Twin Turbo surging noises?

[90TurboVan]

Strange TT noise - Video

Any ideas what would cause that? Twin mitsus on a 2.5 Neon head hybrid. It made the same noise with twin garretts, I thought it was surge so I went to the smaller mitsus. It does it with both wastegate actuators tied open or closed, but not if one is open and one is closed. My calculations show that the mitsus are to the right of the surge line with my engine/head, and DblTrbl had twin mitsus on an 8 valve. There is no boost leak, it isn't the BOV, and it does it from very low boost (<2psi) all the way up to the max, though increasing RPM's seems to make it go away.

[PistonPL]

Quote:

Originally Posted by 90TurboVan Strange TT noise - Video Any ideas what would cause that?

do U have any diagram how is it connected? maybe something is wrong on base level?

EX - exhaust from cylinders
T - turbine



?

one of ideas in second scenario:
one turbo spools faster, and makes vacum before other turbo so it can't spool up as it should. wires of ex gasses makes that noise.

eaven if U have separate connections (2cyl connected to each turbo, scenario 1) exhaust gasses can "suck" from the other side and make vacum for turbo that spools slower. could soud like in Your car.


scenario 1 is the only way and independent exhaust pipe for each turbo (or for test just let the exhaust flow directly form turbos)

generally i'm interested in this topic cause i'm in the middle of twin turbo application for 2.2 T2 Daytona but with turbos in the rear of the car, two throttle bodies etc.. just to see what will happen

[moparzrule]

+1 for pics/description of how you got the turbo's hooked up.

[shadetreeshop]

sound like someones hacksawing on a piece of pipe ?.

you shouldn't be in the surge area. exhaust energy has been halved .

[PistonPL]

Quote:

Originally Posted by moparzrule +1 for pics/description of how you got the turbo's hooked up.

is this q to me?

mine isn't hooked jet. place where normally speare tire lies have to be chopped off. this will probably weaken the construction so i'm waitng for cage installation first.

i will send photos wherewer it will work or not. i do it just for fun and i'm not really shure that will work at all.

[PistonPL]

Quote:

Originally Posted by shadetreeshop exhaust energy has been halved .

yes. that's true (maybe not halved but lowered for shure). but here is place for testing with hybid turbos.

and..
if You mount turbos in the back You can get rid off intercooler, cause long pipes with (i don't know exact word in eng) radiator-like mounted "wings" coming directly to TB are long enought to cool down compressed air.
also engine bay is cooler.

as i said before. it's a test.

[speeduphoria]

Finally have some progress

[PistonPL]

so:
turbos are ok cause U checked mistu and garret combination - effect is the same
bov is ok as U said
so there gotta be something in pressures generated by turbos. exhaust pipes are independent so problem is BEFORE turbo.


now, im wondering is it ok that You have connected exhaust from cyl1+4 and exhaust from 2+3.

in pairs they work together, but ie.: when 1st have ignition 4th is taking air.

maybe pressure of exhaust gasses from 1st cyl push a valve of 4th cyl valve?

just a suggestion.