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Ive got a gcg highflow ball bearing turbo on an rb20 I have 3 inch full exhaust, fmic, its running 10psi. It just starts making boost around 4000rpm and reaches full boost around 4500rpm. Was just wondering if this is normal for this setup or is there something I can do to change this

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Ive got a gcg highflow ball bearing turbo on an rb20 I have 3 inch full exhaust, fmic, its running 10psi. It just starts making boost around 4000rpm and reaches full boost around 4500rpm. Was just wondering if this is normal for this setup or is there something I can do to change this

Check that you have enough preload on the actuator.

How could I check the preload on the actuator?

And its a standard ecu

Move the push rod on the flapper or remove it and make sure there is sufficient effort to get it back on.

Also, is it a bush bearing highflow Or ball bearing?

if it has an adjustable turnbuckle on the waste gate adjust it in ( smaller in length) by half a turn and go for a test drive and repeat

could also be bad cam gear timing ifs its been touched recently

Edited by Dan_J

its a highflow rb25 turbo so bigger twice over than a standard rb20 turbo, I'd expect it to come on around then

winding up the actuator with stock ecu is a very bad idea as it will raise boost once

the correct pre load is reached

if you do it drive very carefully and watch your boost gauge

as soon as it starts to run more boost wind it off half a turn till you tune it

Edited by 1400r

i used to make 10psi at 4k with a s2 r33 front/ 0p6 rear trubo on the rb20 with the stock smic

for the gears, just confirm so its not a tooth or 2 off, the dot on the gears should match up with the cam gear cover backing markings

double check cas timing

stuffed cat?

if its just turbo lag you can get adjustable cams , retard exhaust and advance intake

shorten cooler piping

tune

A photo of the turbine wheel would be good. I've had few of their high flowed units came in for service, they were carried out using factory bearing housing, with cropped TA34 turbine wheels. if that is what you've got in your Rb20det high flowed turbo then yes it will be laggy, how ever it should be ok top end wise.

turbocharger configuration for Rb20det needs to be treated as a Sr20det, Turbine wheel to any thing above the size of a 2530 will feel laggy.

^^ im sure you would lol. The most fun to drive rb20 i've ever been in had a standard turbo , it was rather stripped of anything that wasn't necessary . People place too much emphasis on bigger turbos and expensive things to make their car faster , without doing the easy free stuff first! . I remember an interview with the late peter Brock and listening to him explain how he took like 30kg out of his Torana just by shaving all the excess off every bolt on his car ... My point being , that turbo has probably made your car slower over all , what hyper gear said about rb20 being similar to Sr is somewhat true , for street duties i don't think you would find much better than a 2871r or high flowed std 20 turbo .

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