Fuel mixture

[millsn]

Car was rolling roaded by Road n Race then I fitted a bigger bore exhaust and collector knowing I'd need a remap. funny thing is, since fitting the exhaust the car runs very hot unless at tickover where it runs normally. As soon as the revs rise the temp quickly follows. Question is, can I really have impacted the mixture so much that it impacts head temps to drastically? I cna test by adding fuel but I was interested in anyone else with similar experience. Car is a 2.0 zetec

 

no.6

[Stationary M25 Traveller]

My 1.8 k-series seems to warm up much quicker with the new 4-2-1 exhaust.

 

 

[Steve, Carol and little Cl]

If the engine runs with a lambda sensor, then any change to the exhaust system as such could lead to inaccurate results from the lambda sonde. Usually, the lambda sonde is positioned such that it can analyse the mixture from all of the cylinders and such that no one cylinder has a greater influence on the reading than the others (although, obviously, no system is perfect). If you make any constructional changes, you may well effect what the lamda sonde sees. It may measure the oxygen content based much more on a (or several) cylinder(s), giving non-represenative oxygen contents for all of the cylinders on average. Of course, this is only a possibility. If you wan to ensure that all the hardware still works correctly, put your old exhasut system back on and see if the engine runs fine. If it does, it´s most probably down to the exhaust system.

 

Good luck

 

Steve

[millsn]

The old exhaust is the new exhaust so I can't change it back. No I can figure it out by adding more fuel (but it'll take a while because I haven't yet wired back up the ECU comms lead).I just wondered whether anyone else had had a similar experience. I run open loop TBs, i.e. there's no lambda at all and no air temp sensor either. Seriously, the only change I have made is as described and the car now runs hot.

 

Edited by - millsn on 16 Mar 2009 21:35:21