Rolling Road results for a Fuel Injected 1040cc Imp Engine

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Joined: Tue Jun 24, 2014 5:57 am
Location: Lincolnshire Coast

Rolling Road results for a Fuel Injected 1040cc Imp Engine

Post by Charlie54043 »

This is the last in a series of 5 posts about “ Fuel Injection Build and Mapping”, and details a Rolling Road test

Before we get to the Rolling Road test, it may be helpful to outline the engine Spec's:

The Induction, Cylinder Head and Exhaust are:

4 x 36mm throttle bodies into 400mm long x 27 mm dia inlet manifolds
Multipoint Fuel injection ( with Closed Loop) and Ignition timing controlled by a programmable MegaSquirt ECU
Reg Pattern modified Full Race Sports Cylinder head, with 27mm inlet ports, 1.4” inlet valves, 1.25” exhaust valves and 3 angle Ali/Bronze valve seats.
Combustion Chambers balanced to give 11:1 Comp Ratio.
R20 Cam.
Stainless steel copy of Janspeed small bore exhaust manifold.
OEM Suzuki Hyabusa Titanium silencer.

And the “structural” parts:

Cosworth lightened Cam followers
Bronze valve guides
ARP Cylinder head Bolts
Wills Rings head gasket.
74mm bore Wet Liners shrunk into a 930cc Block
JP 74mm Pistons with 5/8” gudgeon pins.
Lightened 5/8” conrods with Cosworth Bolts
Standard Crank with Vandervell bearings.
Uprated standard Clutch
Lightened steel flywheel with High Tensile bolts
Pulley,Crank, Con Rods, flywheel and clutch Assy. balanced by Vibration Free
6mm Steel Sump Sandwich Plate with fitted Main Bearing Spacer Blocks and High tensile studs.
Hi Capacity Oil Pump.
13 row oil cooler
Large Front Radiator.

The Rolling Road plot:
Power Plot 2.jpg
Power Plot 2.jpg (202.24 KiB) Viewed 2122 times

The Air Fuel Ratio was between 12.7:1 and 13.0:1 for the whole run.

As can be seen, a reasonable amount of torque is produced at 2500 revs, peaking at 4600revs and not falling away too quickly. This gives a well mannered road engine, but with peak torque at these Revs, the engine was never going to be a producer of Mega power.

However 79 bhp, or 76 bhp/ltr for an elderly 8 valve engine is pretty good and putting this into perspective, another Gem of British engines, the 1400cc Rover K series produces 75 bhp/ltr.

The engine drives extremely well, idles steadily at 700 rpm, is quite happy to gurgle through town at 1200 rpm in 4th but then Rasps and Snorts to 7000 rpm when overtaking in 3rd.

In conclusion, modifying the 875 engine to 1040cc with Fuel Injection has produced a reliable, lightweight, powerful, modern road going engine which is ideal for undeniably the Worlds finest sports car!
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Re: Rolling Road results for a Fuel Injected 1040cc Imp Engine

Post by Johngrib8 »

Hi well done getting it all done, looks impressive torquey enough I had same cam Reg pattern head associated with almost identical set up on twin 40s never got it tested on a rolling road but it was a 998 and it could be your set up may have been a more cost effective option as the twin 40s are £400 each now could be less thirsty and more slow driving friendly.

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