SR20det boost problem

[kassed33]

i have a S14 sr20det w/ a garrett 2871r .64 AR, apexi safc and avc-r, Z32 maf, and RS enthalpy ecu tune. I have had it dyno tuned. But when i am on the highway and i get on the throttle, it will boost over the set boost in the AVCR, regarless of how i set up the config(wither its a higher boost level and a low duty or viseversa) and not only does it go over the set boost but it dosnt hold a steady level. It will boost to say 1bar then drop to .7 then up to 1.2 then down to .8, all while my foot is steady on the pedal. Can't figure it out! Any and all help i can get would be great!

[DrifterProdigy85]

Does the car boost fine with the AVCR at the OFF setting? What are your boost setting for A and B? How i have mine is the Wastegate is set at 1 Bar (fully tightened). The A setting is 1.3 Bar which is 53-55% Duty Cycle. The B setting is 1.15 Bar which is 43-45% Duty Cycle. Im sure your settings will differ from mine but there just an example.

Im sure your aware of how the AVCR works but ill go over it just so everyone knows. You set the Desire Boost to whatever you want to achieve then adjust the Duty Cycle for the boost to reach the Desired Boost. Once the Desired Boost and Duty Cycle correspond with each other then it goes into a learning mode wich automatically calculates the Duty Settings for each NE Point (RPM Point) you have set. Ive found that if you set the Duty higher then the Desired Boost, it will go into a safety mode by trying to cut boost down to where it should be set at which shows you need to lower the Duty Cycle.

[kassed33]

i'm not sure what it does with it off, i havnt tried. For B i believe it is set at .8 and the duty at around 65% and it boosts up to about 1.2 and fluxuates. And at A it is set at 1.7bar at max duty, i didn't dyno tune the car on low boost just on HI. And in order to get the boost up to the 1.7 and the HP to where i wanted it i had to crank up the duty all the way, it makes me think that i may have a boost leak somewhere but i def can't hear it even when i tried looking for one.

oh and it dynoed at 348whp, 325tq @25psi ish

[DrifterProdigy85]

Whats the Actuator pressure set at? If your running 25psi then you should have the Actuator fully tightened so the boost controller has an easier time holding the wastegate shut. Youve got some really low numbers for 25psi on that turbo. I got 353whp @ 15psi with a cracked manifold. Also FYI, the 2871R is past its effeciency range at 21psi. No need to boost the piss out of it if its not gonna make extra power.

[GSXRJJordan]

I agree with Prodigy, you're going overboard with >20psi, especially with the .64 hot side - the .86 breathes a bit better on the top end. As far as your boost problem, it sounds like your wastegate should be tightened almost all the way (tight enough for your .8 low boost setting), but it's still going to have a hard time holding 20psi, not to mention 25.

[kassed33]

thanks, it was the wastegate, the screw was pretty much all the way loose, it must have moved from vibration from where i had orginally set it. But as for the dyno #'s it might be low for that boost but not for that turbo, typical output is 340whp ish at around 18psi, this is my dyno sheet while it did take a high duty cycle to get the #'s because the wastegate was opened the turbo continued to make power all the way till 6000rpms at the 1.7bar, and should make a bit more than the 348whp with it now set correctly i would guess around the 360 range, and hopefull with out blowing my head gasket.

[DrifterProdigy85]

What cams and intake manifold are you? Asking cause your dropping alot of torque after 5700rpm. With decent cams and stock intake manifold, the 2871R .64 is capable of 360-370whp @ 19psi. Just trying to help your setup out some to get more power.

[kassed33]

i have stock cams and stock manifold, yea i was thinking of doing cams, metal headgasket and manifold, but i dont have the cash right now and i wasn't sure how much power they would give me cause i know that cams don't really give much power on small displacement engines like they do on large ones. But 370whp sounds pretty damn good, hey my goal with the car was 350 and keep it reliable for a daily driver, so any more i can get is great, thanks for the help!

[kassed33]

i was thinking 264's do you know how they are for daily driving? i dont wan't a shitty idle that i cant stop at a red light with out it stalling you know, so i know i dont want to go 272's

[s13gold]

if ur just dd and once in a while track car, go with 264's but if u want a monster u gotta go with the higher lift.