Old Turbo (TA61)

[ttipe]

At about 10 psi my turbo (TA61) starts to "howl" like a car with a ported blower.I checked for any stupid stuff like a failing bearing,journal or a belt.I have been meticulously working on taking inefficiency out of the induction system,exhaust system and turbo.I had the car out the other night and it pulled hard for 10 psi boost.I have no numbers yet but I'm just wondering if someone else has seen this as well.The car has all the equipment to tap the tens (ie;ported heads & intake,ported exh manifs,PTE slic,60#s,denso 280,alky,TT,etc).Your comments are greatly appreciated.

[SuperSix]

Only thing I can think is that it may have to do with the ported exhaust manifolds causing the roar..

[Steve Wood]

The TA61 was one of the early variations.  IF, I recall correctly, it had a tendency to have some compressor surge down low.  Does it feel like it is slowing down slightly when the noise starts, or is it worse at part throttle boost than at wot?

[ttipe]

I'm wondering if the new filter (Amsoil 9x4 cone,radiused neck and inverted cone in the end) is allowing noise that most don't hear since they are running a K & N.From a fluid mechanics standpoint it will allow a greater laminar flow crossection through the neck of the filter due to the radiused neck to cone.The filter surface area is greater than the K & N due to the inverted cone in the end of the filter.I was testing out on the freeway (really playing since I have no data) coming home from Woodward and I have never seen the car run like that at low boost.I have not got any time into the tune and yet it ran great for 10 to 12 psi on pump gas and alky.The turbo has serious work internally and to my knowledge the TA61 which I have has never surged.     

[SuperSix]

Do you have a K&N to swap? (Maybe a stupid question)

[Steve Wood]

I am running a similar design on one of my cars...I think it does allow a bit more sound just as the K&N does over the stock enclosed filter

[ttipe]

Thanks for the inputs.I'm going to keep running a TA61 because I'm trying to have streetability and a bit of punch at the same time.I'm thinking about converting to speed density to minimize lag and improve airflow efficiency.I'd like to tap the 10's at 25psi which is a lofty goal.I have other irons in the fire but I'm not sure whether they are worth mentioning. 

[Steve Wood]

The 61 is barely enuf to get into the tens if there is a good synergy between the parts.   Some of the newer turbos spool a lot better than the older ones did at comparable sizes, but, they are not cheap.  A BB 66 will work very well and be very streetable without undue lag.  Takes about a 3000 stall, ideally.  Sometimes you can find them at a relatively reasonable price.

It helps to have a number of irons in the fire because sometimes you just have to walk away from one in order to avoid mayhem