My main thing to check was that there was nothing wrong with the map that has been on there for the last 10 years that I have owned the car and that there are no major problems now that I have removed the sausage filter and fitted a plenum and inline enclosed filter. All to beat the tight noise limits on track days.
So I got to ATSPEED earlier than needed this morning. I unloaded the car and had a nap in the morning sun while waiting for Colin and Ian to arrive.
- First up was to check that they could connect to the ECU. Done
- Next up was to balance the quad throttle bodies. That took longer than planned as the OEM ones are fiddly. Done
- Then it was to run it and see where it is at now. It was ok. a little spiky on the map apparently and running leaner then Colin would have liked.
- I was there to see what impact the plenum made so he did runs with, without and with 20mm spacer added for extra capacity plenum volume. It turns out the engine likes to have no resistance (surprise!) with about 7bhp gain made with no plenum. I cant have that as I know it is really noisy and I need to quieten it. The difference with the plenum without the spacers and with was surprising as the spacers made it loose a little over not having them fitted. This is good for me as I wsated to run without spacers for packaging and neatness under the bonnet. Happy times.
- So then is was to check and set the VVT. Done.
- Finally it was onto finer tweaks across the WOT and partial throttle rev range.
The results:
- So stock figures for these 4age 20V black tops (which are apparently optimistic) are 160 bhp and 119.5 lbft.
- The graph provided by the person before me when I bought the car showed 151bhp and about 122lbft
Blacktop dyno plot
- Today the result was 164bhp and 128.8lbft.
final print out
- Obviously numbers can vary on many factors including temp, pressure, rolling road accuracy etc. So below is a screen grab of the 1st run and the last. It paints a more honest picture I think.
screen grab of 1st vs last
So I actually think the gains made today are small but significant. The power is up a little across the whole range and there has been a flat spot overcome around 6.5k and power is still up to OEM factor optimistic levels, not bad for a 25 year old car. The main thing for me is confidence that the engine is mapped and safe to run on that inlet plenum.
Overall I think that Colin (who worked on my car so I had most dealings with) seemed to know his stuff and do a good job. Its obviously hard to really tell and as its been so long, with many changes, since I last drove it I may never notice. It cost £650 for around 5.5 hours work, which seems a lot I guess but I am happy with knowing the car is good to go.
Now I need to cover some miles while the summer is still here and do some trackdays. Whoop whoop!