[BigShow]

As promised (a little late, I went hooning last night ) here are the results...

Car tested: Mini Cooper S BRG
Build date: Jan 2003
Mileage: 32,823 miles

Firstly a big ‘thank-you’ to the guys at 1320autos for their fantastic service and advice, I can’t recommend their expertise highly enough.

About 6 months ago I visited 1320 having had a Powerflow cat-back exhaust fitted, the dyno results showed 182.5bhp, a theoretical gain of 19bhp over the manufacturers quoted figure for a stock MCS.

The objective of the yesterday however was to test the gain (or not ) of adding a cold air induction and then fitting a new ‘race’ manifold & de-cat and testing again.

The CAI is the V2 from Alta:

http://www.altaminiperformance.com/s.../192_large.jpg


The manifold a 4-1 stainless steel example from 2fast2cool on eBay:


BMW MINI COOPER S 4 BRANCH EXHAUST MANIFOLD & DECAT CAT on eBay Exhaust Components, Performance Tuning Parts, Car Tuning Styling, Cars, Parts Vehicles (item 220138107949 end time 14-Aug-07 20:49:06 BST)

Alta V2 CAI comments:

I’m personally a big fan of the Alta V2, it looks good in the engine bay, it makes for a great induction noise and also feeds more supercharger noise into the cabin which is just addictive. I’ve seen so many manufacturers claim gains of up to 12 BHP after fitting their CAI’s but in all honesty the added noise was good enough for me….

… which is a good job, because the dyno run showed a gain of just 1bhp! But… it’s a gain and not a loss .

2fast2cool (eBay) 4-1 Race Manifold & De-Cat comments:

The manifold arrived in great time, exactly as described by 2F2C and at £199 was extremely good value. The quality of the item was superb, the header flange was found to be nice and flat, all the holes lined up nicely making it an easy fit and the welds were also of great quality. Overall the opinion was that it was certainly better made than the JCW Manifold , which is high praise in itself.

It is worth noting however that the manifold is only suited to a stock head configuration as there is not enough ‘meat’ with which to port match to a fully ported/cnc head due to pipe size and placement, however it was certainly good enough for the stock head. Once fitted the exhaust was about 20-30% louder than before. To give you some idea how loud, the poweflow cat-back was measured a few weeks back at 98db (4k RPM outside the car). The advantage straight away was a more ‘bassy burble’ at idle and a very hard edge scream at high rpm. I will however be tweaking the back-box because there is too much resonance between 55-75mph. I put this purely down to the way I designed the Powerflow exit (see pic enclosed). In terms of general noise, although loud it is much improved and thanks to the fitment of oxygen sensors on the manifold no engine warning light is illuminated. Overall impression I would say is excellent.

Results:

Now the juicy bit… the manifold gained all the way from 2400 to 6800 RPM but unfortunately the best delta was 2.5bhp, this shows how good the stock manifold is with cats in place and with a stock pulley. Paul and Thomas believe that the delta will be a lot greater once we bolt on a 15% pulley in say comparison to adding a pulley to a car with a stock manifold. Although the result could be seen as disappointing you have to consider the effects of all the mods together. For this reason I have agreed to take the car back to 1320 to add a 15% pulley and Alta V2 Intercooler with dyno runs in between fitting. The exact gains of the manifold and de-cat are attached.

Would I personally recommend the 2F2C manifold & de-cat….? For quality, noise and ease of fitment the answer would be yes… but would I recommend it to obtain big gains in BHP?? Well the results speak for themselves and so the answer would have to be no.

However… having spoken at length with Paul and Thomas yesterday the key here is that no manufacturer of a manifold and de-cat will give you ‘big gains’ after fitment to a stock car (manifold, de-cat and cat back exhaust perhaps). The key is to pick a choice of modifications that work in tandem around the age old theory of getting air into the engine more efficiently and getting exhaust gases out of the engine more effectively.

Components that influence airflow into the engine are:

• air filter
• intake air piping
• ECU/MAF
• throttle body or carburetor
• intake manifold
• camshaft
• intake port and valve of cylinder heads
• supercharger

Components that influence airflow out of the engine are the:

• exhaust valve and exhaust ports of the cylinder heads
• camshafts
• exhaust manifolds
• exhaust tubing
• catalytic converters
• muffler

So with this in mind I’m now embarking on a personal journey with 1320 to fit the parts that best suit my car and the reason I bought it, namely track-days, tunnel runs and for my GF to still be able to (and want to) drive it on normal roads when she wants to.

The next few months should be fun