will .83 A/R help in my application

turbo6man

Member
Hi, I have an opportunity to trade my precision .63 A/R exhaust housing with a .83. The turbo I have was sold by precision and it was called the stealth model which is I believe a 68MM. I took my car to the track last weekend and ran a 10.47@127.8 I shift the car at 5600 and have a 12% converter slippage which I am about ready to fix by buying a converter from dusty. Also I just completed(but have not run) a NOS dry shot which will assisting in boosting off the transbrake. Please see sig below and advise me if I should make the switch. Thanks, James


Also if anyone has information about this turbo or real word usage please let me know. I really want to run a 9.9999999:biggrin: with this car and am not sure if turbo is right for my application.
 

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I'd assume your a ported head car, big roller cam and running a lot of boost so the .85 Precision will probably net you some HP/TQ vs most of us on the top end. With the NOS you can negate any rpm loss on the transbrake from the bigger housing.
 
At your current mph it will do very little for power but with N2O you will likely spool faster than you did with any old combo you had. Plan on 30+psi with that old turbine design to crack 133-134mph and have 9 sec potential
 
Thanks guys I think I need to rethink this. So my options are to get the elusive 9.99
OPTION ONE: Have Dusty make a converter then turn the Boost up with the turbo and exhaust housing I have to how high? The car now weighs 3250 with me in it. With a good tune in it on E85 how much timing(at 22degres now) and boost(at 28psi now) and what will an iron headed with ARP studs and RJC gaskets hold (i would never hold you to your answer just like to take in to consideration your input)

OPTION TWO: New turbo (Please help me select the correct turbo for my ET goal) then have Dusty make a converter for this application. What boost and timing would it take to make this option work?

Which option would have a higher likelihood of staying together?

Last thought: the posts I make really help and I would not be running the 10.4's that I ran last weekend without Bisons previous replys to other postings about gear ratio/tire size and tune. Also GNVYUS 1 helped alot in building the correct fuel system. What I am trying to say is thanks to you and all other posters Who really DO make a difference. I am serious about running a 9.99 And want to plan accordingly over the winter to make changes to get there orrrrrr :eek:blow it up trying:eek:
 
I noticed you have the stock headers, so if you were to ever swap them out, go with the 4 bolt turbo flange (Arizona GN sells them) and get the V Band 3.5" DP from either Arizona GN or BuickGN. The T4 .68 housing on that same turbo would probably wake it up at least 40hp around 30psi, then the headers at your power level are 20hp+ for sure so that 9.9 would be much easier with the same turbo and boost minus the exhaust housing. The PTC alone will get you closer so you've got this. ;)

The NOS though will get you the high 9 if you get the launch right and keep it flowing throughout the run. Tune Tune Tune if you feed the GN the bottle the whole run. :eek:
 
Thanks guys I think I need to rethink this. So my options are to get the elusive 9.99
OPTION ONE: Have Dusty make a converter then turn the Boost up with the turbo and exhaust housing I have to how high? The car now weighs 3250 with me in it. With a good tune in it on E85 how much timing(at 22degres now) and boost(at 28psi now) and what will an iron headed with ARP studs and RJC gaskets hold (i would never hold you to your answer just like to take in to consideration your input)

OPTION TWO: New turbo (Please help me select the correct turbo for my ET goal) then have Dusty make a converter for this application. What boost and timing would it take to make this option work?

Which option would have a higher likelihood of staying together?

Last thought: the posts I make really help and I would not be running the 10.4's that I ran last weekend without Bisons previous replys to other postings about gear ratio/tire size and tune. Also GNVYUS 1 helped alot in building the correct fuel system. What I am trying to say is thanks to you and all other posters Who really DO make a difference. I am serious about running a 9.99 And want to plan accordingly over the winter to make changes to get there orrrrrr :eek:blow it up trying:eek:

If it were me id turn the timing back to 19-20* and run the boost up to 30-32psi and work on leaving hard. I ran 33psi for 3 months on a stock bottom end before the #1 piston cracked. The engine had about 150k on it. The car was 3600+lbs. It went 10.33@133.4 at 28psi. It was a t-netics 6680 BB turbo. I think you have enough turbo even though the ex wheel is an old design and its easier and plenty safe to run a couple psi more with slighlty retarded timing than to replace the turbo. If you want to pay the shipping try my 6680 turbo let me know and ill email you.
 
Thanks guys, I think I will go mild with the timing, up the boost and see what the NOS assist does for me. Since you know my combo and my goals. What would the "OPTIMUM" turbo for my application be :confused:
 
Thanks guys, I think I will go mild with the timing, up the boost and see what the NOS assist does for me. Since you know my combo and my goals. What would the "OPTIMUM" turbo for my application be :confused:

That would depend on if you were looking to optimize horsepower or have a car that is more fun to drive and good response. A 6765 BB would be fun but any of the 80 or 68 trim turbos 66-76mm would make more power if you decide to lean on it. Let me know if you want to try the 6680. I made enough power with it to push a car the weight of yours to very low 9's.
 
OK Bison you have really got my attention with your turbonetics 6680. I found an old post where you made stupid power with that turbo. I have a few questions for you?

1)How will my ported irons with bigger valves shifting at 5800 work with that turbo compared to the Aluminum heads you had shifting at 6200.

2) I cannot find the specs for the 6680 if you were to compare it to my old stealth turbo what would the comparison be.

3) Will back pressure be an issue for me to build the boost I need to build with the 6680 to get me there. And would you have concerns with the cylinder pressures I will be at?

Additional info:
My cam specs are ATR roller cam kit p#RP309G Duration @.050 was 212/206 and lift with my stock 1.55 rockers is .467/.453
the valve springs which came with the kit were set up at 125# closed and 325# open (Need to change springs this winter any suggestions)?
.030 bore with TRW forged replacement pistons OEM compression

Thanks I really appreciate everything!!!!!!
 
OK Bison you have really got my attention with your turbonetics 6680. I found an old post where you made stupid power with that turbo. I have a few questions for you?

1)How will my ported irons with bigger valves shifting at 5800 work with that turbo compared to the Aluminum heads you had shifting at 6200.

2) I cannot find the specs for the 6680 if you were to compare it to my old stealth turbo what would the comparison be.

3) Will back pressure be an issue for me to build the boost I need to build with the 6680 to get me there. And would you have concerns with the cylinder pressures I will be at?

Additional info:
My cam specs are ATR roller cam kit p#RP309G Duration @.050 was 212/206 and lift with my stock 1.55 rockers is .467/.453
the valve springs which came with the kit were set up at 125# closed and 325# open (Need to change springs this winter any suggestions)?
.030 bore with TRW forged replacement pistons OEM compression

Thanks I really appreciate everything!!!!!!
Car was 3600+lbs with me in it. I ran it with decent iron heads 3 years ago on a stock bottom end and 212/212 cam. It was about 8.4:1 CR. I ran comp 941 springs and .497 lift. It went 10.33@133+ on the only pass i made with it with that combo. Lazy 60' and 28.5psi. Id go with 26918 springs shimmed to about .050 from coil bind and go to 1.65 ratio. The 6680 will make more power than your stealth based on the old Q trim wheel yours appears to have and most likely will spoolup twice as fast. Backpressure will be as low as it could be since the 80 trim S/GTQ is the largest ex wheel you can get in a 3 bolt. The car went 1.59 60' with a 3psi foot brake launch. I made a lot more power later that year but never ran it at the strip. The 33psi i was running would have put the car well into the 9's with conservative 60' times. I shifted at 5800 with the 212 cam and 28psi boost. It pulled to about 5800 in 3rd on the 10.33 pass. Converter slip was around 3% with the 9.5" PTC i used. The power charachterisitcs are the same as a GTQ TE45a. The power potential is around 800hp or slightly more with the correct combo.
 
BISON, I really want to get this right, so to answer your question and to lay it on the line I am looking optimize horsepower and use the NOS assist to spool it whenever needed. I have a buddy who has a filling station and I think the 10lb bottle will last awhile with the small shot I am using.

What about this 74mm "journal" in the for sale section? http://www.turbobuick.com/forums/parts-sale/332856-precision-74mm-turbo.html
With N2O it will be ok. Im used to having my engines come into power within 1 sec of flooring the pedal. With a journal GTQ on a small engine it will take longer without N2O. The 6680 ive been running has made more power than anything ive run or been in that still retained the 3 bolt housing. Most guys seem to hit a wall in the mid 130's regardless of the turbo. They think they can make a lot of power and not crank it up. This is not true. When you want to run 140+ you need to turn it up or go to a different engine.
 
When is the ex closing at .050 lift on your cam? What is the separation?
 
Sorry it took me so long to reply the last few days have been crazy at work. Here are the cam specs. Bison did you want me to contact you privately about trying the turbo.
 

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update

Here is what I am doing: I am Trying Bisons 6680. Dusty Is making me a converter. I lengthened my rear four link bars so I could step up to a 29" tire, and I am replacing the valve springs. When I get it all together and tuned and a nice day for the track I will update.
 

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