A Bit Of Rb20det Tuning Needed

[Lum]

Well I've got some spare cash and rather than pay off my one remaining credit card (which has a super cheap APR for the life of the balance) I figure I'll throw some of it at the Cefiro, it's going in to get the clearcoat redone to remove all the scratches and swirls next week, but I'd like some more performance too.

I want to leave it as an auto (because I'm a lazy git) and it's used more for playing about in the back roads through the Welsh valleys rather than seeing any track time, so I'm more interested in torque and mid-range acceleration rather than making big BHP, though it would be nice if my GFs 250bhp SP13 didn't beat it in a straight line, even if my 4WD makes up for it in the corners.

Currently it's totally standard apart from R33 GTS-T brakes, camber adjustable upper arm bushes and 16" wheels that are 20mm wider than standard, oh and a few gauges.

Where to go from here? I'm thinking a custom straight through exhaust to begin with since I don't need a cat to pass inspection, but then what? turbo (which one?) R34 intercooler, one of those Apexi cone things, and a Nistune map?

[Nic_A31]

Does yours have a blow off valve?

If not, try and find a Skyline blow off valve, then, you can increase boost.

Finding a RB25 turbo and using the RB20 actuator is ideal, stronger turbo with 10PSI.

Given the cars age, Splitfire coilpacks might help.

Aftermarket exhaust manifold and a " Split" dump pipe will increase low end response.

Wish we had your laws here, no cat is awesome fun, especially with a Bee*R limiter.

R34 side mount intercooler is a good upgrade if you dont want to hack the front bar to fit a FMIC in.

Open up the intake a bit with a pod filter. Look in the tutorials in the Naturally Aspirated Performance area on this forum, couple of good write ups on how to make heatshields and cold air intake using a pod filter.

Strut braces and coilovers might also help you out (rememebr since yours is AWD, you need R32 GTS4 or R32 GTR suspension and strut braces... NOT S13).

[daisu]

I'd start with the exhaust, it will make a decent change. Turn the boost up a little. Should be a decent increase for a street car.

[Nic_A31]

Exhaust mods alone should increase boost from10PSI to 11-12PSI, any more than that, on a ceramic turbo, without a recirculating blow off valve is going to kill it...hence why I suggested a R32 plumbed-back blow off valve, and then RB25 steel wheel turbo.

[Lum]

Exhaust mods alone should increase boost from10PSI to 11-12PSI, any more than that, on a ceramic turbo, without a recirculating blow off valve is going to kill it...hence why I suggested a R32 plumbed-back blow off valve, and then RB25 steel wheel turbo.

I'm not terribly keen on a BOV. It's a bit of a faux pas here because all the chavs have them, and if they have non-turbo cars then they fit

. You may as well write a sign on your car saying "all coppers are mongs, now please pull me over". I know the CA18DET* people tend to leave alone and enjoy the pigeons sound and resulting pops and small flame in the exhaust. I'd like to keep the car looking relatively standard, since the Cefiro is a complete unknown and doesn't have any of the image problems associated with the more common Japanese performance cars *cough*WRX*cough*

Definitely going with the exhaust first, if nothing else a stainless exhaust is an investment as it's only a matter of time before the standard one rots.

Not sure what you mean by a split manifold? To me the manifold is the expensive bit between the cylinder head and the turbo, but the split is normally on the exit from the turbo? What you lot call a dump/front pipe and what I'd call a downpipe.

*which is just an RB minus two cylinders

Edited July 5, 2010 by Lum

[Nic_A31]

Split dump pipe / down pipe is what I meant.

Skyline factory blowoff valves arent very loud or ricey, they just make a "whoosh" kind of sound, and again, factory Cefiro turbo is ceramic wheel, boost surging back onto the compressor (making that gay ass flutter pidgeon noise) will eventually destroy the turbo at 11+ PSI, so before increasing boost (which opening up the exhaust will, slightly) it's a good idea to take some pressure off the compressor, or aleast get a steel wheel RB25 turbo which is up to it.

If need be, get an eletronic boost controller, and just stay off boost when cruising around town.

[toffy]

all rb25 turbos were ceramic the same as rb20 . my suggestion: r34 cooler , exhaust modifications, new fuel pump , ecu remap , you'll end up with between 150 and 165rwk with a nice torquey feeling rb20 (providing the tune is good)

[Nic_A31]

What bout RB25 NEO ?

I'm positive atleast one of the two is steel wheel. Besides I'm better looking so what I say makes more sense than you Toff.

[Lum]

RB parts are a little harder to come by over here. What about the turbo of an SR20 S14, I think we have an S14 Garrett T28 sat in the shed though no idea if it still works.

And personally I quite like that pigeon noise, though not if it's going to snap the blades off my turbo in the process.

One thing that does worry me though. The posts here imply that 10psi is the standard boost for these turbos. I think I'm only making 7 right now. (Not at home, so can't check) edit: Actually, might be 0.7 bar.

Edited July 7, 2010 by Lum

[toffy]

What bout RB25 NEO ?

I'm positive atleast one of the two is steel wheel. Besides I'm better looking so what I say makes more sense than you Toff.

nope , all ceramic 100% guaranteed , tried and tested X no deal . you can be better looking but i'm older so that makes me more desinguished?

RB parts are a little harder to come by over here. What about the turbo of an SR20 S14, I think we have an S14 Garrett T28 sat in the shed though no idea if it still works.

And personally I quite like that pigeon noise, though not if it's going to snap the blades off my turbo in the process.

One thing that does worry me though. The posts here imply that 10psi is the standard boost for these turbos. I think I'm only making 7 right now. (Not at home, so can't check) edit: Actually, might be 0.7 bar.

well i've seen some running 14.5 psi for years and not a sign of failing but i've seen others spit the wheel off at 12psi , i put it down to tuning

[Nic_A31]

desinguished?

You lose even more points for your spelling.

Edited July 7, 2010 by Nic_A31

[toffy]

haha , i didn't spot that , the 'ol eye sight aint as good as it uster be

[32 4whore]

As stated.

RB25 Turbo, with RB20 Actuator. RB25 actuators only run 6 or 7psi. RB20 run 10psi standard.

FMIC would be ideal.

Full exhaust. Split front/ dump pipe.

Remapped ECU.

GTR Fuel pump or I believe an Bosch 040 would be fine.

Good working coilpacks.

Electronic boost controller if you want more boost.

I had all this on my old R32 4dr and I was making 190rwkw on i think it was 16psi boost.

I did those mods 4 yrs ago. I believe it is still going around with the same mods. So i must of done something right.

[Lum]

Ok it's going in for a new exhaust on thursday, 3" turbo back system, decat with a couple of silencers to keep the police happy and the chavs away.

One thing I'm concerned about though is this exhaust will apparently raise the boost and I don't yet have any other supporting mods in place.

Bear with me here, because it will soon become apparent that I don't know much about wastegates.

I'm looking at one of the Gizzmo EBCs because they're about £170 and seem to get decent reviews, however my understanding of this is that all they do is interfere with the pressure going into the wastegate actuator and thus can make it "see" a lower pressure than it's really getting, so you can be making, say, 14psi but the actuator only sees 9 and thus doesn't open the wastegate yet.

As a result of this you can only raise boost, not lower it.

I'd like to be able to lower the boost to standard, or maybe even lower (for when I have to give the car to a garage to drive). It looks like there's no way I can achieve zero boost but from the sounds of things what I want is the RB25 actuator on my RB20 turbo and then an EBC to bring it back up again when the time is right.

Can anyone who understands these things better than me (ie. most of you) tell me the pros and cons of this setup and if there's a better way to do it?

[toffy]

that's not really something i'd suggest, boost gain from the exhaust would barely be noticable , imo don't touch it , if you want to make it so whatever garage cant thrash it on you , pull the circlip off the actuator arm and wire the watsegate flap open (= no boost or very little) . The reason for the increased boost pressure is because you've just made less backpressure on the turbo/bypass(wastegate... think of breathing through a straw) hence it can spin the wheel easier etc