hks ext. wastegate probs

[supra -steve666]

hello, this isnt on a supra but im pretty sure it doesnt make a diffrence what car its on for this problem, so hopfully sum1 on here can help.

my bro has just had a custom exhaust manifold and hks 40mm ext. wastegate put on his r5 gtt, the ext. wastegate has 2 outlets, top port is put to vaccum, bottom port is to boost.

it wont boost more than 1 bar tho, its runnin manual incar boost controller at the mo (hasnt had time to get the apexi avc-r hooked up yet) but no matter how far we unscrew it (we have even taken it rite out) it wont boost any more than the 1 bar.

thought it mite be down to the in-car boost controller being dodgy, so we disconected this and tryd a under bonnet bleed valve, kept unwindin this until its total out again and still no more boost.

any ideas on what the problem is cos have tryed everything we can think of and are gettin no where at the mo

now i know this isnt the forum for this car but the r5's dont run the ext. wastegate so knowledge of them on there site is very minimal, so if any1 can help with this please do post up, need this car sorted for next weekend as were hoping to go to pod with it.

many thanks steve ;)

[RobSheffield]

What spring is in the wastegate?

[supra -steve666]

we think its the 0.65 bar spring but we are unsure as the ext wastegate was brought 2nd hand

[michel lane]

Does it boost at all ?? and what does it get to before it reaches peak boost ??... If it does boost , can you hear the wastegate opening??.

[supra -steve666]

yeah it builds boost up to 1 bar, its laggy to get there aswell, but it is a new turbo so not sure if the lag is down to that tbh, its got a 2.5" turbo back side exit with no boxs what so ever so its hard to hear anything above that tbh, but there is some exhaust soot in the screamer pipe but it is very very little

[supra -steve666]

could this b down to the spring? is there a way of stoppin the spring/wastegate openin using a manual boost controller or does it have to be a eletrical boost controller as in the apexi avc-r? i no they should just both do the same thing but its just an idea

[n boost]

Hello mate,

It sounds like u may have a boost leak. I would do a pressue test and check vacuum hoses for leaks.
I had similar problems, turned out to be the bov leaking and loosing boost.

[supra -steve666]

weve checked and double but will check again 2moro on the boost system, nothin seems to be a problem on that front, we dont have any bov or dump valves on the system so they cant be a problem, been out testin it again 2nite and tryin different stuff but still no change, boost is very very slow building up aswell

[michel lane]

What size spring is in the wastegate ??. Is it a V band ??or a 4 bolt design ?.. I would turn the boost controller off then take it for a blast , see when it opens. then put the boost controller back on and set it to .2bar increase and see if it hits that figure. If it gets there but starts loosing boost , then you have a boost leak . Look at the turbo housing , make sure its flush and sealed correctly . Is the turbo a totally different turbo to what you have been using ??

[supra -steve666]

yeah its a brand new gt28 so should spool very nicly, completly different to what we had b4, we had boost of 1.5bar on the last turbo, only things weve changed is goin to the ext. wastegate with screamer pipe and the turbo, the spring is a .9bar we tink (it was brought 2nd hand), its a hks standard series 4 bolt design, not runnin the avc-r yet just on the manual controller till we get this boost sorted, weve taken to boost controller out and get 1 bar, we put it in and turn it out (so to increase boost) and no change what so ever, as said before its a very very slow build up of boost to 1 bar and it 5th doesnt even make it 0.5bar flat to the floor ?