Strategies - Supercharged Lotus with 2ZR-FE Engine | AEM
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Last seen: 2 years 3 months ago
Joined: 08/30/2017 - 17:46
Strategies - Supercharged Lotus with 2ZR-FE Engine

Hi all,

I'm based in the UK and have a Lotus Elise 250 Cup with some modifications. The car from the factory has a supercharged 1.8L 2ZR-FE engine outputting 243 bhp and running stock 0.8 bar boost, the supercharger is a Magnuson TVS 900. Toyota has just launched a Yaris with a similar 220 bhp setup, which I think is very close to the Lotus Elise 220 Sport model we have here.

I've installed a free flow air filter (TRD), performance manifold, cat and exhaust system. The stock car is massively restricted with it's stock manifold so these simple mods have made a huge difference to airflow. I've also been logging the car extensively through OBD and also through a Wideband sensor.

I came to the conclusion early on from the logs and the UEGO that the car was instructing the injectors to do something they couldn't do and support peak momentary outputs under high boost so I replaced these 380cc injectors with 550cc Denso injectors I sourced from the US. The car now reacts to the ECU on point and goes rich when it should and throttle response has massively improved. It also idles beautifully, feels much happier and the ECU has clearly learnt the new injectors without doing anything at all.

The issue comes around with the fact that the Lotus ECU is instructing the stock injectors to go as low as 10:1 at WOT max boost (I'm at sea level), with my UEGO telling me it's actually only getting into the thirteens (with modified system, stock injectors). With the bigger injectors fitted, it can now actually get to the 10:1 the ECU is instructing, and I need to change it to adjust it to something a bit more reasonable at WOT. What are the current thoughts about boosted AFR's as my research indicates a wild fluctuation in people's thoughts on this matter?

I'm just interested in suggestions on how best to target this with the AEM F/IC 6 I just bought. The car currently throws a too rich code. Ultimately, I want to go and get it on a steady state dyno and map it from there. However, initial thoughts are:

Map the new injector sizes
Account for the different dead time

What would be a strategy using the AEM to cap the instructed AFR's down to something more reasonable, say 11:1? Adjust the fuel map via the short term trims?

The current CEL code seems to be generated under high vacumn, low throttle opening positions. I will need to log it I think to zone in on this issue but I guess again STFT is the way to look at this?

Many thanks

Last seen: 2 years 3 months ago
Joined: 01/21/2018 - 05:02
Hi Peanut,

Hi Peanut,

Just reading through your post, I see no responses as yet.

Did you resolve the issues you had?

I am considering either the AEM FIC or The Greddy E-manage for my Exige.

I'm looking for some feedback if you can help.



Last seen: 1 year 5 months ago
Joined: 02/24/2019 - 20:48
Hi Peanut 

Hi Peanut 

am also driving an Elise 250 Cup, in Germany. I am thinking about modifying same upgrades as you did, flow air filter (TRD), performance manifold and sports cat as current stock engine cranks out only 235 PS.  Did you measure how much PS your modifications added , with stock ECU program or modified ?

Thanks for sharing your experience!



Elise Cup 250

Last seen: 1 year 1 month ago
Joined: 06/20/2019 - 14:28
there is available solution

there is available solution for lotuses ecu in UK stock 220 with good exhaust and map will do 260 hp good 250 with good ecu and exhaust about 290

Greg Pe