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Old 04-18-2021, 01:49 AM   #23 (permalink)
Master EcoModder
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spyder2 - '00 Toyota MR2 Spyder
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Originally Posted by quagss View Post
Look on the website There is a member AEHaas, who has several exotic cars. Ferraris mostly. He runs 0w-20 in them. I would recommend you try Redline 10w-30. Yes it's expensive but you'll only need to change it once every 2 years maybe.

If you can write a custom tune, you should lean it way out. Forget 14:1, try 18. I would imagine the robust V8 can handle lean burn as the large metal volume and overbuilt cooling system can handle the heat.
Thanks for the comment, I am aware of all this.

The issue with running a light oil is that unlike the BMW S65 and S85 engines which had tight bearing clearances and failures on 10W-60 oil, Vantage owners all run 10W-60 with basically no engine failures, suggesting the oil is pretty well matched to the engine.

Certainly it is unlikely that 10w-30 oil at 100-105C would be an issue for street driving, but dropping 3 grades feels too aggressive on an engine that would cost 20k to rebuild, and it's possible that the thinner oil film will have diminishing returns for efficiency.

I would be shocked if I made it to 2000 miles in any year on the car, so it really doesn't make sense to buy Redline oil for 70 dollars more when my OCI is going to be like 2000 miles. The shelf life of oil is shorter than the time it would take to accumulate 7500 miles. M1 is very very cheap at 4 bucks a quart and the base stocks have fairly good VI.

As far as tuning goes, the issue is this platform isn't common and well supported the way Subarus or BMWs are. Even on a popular platform, lean burn can be very difficult to implement due to the ECU restricting open loop AFR to rich only.

There is a guy who did figure out pretty much all the workings of the ECU and ran lean burn (in open loop), but he spent many years and tens of thousands on his car. The easier way to do lean burn is to replace the O2 sensors with wideband sensors and bias the closed loop AFR, but it requires considerable custom ignition timing adjustments if you want the most out of it, and you need to spoof the post-cat sensors as well, so it'll take 2 wideband emulators + sensors + 2 sensor simulators and quite a lot of money and/or time on a custom tune.

My limited modifications are vastly easier since the OEM already built in all the timing compensation and it's just a matter of accessing a few tables. I will never break even on this mod, but for a little bit more effort over an off the shelf tune I can get my car a few % more efficient than 99% of the others.

Last edited by serialk11r; 04-18-2021 at 02:11 AM..
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