Just wondering what A/R ratio for the turbine housing the turbo guys are running on their single setups.

I have a .85 and am having backpressure issues. It is a precision turbo and they only offer a .85 housing as their largest one. Limit engineering doesn't carry any, and Turbonetics was less than a help on the phone. I would like a 1.10 ratio or so, and turbonetics tech was trying to get me to go with a .69 tangential while i have an on center housing. I don't want to have to change my whole system for a tangential housing.

I was just curious how everyone's housing compares to mine.

Anyone know where else to get a housing? Precision said if i got one they could see if it will fit (they couldn't varify which q-trim wheel i have) and if not they would have to machine it to work, and it wouldn't be a quick process.

Thanks

Bill

 

i am runnin a .98.

what kinda back pressure issues? I have seen cars easily in the 1:2 ratio, (50psi of exhaust for 25 intake). I dont consider that TOO bad.

just gotta have cam timing and stuff right.

 

I don't know an exact number yet, but it is high enough to push open the wastegate all by itself limiting boost to 16 psi. I just made up an adapter to fit on my AIR fitting on the Pass. side header, i will find out for sure exactly how much. Cam timing should be right, it was a purpose built turbo cam made by GTP.

 

Hey, I noticed you're using a deltagate. Are both lines going to it supposed to be hooked up to vacuum? I've got a turbotech setup, and I'm not sure what to do with the top line(currently it's blocked off).

 

bill........all i gotta say is damn...........after reading your site.......my car trouble doesnt seem half as bad.

 

what 'pressure' is the spring set for?


if its set for say 5 psi, then you can only see a pressure delta of 5psi before it will let exhaust through.

take the vacuum line running to the waste gate off, and go see how much boost you see(peak) thats what the spring is.

 

The vacuum line is off (it broke) and all it makes is 16 psi. I have the 9-13 psi spring in the racegate, thats as high as turbonetics makes. I screwed the adjustment screw in all the way to squeek a few more psi out of it. But I would assume that the wastegate as a pnuematic actuator would need the boost signal to operate properly. The boost signal needs to exert pressure on the diaphram of the wastegate and when that pressure exceeds the spring pressure the wastegate opens and releaves exhaust manifold pressure. I understand that the valve itself can be acted on by the manifold pressure and if it would be high enough it could open the wastegate but the valve itself has a much smaller area than the wastegate diaphram so more pressure would be required to make the same force to open the wastegate, thats when overboost can occur. I was under the impression that breaking the wastegate boost source was a bad thing, which it can be, but mine like i said is being limited to 16 psi.

I am no longer running the delta gate, after i switched to the 3" downpipe i needed to switch to the Racegate due to boost creep.

96TurboTA,

The top port you are refering to can actually be used to rig up a variable boost controller. By using a pressure regulator tied to the boost source you can run back pressure on the spring side of the wastegate, thus making the turbo make more pressure to overcome spring force to open the wastegate. I had one a while back and may hook one up again in the future. I had a little 0-10 psi regulator, so i could adjust the boost approximately +10 psi over what the spring was rated for.

Jordan,

Are you saying that if I put my 3 psi or 7 psi spring back in the wastegate and took off the boost line that I would only make those pressures? I wasn't aware of that.

Thanks for the input.

Bill

 

I'm using a .96 A/R.

 

thanks for the help Bill.

 

smoke-
yea, it sounds like you need to get a boost controller back on it!

get some pressure on the top of the waste gate..