boost problems

[reecegze]

Hey guys i own a 4agte ae86.. I recently change my t28 turbo to another rebuilt hiflow turbo.. Since ive put this on the car struggles to make boost in every gear.. 1st full boost @ 6000 2nd/3rd gear makes full boost @5200 So obviously its very laggy.. Ive made sure the actuator is fully closed and check for boost leaks/vaccum everything seems fine there.. The actuator i am using is the stock t28 turbo 7psi with a turbo tek MBC
I had no problems with the response time before with my stock t28 full boost @3800 rpm keeping in mind i didnt use the same actuator on this hiflow t28 as it wasnt long enuff.

So i am trying to find out why my engine is making power so late with this new turbo.. Could it be the actuator screwing up under boost?


Appreciate it guys

[1jz68u]

is the turbo making boost before this time? eg does the BOV go off or do you hear any compressor surge?

if the turbo is making boost at low RPM but the engine isn't seeing it that means problem after the turbo, if not it means a problem before.

not sure if it helps at all but will give you somewhere to start..

P.S. if you were the guy on the cruise last month with the white sprinter, i dont know that having the bent wastegate actuator arm will be helping.

HTH

[reecegze]

It is me but this is a totally different setup now.. New turbo and different actuator.. That worked fine now this turbo isnt boosting properly or it maybe to big for my motor causing it to laggy like a mofo ..But it seems its bleeding boost on low rpm and only making power on 5000rpm +++

thanks mate

[oldcorollas]

how was the turbo "high flowed"??
just by cutting out the turbine cover to allow more gas to flow thru without spinning the wheel? or does it have larger wheels inside?

maybe the turbo is just shit?

[fixeruperer]

^ yeh, throw that other turbo on (if its still in good order) and see how that goes.
at least you will know there and then if its before or after the turbo.

before you do that test your wastegate.

[30psi 4agte]

Is it a roller bearing turbo or a bush bearing?

if its a roller it shouldnt be that laggy. unless there is a compressor mis-match.

What size is the rear housing? this will play a big part in boost response.

[reecegze]

Its a bush bearing turbo.. it runs a machined front housing with slightly bigger wheel. The rear housing is a .64 but with a bigger turbine wheel with extra fin+ larger fine. Core is from a atr28ss Hypergear setup

specs are Comp wheel:
T3 super flow wheel
48.3 inducer, 60mm exducer, 12 fins 6long 6 short Trim 65


Turbine:
65mm TB34 11 fin turbine wheel,
Internals:

T04E 360 degree thrust bearing

[fixeruperer]

.64 isnt that small on the rear for a 1.6, what did the old turbo have .48 or smaller ?

[reecegze]

.64 also. Specs that have been changed

my new Comp wheel:
T3 super flow wheel
48.3 inducer, 60mm exducer, 12 fins 6long 6 short Trim 65

my old standard wheel:
T28 wheel
44.6 inducer, 60mm exducer, 12 fins 6long 6 short Trim 55

new Turbine:
65mm TB34 11 fin turbine wheel

my old turbine
53mm T28 10 fin Turbine wheel

Internals:
T04E 360 degree thrust bearing with 2 piece collar.

my old internals:
T25 270 degrees thrust bearing single collar

So you can see the new front wheel is slightly bigger, the internals are bigger to support boost and the rear housing is .64 still but with bigger turbine wheel with extra fins. What you think about it ? to laggy for a 1.6litre

[fixeruperer]

well i run a .64 (4a 16v) and i dont make full boost till about 5500ish and it comes on about 4400ish, i cant remember the other specs of the turbo.

from 3800 to 5200 is a big jump but 12mm oversize on the turbine is decent to tho i dont know if it would make that big of a differance on lag, have you asked the turbo builder ?

[30psi 4agte]

it does seem a bit laggy. Full boost by 5000-5500 is pretty std though for the 4a and a decent turbo.

A .64 housing is pretty much spot i recon. I was running a .84 on mine with the 3540 but have switched to a .63.
FWIW i see full boost around 5500 rpm.

What sort of exhaust and dump pipe do you have? A decent / non restrictive dump..... one that has the wastegate intergrated into the exhaust can give a more response boost climb.
If things are too clagged up that will slow the turbo down.

What size exhaust are you using? are you running a cat converter? is it blocked?

[reecegze]

exhaust is 3inch free flowing .. The other turbo was fine when i mean full boost i mean only 10psi!!! turbo builder rekons i should get full boost by 4000rpm.. And rekons i need a stronger actuator spring/arm

[30psi 4agte]

well the actuator could be the issue...... so id sort that first. Can you cut it and shorten it to get more tension on it.

Even put a thread on it so you can wind some tension on it.
Similar to this......... i just cut the actuator rod and cut a thread on it. then used it to wind more spring tension into it.

[reecegze]

i just tested my actuator on my turbo.. It opens at 6psi to vent.. bellow seems fine. I took my car for a drive with MBC disconnected full boost of 6psi @ 5200 its makes around 3-4 psi @4500. My intercooler pipes arent leaking, It was running fine with my old t28 turbo with blown seals.. only thing that has change from the old t28 to the hiflow t28 is the actuator as the old one wouldnt reach.

[fixeruperer]

if the rod didnt reach the gate, you could thread it like 30psi said and make an adjustable rod.