Patrick's Twin Turbo 350 Build Thread

Yeah, then I could stick a 2" super sucker on there, have that air screaming down the carb with my K&N directional air cleaner

 

Especially when you cant fit a 4" filter on a SP3 under a stock hood!
Drop base is cheating

 

Hah, I've managed to squeeze a 3-1/2" filter on top along with a 1" tapered spacer under my SP3 because of that cheating L88 drop base....
4" filter barely fits, I've had it on for a while and it's real close.
All under the GS hood....You would need to harness engine with 4" filter to not move more than 1/4".

Good n tight...

 

put tape on it so it slows you down for more even competition?
I got 4" cleaner under hood with SP3 and a plate under carb
They say nitrous is cheating too I say get a bigger engine


Time to line em up boys track is open

 

That hood is totally badass. I think it's the nicest non stock hood I have seen. Good job!

 

Finally an official update! Things that have happened since my last post:

-Installed custom fiberglass hood from Craig. I'm super happy with it, it looks amazing and shaved a bunch of weight off the front end. Craig was awesome to deal with and spent months going back and forth with me taking measurements to build me a custom hood that will eventually connect to the turbos. Sadly I still have a tiny bit of interference at the very rear of the carb hat, so I'll need to notch the new air box, but Craig says he'll walk me through patching that part once it comes time. I have a set of OEM 71 GS vents but am going to try and make my own that look "cooler", that's lower priority though. I did do some nice billet hood pins however, that was stressful but turned out great. You can see picturesof the hood on the car a few posts back (post #395 )

-I installed my dream shifter (well dream if keeping it auto for now). It's a Killduff Machine pull to shift for 4 speed autos. It looks totally bada$$ and I spent extra for a console, and it's amazing to have cupholders! It really completes the look of the bucket seat swap. I still need to mess with the shift cable throw at the trans side, it's not quite right and I'm only getting the 3-4 shift. Seem like the hole needs to move onboard to have a bit more throw. I also want to try the longer 11" shift levers at some point. I haven't had time to hook up the NSS, lockup features, or light up indicator plate yet. I forgot to take some pictures with the matching street bucket seats in there, but this is how it looks with the race seat:





-Got the bucket seat worked out. I'm using side mount brackets bolted to sliders, a bit ridiculous looking underneath but I found that my seating posting was tilted forward too much for my liking with just the sliders. With the side mounts I can tilt it back and also keep the slider functionality. It's an easy swap going from the street buckets to the race seat, 4 bolts and done without messing with the brackets:





-Stupidly I scraped the wiring off of my trans cooler fans going up the driveway. Ended up replacing them with a new set of Spal fans that flow a whopping 27cfm more The springs seem to have settled some more and I may need to raise the front ride height again. I will eventually get coilovers as I'm tired of stuffing spring spacers under there. I love how it looks low but it's a pain with bumps . . . Should I bag it haha? Ridetech make a very nice set of bags that have adjustable shocks built in, but they are very costly and adding a compressor to the trunk costs weight. Still pondering.

-Finally ordered the parts to rebuild the exhaust. Every time I drive on the freeway my girlfriend complains about getting gassed, she claims I must have inhaled too much to smell it anymore but even for me it's getting bad. I think it's been getting worse ever since I started driving the car again. I traced the leak to the downpipe to manifold connection on the driver's side, and tried in vain to seal it up with goop, but no luck. With how hacked together this 2" exhaust is, it has been due for a proper setup from the get go. The leak is also causing my AFR readings to be mostly useless.

My exhaust plan is sort of radical:

>Install the turbos, turbo manifolds, and downpipes, and build the exhaust from there since that will be my final routing (hopefully)

>I bought a 2.5" pypes kit that includes no crossover pipe or mufflers and is meant for the GTO through valance exhaust. It's PN SGA-29. It was only $400ish from summit, sadly it's 409 stainless not 304 but that's ok for now and my climate. 3" would have been nice but decided the fitment issues wouldn't be worth it at my power lever, plus my downpipes are 2.5" aluminized anyways. I'm planning on trying the straight pipes first and can add muffler if it's too obnoxious, but I've been told the turbos quiet it down a bunch.

>I recently acquired a NOS 71 N25 bumper so I'm planning on doing that conversion at the same time. Since no one seems to make 2.5" or 3" N25 tips anymore, I'm going to make my own set. I'll post that project in a separate thread but might consider making them available to people if they turn out nice enough! With the design I have in mind I should be able to make them in any exhaust diameter. Will be adding 02 bungs to each downpipe, 1 for my AFR gauge and 1 for the EFI 02.

>Lastly, I bough a new pair of cats for the system to make it even less smelly and better for the trees. Everything will be connected with VBands, going to try the summit brand ones, they are more than half the cost of vibrant and Ill be using 7 of them in my system.

That leads us to turbo specific stuff:

>I recently changed jobs and sadly am making a bit less, so I've been toying with the idea of doing a homebrew blow through carb. I bought a crusty 600cfm Holley 4150 (list 4776) for $100 off of Craigslist and am currently spending my spare time cleaning the literal crap out of it. The metering blocks and main body are filthy with old brown gasket. I already milled the choke horn down at work and might throw the Hanger18 parts at it for cheapish and see how it runs on 3psi.

**EDIT** Holley was having a big sale on the Sniper 1 systems since the Sniper 2 is out, and I just couldn't help myself. I just got paid from some welding side work and thought "its now or never". I just bought the Sniper XFlow this morning in shiny silver, the 4 injector version good to 690HP with boost! I've been eying this damn EFI for almost 4 years, I can't believe it's actually going to happen! This means I can FINALLY start actually hooking the turbo stuff up.

>I'll need to build the oil feed/drain lines for the turbos

>I'll finally be upgrading to -8an nicopp fuel lines from the 3/8" rubber hose I'm running front to back now (I know I know)

>I will install my Holey boost referenced FPR and filter

>I will change from my hacked together modified fuel pickup to the one meant for my sniper tank

>Likely I'll step up to a 340LPH pump (it comes with a 255)

>I'll probably try and get the intercooler welded together and plumbed

Other random stuff to be done:

-I bought a summit transmission safety blanket that I still need to install. I want to keep my legs and anything helps!

-Ditto with new u-jonts, I have them but gotta get them installed. I also need to build a driveshaft safety loop.

-I just scored NIB TA Performance Rear End Girdle that should fit my 66 Pontiac 8.2, more strong = more better

-Need to install the sweet new coolant overflow tank I got from Ractronix, I found that the stock one was leaking around hard corners. I RTVed the top on which is ok for now but would like to relocate the overflow at the same time so my line doesn't run all the way across. Since I have a custom radiator setup the filler neck is now on the driver's side.

Lots to do! I'm guessing all of the stuff listed above will probably take me a year or more with how often I'm able to get to the garage these days.

 

Good job!!
Whatever mufflers you choose, make sure they’re a “straight through” design, no crossflow or loopy loop designs for turbo cars, turbos HATE back pressure!