"upgdrading" To A Smaller Turbo?

[SS8_Gohan]

Hey guys'n'gals

now i'm far from any sort of performance/modification expert (as some of you are probably thinking from the thread title) but i kinda had an idea that i wanted to run by some of you guys.

At this stage, i don't THINK i want to have a car with huge power, i just want response, response and response. And after driving my dad's 335i every now and then, it's just insane how it feels like a N/A car and you would NEVER pick it was twin turbo. It's something i'd like to achieve with my 34.

I don't know if it will ever be possible to get that sort of response (i know the bimmer has direct injection, and probably a lot of other fancy trickery) from the RB

So my plan was to "upgrade" to a SMALLER turbo, but strengthen it (steel wheel?) so it can cope with more power than the stock turbo (200'ish rwkw), in an effort to get past the 200-210rwkw barrier for the standard turbo, but at the same time, become significantly more responsive.

Something around 250rwkw i think would be nice, or maybe even 230rwkw. I think 230rwkw with the response of the BM twin turbo engine would be a shiteload of fun and be what i'm looking for. And maybe it isn't about getting much past 200rwkw, but just picking up a crap load of low/mid torque? Don't think the BM's run much more than 200rwkw...

Because once i get my boost sorted (not holding to redline, got the spec-r waiting to go in) i will have maxed out the boost and power for the turbo. Decision then will be either happy with the power, or go turbo/fuel pump/injectors.

anyways, flame suit is on... just thought i'd get some opinions as i know there are a heap of knowledgeable people specifically in this section.

cheers,

chinny

[The Mafia]

Its not going to work like that mate.

You can't just put on a "smaller stronger" turbo, and make it work harder to get the same amount of power or more.

Turbos restrict air, and the smaller you go, the more it will restrict.

You need a decent turbo with a carefully selected set of wheels, trims, turbine housing, etc.

Edited November 26, 2008 by The Mafia

[TiTAN]

Something like the HKS GT-RS kit should give a nice responsive 250kw (or the garrett equivalent turbo)

[mitchy_]

the 335 uses twin TD03's.. like my legnum.

unfortunately they run out of puff very quickly, which is something that will happen with smaller turbo's... my peak power is at 5500rpm, but its very torquey up until that point.

[R31Nismoid]

if you want response etc - HKS 2530

[satanic]

Don't the 335s use a variable turbo technology - one turbo is actually larger than the other isn't it? That's how they get the response out of it, and don't forget it has a bigger engine than your 25 to begin with so it'll be a lot more torquey to begin with.

[mitchy_]

nope, just a pair of TD03's pushing 8.5psi

[paulr33]

hello daniel

you dont need lots of power to get response

a good tune, lots of ignition timing, the right gear ratios and away you go

what mods do you currently have

and is your car auto or manual (i think its auto?)

[SS8_Gohan]

would it be fair to say that either the 2530 or GT-RS will be slightly more lag than a stock turbo? by that i mean, any upgrade, will always sacrifice a bit of response to achieve more power?

- full 3" from turbo back (hi-flow cat, but not the big one, BATMBL)

- just jap return flow

- blitz hi-flow panel filter

- splitfires (mod?)

- manual boost controller (original one) set to 11psi, but not holding hence the Blitz Spec-R waiting to go in

- ngk coppers to .8

- Status remap

- manual

that's 187rwkw i think because boost drops from 11psi at 4500 to about 7-8 at redline. Trent said hold boost and we're in the 200's easy. Hence the Spec-R (which he reckons he can get turbo to respond a couple 100 rpm earlier with as well)

but yeah, i guess i was thinking along the lines of full boost at 2000rpm or something like that so perhaps a bit of a dream, but always interested to know what options there are.

gear ratios isn't something that can be changed without replacing stuff in the gearbox yeah?

well... thinking more along crazy lines... how hard would it be to twin turbo the RB25 with some of the BM TD03's??

[paulr33]

the std turbo will give you the best possible response, ie: i dont think theres any other turbo that spools up quicker

the rest, being a larger rear housing, will come on a bit later in the RPM range

that being said a highflow should be pretty much the same, and GTRS is a litttle bit more lag

twin turboing is pointless and expensive for your application

expecting boost at 2 grand seems unrealistic

3 grand is ok

[dano4127]

.........................................RB30DET+GT30=More response than you will know what to do with

Remember the BMW is a bigger motor - that makes a huge difference

[discopotato03]

To get into the same solar system (but not really close) the best I reckon your going to get is with an RB26 top end and probably an RB30 bottom end .

Don't know about the TT Bimmer but many before it had one throttle per cylinder inlet system and you won't get even close to it with one throttle - no matter what size it is . Thats purely for throttle response .

I'd say Bimmer went with two turbos for the same reasons Nissan did , easier to package than one big unit and you get the advantages of pulse separation (with parallell twins on an inline 6 with a conventional firing order) PLUS one waste gate for each group of three cylinders .

Cheapest would probably be a complete RB26 with a slightly higher CR and worked over head with mild cams and a pair of GTSS's .

Granted not cheap but cheaper than the Bimmer engine would be I think .

A .

[dano4127]

Yeah bmw loves the ITB's

[HEKT1K]

the 335i is torquey as.. old man was considering one, had it at 7k rpm on the test drive and it was SILENT. no spooling noise, no exhaust grumble.. i guess they're aiming it at a different demographic, but still.. it wasn't that 'fun'.

performance was definitely impressive though don't blame you for wanting to emulate it

[blind_elk]

hello daniel

you dont need lots of power to get response

a good tune, lots of ignition timing, the right gear ratios and away you go

what mods do you currently have

and is your car auto or manual (i think its auto?)

A bit of compression ratio will also help.

Nissan race team ran 9.3 C/R (stock is around 8.5) and still ran 1.5 bar boost. The Serrias, on the other hand, ran 6 C/R but 3 bar boost. You all know which car was a more responsive car.

[Beer Baron]

you already have a good tuner (trent). ask him what he thinks. but honestly it's not a realistic goal. the best you can do is go to a 2530 or GTRS, to get you to the 250kw you want, but you will loose some response. if budget is not such an issue then the way to do it is:

RB30 bottom end

RB26 head with ITB set-up etc.

ported head but squish zones left well alone

ported exhaust mani

GT-SS turbos

mild cams or even better, V-cam. (these really do help spool up)

good EBC

more than 9:1 comp ratio

this would be super responsive. I'd say you could hit 18psi under 3,000rpm.

[PM-R33]

HKS 2530 is the most reponsive turbo that you can chuck on their relastically speaking. It spools up as quick as the stock one, you won't be able to tell a difference response wise. Friend of mine has one pushing 220ish kw.

[Munkyb0y]

the 335i is fairly quick in stock form. i drove my mate's one.

then i drove it after he installed a Burger Motorsports chip via mail from the states.

32psi, completely stock, besides the chip and a tubular pod filter. this thing is an absolute beast. estimated 300+rwkw by Burger. (i have repeatedly urged him to get on a dyno for saftey's sake).

the power just pours on and on. and still, theres no telling its turbo. feels like a big ass NA.

but theres no limited slip diff on these. open wheeler only. strange.

i recommend you talk your dad into getting one of these chips

[PM-R33]

F**k thats hot.

[mitchy_]

32psi from a pair of td03's?