Spent the weekend working on the old girl. Here is the order and the results of the different turbo housings, compressor upgrade and fuel pin addition...

1. Installed the 12cm W/G and the Stage IV upgrade. Pulled hard and boost was immediate. She felt a little restrictive above 65mph though. Boost was about 10-11psi at cruise and temps were around 700* @ 65mph.

2. Installed the bully dog fuel pin. Felt NO difference at all in spool up or acceleration. It almost seemed as if the ratio of air to fuel was off. Kinda like there was a bottle neck somewhere. Boost flew past 40psi and EGT's were past 1200* real quick. However, I towed a car (about 5000lbs.) to the scrap yard and EGT's remained at around 750* @ 60-65mph and she towed fine. Coming out of the tolls at one point though, I accelerated too fast and caused what I think was turbo bark, so I backed off

3. Because I do a lot of highway, I figured it would be safer to put my 18cm back on and sacrifice a little "git up and go". Definately not the case!! In reality, she doesn't really spool that much slower than the 12cm did, and she is A LOT faster through the gears at all speeds. Definately feel the difference with the fuel pin and Stage IV now . EGT's have gone down by 50* at cruise, and boost at cruise is about 3-5lbs. I guess I was maybe pushing too much fuel for the 12?? Anywho, those are my results. I can't wait to hit the dyno in a couple of months to see where I am at!! Any guesses??

 

sweet results. What made you stay away from the 16cm housing? What kind of boost are you hitting with the 18cm at WOT?

Thanks for the info, keep it coming......

 

i had amazing results with the stage III on my non-ic truck. what kind of drops did you see in full throttle runs? i saw 200-300 on a full throttle stab through the gears with the stage III.

 

pwrtripls1
as far as i've seen the 16cm isn't a large enough difference from the 18cm to justify the cost

 

I just asked because my dad is fixing up a 92' and its a total dog. I am trying to talk him into the 16cm housing and stage III HTT, along with pump tweaks, 4" exhaust, and maybe injectors later.

 

I wanted to try the 12cm with the 5-speed because I have heard good results. I already had the 18 and that spools plenty fast with the fuel that I'm pushing. WOT I am hitting around 35lbs of boost and temps are around 1300*. The stage IV lowered temps, but the fuel pin raised them back up!

 

did you modify the 12cm at all? drill the divider? did you have a boost elbow?

 

I didn't drill the divider (in case I wanted to sell it) or do the elbow. To be honest, it dropped my highway MPG a little more than I wanted, and running 10+lbs of boost with that whistle for a 3hr trip (going to work) was gonna drive me nuts, I guess I am getting old I really think I am faster though the gears with the 18cm, My Getrag shifts really smoothly and I can keep the turbo spooled up through the changes. Plus I feel that I can get the full benefit of the 3200 spring and the fuel pin in the upper RPM range with the 18cm. With the 12cm I felt like I was running out of boost before the pin and spring could work their magic

 

Im having the 16cm housing installed. Currently has the 21cm housing. Some trucks came with the 18 others the 21. The 21 flows more air on boost cause theres more room there to flow. Its a dog, very slow to spool up but never ran over 900 degrees 6" post turbo. My fatherin laws 92 has the 18, pump tweaked a little. It gets with the program and on long hills heated up a little more than mine. I will let you know after the install how mine responds.

 

Turbo bark is the "WHOOSH-Whoosh-whoosh" sound made after you take the foot off the fuel pedal too quickly. It's the pressurized air going the wrong way through the turbocharger inlet.

Don't know what you were hearing could've been, if it was under acceleration.