After ten months of agonizing work, I finally finished my conversion to two independent twin turbos. You may have seen the previous threads where I was doing fab work on the manifold, etc. I promised everyone that I would post when I was finished.

I got everything back together this weekend and got the final welding completed on the hard pipes last night. I drove the car a good bit today and except for a few minor details, everything is running great. I am being very conservative on the boost at 9-10 psi for right now but I must say at 10 psi it pulls better than I imagined. I have yet to put it on a dyno but I estimate that at 10 psi I am doing around 300 bhp or so.

The power is trickling off from 7k+ since I am running a cat. I got a high-flow cat to see how things would behave with it in but I designed the exhaust system to be easily separable between the two mufflers so I can drop the entire rear section and still have decent muffling for track use or just waking up the neighbors.

The body is next on the list - looks like hell right now. Needs a paint job and such but who cares about that, right?

There are a lot of details that I can't think of right now, so if you're curious as to how I did something, ask. A quick mod list:

2 Garrett TB25 turbos on a custom SS manifold with independent runners - one turbo per rotor
massive spearco core intercooler
APEX'i Power FC, slightly modified base map
Custom fuel: -6 lines and 2x550cc and 2x850cc injectors (I have a spare primary rail with 2x850cc's ready to go for later...), BG FPR
All emissions removed, except for a cat (meow)
Double throttle removed, AWS removed, etc, ISC still operative
No A/C, Power steering, etc
Power steering rack replaced with '88 manual rack, Eibach pro-kit, etc
Trans brace (thinking about ditching that in favor of my dental integrity)
Poly motor mounts
CSF Aluminum radiator (very nice, keeps it very cool)
Battery relocated, full-size optima in rear hatch area
Full autometer dash: tach, water temp, oil pressure, fuel, boost, egt. Still need to do a speedo.
Exhaust - magnaflow 2into1 center -> hi-flo cat -> PFS catback
Running premix @ 128:1-ish
Stock wheels/body/interior otherwise

Little things I still need to attend to: idle control. My idle is really unstable, I need to adjust the screws and the PFC params. I also am going to go to all BUR9EQs later on but I am running 7 leading's now in the interest of easy start. I have a crankcase vacuum and a Greddy catch can on the turbo inlets but nothing on the manifold - I need to add a PCV valve and put some vacuum there as I am spilling a little turbo oil from the seals at idle as a result. I have an exhaust leak, and my new transmission is leaking from the output coupler (bad/no seal?). Running lights stay on all the time (relay?). Need to get the shifter turned down and re-died for my ****; I need floor mats and a paint job. Eh. Short list huh.

Thanks to everyone who gave me input on this project, and big thanks to JSJ for assisting me in troubleshooting my start/idle problems over the last few months.

PICS to follow:

 

Manifold stuff

 

mounting

 

very nice....

 

radiator, catch can, etc

 

veryu clean

can u make me a manifold haha

 

very nice!

 

And finally the finished engine bay. In case anyone is wondering, the intercooler is ducted underneath and insulated from the radiator by a sheetmetal airbox.







and dash

 

rediculously large project...reminds me of the one I just finished...I'll bet your pretty glad its done...Looks really sweet. Congrats

 

very nice! All this wasdone yourself? And at what rpm's do you get full boost?

 

I've always been really curious as to when this setup would get full boost? I was actually thinking you would need gt25s to make it any fun? Was I wrong? I hope so..

 

Nice. Glad you finally finished it. I'm sure all of the local guys will want to check it out.

 

I have no problem at all with lag. I can hit 9-10psi where I have it wastegated at around 4k. It really is fun

 

looks really nice...i hope you can get good reliable hp numbers out of that setup...well hope you have fun with it...sure looks like you did
peace out

 

oh yeah if your located in alabama and you want a really good tune, for your power fc come down to ASI Racing and chad can tune your car for a great price. plus we would all love to see that setup in person.

 

Sweet job, looks real nice. How do you think the intercooler is going to perform at the angle it's mounted at?

 

It's doing pretty well. Air temps stay around 40 degC at cruise when the ambient temp is about 22 degC. The duct underneath has a scoop that extends into the stock air duct area (over the driver side of the radiator). I am still working on this part - the airbox on the lower side of the intercooler is about 2" thick and extends over the whole surface of the intercooler and seals with rubber, so any air entering the duct has to flow through the intercooler. The original plan called for a ducted knightsports-style hood, which will put the ducts right above the intercooler and suck air through it- a-la Porsche 968 Turbo RS - will attend to this as budget allows.

 

:applause:
looks simply...fast

 

very impresive, good luck in your further modifications

 

It looks nice, and hope your happy with it!! I have a few questions though...

Why not run piping under the intercooler for the filters? It looks like how its done right now its just sucking hot air from the motor.

Also, do you have ducting in the endtakes of the intercooler? It appears that the air will mostly be traveling through the bottom instead of through the whole intercooler. Obviously if you have ducting it will solve that problem.

I'd assume theres a reason why you have the intercooler in the location you have it, but why not turn it around so that the inlet and outlet are closer to the turbos and TB elbow for less intercooler piping?

Did you think of dual inlets so you didn't have to join them into 1 pipe? I'm not sure if it creates alot of turbulence doing that, but I'd think usuing 2 inlets would have far less, if there even is much joining them to 1 pipe?!?!

-Alex

Edit: Also, is there any reason why you chose not to use equal runners on the manifold?

 

I remember reading in one of the previous threads someone brought up the possibility of the different runner lengths on the exhaust manifold to each turbo posing a problem. Were they incorrect, or was this compensated for some how? or am I just remembering incorrectly?

BTW looks like a quality job

 

The only problems running unequal runners, that I can think of, would be a slower spool compared to equal runners, and with the shorter runner running hotter, they would expand diffrently wich could cause cracking.

-Alex

 

In one of his previous threads I think he mentioned the difficulty of fitting the downpipe with the turbos right next to each other.

 

I saw you build up pics . Really nice to see that you finished your project . I was wondering about a few problems in the pics you shown . One would be the turbos so close to the manifold with no heat shield . Two, the weird 90 degree bents on the intercooler . Three From the looks of your pics your v-mount is reversed . is there a reason for that ... Good to see that you have ducting to it

All in all , great looking project . Hope you get the idle worked out . :burnout:
more pics and a video would be nice ..haha..

 

There's no room, the intercooler airbox is between the intercooler and radiator.

Big airbox under intercooler forces air from front of car through the intercooler. Rubber-sealed to intercooler bottom. Will take pic

Just fitment. Rotating the intercooler means I have to make some nasty bends if the inlets are closer. I would have preferred a 2 inlet cooler but I got a killer deal on that cooler with endtanks already on it and I have a very nice Y-pipe

Equal runners? Yes, that would have been nice too, but I didn't have the space, time, skill, money, or extra SS bends to mess around with a zillion configurations to get equal length or closer to equal length. Under higher pressures the effects of resonance dissipate so my only concern with the short front primary is the heat that it will induce on the turbine blades. We'll see what happens.

I'm going to bed for now guys, thanks for your interest!