Sorry for a bit of grave diggery, but my project for this summer has been to work on my IATs’ on my 2006 Exige S with the Lotus 260bhp upgrade. In the name of trying to whip up a bit of discussion on the forum I thought I’d post my findings.
I’ve been using Blyton Park trackdays as a reference point as it’s relatively easy for me to repeat, so no Spa figures I’m afraid - but hopefully useful to somebody.
The modifications I’ve done are:
2.5" pipes to the IC shroud from the sidepods
OEM intercooler
DIY heatshield under the IC
“Mail Slot” modification
Wider mesh on sidepods
Dual Catch-cans
I logged the temps using my ODB reader and the Android Torque app, and plotted the data in Excel.
I did some mid-year logs too at different circuits with wildly different ambient temps, but logged here for completeness. As you can see, I was working with much higher ambients and my changes managed to nullify that increase and even improve upon the much cooler ambient baseline - so it was reassuring.
I had no real idea what the correlation would be between ambient and IAT, but since adding the ducts and heatshields I’ve had a consistent 33ish degrees delta between ambient and average IAT reading on circuit. Pre-modifications that was closer to 50! This delta would suggest that the catch cans and letterbox have been marginal (if at all) gains, and the bulk of the improvement was from the ducts and/or heatshield.
So I’ve come to a bit of a conclusion that adding the ducts & Co is really good value for money/effort, but the two pieces of information I’m missing are:
-How would this change if I uprated the intercooler core itself? Plenty of posts on Exiges.com about this but some rather contradictory reports of the effectiveness of changing the intercooler. Going aftermarket with OEM airflow can be a downgrade in some cases, but how about with my new ducts?!
-How would this compare to a modern chargecooler setup? If a water based system could get me in a position where I was comfortably under 50degrees avg regardless of ambient, then I think it would be worth stepping up.
I’m almost certainly going to end up chargecooling this car, and this was never an exercise to save money on that front - but I did want to have a bit of fun and make some nice easy incremental updates throughout the year.
It’s clear that I’ve made a solid gain with this setup but the temperatures are still almost always over that alleged 50degrees threshold at which timing is pulled a bit.
When studying the data a bit more you can see big gains in how quickly the intercooler core recovers back down to a “resting” temperature, and the sessions on circuit can be much longer before the resting temperature starts to rise (heat soak).
I’m now at a crossroads, I’m pretty sure I want to continue making improvements but chucking some cash into a new intercooler is going to go a significant way towards the cost of a chargecooler setup. This winter I’m likely to have the front clam off to sort the rad and other bits out so would be an ideal time to do a CC install if that’s the route I go down.
My main concern with the CC is how much extra weight/complexity I’m adding to the car. Already having aircon anxiety with my sill pipes so don’t want to add more mess if possible!
Since this thread was started, DIY data logging is accessible to everyone thanks to ODB readers and apps such as Torque - so wondering if there’s any up to date stats that I can add to my findings to plot a course forward!
) and the car was an absolute monster all day.
