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Fuel delivery

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tr7v8mike Avatar
tr7v8mike Gold Member Michael Booth
SYDNEY, NSW, Australia   AUS
Hi,

I have a warmed-up 4.6L Range Rover engine with 14CUX EFI (Tornado chip) on top. Its time to overhaul the fuel delivery system and I'd like to do it right the first go (just for a change). The car goes well up to a little over 3,000 rpm then the power dies off. I'm suspicious that its fuel starved.

I have a swirl pot in the boot, the original hard fuel line (which looks too small), a pressure gauge inline and a choice between vacuum or manually-adjustable regulator.

I'd be most grateful for advice on how to put this together. What size fuel lines? What type of lines and fittings (hard, braided, nitrile)? Optimal pumps and filter? What is the optimal fuel pressure? There is a narrow aperture pipe at the entrance to the fuel rail that the fuel hose fits onto. Is this a problem?

Cheers (and Happy New year)

Mike

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darrellwalker Darrell Walker
Vancouver, WA, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
First thing to check is fuel pressure when the power dies off. That should tell you if you have a fuel delivery issue. It could be as simple as a clogged filter, if you haven't changed it recently.

The stock lines are 8mm (or 5/16"winking smiley, with 12 mm between the pump and the tank.



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, OR, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1504623 by tr7v8mike Hi,

I have a warmed-up 4.6L Range Rover engine with 14CUX EFI (Tornado chip) on top. Its time to overhaul the fuel delivery system and I'd like to do it right the first go (just for a change). The car goes well up to a little over 3,000 rpm then the power dies off. I'm suspicious that its fuel starved.

I have a swirl pot in the boot, the original hard fuel line (which looks too small), a pressure gauge inline and a choice between vacuum or manually-adjustable regulator.

I'd be most grateful for advice on how to put this together. What size fuel lines? What type of lines and fittings (hard, braided, nitrile)? Optimal pumps and filter? What is the optimal fuel pressure? There is a narrow aperture pipe at the entrance to the fuel rail that the fuel hose fits onto. Is this a problem?

Cheers (and Happy New year)

Mike

Mike:

Are you sure it is fuel starved? The stock cam is going to be set up for torque (assuming it came out of a Range Rover). Stock the engines are set up to go up to about 3500 RPM, and after that not much happens.

Since the car is injected, 45-50 PSI should be plenty, perhaps with a vacuum activated fuel pressure regulator to drop the pressure when it is idling.

Assuming the engine is otherwise stock, the bolt on stuff should be attempted first (cold air kit, low restriction exhaust, under drive pulleys especially the water pump, cooler thermostat, etc). These will give you more top end, but don't expect miracles. A more aggressive advance curve, along with a bit more ignition initial advance will also help. Each of these is worth perhaps 2%, not enough to feel but they add up.

After that, you are looking at internal modifications. Raised compression will give you 5-10% for each point, porting the heads another 5-10%. Compression will raise power all across the RPM range, from idle to red line, porting will affect top end only. A three angle valve job is worth another 1-2%.

A mild cam will shift the entire power band up (easy does it, most people over cam their engine for the street). Crower and in one or two cases Kent Cams are the only ones making decent cams for the Rover V8 at the moment. Piper Cams designs are all obsolete, and Crane, Comp Cams and other US specialists have stopped offering cams for the 215 V8. Everybody else still making cams for them are using old tooling and designs that are not worth considering.

IIRC correctly, you have already done some of this stuff (?), so forgive me if I am preaching to the choir.

A list of your mods would be helpful (and apologies again if you have already listed them in another thread. I am old, and I seldom remember what I had for breakfast, much less discussions in these forums).

Vance

PS There may be someone in Oz that has invested in modern designs for the V8 lump. I would need to see some specs to be convinced, however.



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore

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