Apollo Racer Build Thread, Numeric 981 Shifter Upgrade Options

[rnellums]

I am starting this thread to document the build of my recent acquisition of a car I am going to name Apollo. It was previously owned by a fellow out in Illinois and was sold to me via 914 LTD. From what I know It was a purpose built Auto X car, but only has about two hours of run time on the engine.

Here are the specs as I received it:

Exterior Mods:

• Factory Steel Flares
• Newish Silver Base/Clear
• Fiberglass 916 Style Front Bumper
• Fiberglass Stock Style Rear Bumper
• Fiberglass Hood With Headlight Delete
• Fiberglass Trunk
• Fiberglass Painted Rocker Panels
• Painted Targa Top
• Lexan Rear Window
• Lightened Door Skins
• Original Doors, Hood, Trunk
• No Wipers, Headlights
• Rear Porsche Reflector

Interior Mods:

• Koenig Race Seats
• RaceTech Leather Wheel
• Amco Console with Assorted Gauges
• Welt. Short Shift Kit
• Bolt in Cage with Door Bars
• Simpson 4 pt. Harnesses

Suspension Mods:

• Rich Johnson 5-Lug Conversion
• Front Volvo Big Brakes
• Front Vented Rotors
• 911 Front Struts
• Koni Adjustable Shocks
• 914-6 Rear Rotors With Stock Front Calipers
• 22mm Front Torsion Bars
• Welt. Adj. Front Sway
• 180 lb Springs w/Adjustable Perches
• Hoosier Road Race Radials

Engine Specifications:

• Front Mounted Oil Cooler
• 2.4 L 4-cyl built by ROCS auto
• 103mm J+E Forged Pistons
• 1.8L Stroked to 2.0 Specs
• 48mm Intake
• 38mm Exhaust
• Chromoly Pushrods
• High Flow Oil Pump
• MSD Ignition w/ Adj. Rev. Limiter
• 44mm Dual Webers
• Lightened Flywheel
• Kennedy Engineering Stage IV Clutch
• Ported, Polished Heads with 10:1 Compression
• Port Matched Manifolds
• Kerry Hunter Headers
• Claimed 180 HP
• Claimed 170 ft-lbf Torque

Transmission Specs:

• Recent Rebuild by 914 LTD
• Quaffe Torque Bias Diff
• Shortened 5th Gear

Misc:

• 5 Gal Fuel Cell
• New Bearings and Bushings
• Blue Brake Fluid
• 8x15 Fuchs
• Claimed 1600 lb Weight

And Now the pictures!

[rnellums]

Your header is way too small for a 2.4L.
I guarantee it's holding the engine back - a lot. There's at least 10 more hp & 10 lb-ft torque available just by replacing the exhaust.

You should have 4 EGTs to monitor the fuel mixture of each cylinder at WOT.
Single O2 sensing doesn't have much value on a race car.

I don't understand why the oil thermostat would be placed in the front trunk so close to the cooler.
It should be closer to the engine to shorten the route when the oil is cold.
Also, IMO hoses that long should be -12, not -10 (definitely not -8).
No tuna can, or accusump? The engine won't last long once you start pushing it around at a competitive event.
You should consider moving up to a dry sump oil system right away.

Where's your adjustable brake bias control?

Stage 4 clutch is overkill. Your leg's gonna get a work out.

I think I am at least going to keep the headers for now, but need to be thinking about upgrading to better flowing. I know you are biased, but are there any other high flowing header systems out there besides yours?

What would I use EGT data for? just determining which cylinders were lean under load?

I am planning on getting an Accusump system ASAP, what is the preferred size for this application? 3 qt? I had heard some talk about the front trunk being the best mounting location for an accusump for weight distribution, which would only work with a front mounted thermostat. but then you have some excessive pumping distance.

If i were to relocate the thermostat, where would the preferred location be?

I have switched the 5 gal race tank out with the stock tank since 5 gal on this engine isn't worth much anywhere but autoX.

I have not seen any adjustable brake bias control, so I am operating under the assumption that it has a stock proportioning valve.

I have cam specs somewhere and will post later. the heads have stiffer return springs so I place the true redline around 6500.

You could build the car to run in HSR. Most of the mods you have minus the engine could allow you to run in the 2.0 Challenge class. You would have to swap in a 2.0 six, but you could at least show up and run for a while until the 2.4 gives it up. No one will complain because you will still be down about 50+hp. But you will have tons of people to race with in 914s and 911s. Plus they run a treaded vintage tire.

Get some ducting for that oil cooler.

Also toss the clutch and get a decent clutch. No sense in destroying the thrust bearings on the engine with a massive clutch. maybe an aluminum S pressure plate for racing. I would use a sprung hub clutch just to help keep the transmission alive.

Get a proper breather can on there and toss that crappy filter stuck on the side of the oil filler neck. It will keep the oil off the engine and engine bay.

I'm working on the ducting bit.

Am I right that you are essentially saying I should revert to a stock clutch and pressure plate?

HSR looks pretty awesome

If you want it and end up out this way I have a stock fuel reno I'll give you.....has some rust in it.

Beautiful car!

What is a stock fuel Reno?

[ChrisFoley]

I think I am at least going to keep the headers for now, but need to be thinking about upgrading to better flowing. I know you are biased, but are there any other high flowing header systems out there besides yours?

Primary lengths are ok on your header, just the diameter is too restrictive.
1 5/8" MSDS 4 cyl header (KHH clone) would be a better choice for about the same investment as the KHH was.
I don't like the long length of European Racing Headers for an engine with higher than stock power band.

What would I use EGT data for? just determining which cylinders were lean under load?

Too lean spells disaster at WOT. Also, if you have any problem with only one cylinder (or one bank), your O2 readout isn't going to help with the diagnosis.

I am planning on getting an Accusump system ASAP, what is the preferred size for this application? 3 qt? I had heard some talk about the front trunk being the best mounting location for an accusump for weight distribution, which would only work with a front mounted thermostat. but then you have some excessive pumping distance.

3 quart, yes. As close to the engine as you can within reason. A check valve in the accusump circuit prevents backfeed to the cooler.

If i were to relocate the thermostat, where would the preferred location be?

Firewall in the engine compartment if possible. You want your oil to reach the thermostat cracking temp quickly.

I have not seen any adjustable brake bias control, so I am operating under the assumption that it has a stock proportioning valve.

You can put a knob style prop. valve in place of the stock regulator. It just means you won't have cockpit adjustability.

I have cam specs somewhere and will post later. the heads have stiffer return springs so I place the true redline around 6500.

Single springs with such large valves may prevent you from reaching 6500. As long as you have the 1 1/2" header it won't matter much, you're losing power before 6000.

Am I right that you are essentially saying I should revert to a stock clutch and pressure plate?

I'd look for a 911S aluminum pressure plate and matching clutch disc. It will handle your power and is easy to operate.