Precision .85 A/R exhaust housing

[boostedLC2]

I'm interested in hearing from anyone who has changed from a high flow Precision .63 to the .85 A/R exhaust housing on a 50 series turbo (especially PT52). Are there any gains in ET and/or MPH to be had on a low 11/high 10 second car? How much did it hurt the launch or low speed driveability?

Thanks for any feedback,

Jim

 

[Scottie-GNZ]

Jim,

can you give some more details on the combo that you used to accomplish that 11.16 timeslip and what does the car weigh w/driver?

TIA

 

[boostedLC2]

Scottie,

The motor is all stock except for GM Gen IE V8 valve springs. Trans is all stock except for a couple of minor tweaks I did myself (poor man's shift kit). I'm using a new 10" Yank converter which stalls at 3400 rpm at 5# boost and I lock it just past the 1/8th mile. As the sig says I'm running a PT52 (w/ .63 housing) and PTE F/M intercooler. Delphi 50# injectors, stock MAF with my own 22 deg chip, Walbro 340, THDP, ATR 2.5" exhaust, etc....

In race trim the car weighs 3450# with me in it. I run a 50/50 mix of 110 leaded and 100 unleaded and typically set the boost at 25-26#. Last time at the track, launching off the foot brake at 5#, I got a 60' of 1.49 sec.

HTH,

Jim

 

[boostedLC2]

ttt

 

[TurboDave]

Although I've made such a swap on my 86 and documented the results, I'm afraid my car and turbo aren't quick enough to fit your criteria.

 

[boostedLC2]

What were your results Dave? Did you do the swap on a 50 series or a TE44?

Thanks for your time.

Jim

 

[TurboDave]

It was with my 44, and I gained just over a tenth, 1.5 mph.

 

[TurboBob]

Dave,

You switched twice, from the garrett to a .63 PTE, and then to the .85 PTE.

I just don't remember the incremental changes......

Bob

 

[TurboDave]

Originally posted by TurboBob
Dave,

You switched twice, from the garrett to a .63 PTE, and then to the .85 PTE.

I just don't remember the incremental changes......

Bob

Correct. I gained about the same amount with each change (1-1.5tenth and 1-1.5mph with each housing upgrade). The turbine housing changes got me into the 11's (11.90's@114.5). The Translator/Extender and MSD's took me where I am today

 

[boostedLC2]

Thanks for the info Dave/Bob.

Dave - did you notice much of a change in driveability or low end launch/60' when you went from the high flow .63 to the .85?

Jim

 

[boostedLC2]

Dave - any comments on the driveability or launch?

Jim

 

[TurboDave]

Sorry, been busy

No changes in driveability that I was able to notice. Nothing changed in my 60' times. I was running 16" MT E/T Streets for the last couple years, so my 60' times pretty much sucked, but consistently sucked. Around 1.68(best) to mid 1.7's

 

[azgn]

slowed my car down switching from a Garrett to Precision.....Garrett is back on there (.63)

a 1.49 60' is very impressive on 5 lbs....I need 15 lbs or better to get 1.4x 60's (on 28X9 slicks....3600 stall)

 

[J Banning]

I had also pondered the thought of going to a .85 housing (I'm running a PT51). With a 5# launch I'm seeing 1.54-55 60' times. That's with a 28" tire and the Precision .63 hounsing I'm running now. Car weighs 3600# with me in it.

-Banning.