Rb20 + Gt2535 = Not Responsive

[works 510]

Guys,

I have a rb20 running a 2535 running 14psi using a bleedvalve (yes I know, but my elec boost controller died recently...)

It makes full boost at 5k rpm

any idea's what could be the problem? Surely the 2535 cant be this laggy

Yes i did abit fo a search...

Cant find any boost leaks, found a few suspect connections and fixed them up, advanced the timing slightly.

Any help would be awesome, as its not very drivable

Cheers,

Dan

Edited April 5, 2008 by works 510

[eddieeeee-ro]

ecu+ a good tune?

[works 510]

Still stock ecu at the moment....

lack of funds for a re-map

[PM-R33]

Thats ur problem then. Need the ECU.

[kretch]

my rb20 with 2535 came on full boost b4 that and i was running stock ecu was running 1.2bar booost but

[R338OY]

A tune is probably the answer. Maybe your timing is a little off.

Dyno will solve both.

[abu]

Get a tune

Do you have supporting modifications?

[works 510]

Supporting mods.

gtr or 040 pump, i have to check it

3" exh with GKtech dump and hks front pipe, cat is std for now.

evo3 intercooler and home made piping

awaiting to install gtr injectors

blitz pod

Ill get a tune asap

[dmr]

a 2535 on 14PSI has more flow than a standard turbo on 14PSI and will be coming close to maxing out your injectors. make sure you install the GTR injectors before the tune.

[abu]

Yep must be pinging its head off at 14psi and injectors are probably maxing out too

Get the GTR injectors installed and get it on a dyno - REMAP/PIGGYBACK/STANDALONE but either way you will see improvements

Put the boost down before you blow something

[Bumblebee]

tune isnt gonna bring the turbo on song any quicker... exhaust flow governs how quickly ur turbo comes onto boost..

first thing u should look @ is exhaust flow properties. check ur cat, make sure nothings block and ur exhaust is as free flowing as possible.. check wastegate operation as thats what controls the speed of the turbine. if its opening a lil too early and slow enough, it will make ur turbo laggier than it should be. spring tension is something to check for on the gate.

2ndly cams with more duration and lift will bring the turbo onto song quicker, but ull need supporting mods.

If its an aftermarket manifold, wrap it up. heat = energy. the more heat u can keep inside the exhaust the more energy will be exerted to the turbine wheel at a higher velocity hence reduce lag.

check ur intake for restriction.. try blowing through a kfc straw or sucking.. not very good for flow compared to something bigger like a maccas straw.

a tune will only make what u have a lil more drivable.. but it wont bring ur turbo on full song any quicker.

START WITH THE WASTEGATE SPRING TENSION FIRST

[GeeTR]

^^ Macca's straw FTW!

PS: Iv seen increased ignition timing changes raise fullboost point by 300rpm.

Dato 1600 FTW!!!

I spent my youth droooooling over 1600's...

thats all.... *cough*

[r3240sx]

^^ Macca's straw FTW!

PS: Iv seen increased ignition timing changes raise fullboost point by 300rpm.

Dato 1600 FTW!!!

I spent my youth droooooling over 1600's...

thats all.... *cough*

A solenoid type boost controller made a world of difference for me. By the way, that much boost through that turbo WILL melt your pistons if you're only running stock injectors, please turn the boost down for now!

[limpus]

The hks2535 isn't the most responsive thing on a rb20...in fact...just about any turbo except for the stocker won't be responsive...i know because i've got a 2535 on a rb20...however...yours seems alot worse...

The guys here have basically covered all your bases...restrictions in your system would be first thing...and then after getting the proper support mods a tune will go a long way to improving driveability once you dial some timing in...if you cannot afford engine management and a tune now then suck it up and drive it the way it is...do not run at at 14psi...turn it down to 10psi and run it till you can afford it...mind you it will run like a POS till then...

HKS turbos usually come with an adjustable actuator which you could possibly shorten to bring on slightly better response...mind you max boost will also rise so be careful...and when the time comes for the tune...running higher max boost will also improve boost resposne down low...i have attached my dyno graph from my recent tune...it should give you an idea of what boost response vs rpm you should be expecting...thats at 19psi though so boost response is abit better but its still gutless down low...

[works 510]

Thank for the help guys

Ill turn the boost down for now and have a look at the actuator.

As for restrictions in the exh, the only one I have is a stock cat (been gutted tho)and funds are minimal at the moment

The rest of the system is either brand new (catback was made a few weeks ago) or in good nick.

I had a play with the timing last nite, didnt really bring the boost on earlier, but it seemed to gain abit of power

Intercooler piping? Its not the best and long, could this make it worse?

Sorry for the questions, ive been playing with weber powered nissans all of my life

[Finny]

Thats an RB20 for ya

Re-tune, retard the timing down low.

My mates R32 GTS4 RB20 spools at like 4000rpm and thats dead stock.

[abu]

Thats an RB20 for ya

Re-tune, retard the timing down low.

My mates R32 GTS4 RB20 spools at like 4000rpm and thats dead stock.

well its must be fkd then hey

[limpus]

Thats an RB20 for ya

Re-tune, retard the timing down low.

My mates R32 GTS4 RB20 spools at like 4000rpm and thats dead stock.

Retard the timing down low?!!!

[1400r]

it will be the hks actuator not setup right

I think there was one with the kit softy bought off me

they need yeaps of pre load to get them setup right

setup soft they will still run 14psi just very late in the rpm like what your getting dont expect much under 3,500rpm even setup right though

you should be needing to use two hands to put the rod onto the clip

[works 510]

Sweet will give it a go.

And also its running .7bar now, just off the actuator.

Cheers.