Running a bit lean ?

[mgaut]

I recently had the car on the rolling road, and whilst the bhp/torque figures are good for a 400 (222bhp/238lb/ft) the fuel/air mixture (if that's what it is) was running around the 13 mark on the graph (apologies if this isn't fuel/air, and I haven't got the ability to scan the graph).

Aside from some ACT hoses and trumpets, the car is, as far as I know, standard.

Can anyone with some knowledge explain what this is all about, and suggest if I need a solution (fuel regulator?).

Should have paid more attention at the time !

Mike

[GreenV8S]

That power is very respectable from a 4.0L, and the fact that it is also running lean (presumably under power) may just mean that the fuel supply hasn't been increased to match the extra air that is going in. You may find that getting the fuelling tweaked gives you even more power as well as reducing the danger of pinking, allowing you to run more advance, more power again, better throttle response and so on.

[mgaut]

GreenV8S said:

You may find that getting the fuelling tweaked ...

can you explain how please ? I didn't think you had any control over that with the standard ecu ?

Edited by mgaut on Monday 29th January 21:10

[trackcar]

13:1 is lambda 0.88 that's perfectly acceptable, in fact some tuners say lambda 0.85 to 0.88 is best for power on the RV8 .. who told you that was weak?? sounds just perfect to me!

Edited by trackcar on Monday 29th January 23:58

[mgaut]

trackcar said:

.. who told you that was weak??

and you think I'm falling for a spell in the sin bin ??

If that's perfect I'm a happy Chim driver, but I'm still interested in how to adjust the mixture.

Mike

[mongoose]

mgaut said:

trackcar said:

.. who told you that was weak??

and you think I'm falling for a spell in the sin bin ??

If that's perfect I'm a happy Chim driver, but I'm still interested in how to adjust the mixture.

Mike

As Joo says,there little wrong with that mixture,perfectly safe unless you also have much leaner patches.I bet i could guess where you might have been told such things,but you wouldn't go in the sin bin for saying that,and theres always e-mail off forum if you feel it would be better.Theres not too much you can do to alter the fuel mixture easily and predictably without expert help.The TVR std map is usually very good,despite what you might hear from some.Personally i would just leave well alone as is,unless you want to modify,then there are many cost effective options for mapping work etc.

[mgaut]

thanks for that; the "running lean" came from a reputable rolling road; the figures should be closer to 12 than 13 if I recall correctly.

I understand that by mapping or replacement ECU (where's me wallet ?) you can do some great mapping, but Peter's "tweak" comment leaves me wondering how this is done.

Mike

[trackcar]

nah, unless we're not getting all the info here you're being told some really screwy info. I'd go get several other opinions but on the face of it it sounds like you're being massaged into getting work done that isn't needed .. running it into the 12s AFR is so safe you could srap a light pressure turbo to it lol

[mgaut]

If the figures are fine by you, I'm happy to let this one rest; many thanks

Mike

[That Daddy]

trackcar said:

13:1 is lambda 0.88 that's perfectly acceptable, in fact some tuners say lambda 0.85 to 0.88 is best for power on the RV8 .. who told you that was weak?? sounds just perfect to me!

Edited by trackcar on Monday 29th January 23:58

Right on the money.

[Podie]

That Daddy said:

Right on the money.

As ever...