Collated Rolling Road Modification Results

MG TF 160 52plate 70,000~ miles



Rolling Road - Revivals http://ift.tt/QEwXBO



I have collated a few threads into just one so that its easier to read as a single journey. I planed on recording the benefit or detriment of each performance mod I make to try and find some fact behind some of the claims or advice that is out there for our TF's. Every time I made a change I had it on the Rolling Road.



My results are not only to prove to myself that a mod has worked or not, but also it may help someone save money in the future if a mod hasn't given what people would expect.



Now I had Athena RR'd when I first got her and it wasn't a great RR (She was producing 174bhp supposedly....), so I found somewhere else, however sadly this was after I had fitted the Daytona and 4-2-1 from Mike Satur and an ITG Maxogen, so I don't have an initial run to compare these items which is irritating! But I did have a run with them on so I have my baseline - 151bhp.

Athena was Z&F'd at the FRL (Stage II remap with no burble) and I fitted the Mike Satur Sports Cat. Below is the new results 160.4bhp







Below are the Old results vs the new you can see the new Z&F map has made a much smoother acceleration, and at 5000~rpm there is a 15bhp increase.







Next I removed the Sports Cat and fitted the standard cat, I ran the engine for 20mins so the cat was warm, then the RR gave the car a few runs to ensure that it was hot to make it a fair test vs the sports cat. Below are the results the standard cat with Z&F remap, it has only given a peak power increase of 3.5bhp vs the baseline run (please note however the map has improved drivability and at 5000~rpm there is still a huge improvement). CO reading were taken with both cats and the standard cat is healthy and has no issues. Below is the Sports cat vs the standard.







Below are all three runs the dashed being the baseline.







So in summary the SS sports cat and Z&F remap has given Athena a 9bhp peak power increase, however you can see that the map has improved it through out the rev range with an increase of 15bhp at 5000~rpm.



The surprise to me was that the sports cat vs the standard cat produced a 6bhp increase. I was always lead to believe that the VVC K series liked back pressure and that the a sports cat would decrease performance. On my TF I have proof that she likes the sports cat.



Some of you may have noticed that the limiter kicked in at 7100 rather than 7450 as per the Z&F remap. I messaged Mark (Z&F)

Quote:

is the vvc operating properly? If errors build up then lowering of the limiter can be a consequence.

Quote:

I had a Trophy report a less than expected gain too a while ago. I also dynoed a race 190 VHPD car - that only saw 172bhp.. In both cases in turned out the bottom end bearings were worn causing engine friction - in fact the Trophy later threw a rod on a track day...my point is variable figures can have many causes... There are no errors from the OBD and the RR had the OBD plugged in throughout too. However I will look into his advise as it could be an early warning of something not happy!

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Next I bought some Mike Satur spec reground vvc cams - the set of 3 can be found here on Mikes page:

http://ift.tt/139pIaR



His spec:

Inlet cam 270° duration and 10.08mm of cam lift.

Exhaust Cam 260° duration and 10.16mm of cam lift



They were fitted by a garage I trust, belts were changed at the same time. Mike suggests that they should be timed up as normal.



The results:



Before 160.4bhp 131.1lbf.ft - after 160.0bhp 128.8 lbf.ft



After Graph:







The results in my opinion are not good... however this is also the point of doing the tests.



These are the results from the same TF and engine; other engines may differ.



Helpful email from Dave Andrews with suggestions:

Quote:

The exhaust cam I fit is 264 degrees rather than 260. I am not a great believer in reprofiling the VVC cams, I am slightly puzzled at the quoted duration of the cam as the VVC normally varies from 220 degrees to 290 degrees by varying the speed of the cams rotation during the open and close periods. The normal way of extracting extra power is head work, and uprated exhaust cam and retiming of the mechs using offset dowels. I would check the timing by measuring the lift at TDC on both inlet and exhaust, when fully retracted the VVC should give around 5 thou lift at TDC and the exhaust cam around 50 thou. However it is not uncommon for the latency in the system to result in retardation of both cams by 6-8 degrees, this will mean the lift at TDC is less on the inlet and more on the exhaust. The offset dowels advance the front mech and the exhaust cam (which in turn advances the rear mech via the rear belt).

Rover of St Albans have measured the TDC for me.



Front inlet - No Lift, starts to open 1 degree after TDC

Rear inlet - 0.04mm

Exhaust - 1.85mm



Dave Andrews reply:

Quote:

They would appear to be around 5 degrees out, so two 6 degree dowels should do the trick.

3bhp increase once timed correctly; Please ignore the dotted lines that's the graph with a standard Cat.

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ITG Maxogen vs 160 Airbox



ITG Maxogen











As you can see with the Standard 160 air box back on, the car produced an extra 4bhp 1lbf.ft. So the Maxogen has stayed off…



Orignal threads with other members thoughts and comments - worth reading!



Z&F + sports cat original thread



MS Cams original thread



ITG vs 160 air box original thread



I have since had a modified Z&F map with the rev limit increased to 7600rpm and also fitted a WON NOS kit…. sadly my number 4 piston has an issue following the NOS and I have yet to discover whats happened. Another engine will be going in and as such I'll have to RR it to compare baselines etc











My own summary and thoughts - The Z&F remap is the best £ to bhp improvement I made and tested. Leave your 160 air box on, improve your exhaust system. So nothing new there… :broon:

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