Wastegate not working

pdtaylor18 · August 19, 2009, 10:18:10 AM

Well I have a HKS Ext wastegate, has to be about a 46mm or bigger but need to measure it up. I have not been able to get this working either via a boost controller or even on spring pressure. My source for the boost is directly of the turbo. I have taken the wastegate apart to check on the diaphragm and thats all ok and the spindle moves very freely. The spring is a yellow one.
The whole setup is 2nd hand with the wastegate, HKS manifold and downpipe and mated with a Garret TO4E turbo. The turbo does have little shaft play side to side and does have maybe 0.5mm in and out play which i am not too happy with. Strangly I can not get the dump valve to work either and that was working on my old setup.
When the car is running it revs as it should and I do get good vac on gauge but do not get a lot of boost when its on load although I am loathed to give it much more until i get the fuelling and map sorted. Its ECU is a FC specific Apexi PFC and I do have datalogit.

So is it simply the turbo not producing enough air? it did blow of one of my hoses due to a loose clamp so i know it has something there. The pipe runs are quite long but this is a big turbo and at present running stock injectors on the PFC to get it all running before I start changing things to suit.
Is the spring too strong? I have little history on the turbo but too be honest I got my monies worth from the manifold and wastegate alone. part number on turbo is P/n - 17200-132100

Why is my dump valve not working despite a good vac souce, is this related.
Could it be that the turbo is just too big? It came off a FC in Japan but no idea on that setup. Just dont want to run it anymore until i can get at least the dump working as I dont want to blow turbo or engine. I did get compressor surge when you rev it from standstill when I let off the gas, an indication to me of the dump not working.

any help much appreciated.

BlitzBoy · August 19, 2009, 10:27:12 AM

What makes you say the wastegate is not working? the wastegate spring maybe is a 10 psi or 14 psi spring, It will only starts to open when it gets near its spring rating, what boost have you run it up to?

pdtaylor18 · August 19, 2009, 10:34:04 AM

Thats just it I have not really run up to much boost and having had a good read of what i have stated and advice from others its maybe the fact that I have not even reached its spring open rate yet and I am worrying over nothing. I think it was compounded by the fact that my dump does not work either and I started to get a few alarm bells ringing. I have not really driven the car as it should yet and this was just a few trial runs up the road, I just would have thought I would get something from the wastegate,especially as its a screamer pipe during gear changes.

BlitzBoy · August 19, 2009, 10:40:18 AM

no you wont get anything from the wastegate until you get near the spring rating then it will open, so worry over nothing dude. Just run with the boost controller off for the time being and map those cells you hit, it will open when you near 10 psi, I seem to remember the yellow spring being the 10 psi one but not sure

In regards to the dump valve it wont destroy your turbo if its not working, you just get the turbo surge, one camp say it will break the shaft over time with the constant surging between gears and the other camp says it doesnt, it all depends if it is a big shaft turbo or small IMO.

pdtaylor18 · August 19, 2009, 10:43:14 AM

pics to show what it is and its size in the engine bay.

pdtaylor18 · August 19, 2009, 10:54:22 AM

As a matter of interest just how important is the siting of the dump valve? I know theres a lot of talk on how far it should be, mine is where I have the space and thats near the FMIC which on my car is almost behind the rad and not right at the front.

Thanks for your imput Blitzboy, very much appreciated.

Prof · August 19, 2009, 11:35:03 AM

I\'m with Blitzboy on this one - probably not making enough boost to open the gate.

As for the dump valve - there probably is an optimum place to site it, ideally after the intecooler and as close the throttle body as you can get it - as that\'s where the backwash will come from when the throttle shuts, but if you\'ve a long vac line to the dump valve, it\'s going to take a finite amount of time for the vac in the engine to pull through the line.

BlitzBoy · August 19, 2009, 11:55:43 AM

I would say just after the intercooler myself for a dump valve

pdtaylor18 · August 19, 2009, 12:30:27 PM

Think I will resite the dump and shorten the hose to it!! think its just too long a run for it as you said Dave.

hashiriya · August 19, 2009, 05:57:09 PM

FYI, The wastegate i\'m sure is an HKS special or special racing wastegate. The yellow spring setting is quoted by HKS as 78.5~107.9kPa (0.8~1.1kg/cmÂ²)

If you are not hitting those pressures, the others above are right in saying that the gate won\'t open.

pdtaylor18 · August 19, 2009, 08:42:12 PM

Thanks for the info on the spring rate.
I have now re-installed the wastegate after taken it apart and that now works fine, must have been a stuck as it works now between the shifts when it did not before.(and a bit more right foot!!) I have also repositioned the dump valve closer to the TB and hence a shorter vac line to it by about 2 feet!!! that now works just as it should.
Thanks for all the help.

Wastegate not working

hashiriya