Does anyone know any tricks or anything to get higher revs out of these v12s?

 

Get rid of the torque convertor.

That is one of the prime reasons for rev limitations, the convertors explode apparently????.

Manual transmission V12's are capable of higher revs. I "think" the Bathusrt XJ-S cars of the '80's had 7000 change points as mandated by the "race command" of the day.

 

6500 rpm redline isn't enough for you? :-) Are you going racing?

Cheers
DD

 

I seem to recall you have done a manual conversion, correct me if I'm wrong.

If this is correct - breathing and ECU upgrades will help. The stock manifolds flow well The restriction is the TB and small airbox inlet. You can use the stock airbox and replace the inlet with 2" pipe bore the TBs and I would add velocity stack into the airbox.

You don't say how much more don't You are looking tidbits if higher than stock redline then aftermarket ECU will be required megasquirt is good if you are handy.

 

well mine isnt running any higher than 5000!?!? so i was wondering if that had anything to do with my manual conversion? im confused, i also dont have a front pressure regulator at the moment but that shouldnt be limiting me should it?

 

at 5000 rpm does it start cutting out or does it just stop revving up?

 

Front pressure regulator? What do you mean?

 

There are two regulators on the he engine, one infront of the rail and one after it. The i front is the front regulator. And it starts gasping

 

ive got a manual

 

go get yourself a wideband and see what your AFR is past 5k.

 

Correctly referred to as the inlet regulator (RH side) and the outlet regulator (LH side). A fuel pressure test will confirm a regulator problem although the inlet regulator can be removed entirely with no ill effect.

Cheers
DD

 

Is this a Lucas ignition car? If so, is it still on the two coil system? If so, failure of the secondary coil will greatly hinder the ability of the engine to rev up....although the problem typically starts much sooner...about 3500 rpm generally. Just a thought.

I'd lean towards a fuel delivery/fuel delivery problem myself.

Do you have a fuel pressure gauge?

Cheers
DD

 

I think secondary Lucas coil too..., but it is helpful if you would let us know what year model, engine, etc. you have when you post, that way you won't get sent on a goose chase that doen't apply to your car. In a nut-shell, 1988 and older are referred as 'Lucas' cars, and 1988.5 and newer are 'Marelli' cars...so designated by their ignition systems manufacturer.

Dave
Dave

 

do i have to weld a new o2 senson into yhe exhaust?

 

No, you need to check fuel delivery and pressure, and check your primary and secondary ignition. I know that's sound pretty dull and boring compared to the coolness of wideband oxygen sensors but, well.....oh never mind


Good luck,
Doug

 

The problem is i cant check the fuel pressure while its running under load

 

Why not?

 

probably because he doesnt have a cabin gauge?

wideband. it will tell you if your starved for fuel up top. fuel delivery issues, etc. you could have plenty of pressure but an injector issue that you would never detect with a FP gauge.

we use widebands for our Grand prixs, especially turbo swaps to see if our injectors arent delivering enough fuel under boost.

 

You do not need a cabin gauge. You connect it and route the hose out from under the hood. Tape the gauge to the windscreen and off you go.
Of course this is not as cool as a cabin gauge or a wide-band O2.

In this situation measuring the air/fuel ratio does not really tell you much. You are not trying to tune the engine management system but rather you are trying to diagnose a problem. You need to make sure your coils are good and you have enough fuel available. These cars are not that complicated. They can be intimidating yes but are very simple compared to modern cars. Just have to start with the basics and check everything. You will drive yourself and your bank account nuts if you just start tossing parts at it or trying to second guess everyone's advice. There are some who just won't listen. Hopefully you are not one of those or you will never fix your car.

 

a cabin gauge will still be useful anytime your motoring about after dark.