T28 Hiflow Boost problem

[macka]

My T28 has had both wheels replaced with hiflowed units and now i cant hold boost it creeps up and up till redline!

Do i need a stronger wastegate actuater? it already seems pretty strong

thanks

mac

[adam 32]

theres a guy on here, Joel, hes having the same problem with his 32 and there was something mentioned about an actuator spring. he might be able to help ya...

[macka]

Ta

I think i might of found out what it was,

the usual spring isnt strong enough but by jeez i can hardly move it!

That means i cant tune it until i get another actuator waaaaahaaa

When will it end!

[adam 32]

yeh, cars suck!

how much is an external wastegate out of interest? do they hold boost better? and why do they only put them on bigger turbos?

would this be an option for you or are they real expensive...

[MYGTST]

you can ad an external helper spring on the actuators arm

its backyar mechanic style but does the job till you can afford a better actuator if you like gimme a ring an ill show you how fit one and make it work properly without damage

also ita can be removed at any time to make the actator back to stock

[macka]

External wastegates are round the $1000 mark :confused: They would be heaps better but also have to adapt headers to suit them another $1000.

The wastegate is pretty tiny and alot of air has to force thru if i had a gt ballbearing turbo id put external on :uh-huh:

MYGTST I am thinking about this thanks for bringing it up do u think this is the problem or could my wastegate just be too small and exhaust air is still getting forced thru zorst as i am making more and more HP thru revrange?

[macka]

Actually........if i had more spring tension it would keep it closed more but i want more waste air to flow thru wastegate instead it is increasing boost from the wastegate not being big enough??

I wonder if a dump pipe will help flow thru wastegate?

[adam 32]

macka get a dump pipe anyway

if th spring is stronger it will just stop the boost from creeping up... it will hold the level more efficiently. there isnt a problem with the boost controller/solenoid is there...?

[turbomad]

By the sounds of it your wastegate is now too small for your turbo, to test it disconnect the arm from the actuator so your wastegate flap is basically free and open all the time, drive the car at full throttle, it will be laggy because the wastegate is fully open but when you get close to redline you will soon discover what your minimum boost level now is.

[macka]

Well ive tried boost controller and then intake pipe straight to wastegate and it still pushes 8psi-10 11 12 14.........by redline

but not all the time, Adam yesterday it was on 10psi solid and seemed to be working.

I think it is confirmed that wastegate is too small.. but im thinking if i get a dump pipe those waste gases coming from wastegate will have a smooth flow out instead of stock pipe setup and may be enough but this is happening even at such low boost........

I will try disconnecting actuator arm and see how goes cheers turbomad and adam

[meggala]

what size wheels did you get macka. hks make strong actuators.

thats what you looking for but ring the shop that built the turbo to check with them they might have a simple fix.

meggala

[macka]

How can it be the actuator if im gaining boost, air is escaping thru turbine cause wastgate is too small.

I cant pull my actuator its too strong or im too weak

[macka]

58mm comp wheel and t4 vtrim exhaust

[adam 32]

you could check the wheel sizes against other turbos to see what wastegate system theyre using i guess... i know in the GT series the 2835 is the first turbo to use an ex gate... is urs as big as this?

[meggala]

sounds like a very big turbo to me.

don't drive your car with the actuator disconnected.

I know it sounds silly but ahve you checked all your lines for leaks etc?

meggala

[turbomad]

Yeah do the dump pipe and see if you can die-grind the wastegate hole a little larger, you may need a larger flap if you go too big but I think there's enough cover to take a couple of mm off without modifying the flap.

meggala-you can drive with the actuator rod/arm disconnected, not the hose to the actuator though, anyway macka knows what I mean.

[macka]

Adam similar wheels to yours.........u been trying to pm me mate?

Meggs with actuator disconnected u get minimum boost because all exhaust air is trying to force out wastegate straight away..

Its just a t28 hiflowed..

Yeah yeah....Im grinding out wastegate hole as we speak i cant fit a dump on by weekend so will have to do for the moment and im gonna use the standard flap

Hope it works will let u know cause other ppl must have same problem

thanks guys

[adam 32]

well if youve got the same wheels as me, youll be flowing the same air? and if so need a similar wastegate....

but if the wasteagte is too small and not venting enough air, why is the boost creeping up? and why was it working on sudnay?

[turbomad]

If the exhaust gases can't flow through the wastegate then they must pass through the turbine wheel causing it to spin faster and therefore increase boost.

[macka]

Yay turbomad is alright i take back those things i said earlier about you :lol: :lol:

Chucky had day off today so i told him (nicely) to take turbo off and ex housing from turbo and mill out :-) he also ground away a small part of the dump and we put back together this arvo.....

walaaaaaaa boost controller throws boost straight to 10psi and holds..

Wind boost up to 12 psi and by 7000rpm i get 13 so it helped heaps and itl do until i get my dump pipe...but adam yes it is on the edge...

Now with reasonably steady boost can get it tuned before weekend and hopefully dyno reading as well