SE overboost?

[danny tattersall]

I have recently fitted the high torque chip and now the boost goes right off the end of the gauge. Once you have used this level of boost,it is not possible to get above 0.6 bar unless you drive 'normally' for five minutes or so. It will then boost very high again. The engine does not cut out or anything, it is just that I back off the throttle when I see the gauge reading so high. Before fitting the chip the car would boost to about 0.8 bar and then drop to 0.6 or so as normal. I have tried lengthening the wastegate rod, which helps a bit, but I have to lengthen it so much that the wastegate is slightly open all the time. You get the rattling noise from the wastegate because it is not being pre-tensioned by the spring in the capsule. Anybody any ideas what is happening? I have not reset the ECU yet but it may be an option. I do not think there are any leaks to the wastegate actuautor as this would cause extreme boost all the time. Thanks in anticipation of your advice guys.

[feffman]

Danny:

I installed the Moto-Concepts 330HP chip in my S4 and it took about 100 miles for the computer "to learn" the new boost and fuel set up. Readjust yoru waste gate rod to the stock setting, pull the ECU fuse overnight, then drive tha car for 100 miles and see if this helps it run correctly.

Mark Pfeffer

[lotusespritworld]

your gauge only reads upto 1 bar. The new chip will provided more boost than 1 bar, so it's not really of any use. This is why I installed a turbo timer with a digital boost gauge. highly recommened.

www.lotusespritworld.com/EMaintenance/TurboTimer_reviewed.html

As said, you also need to run the chip in for around 30 miles. Slowly increasing the amount of boost used.

kato
Lotus Esprit World

[danny tattersall]

Thanks for the replies. However, I have done over 700 miles since fitting the chip. I did the first 500 of those miles in two long trips though, which could have confused the ECU. I can not understand why it lets the boost build up so high and then restricts it. I will try resetting the ECU - I have freescan and can do this without pulling the management fuse. I will keep you posted. Cheers.

[sanj]

It sounds like your chargecooler pump may not be working. If you are able to maintain full boost for only a brief time, and then cannot attain fullboost again for several minutes, I would check the operation of the chargecooler. With the engine fully warmed up, make a few full-throttle blasts in a safe place, then pull off the road. With the engine still running, carefully check the temperature on the top of the chargecooler with your palm. It should be cool to lukewarm. If it is hot or you burn your hand, chances are your pump is not pumping. Don't expect that you will be able to achieve sustained 1+ bar of boost with the stock turbo, even if everything is perfect, there is too much heat build up.

Hopefully you know where the wastegate adjustment rod was set so you can put it back, you should not normally have to adjust this and it should be put back to the stock setting before you do anything else. You can disconnect the wastegate solenoid electrical connector in the rear relay box for testing, you should see about .5-.6 bar maximum with it disconnected. You might get a check engine light with the solenoid disconnected.

Cheers,
Sanj

[danny tattersall]

Sanj,thanks for the input. I reconditioned the chargecooler the other month and it works fine. The plenum remains cool to the touch even after hard driving. I am going to reset the wastegate rod and ECU and see what happens.