Let me start by saying I’ve owned and driven both remapped and boxed diesels before, and I’m fully aware of all the pros and cons for each option. However, in my experience, the box felt faster than the remap, despite having almost identical figures on paper, and I can only assume that’s to do with the way the power is delivered.
The other factor that’s swayed me towards a box again, is the new MOT regulations. Nobody’s quite sure yet what exactly they will and won’t be able to see, do or check, but there is a specific reference to alterations to the ECU – and I thought a box that could be physically removed was a better option.
The CRD-T box has 4 pre-loaded maps, each with different manipulations of fuelling and boost levels, and then each of these maps is adjustable by +/- 10,20 or 30% to fine tune it to suit each individual car.
Map 1
This is the ‘basic’ CRD-T map. First impressions are VERY good. The usual sluggish response before the turbo spools up has completely disappeared; the car feels responsive and lively with even the lightest squeeze of the throttle. The first mile of my drive to work is uphill, over speed humps, and it’s always felt like I’ve had to work the cold engine quite hard with the constant speeding up and slowing down. This morning, the car sailed over that section, never having to raise the revs, as there was so much more torque, even at 1000rpm.
And then I got onto the dual carriageway and put my foot down
that instant power delivery didn’t disappoint, and it pulled strongly right through to 4k rpm, when I looked at the speedo and realised I was in license losing territory
Contrary to what I thought, and something that I’m very happy about, it doesn’t seem to have affected the accuracy of the OBC at all. I know that a round trip to work would always return 35mpg previously, and after resetting the trip computer before leaving home, it showed 37.1mpg arriving back at home 40 miles later – even after driving a bit harder than I normally would, just enjoying the extra power available. If that continues, that’s going to be extra miles out of every tank – the box will pay for itself in no time!
Map 2
This map has the same boost levels as Map 1, but slightly increased fuelling. Despite this, it doesn’t feel quite as responsive under light throttle, or quite as smooth as Map 1. The difference is noticeable once you put your foot down though, the power comes in even harder
OBC showed 39.6mpg for the same journey, which is an outstanding increase in economy given the power hike, but I think for my driving style, and the majority of the journeys I do, Map 1 is better suited. This would better suit someone who drives hard a lot of the time, which to be fair, I don’t.
Map 3
Same fuelling as Map 1 this time, but with increased boost. Instantly felt much better than Map 2, the initial responsiveness that I’d enjoyed from Map 1 was back, and the extra boost gives a lovely smooth delivery of power right through to the redline. Typically, when I’m trying to do a comparative test, my trip to work with this map was in very heavy traffic :mad: I’ll see what the OBC says when I get home, but this is almost definitely the one I’m going to stick with. It suits my driving style and the car perfectly.
Map 4
This map has no extra boost at all – it’s just increased fuelling, the same as (presumably) the CRD2 or Red/Green boxes. TBH I’m not going to try this one, it seems counterintuitive to run a 1-channel map on a box that can manage 2. I’m sure there’s a reason for having it, but with 3 other choices, I don’t feel like I’m missing out
Now I’ve decided I’m sticking with Map 3, I need to adjust the power to get the most out of the box. I'll try +10% tomorrow, then +20% if that doesn’t cause any problems. Then I need to think about telling the insurers… Gulp!
All in all, a great big
for DTUK, Andrew himself, and the CRD-T box.