Lotus Motorsport 260 upgrade

The Oily Bits S2 Specific Topics
61

This is my past experience from other cars�

After ignition the ECU checks the MAF/lambda sensors etc and calculates how far out the mix is and adjusts accordingly to try get the magic 1:14.7 ratio. This is when the car is in closed loop. All modifications to the fuel trim in closed loop are recorded down in the short term fuel trim which is an adjustment on the base map � the adjustments can be seen with an OBD reader plugged in.

When under full throttle, the car will revert to Open loop and stop taking readings from the lambda sensor only, and will revert to the base map along with the recorded long term fuel trims - The long term fuel trims are calculated by averaging the short term fuel adjustments over time. Some tuners disable this function!

Although modern ECU�s are quite complex, they are very limited in the adjustment they can do over the pre recorded base map, particularly as map adjustments are not linear and this is why the base map need to be rewritten for any big modifications. Changes in say an induction kit, or varying atmospheric conditions and the ECU should cope. Adding a free flowing manifold may or may not be too much for the ECU to adjust�.

I had a vx220 with highlift cams, ported throttle body, upgraded exhaust and intake manfolds and a whole host of other upgrades and never needed a remap. On the RR the AFR was always slightly rich as the original map intended, but then all ECU�s are different and may not cope as well. It wasn�t until I started changing the injectors that the ECU couldn�t cope with the different pulse rates, and a remap was required.

62

Chris,

Out of interest, did Lotus make any comment about your non-factory mods (e.g. 2bular) prior to or during the upgrade to 260?

I’ve known them to be touchy about upgrading cars with non-factory mods installed, like say a forge intercooler, exhaust etc.

63

It was the lotus garage that put my forge on!

Car also already had 2bular on

64

Sorry, I didn’t mean a dealer. My query relates to the Lotus Sport/factory facilities/upgrades.

65

Right I’ve got the car back and… :smiley: :smiley: :smiley: :smiley: :smiley:

Tim - To answer your question first, no they didn’t say anything to me. In fact they were more than happy to upgrade my car :slight_smile:

Well it’s been a long day but well worth it! I collected the car this morning and after driving back on some very slippery roads, I finally hit the motorway which was dry and ice free. Quick blast of third gear and I was giggling like a girl! It’s superb and I’ve not even taken it past 6000rpm yet because I didn’t want to lose my license!

Anyway, after collecting, I took the car for another rolling road. I’ll upload the video shortly, but here is a snapshot of my power run overlay. The lower figure was my best run before the upgrade and the higher figure afterwards.

All in all I’m very pleased with it. It’s much more responsive, has a good glob of torque lower down in the rev range now, so in the real world, it’s easier to tickle the throttle and it picks up and goes.

Now the final part I had added was a Cup 260 undertray. I had intended on getting the simple Shear Panel “tea-tray” mod that they fit to give the rear more rigidity. However, after a phone call with the factory, it appeared that the “tea-tray” does not fit 2010 model cars.

So, my only option was to fit the Cup 260 undertray for 2010 model cars. This is basically a reinforced undertray section that gives the car a lot more rigidity. Not only that, but it requires the full undertray to be replaced, including rear diffuser. So now my undertray is a nice anthracite colour to match my wheels and is a little shorter (as they are on the Cup 260).

It might not sound as if it does much but heck, my car feels solid like a rock now. Very connected to the road and you really feel every little bump. It is personal preference as it may be too hard for some, but I love the feel of it now. It also feels better coming out of corners as the rear feels fully planted :smiley:

So all in all a great day!!

I’ll post up a comparison video shortly :smiley:

66

Good effort with good result there

Glad you aren’t down here - the mrs and I managed top speed of 20mph today in the TT and X5 retrospectively on our way home from work.

1.5 hrs for 3 miles for her and 2.5hrs for 7 miles for me!

67

really happy for you mate. just hope the weather goets better (for all of us really) so you can enojoy your car properly

68

Really pleased for you Chris, enjoy!

69

Good work Chris glad your pleased with it mate :slight_smile:

70

Thanks guys :smiley: I’m over the moon with it. It always surprises me how a little bit of BHP goes a long way in these cars.



Here is my comparison video of the car before and after the conversion:



Lotus Exige 240 to 260 conversion - YouTube



It’s a shame the weather isn’t a little bit better because I really do want to give it a good drive, but even bimbling around town it feels a lot stronger. I’d imagine this is down to the more accessible torque. Also from my torque curve on the dyno print out, it’s now producing a nice flat torque curve at around 180 lb/ft from around 4800rpm up until 8000rpm.



When the weather is better I’m looking forward to getting the car up to the red line because according to the dyno print out, the power doesn’t drop off as it did before.



Click for a larger version of the power chart - <LINK_TEXT text=“http://i32.photobucket.com/albums/d26/C … /C8UER.jpg”>http://i32.photobucket.com/albums/d26/ChrisBuer/C8UER.jpg</LINK_TEXT>



All in all I’m very happy :smiley:



Lastly, driving around at normal speeds, the thing that has changed the feel of the car quite considerably is the Cup 260 undertray. Lotus kindly took me around to the workshop where my car was up on the ramps so that I could see the new undertray. It’s got the uprated structural parts built into the undertray and as a result the whole car now feels MUCH more rigid. It’s almost as if I’ve put stiffer springs on the car!



A lot of people won’t like it because it does feel like a little racing car now in terms of its rigidity, but personally I think it’s great :smiley:



OK I’ll shut up now :slight_smile:

71

Good video

72

It even sounds better!

73

That’s probably the 2bular system I had put on a couple of months ago :slight_smile:

74

Chris - congrats on the upgrade. I agree with your comments.

The new undertray/shear panel must change the feel of the car
I noticed a difference between my 2007 car and the 2010 car and I guess this is a big part of it.

Interesting to see the power and torque curves in relation to the std 260 map. I guess the extra is down to the cat and exhaust combo. Are you running a standard intercooler ?
If so are you considering a Forge as I am (when the warranty expires) ?
According to all who have had it fitted there’s another 10-15bhp left.
My concern then is the gearbox and when that blows up the next std parts that can’t cope

75

Nice Vid!

You must be very pleased indeed! Some great mods… all you know need me DRY roads!!! :smiley:

The Flywheel mod seems excellent… BIG difference eh!

76

[quote=chrisexigegt]Chris - congrats on the upgrade. I agree with your comments.

The new undertray/shear panel must change the feel of the car
I noticed a difference between my 2007 car and the 2010 car and I guess this is a big part of it.

Interesting to see the power and torque curves in relation to the std 260 map. I guess the extra is down to the cat and exhaust combo. Are you running a standard intercooler ?

If so are you considering a Forge as I am (when the warranty expires) ?
According to all who have had it fitted there’s another 10-15bhp left.
My concern then is the gearbox and when that blows up the next std parts that can’t cope [/quote]

Chris - Yeah the under-tray has had a profound effect on the car. Again I can’t push it in these conditions but driving it around you can feel the bumps on the road a lot more. It also feel more direct from the rear on turn in (if that’s at all possible) and when you put the power down, it feels very positive indeed.

I would imagine that a standard 260 would be around about the 260bhp mark as Jim does say that his exhausts can give anywhere between 8bhp to 12bhp! If I’m getting about 10bhp from them, then that would be about right. However having said that, I have heard that Lotus do underestimate the power on their cars, so maybe all 260’s are actually 270?

I am still running the standard intercooler and yes, I did consider replacing that when my warranty is up. However, I have to say that the car feels so strong at the moment I’d actually question whether I’d need it. Maybe ask me in a few months time once I’ve become used to the new power :smiley:

If the Forge gave between 10-15bhp, then I’d be up in the 280-285bhp mark which is a lot for a little car like this. I think the gearbox is OK up to around 300bhp mind you.

[quote=pete757]Nice Vid!

You must be very pleased indeed! Some great mods… all you know need me DRY roads!!! :smiley:

The Flywheel mod seems excellent… BIG difference eh! [/quote]

Yeah just waiting for the blooming snow to stop and for the sun to come out so I can have a proper play :slight_smile:

I’m really pleased with the whole conversion, but the flywheel especially is great. Blipping the throttle is a lot easier now and the way it picks up and revs is superb. Everything seems so effortless and since picking it up yesterday, I’ve hardly used full throttle as it only needs a tickle and I’m on the brakes again because I’ve blasted up to the car in front :sunglasses:

77

Lotus has always “over estimated” it’s power claiming BHP …15% drivetrain loss…
A proper tune can turn those numbers to RWHP

78

C8uer… on the Forge , it is indeed a great bit of kit and seems to give the 10 ish bhp you mention,however, I believe your car being a 240 already has a better than standard cooler , and , as such you might not see as much benefit as we have .

And Frank …cheers :wink:

79

Jfk - Are you sure my intercooler is better? The only differences to my mind from the 220 to 240 are the clutch, brakes and roof scoop. If the intercooler is improved then fantastic but I’m not sure that it is.

80

ntercooler is the same as all exige S’s, even the cup 260 is. THe only factory cars with a different AC were the 255’s.

Boothy