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MG ZR ZS ZT Technical - MGZR Induction kit

Hi Guys

Spoke to PTP today who are launching a new induction system for the MGZR made by ITG air filters. Looking at their website they have developed kits for many K series engines as these are the guys who sell the K series engine for MG Rover to people loke Caterham, Lotus etc.

Very swithed on crew, the kit has been independantly tested and gained 8bhp increase at the wheel, its not just a filter its a proper inducton ststem including and air box, oerformance filter, ducting etc etc.

A bit steap at around 290.00 but for 8bhp cannot be bad can it? The lotus Elise boys rave about it.

Anyone got an ITG kit and comments?
Paul Freeman

"and I'm in no way connected with PTP or ITG" would have been nice!

Having had some close ties with ITG for a while and developed with them the similar induction kit for the ZS180 I know that these work. Essentially any replacement filter or system that moves away from the enclosed set up of the standard configuration and draws air that is heated by the engine and radiator is a rob Peter to pay Paul situation.

I was researching the idea of using a Rover 820 air box for the basis of a replacement for the standard airbox on my old MGF. The parts and ideas I passed to Rob Bell who has very effectively finished the development. The general idea and principle I found were the same as being developed by ITG with their Mazogen kits and with this route available I went with them.

On the 200/25/ZR front I have for some years been using a 200BRM as a base, the modifications on which started in June 1999 with a modified cylinder head. Note VVC mechanisms are very sensitive to set up! This of course uses the pre 2001 non 160Ps air filter arrangement in standard form and this is restrictive. Having spent many tens of hours on the rolling road some anomolies showed that treating the saloon VVC engined cars with the same equipment as works on the VVC MGF doesn't work the same! But by simply unclipping the top of the standard airbox and turning it through 180 degrees and holding it up slightly with an open bonnet and large fan blasting cool air at the car gave up to 17% more power which was repeatable with the gains seen only above around 3700rpm.

Also interesting was the fact that the ITG system for the 200/25/ZR provided the same results, IOW no losses from the open intake. It was also interesting to note that these gains appeared only above around 4500rpm, giving a clear indicator that the standard airbox and cold air pick up was restricting the power, remember this is a modded VVC so air demands are quite a bit higher.

By rerouting the 'periscope' shaped cold air pick up with or without the end cover the best gain was only 2% above standard - hardly measurable.

As another side test I also used the larger volume ITG Maxogen airfilter and air box used for the MGF and ZS, with the cold air pick up at 90 degrees to the connection to the throttle body. (200/25/ZR is a straight through affair) This was very interesting as it increased power from under 3000rpm and gave a peak gain of 23% over standard. It does illustrate that the larger volume airbox does add something and it is unfortunate that it doesn't fit most 200/25/ZRs. Mainly because ABS is in the way!

Testing the theory that the bigger box was better through airflow and not simply the bigger volume supplying the needs of a 100 bhp per litre engine, I have since fitted the same airbox to son's 1.4 8 valve Rover 100 Gta. This engine has no where near the air demands of the modded VVC and yet the mid range of this car has seen a stunning improvement in performance. No chance to verify with actual comparitive figures yet but so many who run bigger engined Metro/100's have been mightily impressed. Interestingly it was quite easy to engineer a permanent fit to the 100.

So this and much other testing points to some interesting results...

1, The standard airbox used in all non 160Ps spec cars is restrictive, more so as engine air demands increase.
2, The ITG Maxogen kit for the 200/25/ZR was able to match an open intake which has a bell mouth end.
3, The bigger ITG Maxogen system is able through airflow management to increase power beyond what a normal open intake provides.

So when applying the same equipment across the range some variances will be present and to say a linear X amount of power will be seen is usually going to lead to dissapointment.

If the ITG replaces the basic air filter system then a peak gain of 8 bhp on the 105 model will equate to around 10%, a figure I would regard as quite realistic. However don't always expect these gains to be across the whole range they will usually be seen only at higher rpms. I saw between 5% and 11% more on the ZS 180 between 3000 and 6500rpm which sound brilliant, except that the 5% was around 6000rpm and 11% was at 3000rpm. (there was also 10% more at 6500rpm but that is of little daily use.)

Power graphs are usually helpful in showing how useful gains will be and reflect on the area of the rev range you use most.

When replacing the filter on the 160Ps spec engines do bear in mind that they have already benefitted from a factory modified air filter system to claim some of the easy to gain power so the gains, which may still be the same 8bhp will now equate to perhaps 6% to 7%. In fact having seen the results of some rolling road tests on the ZR160 I know that sort of figure was achieved, but only above 5000rpm.

A light and amusing, but factually interesting test is to be seen by following this link It takes ram effect to a limit and shows how difficult it is to simply bolt on something and expect a gain, even when some proven theories support the changes.

Roger Parker

This thread was discussed between 12/02/2003 and 20/02/2003

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