Speed the Lotus Exige

Well that is interesting. I think it is more likely oil tube or not keeping a good o-ring on the tube than an oil temp problem. The other thing I have wondered is could the damage be happening on start up before the oil reaches the cam. But most think it’s an oil temp problem. No one has any hard data to solve the problem. Lotus has never acknowledged the problem.

 

WOW I did not see this a little late but no, thanks goodness.

 

Warning Long post.


After the track day I went about trying to find out why I melted a plug. I borescope my car and other then the melted plug all was good. Some of the more experienced track rats said if the track has a long left hand sweeper it can starve the fuel causing it to go lean, but this track does not have any left sweepers.

I ended up getting a wideband O2 sensor and installing a gage so I could see my AFR. Under wide open throttle they were about where they should be. Cruse speeds were also fine. When I would come to a stop if I did not down shift then the idle would yoyo a few times before smoothing out.

Well I keep researching. I found others who had the same aftermarket SC kit as my car, they had the same problems. The kit is no longer available and the person that did the tunes is noncom. I found out the tuner would tune a very rich AFR to hide knock. The 2ZZ motor is prone to knock. I could not hear knocking but that means nothing.

There is no software to dig into the Toyota ECU that I could find.

I started to think about installing a stand allows ECU so I decided to take some EFI courses to learn more before I decided to replace the ECU with an open unit.

HPacademy had a sale on their online class so I took several of them. They were very good and I learned a ton. I guess enough to be dangerous.

So in these courses they had a good course on knock, what causes it and what can happen if not kept in check. He even said that some times people mistake the effects of knock as a lean condition. Knock disrupts the air/fuel boundary and can cause hot spots. this can cause things to melt like pistons and …….plugs. And as we all know knock is like a hammer on your pistons.

The more I learned about knock the more I have become convinced this is the problem. Also a lot of other things fell into place. For example they covered how race teams try to control heat. If you can control heat it helps to control knock. Adding fuel is one way to control heat. I believe this is also why Lotus put duel oil coolers on the car, to help control heat on the track. These are after all track cars you can drive on the street. Of course too much advance causes knock. There is more to it but I am not the best person to cover the subject.


I bought an ECU Masters ECU Black PNP for the Lotus. No its not exactly PNP. This unit you don't have to mess with the factory harness, just remove the stock ECU and replace it with this unit. My year car has a TMAF so I had to add a AIT post intercooler. The ECU has a onboard MAP, so I also add a reference line to the ECU post intercool. The last thing I did was to add a second wide band O2 and pinned it into the ECU, I no longer have a narrow band O2.


Last Saturday I downloaded a base map and loaded on to the ECU. I needed to go through several checks before starting the car but could not help but hit the start button. It cranked up and idled fine. But my AFR’s were very lean. I spent about 30 long nerve racking min trying to figure it out. I am on a group with some guys in England that have Lotus with the same ECU they were helping a lot.

The original SC is a MP62, my car has a TVS 900. They believe this is why my AFRs were so lean. Another guy with a setup close to mine with a TVS 900 sent me his map to see if that is a better starting point.


When I get home this weekend I will try agin only this time I will take my time and make sure a test everything before I hit the start button.

 

If this goes south on me I may give Jan a call.

 

Don’t let the plug and play fool you. What that means is plug it in and play with it for weeks to get it started!
Last time I posted I said I had installed a bace map that got it cranked but was way off. Not only were my AFR’s way off but my dash did not work. One of the Lotus owners in England that has a setup close to my car sent me his map. I only had to change the settings for the injectors and my IAT sensor. My dash and all the gages work, it idles and runs good. I also got the car timed correctly. It seems odd to me to check the timing with the light then have to tell the ECU via the PC how many degrees to adjust. Tomorrow after work I am going to adjust the idle down it’s a little high, about 1600 RPM. I need to get it to 950. Also the AFR’s are slightly lean due to the supercharger I am running. I did drive the car just a little Saturday and data logged the drive. I plan on a longer drive tomorrow to try to get it dialed in better.
I bought a old used PC to do this with but the battery lasted about 45 minutes. So I bought a cheep new small laptop. I spent today after work setting it up and moving everything over to it. It’s battery should last about 8 hours. Much better.
I just hope it does not rain tomorrow

 

This past week I spent trying to get the idle down. With a lot of people jumping in to help but no luck. It was decided I must have a vacuum leak. I checked all the piping but could not find anything. Yesterday morning I decided to take a look at the throttle body. It looked ok. I started the motor and put my hand over the TB and the car did not die! That’s a heck of a vacuum leak! Next I was going to tilt the rear clam and start taking everything apart. I was spraying some carb cleaner in different places when it hit my catch cans the idle went down. I disconnected the hose leading to the intake system and plugged it. The car Idled down to around 900 RPM. At first I thought it was that hose but I found that one of the catch cans drain was left open by the idiot that changed the oil! I closed the drain and all is good.
I feel bad a lot of effort was put into helping me with the idle.

Now I need to get the idle up just a little bit. Then drive the car and run some logs and make fine adjustments till it is right.

I think I see the light at the end of the tunnel……………..or is that a train……….I can’t tell

 

Short update. I have the idle at 975 where it should be so it does not die when I come to a stop. The problem now is it is at around 2 BTDC it should be at 5, idling.
The gas gage showed I was almost empty. When I filled it up it took only 5.6 gal. It’s a 10 gallon tank so the gage is off. I will tackle that later. First address my advance at idle then fine tune my AFR’s. I need to set my fuel pressure also. Then I will correct my fuel gage and make sure my Speedo is correct.

 

Here is a shot of a log I ran the other day. You can see one of the windows I have open is the Tune Display it shows the ignition angel among other things. The ECU has a USB cable that I ran into the cabin. This is how I connect my PC. the OBD port is no longer used.

 

It could. Part of the set up is to tell the ECU to lock at 10 BTDC. Then disable the injectors or fuel pump to keep it from starting. While someone is cranking it over you check the timing with a timing light if it is not at 10 you adjust the ECU till it is. Then you start the motor and check it running. If it stays at 10your done. Unlock the timing on the ECU. Now using the crank position sensor the ECU knows where the crank is and can adjust the timing on the fly if needed. I don’t completely understand setting the idle but there are a couple adjustments you can make to effect it, also there is a function called idle correction that can adjust timing and fuel to get the idle where you want it for a given temperature. There are several tables you can adjust including coolant temp.

The fiddle factor is very high

 

I took several online courses and there is a group I am in with a bunch of guys in Europe that are helping me a lot! It’s more than I thought it would be but I am having fun learning how to do all of this.