The V8 Owners Forum -

Hi,

Where going to use a 4.0l V8 engine with thor mannifold in our new offroad buggy.

The plan is to do some modifications, 'low budget', but still gain power. I thought allready to do the following:

- make a costum intake mannifold (or midifie the original) so I have 2 throtle body's, 1 for each bank. So I can use 2 smaller airfilters and still gain power.

- change the cam (and lifters off course) , what cam would you suggest to use. Torque at low rpm is the most important, as the max speed would be 120 km/h.

- injectors are the green ones, do I overhaul those or are there better to use?

- Are there any other easy modifications I can do to gain power?

We will use a bosch fuel pump and a fuel pressure regulator to have the correct fuel pressure.
The motormanagement will be from: http://www.lloydspecialistdevelopments. ... ms-roverv8

Many thanks for all the information!

Why not start with a 4.6? That'll give you more power / torque from the outset.

If you are going to make your own manifold, then why start with the Thor? This is well tuned for low down torque (which it does very well), but people generally use one of the earlier ones for more outright power.

Chris.

I have allready a 4.0 that's why I will keep that, otherways I also have to upgrade the auto box.

The thor manifold I would use as base to modifie - change this, have a spare one.

You don't have to upgrade the 4HP22 if you go 4.6. I have been running a 4.6 on my 4HP22 for years......

Chris.

+1.

4.6 and 4hp22 is fine - just keep the ATF clean.

I've been running approx 270bhp in mine, and she has been worked very hard, towing some heavy stuff long distances.

Vehicle had done about 95k before I changed the engine from 3.9 to 4.6, and have done 40k since. No problems - just change the ATF and filter a bit more often - i.e. every 20k miles.

If you are putting it in a buggy, then it will certainly be fine, cos the buggy will be very light indeed.

I would only change to a 4hp24 so I could have compushift, but at £750 - maybe not...

Besides, a buggy is probably best with a manual.....

Hi

I know a 4.6 would be better but I have a 4.0l at the moment, and I want to keep this a "low budget" build. If the 4.0l dies then I can search a proper 4.6

So could anyone help me with my questions above?

And for the buggy is an auto gearbox all the way to go. No clutches to burn, auto is the best.
drive allready a long time with auto boxes offroad and never want to go back to manuel.

My feeling is BMW with the Thor spent a great deal getting the best they could at low to medium revs. At the expense of top end.

If you want to get a better top end the simple way is to go back to the earlier plenum - which was originally designed for car rather than 4x4 use.

Trying to modify a Thor for better top end is rather untested water...

Also changing the injection on a Thor isn't likely to give any real benefit - unlike with earlier systems used. Especially at the price.

DaveEFI wrote:My feeling is BMW with the Thor spent a great deal getting the best they could at low to medium revs. At the expense of top end.

If you want to get a better top end the simple way is to go back to the earlier plenum - which was originally designed for car rather than 4x4 use.

Trying to modify a Thor for better top end is rather untested water...

Also changing the injection on a Thor isn't likely to give any real benefit - unlike with earlier systems used. Especially at the price.

Ok so overhaul the original injectors is the best.
any tips for camshaft?

thanks!

Do the injectors need overhauling? Again, I'm not convinced fitting an non standard cam will be of any benefit. Although replacing a worn out one will.

DaveEFI wrote:Do the injectors need overhauling? Again, I'm not convinced fitting an non standard cam will be of any benefit. Although replacing a worn out one will.

engine didn't run for a few years.
So I want to make sure everything is good and Ok. will let the injectors test, if needed overhaul them.
Not that expensive.