Performance for the Discovery

[redrover51]

Yes, I agree the 4:11 theory is *"somewhat"* accurate...but what is the over-all cost, of the gear change, tire swap, plugs, chip, wires, exhaust, cash total,? parts only, (the labor to install is an act of love). *Increasing tire "height" in itself will put more stress on the diffs., but nullifies some of the lower-end torque gain. To benefit fully from a 4:11 change, stock wheel height will facillitate more low-end response, and also decrease M.P.G.. I am not attempting to "dampen" the spirit of these mods, but rather, I am seeking a simple approach to increase, with-out the financial extensions caused by the proposed conglomerate remedies. Wow! did I say that! Cool. I doubt that I am correct, but it was fun! Yu guize iz alwrite!

 

[Slam]

Wow

Ok- So what you are saying (because I don't speak big words) is that you want to basically increase performance (HP and gas mileage) without using enough money to buy a new Land Rover? Maybe we should think of ways to increase performance in a cost/performance increase ratio to try and determine what is the most important and effective for our money...

 

[redrover51]

Thanks Sam! I knew you would find some humor in my last post...I have spent so much $ on "new ideas", that I guess I'm just searching for "the easy way out" when it comes to solving these power/economy problems. I appreciate your willingness to find some answers also. I will keep-on keeping-on in my search for some simple, low-cost remedies for Disco-owners, so we can have enough $ left for having fun. I am NOT a negative person...I have just become a bit chaffed by the cost of things. I am now going to e-mail some LR mechanics, and do a little research for us...I'll get back to this post hopefully with some direct answers... soon...Thanks Bros..

 

[Sergei]

Of course K&N alone wont gain you much. You increasing intake flow, but since output (exhaust) is same - bugger all will happen. You need to upgrade both intake and exhaust to see real results.

Basically ways to get better mileage/performance off any rig:
- better oils
- proper alignment/balancing
- improving aerodynamic (remove roofrack & etc)
- remove extra weight (sliders, skids, heavy bumpers)
- airing up properly
- upgrade air intake
- upgrade exhaust
- upgrade spark plugs & wires
- clean valves (BG44K every now and then)
- clean filters
- check brakes for touching disks while pedal isnt pressed
- be easy on pedals, use momentum

if you feel adventurious you can also upgrade timing, play with fuel mixture settings.

Regearing wont help mileage ever. In fact it will always decrease it, as engine has to work harder. It will, however, improve perfomance on the road - as in torque values.

Cheers

 

[Slam]

- upgrade air intake
- upgrade exhaust

What kind of air intake and exhaust would you recommend, or do you use?

 

[ModRover]

Power

The only thing I have found to increase power in a Rover product is cubic inches. Hands down.

I know that port matching the intake to the heads does reduce the turbulence and increases in power have been felt. This is not really worth doing until you actually need to get your heads done anyway as it's not THAT noticeable.

Headers make a small increase too, but once again not THAT much. Doing some port/polish and headers in always a fun thing to try. Actually, the stock exhaust manifolds are pretty good. I remember reading a test flow report on them a long time ago and they did pretty good. Port matching these might be something to try before getting actual headers.

Stock ignition is another thing that improves power. Remove the stock setup (you guys and gals with the non-GEMS distributor style ignition) distributor and gut it. Then, install a Crane ignition system. I've actually installed a HEI ignition setup in my twin SU carb. fed motor. This was to be used in the Buick 300 (you have to remove the worm drive oil pump thingy from your old dist. and put it on this one). I don't know the ins and outs for installing this in an EFI model so I guess I just mentioned this just to mention it. bah haha

OK Back to cubic inches. This is the best way to increase power in your rig. It's not cheap. I'd say deal with the power of the rig now and when the time comes for an engine rebuild... go bigger. I put a 4.2L in my old 1988 Range Rover and couldn't believe the power increase. I got it from a wrecked LWB and just did the heads, timing, cam/lifters on it. This is a great upgrade for all that use the 3.5L and 3.9L.

For all that have the 4.0L and 4.6L ... hmm... well, JE (England) does make a 5.2L Rover motor! Very expensive, but lots of fun. I put one of these into a Disco that had a 3.9L. WOW! Big time power diff.

So, in a nutshell... do the ignition swap (it gets rid of that crap stock module anyway), maybe try port/polish of intake manifold, maybe try port matching the exhaust (do these port matching on the manifold sides as you don't want to mess up a head!), and K&N if you like them (I'm not a fan of them).

The diff. gearing swap is a great way to get back the "power", but it's not actually a power increase as much as just making things easier on the rig. It will feel more powerful as things are not working as hard. So, do this if you've gone with 33" tires when you're RR used to have those stock 205.

These rigs are heavy lumps for sure. Power doesn't really come cheap with them. The little things might add up, but I'd do them when you have to take them apart rather than just to try it. I don't know that it'd be worth the time unless you like wrenching. Sometimes it's fun to experiment (unless you have to use the rig the next morning for work! bah haha).

I know I've probably forgotten somethings here, but this is just a few things on my mind. Take them for what it's worth and have fun!

My .02,
Michael

 

[redrover51]

Excellent advise! The depth to which you have ventured with the LR line is "very impressive!" Engine change-outs are not for the "faint of knuckles." I just returned from Land-rover Knoxville, Tn. and had a few cool conversations with thier mechanics. It seems there is an English Company that has a performance cam. I was told I could find it if I searched for "Land rover acc. engine. cams" I have not yet attempted it, but I will tonight. Porting and polishing has always been a favorite of mine! If it goes in smooth, it will go in faster! Talk later! Redrover51

 

[LRWheelman]

Happy W/my power, have K&N, NGK plugs, and Taylor Spiro-Pro wires. All available @ your local speed shop! (I use Bumper to Bumper)

 

[joey]

On my '97 4.0, I have 8.5mm Magnacore wires, Champion plugs, stock air filter and Headman headers with flowmaster series 40 muffler. I would say if runs pretty good maybe 15 to 20 horses over stock... Planning on Rechipping the ECU, Recamming it later this year or early next...but the best source of performace you can get is to remove the Fan....when the temp drops below an average of 75 deg I remove mine and gain 2 miles to the gallon on the highway and you can feel the difference in power.... working right now on getting my duel electric fan custom fit to be stuffed in, so I don't have to worry about removing the fan anymore...that should be very nice on fuel when done.

 

[Ares]

My $0.02 is that the K&N is pure BS, especially for an offroad vehicle. Get a NAPA or WIX filter and go. Change it when it needs changing. Im new to the LR arena, but I think the other ideas are on track... ignition system and headers are good realistic improvements to almost any vehicle. If one wants more, why not look into supercharging? Matching the intake runners to the intake ports may give you some, but I dont think that alone will give any "seat of the pants" difference without increasing valve lift, duration, and flow through the rest of the intake/exhaust ports/valves/bowls. Simply smoothing the ports may help, but if its too smooth in a certain area the fuel can condense and pool... not good for idle quality. I would be reluctant to let someone grind on these heads without experience and flow bench data on LR heads. You can really screw up a head quick by grinding too close or into a coolant passage. Grinding in the wrong area can make the heads flow worse. I wonder what the LR V8 heads flow. It may flow pretty well from the factory and may respond well to just a cam with more lift and/or more duration, and customizing the ignition curve.