Thread: Mod 300tdi vs isuzi 4bd1t

Just to compare my factory stock Tdi has 63kw dynoed at the wheels. Pat

Hello XRAYXRAY,

I have some considerable experience with the ARMY Perentie vehicles which have the Isuzu engines (4BD1 & 4BD1T). In my experience you should be able to use the standard gearing, this is in fact what Land Rover engineers designed the vehicle for, towing heavy weights.

The 4BD1T is a bomb proof engine however the 4BD1 and 4BD1T are not identical. Please ensure you get a genuine Isuzu factory 4BD1T.

The weak point in this role is the clutch.

For highway driving you may wish to invest in a Rocky Mountain overdrive, this is technically superior to the GKN as it is self lubricating and has an epicyclic gear train.

As others have suggested, you may need to budget. I have formally investigated upgrade of the engine which included variable geometry turbo and water to air aftercooler. The ARMY installed an air to air aftercooler on some 4BD1T engines and received a measured 20 Kw more power. If you can afford a new turbo and intercooler the engine will run cooler and more fuel efficiently. Industry experts have stated the Isusu 4BD1T crankshaft would absorb 500 HP, so you are most unlikely to damage the engine!

Again, I think the Defender gear ratios are fine, again towing 3.5 tonnes is part of the Land Rover engineering design, the R380 has five gears over the same spread as the LT95A which has proven to be a superb gearbox. Of course your alternate if to install a ZF Auto, the torque converter will absorb all the shock loading of start off and with its inherant lock up clutch is a mechanical connection once engaged. It this role you just have to ensure the transmission cooler is large and clean for good heat loss. The alternate is an Alison AT545 which has been installed in Isuzu trucks, see you local Detroit Diesel/Allison dealer for details of the bell housing which should be avail;able as a spare or from a wrecker.

I once towed a laden 6x6 with another laden 6x6, a GCM of 11.2 tonnes and had no trouble at all. LT95A standard gears, High Range 0.96, Diff 4.7. Max road speed 95 Kph @ 3300 RPM (later 105 Kph @ 3600 RPM).

Good luck, I would love to see your end result.

XRAYXRAY,

Sorry for the late reply. Did you look at the 2.8 TSV engine from UK? also a simple way of helping you engine to breath is to ceramic coat the exhaust manifold, or wrap it with heat proof tape. This keeps the heat in the exhaust gases and makes them flow fast rather than cooling in the manifold,, slowing down and choking the engine. You can also wrap the turbo body for the same reason and this also helps keep the induction side cooler by barring heat convection from the exhaust side.

MS

just some personal thoughts:

no matter which way you go. i would up grade the radiator and intercooler. the stock ones are marginal at best! also make sure you replace the LR temp gauge and sender. these are very bad!!! they seem to have a buffer built in, in other words it will read normal from say 88c to 97c.... not so good hey!

i HAD a 300tdi, its just not designed for towing or any decent weight. sorry but true. i bought my 110trayback with 48000km in VERY good condition. i had it serviced EVERY 10000km without fail. it had a 3 inch mandrel bent exhaust, the fuel turned up a bit and one of "Jase's" upgraded intercoolers.

8 months ago the head needed to be replaced because of a crack in the galleries. 2 months ago it spun a bearing from the crank to conrod. i no longer have a 300tdi.

i use my truck to tow my trailer to work. dual axle about 1.8t, stock gearing except for maxidrive 49%lowrange. it didnt like taking off from stand still and didnt like hills either.

they just dont have the design to be long lasting if used for what the truck can do. and my personal opinion is any "hotting" up will only reduce the running life of the engine.

Serg

Just an update everyone,
I decided to upgrade the existing 300tdi.
I ordered a VNT Turbo kit which includes a new exhaust manifold and dump pipe.
A full size intercooler.
An Alloy radiator with integral engine oil cooler which now extends into the area occupied by the original intercooler.
These items are now on the way from the UK and were ordered from Allisport.
With fuel pump tweaks and mandrel bent exhaust Allisport have projected an increase to 155+ horsepower so we shall see,plus a magor gain in torque at lower engine revs.
I have replaced a few components and have plans for some further modifications.
So far I have replaced the R380 with a new unused crate gearbox,I have replaced the transfer case with a Disco unit with 1.22 gears.
Extra heavy duty towing clutch from Exedy clutches,new brakes,new shocks plus lots of minor stuff,and fixing oil leaks,the vehicle was purchased with a few dents so those dented guards are being replaced.
Eventually I will respray in metalic red to match the boat.
things to do-Install Pyrometer,Fabricate Chequer plate aluminum bonnet panels with pressed Louvre's to assist in engine bay ventillation,soundproofing,remove tub and fit a custom tray.
There are some things I would like to do and maybe you guys can suggest how I go about it-oil cooler for gearbox,and I will probably fit a bigger sump pan to the transfer case but I will weld some heat sink extrusion to it.
And I'm open to suggestions from AULRO Knowledge Bank(you guys).
Cheers Mickey.