RazMan
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| posted on 30/3/10 at 12:17 PM |
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Do high lift cams need more fuel?
After installing some performance cams in my V6 I was wondering how the mixture will be affected.
The cams aren't too radical but as my setup doesn't have a Lambda sensor to make small adjustments it will probably need some mixture
tweaks in the map to get the most out of the cams.
Can anyone give me an idea of how the mixture will change? I just want to be sure that I can run it for a short while before shelling out the beer
tokens on a remapping session.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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turbodisplay
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| posted on 30/3/10 at 12:41 PM |
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Yes as the amount of air getting in will be more (higher VE), more fuel is needed to prevent running lean.
If the ecu has a MAF sensor then moderate increase in air flow will be automatically accounted for, MAP based fuelling will be affected.
Darren
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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mookaloid
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| posted on 30/3/10 at 12:43 PM |
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I suppose that the point of the cams is to get more fuel/air mix into the cylinders more efficiently to increase the power of the engine.
If your set up doesn't have the lambda sensor to give feedback to the ecu and adjust the mixture then well....
draw your own conclusion.....
"That thing you're thinking - it wont be that."
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RazMan
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| posted on 30/3/10 at 01:00 PM |
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Pretty much what I was thinking - the car seems to run fairly well except for some 'hunting' when cruising on small throttle openings (an
indication of a weak mixture I suppose)
My setup is based on the TPS and mixture so no MAF or Lambda to do the clever stuff.
Ah well I had better break open the grandkids' piggy bank then 
[Edited on 30-3-10 by RazMan]
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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turbodisplay
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| posted on 30/3/10 at 02:27 PM |
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If i were you I would fit a maf sensor.
That way any small mods in the future will not need a remap, at most a small tweak.
Also the most accurate means of fueling.
Darren
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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daviep
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| posted on 30/3/10 at 02:29 PM |
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quote:
Originally posted by RazMan
My setup is based on the TPS and mixture so no MAF or Lambda to do the clever stuff.
How does the system determine the mixture without a MAF or MAP or Lambda?
I apologise for my ignorance.
Regards
Davie
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MikeRJ
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| posted on 30/3/10 at 02:37 PM |
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quote:
Originally posted by turbodisplay
If i were you I would fit a maf sensor.
MAF sensors and lumpy cams do not usualy play together well.
quote:
Originally posted by daviep
How does the system determine the mixture without a MAF or MAP or Lambda?
This is the Apha-N system, it uses a combination of throttle angle and engine RPM to determine fuelling. about the simplest system possible that
yields useful results, and pretty much the only system that works reliably with really radical cams.
[Edited on 30/3/10 by MikeRJ]
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turbodisplay
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| posted on 30/3/10 at 02:43 PM |
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High lift are not lumpy cams, long duration is as there is gas reversion pulses in the inlet manifold, which will trick maf and map sensors.
I think it is possible to use tps at low rpm and maf or map at higher rpm - best of both worlds.
A nice big plenum will serve to dampen reversion pulses as well.
Darren
[Edited on 30/3/10 by turbodisplay]
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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RazMan
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| posted on 30/3/10 at 04:35 PM |
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My car has been running fine with the std cams for 3 years on this simple setup but it does have the ability to use a Lambda sensor - in fact the
cable is there so all I need to do is bung in a sensor and switch it on (if I knew how )
Would it be a good idea to get it totally remapped with the Lambda switched on or is there some way of doing it DIY style, and save a small fortune on
the rollers? I am sure the adjustments will be quite minor so maybe the sensor would be able to to it without any more interference (if it ain't
broke etc)
p.s. I'm using an MBE ECU & Easymap
[Edited on 30-3-10 by RazMan]
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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RazMan
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| posted on 30/3/10 at 05:56 PM |
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Having done some Googling it appears that the Lambda part of the MBE is a nightmare to set up and the ECU needs to be sent back to be calibrated
before switching it on (it might just be the company making a few more quid though)
I am now thinking about getting one of those cheap (£150ish) wideband kits and simply adjust the mapping manually using the kit as a reference. Or
would a kit interface with the ECU without the need for calibration?
On the other hand I could spend a little more and get it mapped by a professional. I like the idea of doing it myself but I wonder how easy it would
be to get things badly wrong when something goes bang!
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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MikeRJ
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| posted on 30/3/10 at 06:18 PM |
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quote:
Originally posted by RazMan
I am now thinking about getting one of those cheap (£150ish) wideband kits
As long as it's TechEdge or Innovate etc. Not JAW.
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RazMan
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| posted on 30/3/10 at 09:26 PM |
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Thanks for the tip Mike - looks like the Innovate LC-1 is the choice then.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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