Thread: Questions re 4L to 4.6L and more...

I went to a 4.6 about a year ago. Found the following, swapped ecu's back and forth and found no difference. You need to watch your source block for the fixing for the crank position sensor. A genuine 4.6 (say from a P38) will have a different alloy plate fixed into the back of the block. It's not a hard swap from you original block but you should do it before you get it all assembled (sound like voice of experience?). If you get a hatted 4.0 then it should be ok.

Sourcing the bits to upgrade could be harder than you think. Make sure you fit studs to the heads and main caps. Ring around the wreckers, I picked up a 10,000k rebuilt 4.6 for $2200-. Spent more than half of that in the previous 6 months chasing blown head gaskets.

If the MAF is original plan to replace anyway. You'll know about it when it goes.

The 4.9 stroker kit from TRS provides everything you need to fix your own block,, around 3K
top hat liners are $28 each,,

just needs a bit of machining,,
(anyone costed this??)

there are quite a few cams around,,
the idea is to find one that makes more torque than the standard cam at 2K revs,, thats not easy at all,,,
TRS reckon around a 25% torque increase with the kit,,
which sort of makes sense--

but then you'd have to worry about the boxes ability to cope,,,

Hmm ok. I'm still awaiting a couple more email replies from the UK. There are a few options I guess with sourcing an exsiting 4.6 to top hat, buy a stroker kit or import a 4.6 short motor that has been top hatted. If I get a stroker kit locally, the main cost would be machining. Anyone here have a price quoted for top hats into their block? I'm guessing anywhere from $600 to $1000. 4.8 would be the maximum I'd go if the existing ECU can cope with the increase in cubes.

A lot of money for the extra 600cc thou

Now if someone here can confirm that ACE, SLS and ABS don't communicate with the engine management I could go the Holden/Chev with a GM 4 speed auto and I'd do it tomorrow.

You said you were a blue oval man
I cant confirm your question but I always considered a aftermarket ECU could be configed. An LS1 in a D2 would be sweet...

You're right northiam, I'm a blue oval man and I guess the consideration for a Holden/Chev is mainly because of the adapters on the market. The hardest part of all is the Bosch Motronic engine management. I've found some useful information on it on the web but nothing yet that shows that the LR version can be manipulated so that it can run a LS1, LS2 or Holden. The other alternative is to just keep it as it is but with intended 4.6. It's just alot of money for 600cc more.....

Hmmm maybe I have made a potential break through in the Discovery 2 and P38 "repowering your V8 world"? The only other inputs that I can see are the transfer case low range, fuel tank and level inputs, and the CAN bus lines for diagnostics etc.

In an imaginary world, right now one could buy a alloy LS1 motor and matching 4 speed with GM PCM to control both. Buy the adapters for the GM auto to LR transfer case, engine mounts etc. Assuming the LS1 runs a return line for the EFI, run a return line back to the disco's fuel tank. That leaves me with the future upgrades of the diffs, driveshafts and axles. One would then ask, why did I buy my disco for in the first place???

My brain is hurting right now

My assumption on the ACE is that it would get a speed signal at the very least. The ABS/TC/HDC is all driven from the Wabco modulator and control unit which would also have its own speed sensor too. I wouldn't know if the ZF box control unit interfaces with either of these though. More research.

**Oh and another thing I should fix is that HDC is controlled by the engine management system.