on full boost my T2 makes a fluttery noise running 14psi, boost gauge bounces about abit to when this happens. am thinking theres a leak on the boost hose's somewhere, failing that what else could it be? accuator? ive had the turbo rebuilt and its only done 600mile and just started doing it. theres no play in it and its not smoking. if u slowly accelerate it doesnt always do it.
any advice would be grate please.
ben
Originally Posted by bennyboy
ben its nomal mate its the accuator mate not anything to worry about
really? it never use to do it with my standard turbo?, i have a spare actuator would it be worth trying it? or am i just worrying over nothing?
Does it happen when you let off the accelerator?
And are you running without a dump valve?
If both of these are a yes, then it's perfectly normal
Nothing wrong with it... Always more audible when using a different air filter.
Put a dump valve on, if you prefer.
A good explanation;
http://www.google.co.uk/url?sa=t&sou...utoKsvHCxf7uTw
Compressor surge is a phenomenon experienced when boost pressure inside the intake tract builds up and has no convenient relief method. This is usually caused from the throttle plate closing quickly. Changing load conditions (off throttle) resulting in varying amounts of exhaust gas can also simulate such conditions.
In such a case, the pressure takes the only way out through the turbocharger compressor housing. The unique sound is caused by the pressure charge encountering the spinning compressor wheel on its escape from the engine.
Compressor surge goes by many other names such as compressor stall, turbo dose or dosing, pigeon, turbo flutter/chatter and sometimes mistakenly wastegate chatter.
But is it harmfull to turbo's ???
Short answer is no. Long answer is maybe.
http://www.google.co.uk/search?q=com...iw=981&bih=633
i love the way people give useless advice on the internet.
sorry i should be more specific lol.... i meant from the first few results on gordons google search. Its painfull to read.
does anyone have a boost gauge fitted before the throttle blade? can they see what sort of pressures are created from this surging? my opinion on no dv is perhaps the sudden increase in boost pressure on the compressor side and a loss in pressure on the exhaust side could cause the shaft to skew and perhaps be more likely to touch bearing surfaces??
yes i have a gay valve on, not through choice though, was told it would help my turbo last longer, (that old wifes tale again) it does it with or with out the GV on and the noise only happens while onboost not when you lift off, with the GV off the noise when you lift off sounds sweeeeeet! its just this fluttery noise on boost thats bugging me, use to get a nice woooooosh on boost now its fluttery. gonna try a pressure test on my boost pipes tonight and maybe a different actuator, is there any way of testing the actuator? would it be worth a try with the filter off? i know its not the done thing but would eliminate it.
cheers ben
You can test the actuator with an old tyre valve. I used one from an old bmx inner tube.
Push it over the end of the actuator port and pump it up and see what pressure it opens at and if it holds the pressure.
Or simply take the hose off the other end and blow down it to see if it's broken.
Are you sure the noise on boost isn't det/pinking?? have you turned up the boost when fitting the new turbo?
yes ive turned the boost up, a little bit. whats det/pinking?
It's basically the ignition of the fuel/air mix by the spark plug isn't optimum... You're running too much boost/advance for the amount of fuel thats being squirted in.
You know the GT's "bad reputation" of blowing head gaskets... well thats because of excessive pinking/detonation. The head gasket is the engine's fuse, and is (normally) the first thing to let go.
Pinking sounds like dropping a bag of marbles on the floor.
The GT does have a knock sensor linked to the AEI, but isn't worth piss.
I'd get a AFR gauge in there first, before you tinker with the boost/fuel too much.
Further reading.
http://en.wikipedia.org/wiki/Engine_knocking
what pressure are you running? what carb mods, any ignition advance/retard and do you have an afr gauge if so what are the readings on boost?
yeah got a afr gauge, its in the 12s when on boost, but running abit rich when just driving about another problem i need to sort out, the only thing ive altered in the carb is the main jet size (1.5mm) cos it was running lean on boost and i wanted to run more boost, i found out later i should of altered the second stage jet 1st, (hence running rich when driving about) could this be related to my problem?
tonight i did a pressure test on my boost pipes while it was all connected, dump valve was leaking so binned that and put a bung in, the 2 pipe outlets were leaking on carb top so locktighted them in, then the accelerator pump was leaking, took the carb to bits cleaned all the jets out, the diaphragm in the accelerator pump doesnt seem to be ripped or damaged?
am i right in saying when doing a pressure test it should hold pressure?
got it all back together and did a road test with out the GV, it still flutters at 14psi but if you hold longer than i have been doing it creaps round to 18/20psi.
actuator seems ok and holds pressure.
this is starting to do my head in!!!!!!!!
how are you controlling your boost pressure? what actuator do you have and what pipework to it? 1.5 main jet will fuel pretty poorly off boost and isnt the way forward. i'd go back to the standard main jet and drill the 2nd stage out
just a standard actuator with 1 pipe off the front outlet to the carb top, boost is controlled by actuator arm, did have a adjuster in that pipe but removed it to eliminate it. i have a spare standard main jet to put back in, what size hole should i drill in the second jet? i noticed it looks likes the hole is stepped inside the second jet will this effect anything when i drill it out?
i personally would try 1.2-1.3 2nd stage at first depends what boost your running, what spec turbo do you have?
its at 14 atm but i want about 18psi, its a T2 just had it rebuilt with 360 bearing.
I removed my DV after doing this test. I did a pressure test on my boost circuit to find my 3 DV's leaking only to find that the will not seal unless = pressure is applied to both sides of the DV. I now run a DV again.
1.4 should be good for around 18psi with a standard main jet. 18psi is quite alot to run from a t2 turbo, i think if you need your jets to be that big to fuel correctly you need to look at a few other things first, sounds like you may have a fuel supply issue, theres a little filter in carb where the fuel enters, theres also your main fuel filter, check fuel pipes for kinks and or small pipe joins, check your fuel regulator is working, check your fuel pump is up to the job, and its supply voltage is good. Also check your exhaust system for any signs of gasses blowing, any leak in your system will allow oxygen in to be measured this will also give you a lean reading when potentially your engine could be running rich. check your gauge is callibrated too if possible.
thanks for that mate, i'll probably be putting mine back on but id prefere to leave it off!
thanks tony i will have another play tomo night or at the weekend, and let you know if the problem is sorted!
sorry kinda going off topic alittle, the fluttering sound could be caused by a few things, do you have a choke flap? if so make sure its fully open when its off. check actuator piping is secure
The pipe to the acceleratop pump on the carb always leaks. Just disconnect the pipe and block it off at the t-piece, makes no difference
Get a vid of the noise if possible, its a bit of a needle in a haystack situation without hearing it.
right tried to do a video yesterday, wasnt a great success theres that much incar noise you can hardly hear it.
heres a list of things ive tried so far,
pressure tested all boost pipes and intercooler
tested actuator
cleaned out and rejetted my carb so its AFR is running right
removed boost adjuster
tried a new boost gauge
blanked off accelerator pump pipe
none of these made any difference,
i then took my air filter off soaked it in brake cleaner and blew it out with an airline,which made the flutter not as bad, when i did my engine rebuild i fitted a big FMIC???
I also fitted a big jim down pipe with a home made side exit exhaust with a cherry bomb in the middle. im starting to think theres not enough back pressure??????
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