FC is great to tune if you have the software for it and a laptop, that way you dont have to **** with the commander so much inputting a million values. Turbo XS NOT TO BE CONFUSED WITH XS POWER i saw had a pretty cool standalone for the RB25DET that worked on thier car quite well.

650's sound like a good choice for injectors.

Something that most people dont think about as much is how the engine is stabilized. Engine Tq dampeners or stiffer mounts will also contribute to response, so keep that in mind as well.

[Sil240]

YupI'm with him on the GT3071R, Apexi Power FC, and I would go with cams if you have the money if not, not a biggie. Actually on the whole setup.You could also use ATP's Internal wastegatehttp://www.atpturbo.com/I was thinking about the same thing for my 20

[krayton]

since you dont wanna tear that engine apart, order that accusump now!

and whats all these problems with aem? ive seen a few problems with some other people, but i saw them get worked out on the aem forums. but aem built a good standalone, then their division just adapts it to specific cars.

mines worked flawless, and havent really had a problem as of yet.

and joe, id still worry about that crank collar. do you wanna just run it and see how long it goes, then switch to the ls1 :o

but what we do to the cars on the track, the RBs are really not built for that abuse out of the box

[Joe]

I know budget power and reliability should never be used together because i tell people that all the time but rest assured i would rather not have my car finished than do it half assed.

ive been looking at the internal gated GT3071 and like it. i really need to get off my *** and graph everything on a 3071 compressor map to see how efficent it would be but i have a feeling it should be right about perfect for both of those power numbers. what AR tho? .83?

cams would be something i would do when necessary i.e. during a rebuild. 400 seems to be the magic number for the rb25 without having to do some big internals so thats another reason im trying to stick to that number.

[Joe]

since you dont wanna tear that engine apart, order that accusump now!

and whats all these problems with aem? ive seen a few problems with some other people, but i saw them get worked out on the aem forums. but aem built a good standalone, then their division just adapts it to specific cars.

mines worked flawless, and havent really had a problem as of yet.

and joe, id still worry about that crank collar. do you wanna just run it and see how long it goes, then switch to the ls1 :o

but what we do to the cars on the track, the RBs are really not built for that abuse out of the box

accusump will without a dobut go on with this setup.

i dont know about all those problems with the AEM. the only things i know of are a good precentage of them are bad out of the box, but they are all replaced for free by AEM.

i know the rb isnt built for the kind of abuse we throw at it bro but this is the way i see it

tuning, oil, water temps. if you can keep all 3 of those in check the engine will last practically forever. 400whp isnt really THAT much power. the accusump will take care of the oil for track use, Tony at UMS is probably gonna be tuning it, and as for water temps, well thats a crap shoot. stupid arizona (BTW new radiator/ducting worked alot better this weekend. it was way way better than last time it was 100 degrees air temps)

[Carl H]

hks gt-rs turbo, 550-600cc injectors and power fc.done.iirc nengun is offering a complete upgrade package which has the above for about 3k, killer deal if you ask me.the gt-rs will offer the response you want as well as the power you want...http://www.nengun.com/catalogue/product/26

[Joe]

ehh im trying to avoid the power FC, just not a fan of it.

not to mention im an AEM dealer so i can get an EMS for way cheaper. paying retail is for suckas.

and im poor. this will be purchased a piece at a time

[eh?]

High flowed stock turbo (ie australian gcg turbo)Power fcZ32 mafhigh flowed stock injectors (550cc)

GCG is expensive but you won't have to change oil/water lines and get a new down pipe.Aem... stay away. You don' t need it for only 400whp. As fas as being bad boxes? no they aren't bad. They're just pathetic at reading the nissan CAS. My problems aren't fixed and the other RB25 owner on the AEM board (Taffy on 240sx forums) just gave up on it.

[the_momo]

im sure youll be against it, but have you maybe considered two turbos? you can do something in the t28 range and get great spool and with two, youll still get a pretty decent cfm. i have a friend with a 510 with a ca18 and a disco potato (love the name) and it spools full around 2k. pulls 16 psi all the way to 8k (he really over revs his motor too much) if im not mistaken, gtr manifolds would fit and they are t2 flanges arent they? just my 2 cents.also, im going to do megasquirt on my rb when its rebuilt. itll only cost me 600 ish all said and done (im doing external msd coils and a msd crank trigger wheel, easier than using the cas in my opinion.) and i bet you could get a dp for the twins to fit pretty easy. just a thought. hks turbos are expensive.

[the_momo]

also, go top feed, youll have more options for injectors, lots of different sizes (since you are going standalone anyway, impedance wont matter really.) and you can get a pretty hks fuel rail. i want one of those.

[Carl H]

proly bolt a rb20 fuel rail to the rb25 intake mani...

[Joe]

High flowed stock turbo (ie australian gcg turbo)Power fcZ32 mafhigh flowed stock injectors (550cc)

GCG is expensive but you won't have to change oil/water lines and get a new down pipe.Aem... stay away. You don' t need it for only 400whp. As fas as being bad boxes? no they aren't bad. They're just pathetic at reading the nissan CAS. My problems aren't fixed and the other RB25 owner on the AEM board (Taffy on 240sx forums) just gave up on it.

1) 1900$?!?! are you insane?! i could get a GT30R, HKS cast Manifold and all lines and fittings for that price!!!

2) AEM may be overkill, but again, i get them for cheap. an EMS will cost me just a bit more than a power FC.

3) yes, 35% of aem units are bad out of the box. they have no way to test them from the manufacturer so they just send them out and replace them when they arent working. and i know about them having problems reading the nissan CAS, im talking about something else.

[eh?]

Australian

recheck your currency. Yes it is still expensive.Buy a used PFC, I sold mine last year for $400.As for them AEM, so great you know of two issues with them, would you still want that headache? That thing stranded me 5 times and I've almost gotten into an accident twice. And just so you know- Taff was the Test mule for the RB25 ems and even he couldn't get a fix from AEM..

[Joe]

im gonna stay away from twins just because of the amount of fabrication involved. time is not a luxury i have to waste. basically once i have all my parts in the next couple months im gonna have between 2-3 weeks to do everything between events.

carl, if i switch to topfeed, thats the route ill go. i dont need no bling.

[Joe]

Australian

recheck your currency. Yes it is still expensive.Buy a used PFC, I sold mine last year for $400.As for them AEM, so great you know of two issues with them, would you still want that headache? That thing stranded me 5 times and I've almost gotten into an accident twice. And just so you know- Taff was the Test mule for the RB25 ems and even he couldn't get a fix from AEM..

still 1500$ US. plus shipping.

and krayton has an EMS he bought from my shop, and its worked flawlessly.

[StricNyne]

deatschwerks makes good injectors, for awesome prices i got a set of them and used stock fuel rail, i would like carl said go with a gt rs turbo, dual bb FTW, forcedperformance.com has good deals going on but i try to keep my purchases with nico sponsoers, i know injectedperformance.com cut me a awesome deal on a vortech sc and rps flywheel / clutch combo so i would DEFINATELY recomend him.

[wawazat8402]

Yeah, theres really no need to go top feed unless you need injectors larger than 800cc. Deatschwerks sells drop ins for our motors up to 810 or so I believe.

[Joe]

im gonna try to stick with sidefeed because i *think* its gonna be cheaper than switching to a top feed rail and buying injectors.

as for the turbo, christ i dont know. thats why this is so hard. there are so many options that will do what im asking for i just dont know which will do it the best.

as always, i appreciate everyone's input. even if i dont agree with your opinions i will take them into consideration.

[Carl H]

honestly man gt-rs is the best route, gt3071r looks hella good on paper not so much in real life.

[Joe]

why is that?

[Carl H]

well one of my mr2 friends and i were discussing fitting a gt3071 to his 3s-gte and we did up some figures and looked around abit.on paper the compressor wheel is absolutely effin amazing, it beats the gt30r's compressor map, but in reality the turbine wheel isnt the greatest and it actualy hinders performance.sure it feels like its spooling fast but its because like the gt28rs its actualy surging...not really an ideal setup imho.

[the_momo]

the best opition that i can see is go with something that will initially spool slower on a stock motor and ultimately give you a higher power ceiling and put in a set of cams that will open up the motor a little on the lower end. maybe a longer exhaust duration to help spool a little on the low. then do something dual bb bigger than the 3071. just a thought. if it were just for drag, id say big t4 and a shot of nitrous, but that would be usless on a real racecar... good luck with your hunting.

[Joe]

cams are going against my semi-budget setup

i found a t3/t04e BB setup for under 1000$, im thinking of going with that. should be good to 425whp.

[the_momo]

ha i like your logic. im mega budget man. i make most of my crap if i can. if i were to buy onely one thing expensive, it would be a set of cams. more only to just say...i have hks cams. im know. lame. oh well.

do rb26 cams fit? seems like you could pick up a set of those on the cheap and make a decent improvment. or, cam gears. maybe i dunno. i say run methanol. super lean afr will give you the power you seek. and 1 dollar a gallon isnt bad. although thats for large quantities.

im curious how the aem works out. keep us posted. i think im still using megasquirt. maybe. we'll see

[RB20DETodd]

hks gt-rs turbo, 550-600cc injectors and power fc.done.iirc nengun is offering a complete upgrade package which has the above for about 3k, killer deal if you ask me.the gt-rs will offer the response you want as well as the power you want...http://www.nengun.com/catalogue/product/26

nice site carl!! thanks

[Joe]

ha i like your logic. im mega budget man. i make most of my crap if i can. if i were to buy onely one thing expensive, it would be a set of cams. more only to just say...i have hks cams. im know. lame. oh well.

do rb26 cams fit? seems like you could pick up a set of those on the cheap and make a decent improvment. or, cam gears. maybe i dunno. i say run methanol. super lean afr will give you the power you seek. and 1 dollar a gallon isnt bad. although thats for large quantities.

im curious how the aem works out. keep us posted. i think im still using megasquirt. maybe. we'll see

no methanol. i will do 80 minutes of track time in 1 day some weekends, im not dealing with that bull**** on top of regular stuff that goes on.

all of this needs to be on 91 octane.

id rather make 325whp on 91 than 365 on 105 and save myself 75$ a weekend in race gas

[gawdzilla]

i'm not sure about others, but 650s on stock fuel system (8mm barbed hose+rail+in tank pump) is too big.

i ran 550's and made 400 and some change rwhp... with duty cycles in the low 90s.. granted i was fairly rich, the duty cycle was a good deal higher than i anticipated which makes me think the fuel system is maxing out. most ppl say on the S chassis the max you can safely run w/ the system is 700cc on an SR. 700x4 = 2800cc. 550x6 is 3300cc already... just something to think about.

650 x 6 is a big injector that you can't "fully utilize" with the stock system IMO. i think even 550 is pushing it.. i think mid 300 wheel is a safe number to aim for, and they can be obtained with 550cc's.

with budget in mind i'd keep the stock mani and run a pfc with a z32 maf, maybe even safc if you want to save another few hundo. safc will still work fine for the occassional 400 wheel dyno pull imo.

[Carl H]

i think the trick is having a pump capable of suppling the injectors.i run a tomei r32 gtr pump in my tank and its rated at 550hp, and i would assume thats on a stock fuel system (well supply and return lines at min.).i run 720cc injectors in my car, overkill yes,but it offers EXTREMELY lowe duty cycles which are good for long pulls, and if you are going to be seeing wot for quite some time over a large range of rpm then a large injector would be good as you wont be running near limit.

[Joe]

right now ive got a walboro 255lph, that should be overkill for a 400whp setup. but i want to hear more about the stock fuel system not supporting it. you realy think it isnt enough?

and i actually got a turbo. one of my good friends has a RB25 direct replacment IHI turbo good to 500hp lying around he is hooking me up with.