Esprit Mods

By Lewis Gaskell
from Lotus email list May 18, 1998)

Atwell, You are right when I first bought the car and met you, I had only owned it a month. That was also the first time I took it on the track. I guess thats also when I discovered its shortcomings too.

I don't really like modifying the car or change it for the sake of change but to improve the weak points. The turbo, for instance, looks exactly like the the one that was taken out , the difference is all internal. That also gave the biggest jump in performance. I did add a water injector for a couple of reasons, it the po' mans intercooler. Prevents detonation, cools the turbo air, and adds power( very helpful when you live at 8000'!) . It also is easily removed. I don't really recommend it though for daily driving. I am able to run 12 psi boost..

Even if you adjust the wastegate to open later to give more boost you still have to contend with the overboost switch which cuts the fuel pump off over a certain psi. You need a Fuel Cut Defencer and then you need the boost control. HKS and Greddy offer these so that you can get a preset overboost for a short period of time , set by you.

Simply putting in a manual variable boost control won't cut it since it will never overide the boost transducer which is located on the right inside the body near the gas cap area. remove the panel above the air cleaner to get at it.

A far better way is to upgrade the existing turbo for a higher cool air flow, which gains more hp at the same boost, a better/larger intercooler will work as well. Alarger flow turbo will gain you 30-50 hp. The intercoolers are pretty small to start with. I went for the turbo upgrade and the full boost comes on later( 3800 rpm) but pulls up to redline with 45 hp more.

My friends car has 400+hp rear wheel !!

The last thing you want to touch is the boost. High Boost = High Temp=Detonation=Blown Piston!!

The fuel cutoff is blocked by a Fuel Cut Defenser which lets you set a fuel cut off point for going over 10 psi., ( at high altitude the car automatically goes to much higher boost) I have seen over 1.0 bar.I added Magnecor wires , they did very little and cost a lot. Used Motul 600 brake fluid, with a 585F boiling point, helped immensely!! I checked last week and the brakes get to 600F! on the front. You can get it cheap at motorcycle shops.

Added cross drilled Brembos to the front for better cooling and less glazing. The fronts were worn anyway. They run more consistent. The combination of the two has eliminated brake fade altogether. I also use the carbon / kevlar pads. They are good for the track but don't grip as well for daily use. I don't use this as a daily driver either.

The SS clutch line helped quite a bit as well, it shifts like a car now!

The SS brake lines have not come in yet from JAE, ordered two months ago. Put a K&N filter in after being quite naive and paying full list for GENUINE lotus parts, I am a little smarter now. I guess it helps somewhat especially with a higher flow turbo/exhaust combo. I have two exhaust pipes one is the stock and the other , (you saw) is the non-cat. Flowmaster pipe, they bolt on and off with three bolts. So it pretty quick on emissions day! It made a large difference in power and reduced lag, it weighs about 50lbs . less too. Pretty loud though. Took the four alarms out of the car saved 18 lbs weight and the battery doesn't go dead, the downside is the car doesn't talk to me anymore!

Found that for touching up the silver paint wheels you can use GM7188 color and clearcoat for a perfect color match.It comes in those small spray cans at most auto stores. For some reason the paint discolors.

The tires are the same Comp T/A R-1's 265/50-15 rear and 225/50-15 fronts. Don't last long and are not good in the snow, so people around here warn me!

The next thing I will do is add a blow off valve to the turbo plenum to reduce back pressure surge. This occurs when the turbo boosts up and then you shut the throttle closed , as in between shifts. The turbo never stops spinning so the pressure builds when,you close off the air flow. That pressure backs up to the turbo and slams a reverse pressure against the turbo vanes. It can blow up the turbo over time and slows the turbine speed down. Adding a blowoff valve gives the air a place to escape and turbo never does see a large surge. It also alows the turbo to maintian a maximum "spin" so that when you hit the throttle the boost is already there. It also aids in preventing overboost as a third failsafe, like Chapman everything has to have at least two functions. So I am covered there.

The other Espriter's are all over the map. One has a dyno in his shop and can tell me his upgrades and what to expect. The turbo and intercooler upgrades are the biggest things you can do to increase performance.

I do get to track days a few times a year mostly with the BMW club, just found out that the MB club has events twice a month with a combination of clubs. The price is only $58 that way.

Hope this helps other owners