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Discussion Starter #1 (Edited)
Hey guys, I wasnt sure where I should post this but figured this was the best place. What is the lag difference going from an 81 to a 96 on the same turbo. Also is there any difference b/w a 96 and a 1.00? Im guessing not since the 1.00 is only bigger due to the division.
Im going to be running 32psi max on a 76mm turbo. Would I benefit from the bigger housing?
Your input is appreciated.
Thanks Ryan
 

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I hate it. very noticeable lag on my 76 going from the 81 to 96.

also the power comes on more drastically.

im boosting in the 30 psi area and the 81 was much smoother and had a better overal power band. to take full advantage of that 96 housing, you gotta be pushing mega boost and the head better be good because it pushes the power further to the right.

if youre running a precision turbo & want to trade housings, let me know. im going back to the 81.
 

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I have the innovative. Just add 200 N2O and hit the button at 4000 and 11mm L-19 head studs and it will push you deep into the 9's I also suggest motec m-600 plug and play and their traction control and that will eliminate wheelspin
 

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I hate it. very noticeable lag on my 76 going from the 81 to 96.

also the power comes on more drastically.

im boosting in the 30 psi area and the 81 was much smoother and had a better overal power band. to take full advantage of that 96 housing, you gotta be pushing mega boost and the head better be good because it pushes the power further to the right.

if youre running a precision turbo & want to trade housings, let me know. im going back to the 81.
Interesting, I don't normally hear people have that strong of a negative impression of a housing change that minor.

I think the most important thing about deciding what housing to go with is the backpressure in the system. If your .81 housing can keep the pressure ratio in about the 1:1 range, then it's fine - if the backpressure is skyrocketing, I'd deal with the .96 A/R. Just my opinion.
 

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600-800rpm going from .81 to .96? that doesnt sound right at all... thats the difference going from a t61 to a t76 isnt it?
 

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I think you guys missed the part where he's 32 psi max out of that turbo.

at that boost, the gain in peak power was not worth it for the trade off in lag on the street. the .81 made a more linear power curve and was much more fun to drive on the street. I need to check my old logs, but I think the housing change made the turbo come on nearly 300-400 rpm later. or atleast it felt like that to me.

now at the dragstrip, I hardly noticed the difference since im just revving it all out.

so im not dogging the housing change completely. im just giving the guy my feedback since he doesnt seem to be the crazy drag racers we are. ;)
 

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I think you guys missed the part where he's 32 psi max out of that turbo.

at that boost, the gain in peak power was not worth it for the trade off in lag on the street. the .81 made a more linear power curve and was much more fun to drive on the street. I need to check my old logs, but I think the housing change made the turbo come on nearly 300-400 rpm later. or atleast it felt like that to me.

now at the dragstrip, I hardly noticed the difference since im just revving it all out.

so im not dogging the housing change completely. im just giving the guy my feedback since he doesnt seem to be the crazy drag racers we are. ;)
No I didn't really miss it, my thoughts still hold true. 32psi doesn't necessarily mean that he won't have high backpressure on an .81 housing. I agree with you though, if you're not straining the turbo then sure run the smaller housing...you probably have more around-town driving than racing. I just think that to properly pick an exhaust housing, backpressure monitoring is required. We don't know what headwork, cams, exhaust size, etc he has...not to mention he could have a turbine that doesn't flow well itself.
 

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The most I would imagine is 300-400 RPM difference before you reach full boost. If you are running nitrous I would go with the biggest one. It is really hard to say without the compressor and turbine maps. If you could supply those I could give you a better estimate
 

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Discussion Starter #12 (Edited)
I dont have the compressor maps. Im getting this turbo custom built by my turbo guy.
I cant see how it would be stupid laggy since lots on here use a GT42-76 and that is a pretty big turbo . On my current 76 with 81a/r I get 12psi in 4th at 4K, not sure when i hit full boost. Im still on alpha soup and will be switching to an AEM.

Mark you are correct. Backpressure is key.
The car has a built head and 272 cams with a 10.0mm lift. Bottom is built also. I will be spinning it up to 8500-9000rpm. 6spd.
Anyone else have data on lag from an 81 to a 96?
thanks
 
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