Allison admits to front exhaust handicap
James Allisson, technical director of Lotus Renault GP has admitted that the front exit exhaust (FEE) has handicapped the team's car to perform well at low downforce circuits. He also pinpoints the exhaust system for lacking downforce at low speed tracks.
It is no secret that thus far the Lotus Renault R31 has been under performing at low speed circuits, and the Singapore GP was no exception.
James Allison: "Anybody can spot that we have suffered very poor performance at Monaco, Hungary and Singapore. It is much harder to say with any precision just what it is about our car that can impact performance at these low speed tracks. Neither is it clear why Singapore was notably worse than either Monaco or Hungary. The simplest explanation is that there is not enough downforce in low speed corners."
Allison also doesn't make it a secret anymore that part of this performance problem is due to the team's radical forward exhaust blowing system.
"We know from our experiments with rear blowing exhausts earlier in the year that they do offer a lot more rear downforce – especially at high rear ride heights. We know that slow speed tracks allow the rear to be held up high in all the corners and we know that rear downforce is a prized asset for coping with the traction demand at these tracks."
"We also know that the forward exhaust, by contrast, performs more strongly once the rear ride height starts to compress – something that cannot be avoided in medium and high speed corners. It is probably reasonable to conclude that this is the basic mechanism behind the way that we shed so much competitiveness at slow speed tracks."
But the system is not the entire story. Due to blowing the exhaust under the floor, the team has found its car extremely sensitive to geometric misalignment. Even more so, where the R31 is already lacking performance it is all the more sensitive, making it even more difficult to set the car up correctly.
Talking about the Singapore GP specifically, Allison said: "We were plagued by rear wing and floor issues that all seem to be even more sensitive at very low speeds than they are at the higher speeds where our car is more comfortable."
To make matters worse, Allison and his aerodynamicists have found the exhaust concept much more difficult to develop than they expected. As a result, the performance advantage that LRGP saw compared to its prototype of the rear blowing exhaust during the design of the R31 is all gone and reverted in a disadvantage.
Allison finally said that, while these problems are difficult to solve this year, next year's car will have a periscope exhaust system - as the regulations mandate - while the car's setup difficulties can, according to the technical director "all be engineered out of the R32".
