Boggy Mc Bog

[Dale FZ1]

Did you have them do the job, or bought off someone who did?

Do you have any detailed pics of the unit prior to installation that might show the ID tag, or are you able to read them in-situ? It'd be interesting to know what spec you have.

A fairly common MTQ high flow for RB seems to be the BB GT2876 cartridge into stock housings. Despite some commentary about that spec being laggy, I know of a couple of people who ran it using OP6 housing and were very happy with the response and output (on an RB25 though).

I'm with the idea of getting the tune sorted. Provided the fueling is reasonable, get some ignition timing into it and watch things spark up.

[RaZ_TuRbO]

Yeah im def thinking the tuned will help..i bought it off here but it seemed in great nick and it had 2000kms on it..ill try and see if i can see the id tags. There another little thing that got me worries which i thought was a leaking noise somewhere.. but Might not be a leaking noise after all..theres like a tinny rattle sound.. definety from the turbo side.

Edited January 8, 2008 by RaZ_TuRbO

[FATAZZ]

check your manifold studs,they might have snapped.

[discopotato03]

RaZ to my way of thinking its more ignition timing to suit the engine not the turbo .

Generally when the factory specs small turbos for small capacity engines the gas passages have to be smallish to get enough gas speed into the turbine to spin it (and the compressor wheel) fast enough to make positive pressure - boost .

Small capacity engines , particularly low compression ratio ones , don't make much torque off boost so its more important to get boost happening sooner than a larger capacity engine would need .

The down side is that small passages become a restriction high up the rev range especially when the boost is greater than std . The factory knows this and tunes the computer around the amount of advance the std engine can take without detonation . Knock sensors and smart electronics try to keep it just under the detonation threshold for variables such as fuel octane and inlet temp etc .

Once you start to "uncork" the hot side the std computer doesn't know to compensate and ramp up the ignition timing .

It'll probably feel flat because the larger turbo passages and wheels have less restriction to exhaust flow meaning later onset of boost - turbo response is directly related to gas speed through its turbine blades and in this case the required gas speed will occur at higher revs .

When you can advance the ignition timing to its best torque point its firing the mixture at the most opportune time for the available cylinder pressure to do the most good - not just to suit emission or anti detonation requirements .

Bush/plate turbo bearings . Unfortunately a bit crude by todays standards and only still with us for costing reasons - arguably .

For a pair of bushes to support a shaft there needs to be a fair area in contact to do the job properly . The shaft actually floats on a layer of oil and its this oil shear drag that slows the rate of acceleration of the turbine/compressor group . The plate thrust bearing system also has the same problem only because its diametre is greater than the turbine shaft it has greater surface speed and they fail easily under highb shaft speeds and thrust loads .

Hardened steel ball bearings are a quantam leap because they have far less friction , only point contact between the balls and their races AND much much better thrust support . Annular contact BB's support radially and each support thrust loads in opposite directions so its all good .

The better BB turbo use open bladed light weight high speed wheels so less innertia to over come and are much more compact for similar gas flow rates than the old dinosaurs .

So if you've gone to a larger turbo with bush bearings its natural to expect it to be laggy all else being equal . I ah think a std RB25 turbo may have been a better first step given that they are reasonably cheap if you shop around and they bolt up with minor alterations .

Cheers A .

[luke20t]

i had a standard rb25 turbo on my rb20 and wasnt laggy at all

from memory made 14psi by about 3200

first thing, get it tuned.

maybe your BOV isnt workin properly too?