Wastegate problems (50mm KKK) Plz help..

[Mulisha]

hi guys

I just replaced my clutch in my car becuase i thought my clutch was farked becuase when i went to change gears at 2500rpm and push the clutch in it would just rev the engine..

I now have found out after spending $800 on a new clucth (needed a new one anyway) but my wastegate or something is playing up.

This is what happens i'll try explain best i can..

Take off in drive throw the gears rev to 2000rpm or so quite easy on everything then get into 3rd and bring up the revs and when u get to say 2800 and go to change gears the car will just rev heaps high and clucth will make a scrtaching noise and seems like the car doesn't respond when u take the foot off the pedal to change gears and just keeps reving for a bit like 2 seconds or so while u need to change gears..

Also when ur doing say 100 and put ya foot down to take off again when u get boost up etc and take ya foot off the car seems to keep acclerating for a second or two and then stop..


What do u all reakon i'm going to go for another drive now and see what happens when i test something out and i'll let u know..

Thanks alot in advance

Rick.

[Mulisha]

Went for a quick run to try a few things out !

I got in 3rd and wound it up under for throttle to 4000rpm (redline) and my brother watched my boost hit between 17 or 20 psi it was tunned on the dyno 12 days ago and maxed 14.4psi and was tunned to that.

When u drive up to 4000rpm and back off it will keep driving for about 1 second then it will back off and BOV will go off etc..


What do i do???

My Wastegate has 2 fittings one on the side of which is what i use know and one on top/ on bottom of it that just sits there.

Have i farked my engine from doing a few runs to 20psi when tunned for only 14.4?

Thanks for any help

Rick.

[PGS 4WD]

The reason for the revs hanging is probably the gasresearch carby, it gets technical but the low pressure area at the leading edge of the butterfly blade is so strong it holds the throttle open, you need a big fat secondary return spring, all gasresearch carbies do this under higher boost, this is also going to give your clutch a flogging as even though you are coming off the throttle, the throttle isnt actually coming back, you may find it is even light under foot on the pedal.
It wouldn't necessarily do this on the dyno as you dont generally change gears on the dyno under load, the power run is done in one gear.
If you don't have an increase in blow by, a rough idle, smoke from the exhaust then you are hopefully still good. Wouldnt do it often though as it will be lean without sufficient fuel supply and the hot/lean mixtures can weaken the piston(they go soft) and holes in the crowns result.

Joel

[Mulisha]

The reason for the revs hanging is probably the gasresearch carby, it gets technical but the low pressure area at the leading edge of the butterfly blade is so strong it holds the throttle open, you need a big fat secondary return spring, all gasresearch carbies do this under higher boost, this is also going to give your clutch a flogging as even though you are coming off the throttle, the throttle isnt actually coming back, you may find it is even light under foot on the pedal.
It wouldn't necessarily do this on the dyno as you dont generally change gears on the dyno under load, the power run is done in one gear.
If you don't have an increase in blow by, a rough idle, smoke from the exhaust then you are hopefully still good. Wouldnt do it often though as it will be lean without sufficient fuel supply and the hot/lean mixtures can weaken the piston(they go soft) and holes in the crowns result.

Joel

Thanks alot mate

I still don't know why the wastegate isn't working unless my boost gauge is faulty or something..

I'm going to have to ring around today...

I hope i haven't stuffed the clutch it's only like 20hrs old and i don't change gears now while it still reving/throttle it's self..

Thanks again

Rick.

[GRINCH]

take it back to chapmans, it should never have left there workshop running like that. they normally road test cars after i dyno run

[PGS 4WD]

I suspect there is no fault with the wastegate, when you change gears without throttle off the revs spike and the boost maintains boost at max speed-say 5000 rpm for example. When you attempt to slow the RPM to 3500 rpm when you disengage the clutch in the next gear the turbo is producing enough volume to fill the engine at 5000 rpm at the set boost, when you suddenly try to reduce the volume of air down to what is required for 3500 RPM there is an overboost until the volume of air in the intake has been consumed (it is consumed at a lower rate due to the lower engine RPM) and the turbo has to decelerate to the lower speed which take some time therefore you have an overboost.
Normally the excess air/pressure is dissapated through the BOV which activates due to engine vacuum, your BOV wont open until the throttle closes significantly, at the moment with your throttle hanging open this won't happen.
This is also giving the clutch the flogging of its life as they aren't meant to engage under full power, what you hear is the clutch slipping and protesting .
Joel

[bogged]

with all the issues you have had with this thing, and are still continuing to have, you should drop it off somewhere and have it fixed once and for all - or just fuck it off and buy a V8 GQ already setup and sorted - there comes a time when you have to figure out that its not worth throwing good money at things anymore..

YMMV

[shakes]

I still don't know why the wastegate isn't working unless my boost gauge is faulty or something..

I'm going to have to ring around today...

In one of my first posts too you I told you to read around on ricer forums tech articles on how turbo's work.

Re-read PGS 4WD's posts, spend an hour on google understanding what he is saying. THEN come and ask a question.

And I hope you havent glazed up your nice new clutch from not listening to OL advice

[Mulisha]

Thanks alot guys

Cheers Shakes once again

Thanks PGS i hav solved all the probs at this stage and going well !

Bogged i'm happy with it just ironing out all the probs..


When boost said 20psi on my gauge it was wrong and really it was making 14.7psi (MAX).. they tested it on the dyno this afternoon.

My other problem is that the throttle wasn't shutting off he put a spring on that thing my throttle cable goes on ..

So now i'm happy everything is done and sorted and very happy with it now.


If i was to do all this again i would do alot of things different like find 1 shop to supply everything and fit it all not buy bits from vic and get people to fit bits and then i fit bits and so on..

Other then that i'm happy as now for the sake of $20 for a quick dyno run and test drive and a spring made everything better and made me feel better it was all right.

Do you know what 5L and 5.7L V8's make power wise in patrols ?

Thanks

Rick.

[HotFourOk]

Do you know what 5L and 5.7L V8's make power wise in patrols ?

My old boys Holden 5L VS has a mild cam, head shaved, exhaust, etc and makes 250Hp at the treads... could expect the same in a Patrol without spending much cash.
Then again, my old mechanic has a 5L in a GQ with ~800Hp

[cutzook]

mate. not sure if its resolved yet, but give george may a call. he is in kunda park. he is by far the clueist person i have ever met. and i have never seen someone tune a car by ear and be so on the spot in my life. absolute wizz.


cheers joel


i am not sure about the spelling of his last name, so if you cant find in phone book dont give up. he is there somewhere. i can get his number tomorrow for you if you want.

[Mulisha]

Cheers guys

Yeah mate i'll grab the number off u if i do have to sort something out in the future..

Rick.

[PGS 4WD]

Out of interest that wobble in the power graph at high RPM is likely to be valve float, need springs.

Joel

[bogged]

Do you know what 5L and 5.7L V8's make power wise in patrols ?

pretty much the same as you have with 293239048th the problems.

and PGS means you need new valve springs.

[Zac Zec]

If set up right would make alot more torque than a 5L

[GRINCH]

Do you know what 5L and 5.7L V8's make power wise in patrols ?

pretty much the same as you have with 293239048th the problems.

and PGS means you need new valve springs.

if your lucky it will go in that easy, any horsepower upgrade is going to come with problems