New guy here: potential conversion for 1986 951 track car

Dan J wrote:Since your car is already set up for the track, you've presumably got brakes, tires and suspension set up the way you like.  Yes, for now.  Still trying to figure out the right boost/MC combo.  Additionally, I'm planning on installing the Broadfoot fender flares which will require the use of new wheels/rubber.  Currently running the Toyo slicks (not quite where the Hoosiers are but do net about twice the life).

What kind of power was your turbo motor making? Where do you want to be and how much do you want to spend?   This is a reason I'm toying with building a 5.3L -- start small(ish) but with room to grow as a Phase 2.  My butt dyno says I'm currently around 275 rwhp at 1.05bar boost -- about as fast as a well-pedaled Cayman S.  

Consequently, I'm not looking for mega HP -- honestly would like to keep it under 400hp at the crank.  From my research, an aluminum 5.3L with LS1 heads + intake (FAST 102mm TB), and LS2 cam (or the Crane 224/232 cam), and the Kooks/TPC headers should be more than enough for me.


There are lots of ways around the barn and this forum is an outstanding place to get information from hands-on guys who have tried tons of combinations and setups. Aftermarket support is outstanding for the combinations we're using.

A relatively simple approach to 400 rear wheel hp/tq that I used is an '04 GTO LS1 motor with LS6 intake and heads, a medium cam, dual springs, lifters and ti retainers. That plus a baffled moroso oil pan and shorty headers, all running on an F-body ecu. I used shorty headers (back in 2009) but would go with the long headers if doing the project again. Cable throttle is simple using the stock pedal setup.

This combo passes emissions here in Oregon (it has dual exhaust including cats) and runs acceptably cool on the street and track using a stock 951 radiator/fans and remote oil cooler.  Fortunately no emissions here!  My car is currently street legal, fortunately, and it would be nice to keep it that way.


You will need to think about brakes and power steering. It's a matter of personal preference. To keep things simple and analog, I went with a Tilton MC + bias adjuster and manual (non-power) brakes using Big Reds, 2 piece floating 965 rotors and Kokeln adapters. The rear brakes are 951 with 030 rotors. Pedal is firm, but once the pads (EBC) are warm, pedal pressure is acceptable and linear for a race car. Steering is a 944 manual rack. Not fingertip light with 275's at parking lot speeds, but outstanding feel on the track. The only accessory on the motor is an alternator, mounted low on the driver's side.
How do you like the Tilton setup?  It might be easiest/cheapest for a Phase 1 for me to just go with the Ford booster and keep everything else as-is.

As for steering, I already have a manual sport rack.  No plans to change that.

One thing to think about before getting too far along is reinforcing the firewall. That's a weak spot and several people have taken different approaches. Around the brakes, I'm assuming?  Will look into it.  This is a common issue with Subarus.

Over the past couple years the new C7 Z06, GT350r, GT3 RS and guys with over 500hp C5 and C6 Vettes have raised the bar a bit, that's if DE is your thing. To do again, I'd probably go with a slightly bigger cam, better breathing aftermarket heads and long-tube headers. That's maybe another $2k net difference over what I have, but another 100hp. These motors are super modern and straightforward to upgrade, so you can always build up as you go.

As you know, the character of these motors is not high-strung, lightweight, screaming rev-monster though. You might be able to find a light flywheel/clutch combo to help, but it might cost you some low speed drive-ability. I'd always had small displacement, higher revving European stuff prior to this car, but have learned to embrace the simple, robust and relatively inexpensive power and torque. Think NASCAR more than Formula Atlantic.
Good point, thanks.  Agreed, it's not a refined, revvy racing motor.  Then again, neither is the stock 951 motor!

I will probably want to go with a lightweight flywheel.  What's a good company for the LS stuff?  Fidanza?

Dan.

Rich L. wrote:I have the TPC long tubes. Nearly as good, cheaper and will remain available.

Just sayin'...

Rich

Additionally, I'm planning on installing the Broadfoot fender flares which will require the use of new wheels/rubber.

Won't I need the 944 spline on it? Or are you saying that Spec makes a 944-V8 specific package?

Sterling Doc wrote:I have the Spec aluminum flywheel & clutch. With a Tilton Triple pedal, and a 3/4 MC, the clutch is easy, and super tractable. a few Revs are needed due to the low inertia, but I'd say it's very streetable.

Manual brakes are fine with a very aggressive pad (this is key).

My junkyard '04 GTO (5.7) LS1 with cleaned up 241 heads, and TPC short tube headers made 350HP/360TQ at the wheels. Stock cam (smallest LS1 cam outside of a truck application).  No power accessories, though. Just a water pump and alternator.

Can I reuse the Trailblazer fuel rails and injectors?