Toyspeed.org.nz Message Board

by **limbo** » Sun Mar 18, 2012 11:35 pm

How rich can you safely run a turbo car before you end up with carbon build up or washing the oil from your bore or poising your oil with fuel etc.

I am currently running about an air fuel ratio of 10.5 on boost on the stock computer and want to know if that would do any harm long term or if I need to pay up for a new computer and tune.

by **iOnic** » Mon Mar 19, 2012 12:36 am

That's alright - not good but it's not gonna implode because of it. You're not getting the best power/drivability/economy you can though. Pay to get a computer and tune if you want it to run at it's best.

by **Quint** » Mon Mar 19, 2012 7:15 am

Hurray for factory ecus and their safe tunes. :roll:

by **Heylin** » Wed Mar 21, 2012 12:14 pm

yep 1990 MR2 GT, stock ecu was about 10:1 under boost, even upto 19 psi on a ct20b upgrade it still managed this, refused to lean out.

by **steroidcontaskie** » Wed Mar 21, 2012 12:41 pm

+1 for a ECU and Tune

Pay for a aftermarket ECU, or better yet, if you have a friend that has a project car that is never going to work, just take his aftermarktet ECU (it is sitting still in it's box on the passengers seat) out of his car and put it in yours.

by **Lith** » Wed Mar 21, 2012 4:11 pm

limbo wrote:How rich can you safely run a turbo car before you end up with carbon build up or washing the oil from your bore or poising your oil with fuel etc.

I am currently running about an air fuel ratio of 10.5 on boost on the stock computer and want to know if that would do any harm long term or if I need to pay up for a new computer and tune.

How is it at part load, cruise etc? Some of that stuff is what is more likely to cause you issues.

by **steroidcontaskie** » Sun Mar 25, 2012 6:16 pm

As far as I know, Limbo only has the A/R for the dyno run on his car. We could put a wideban sensor in and have a look next time he is in NZ. what numbers would he be wanting on part throttle etc..

by **iOnic** » Sun Mar 25, 2012 6:39 pm

You'll probably find that it's fine at part throttle/cruise as that's almost always off boost and the ECU is in closed loop. Stock ECU's have a habit of just dumping fuel in to save the engine at all costs when they see more boost than they've been told to expect so it'll be pig rich under boost but fine off boost/at cruise/light load.

This is assuming you haven't played with the stock fuel system. If you have, I'd suggest getting a standalone.

by **steroidcontaskie** » Mon Mar 26, 2012 3:54 pm

Pretty sure it has got a 500hp walbro, but injectors are standard (have been flow tested) and it is running factory ecu. Turbo is slightly different from factory and it is running 12psi boost.

by **Mr Ree** » Mon Mar 26, 2012 9:41 pm

On light throttle you can tune it quite lean if you want some good economy.
Mine is circa 15.5:1 on very low throttle input cruise.

by **Lith** » Tue Mar 27, 2012 8:54 am

iOnic wrote:You'll probably find that it's fine at part throttle/cruise as that's almost always off boost and the ECU is in closed loop.

Assuming the O2 sensor is in good nick

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