mg zr 105/120 tuning guide


stoke on trent
R5 GT Turbo
right people i thought id post a bit of a tuning guide for the 105/120 as it seems like the car most zr owners tune the most.

1- cat back exhaust system (janspeed,blueflame,powerflow etc) £250-350

2- janspeed 4-2-1 manifold £180

3- janspeed sports cat £240ish or the de cat £80

4- 52 mm throttle bodie 2nd hand or new from ptp

5- uprate the brakes personally the best way to go is a zr 160 set up you need the calipers,carriers and discs and pads

6- get a set of 30-35mm suspension kit and also look into getting front and rear strut braces i cant stress enough how good this was on my car.

these mods should be a good base to start with and de restrict the breathing of the engine.also at this stage the brakes and handling are up to the task :)

if your still wanting more then this is where it starts to get a bit costly

1- vvc inlet manifold £50-100 this requires the ports matching on the head to match the manifold well worth doing to replace the restrictive inlet manifold.

2- uprated cams either piper 270s which are around £550-600 for the full kit or a cheaper option is the mgtf135 cams (these are what i have) cost me £150 last year. you will require vernier pulleys to time the cams correctly there is a place on ebay that does them for £103 (£111 delivered)

3- uprated ecu i went for the emerald ecu the service is top notch there they cant do enough to help. they cost in between £600-700 and then need to be set up at a rolling road which costs around £250 ish but boy is it worth it. dta also make good ecu's.

if your looking at going even further then you could get your current k16 head ported with big valves fitted this head will then flow a tad more than a standard vvc head, or you could source a vvc head and get that ported but remember you will need to convert it to solid cams and piper do the blanking kits for this.

the power limits of the k series bottom end is around 160bhp and this includes the earlier vvc models only on the later zr160 did they get stronger pistons which could handle 180-185bhp. but if your going to go down the throttle bodied route then id highly recommend getting a set of forged pistons and rods as then the world is your oyster.


Full member
Dublin Ireland
MG ZR 105
Great guide mate. Looking at doing my suspension in a while. I got the 105. What coilovers would you recommend iv'e heard avo are the best for the mg. What you think ?
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