Turbo 3800 T56 Grand Prix

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565bbchevy

Geezer
Aug 8, 2011
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DRIVEN

Geezer
Apr 25, 2009
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*CENSORED*
Small world haha! I live pretty close to the town listed on their banner so you're probably not too far away then.
I'm hoping to hit a local cars and coffee again before the end of the year if I ever get this thing done lol
No, I'm in the opposite corner of the country. I only cross paths with him about once a year for training events. Don't really know him, we just work for the same company.
Cool seeing your car make a couple pulls. Those numbers are really pretty decent.
 
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bs009

Greasemonkey
Jul 26, 2008
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Yeah I should be pretty happy with the numbers but seeing where it made the power and where the boost was at had me pretty disappointed because I know there's a lot more in the current setup haha! Extrapolating that number out to 20 psi means it would be making 400whp at that RPM at the boost pressure I've been running it at.
Right now I'm really hoping to get over 500whp with the stock cam before I go to the next level with the car but we'll see what happens. If it breaks then it's not a huge deal since the current motor has over 230,000 miles on it :LOL:
 
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bs009

Greasemonkey
Jul 26, 2008
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Well I finished mocking up and tacking in the wastegates finally. I'm a lot happier with where they're at and how the pipes split and merge compared to before. This is probably about the best I could do without tearing apart everything and starting over

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Here you can see where the manifold splits between the turbo (down) and the wastegate. Should see a lot more gasses flowing into the wastegate than before with this
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Manifolds are coming off next to fully weld everything, but while they're off I'm going to replace the timing chain and the rear main seal, and double check the torque on the head studs
Made my list of things to work on today and it's a long one!
 
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81cutlass

Comic Book Super Hero
Feb 16, 2009
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Oh and a correction,

When I told you to maybe think about not doing 4.11's or whatever at Power Tour, I was wrong. 3.73's blow unless you have power to go in the 9's. Whatever gear math you did was correct :)
 
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bs009

Greasemonkey
Jul 26, 2008
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Yeah it was pretty much too late at that point anyway from what I was told there haha! I was thinking about changing the order to 3.73's initially but never actually did it.
I have the new rear end sitting in my living room right now with the original gear ratio I ordered of 3.50. Should be far better than the 2.41 I have in the car right now lol
 
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nomoar

Not-quite-so-new-guy
Aug 27, 2014
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Excited to hear how the new turbo does! Where did you get it, what model is it?
 
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bs009

Greasemonkey
Jul 26, 2008
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Smashville
Excited to hear how the new turbo does! Where did you get it, what model is it?
This turbo is just an ebay turbo so nothing too crazy haha!


If it were a long term deal though I'd probably buy a name brand turbo but I'm only planning on running this one for another year or so. Definitely can't wait to see how all of the changes play out!
 

bs009

Greasemonkey
Jul 26, 2008
122
232
43
Smashville
Couple other changes so far, some big some little

Went ahead and swapped out the steering box for a Borgeson box to get rid of all of the slop in the steering wheel.
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So far I'm not really impressed with it, still seems like there's some slop in the box before the pitman arm moves. Might still need some adjusting maybe though.

Went ahead and wrapped all of the exhaust too. Things are going to be a little tighter under the hood now so I'll have to really try to keep things cool.
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Relocating the wastegates also allows me to run a much larger air filter. the old filter was squeezed between the radiator and the wastegate so it's pretty bruised and warped lol
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Next bigger upgrade was 1.9 rockers too. These typically bring in something like 5% more horsepower and lower boost on a supercharged engine so I'm expecting to see a little more here since I'm keeping the boost level pretty high. These will be the key to hitting close to 500 whp on this setup. Stock rockers are 1.6 ratio

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And this upgrade has been a long time coming. I've been wanting to do this since I've had the car. Seems like it's really hard to find a good used rear end. I've tried 2 of them so far and have had bad experiences with them. Plus guys want like $2,000 for a used 10 bolt 8.5" rear end for a g-body.
This was $2,000 brand new after all of the parts it needed to come with it.

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Quick performance fabricated 9" rear end. 31 spline axles, 3.50:1 gear ratio, Eaton Truetrac with 4th gen Camaro axle ends so I can reuse my rear disc brake setup.

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Welded on the sway bar brackets that used to use u-bolts to bolt it to the axle since the backbrace would get in the way of the u-bolts.
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Also modified the shock mount to clear the calipers

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Now I just need to get the brake lines secured to it and figure out some sort of bump stop for it.

Still waiting for the new clutch but once that arrives I'll just need to build my exhaust around it again and I should finally have this thing back on the road afterwards!
 
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nomoar

Not-quite-so-new-guy
Aug 27, 2014
14
18
3
This turbo is just an ebay turbo so nothing too crazy haha!
Well I may just copy you on this, will wait to see how it works though :)

So far I'm not really impressed with it, still seems like there's some slop in the box before the pitman arm moves. Might still need some adjusting maybe though.
Man that is a bummer, sounded like it was supposed to solve everything by the way other people talk about it. I wonder if it's all just a matter of perspective.

You're still on the stock cam right? I've read that you either do a cam or rockers but not both?


Looks like some huge progress with that new rear end, seems like that was the last big hurdle on this build.
 
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